bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurophysiology of pain
Authors: Handwerker H. O.
Published: August 2010

The nociceptive system supports two sensory functions, pain and itch. Itch has often been regarded as a minor form of pain. Recently, it has been shown, however, that the pruritic system is supported by its own peripheral and central neuronal pathways which are closely associated, although antagonistic in some respect. Both the pruritic and the algesic system have their own primary nociceptive afferents. These nociceptive afferents are unique among sensory receptors in their capacity to become sensitized following exposure to noxious stimuli. Consequences of sensitization are increased spike discharges to stimulation and decreased thresholds. These phenomena may be formally conceptualized as leftward shift of the stimulus response function. Hyperalgesia was traditionally seen as the perceptual correlate of sensitization of the algogenic system. The respective sensory phenomena in the pruritic system have been called hyperknesis. Both hyperalgesia and hyperknesis encompass decrease in sensory thresholds and increased sensation (pain or itch) to suprathreshold stimuli, together with spontaneous pain or itch. However, at least in the pain system, the simple conception of hyperalgesia as a linear corollary of sensitization of a uniform nociceptor population is inadequate in the light of the diversity of hyperalgesias which are subserved by various peripheral and central neuronal mechanisms, to different degrees. Likewise, different forms of hyperknesis exist which are dependent either on peripheral or on central nervous mechanisms. The pathophysiology of different forms of hyperalgesia and hyperknesis in dermatological diseases will be discussed.
Tachykinins can partly explain the link within the neuroendocrine‐immune‐hematopoietic axis: novel role for mesenchymal stem cells
Authors: Rameshwar P. , Corcoran K. E. , Greco S. J. , Kang H. , Patel H.
Published: August 2010

The tachykinins are among major regulators of bone marrow (BM) functions. The BM is resident to two stem cells: hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). The adult BM has a finite number of HSCs that are required to replenish the immune system throughout life. MSCs surround BM vasculature, while HSCs are located close to the endosteal regions. The mechanisms by which the tachykinins regulate hematopoiesis require further research. Innervated fibers in the BM form synapse‐like structures with MSCs. We propose that tachykinin‐mediated effects on MSCs are relevant to hematopoiesis, because MSCs: 1) generate hematopoietic supporting stromal cells, 2) regulate the movement of cells in and out of the BM, and 3) regulate inflammatory responses in the BM. This study focuses on the truncated tachykinin receptor (NK‐1‐Tr). Its expression and regulation on MSCs mirrors the brain, but contrasts BM stroma. NK‐1‐Tr is predominantly expressed on MSCs. Because of limited receptor desensitization, we propose that NK‐1‐Tr on MSCs could allow rapid responses to the tachykinins so as to maintain the vascular/barrier functions of the BM, regulate immune responses to infectious agents that could be threat to BM failure, and respond to rapid loss of blood. Part of the mechanisms by which the tachykinins regulate MSCs functions involve novel interactions between IFN‐γ and MHC class II. The findings described in this study hold clues to the role of tachykinins on hematopoiesis and adult stem cell functions in the BM. This report adds to an understanding of the crosstalk within the neural‐immune‐hematopoietic axis.
Melanoma targeting by melanocortin peptides: current status and future perspectives
Authors: Eberle A. N. , Froidevaux S. , Calame‐Christe M. , Tanner H. , Knecht S. , Schuhmacher J. , Saffrich R. , Henze M.
Published: August 2010

Melanoma tumour targeting was investigated with radiolabelled α‐MSH peptides and with α‐MSH derivatives attached to large carriers such as liposomes. The main focus of this paper will be current targeting concepts of melanoma (α‐melanoma tumour diagnosis and internal radiotherapy) using α‐MSH peptides for specific delivery of diagnostic and therapeutic radiometals. Several new α‐MSH analogues (MSH1‐n) were synthesized in our laboratory and conjugated to 1,4,7,10‐tetraazacyclo‐dodecane‐1,4,7,10‐tetraacetic acid (DOTA), a universal metal chelator. The resulting DOTA‐MSH1‐n derivatives were found to retain good binding capacity to the melanoma cell MC1 receptor (MC1R) in the low nanomolar range. In vivo tissue distribution of 5 µCi [111In]‐labelled DOTA‐MSH in female B6D2F1 mice with intracutaneous B16F1 melanoma tumours and with micrometastases in the lung and liver demonstrated that the radioligands accumulated specifically in the tumour tissue, reaching a maximum, for example with DOTA‐MSH4, of 9.43 ± 1.06% I.D./g 4‐h postinjection. Co‐injection of an excess of α‐MSH (50 µg) blocked the MC1Rs and hence reduced the 4‐h tumour uptake by an average of 90%, which indicates that radioligand uptake by the melanoma tumours was a receptor‐mediated process. Blood clearance was very rapid and 4 h after injection, the blood‐associated radioactivity was as little as 0.03 ± 0.00% I.D./g. This was associated with a fast elimination of the radioactivity from all MC1R‐negative tissues, except the kidneys which serve as main excretory organ. The ratios of radioactivity in melanoma tissue to that in non‐target tissues 4 h after injection were all above 10 and often greater than 100, except for the kidneys. The identification of radiopeptide structures yielding reduced retention of radioactivity by the kidneys but nevertheless excellent tumour uptake is currently the main goal of our studies. The specificity of targeting melanoma metastases using radiolabelled MSH peptides was further analyzed by positron‐emission tomography (PET) as well as with autoradiography of tumour tissue sections with surrounding healthy tissue after in vivo injection of the radiopeptides into tumour‐bearing animals: the radioactivity was concentrated exclusively in and localized uniformly throughout the tumour tissue. Non‐radioactive approaches to MC1R‐mediated melanoma targeting include cytotoxic MSH–peptides, MSH–carrier conjugates and MSH–liposome constructs. A brief summary of the current state of the different approaches including their advantages and disadvantages will be presented.
An evolutionary concept for changes of synovial tissue innervation in patients with rheumatoid arthritis
Authors: Straub R. H. , Besedovsky H. O.
Published: August 2010

The pathogenesis of chronic disabling inflammatory diseases (CDIDs) is partly understood. The presently used concepts focus mainly on abnormalities of the immune system, but this view is incomplete. The presented concept is a new framework for the pathogenesis of CDIDs. It integrates evolutionary theories with the classical immunological standpoint, which is further linked with a neuroendocrine immune view of erroneous homeostatic adaptation of the other supersystems (nervous system, endocrine system and reproductive system): 1) In CDIDs, the loss of tolerance against self and harmless foreign antigens leads to continuous immune aggression which is dependent on a multifactorial genetically polymorph background (the initiation); 2) However, advantageous or disadvantageous adaptation to CDIDs were not evolutionary conserved, because CDIDs severely impaired reproduction or appeared after the reproductive phase and, thus, imply a strong negative selection pressure; 3) Reactions of all supersystems are evolutionary conserved for transient inflammatory reactions such as the elimination of infectious agents, wound healing, foreign body reaction and many others; and 4) The sum of the false reactions of all supersystems, conserved for transient inflammation, provides the pathogenetic background for the chronification of CDIDs, because a continuous aggressive situation is created (the chronification). The human disease of rheumatoid arthritis is used as a prototypic CDID to illustrate the integrated view point. The synovial tissue innervation is in the focus of this concept.
Potential role of corticrotropin‐releasing hormone in skin physiology and pathology
Authors: Slominski A.
Published: August 2010

Previously, we have demonstrated the expression of corticotropin‐releasing hormone (CRH) and related urocortin peptides and their corresponding CRH receptors (CRH‐Rs) in the skin and identified new alternatively spliced CRH‐R1 isoforms (FASEB J 2001; 15: 1678–1693). These receptors are functional, binding CRH and related urocortin peptides and activating intracellular transduction pathways, to modify skin cell phenotype including proliferation, differentiation and immune activity. Thus, CRH‐Rs ligands can act as local growth factors and cytokines. In conjunction with the cutaneous expression of POMC peptides and their receptors as well as the expression of genes coding enzymes of corticosteroidogenic pathway, these observations also demonstrate integrated expression of the regulatory elements of the hypothalamic‐pituitary‐adrenal (HPA) axis in mammalian skin (Physiol Rev 2000; 80: 979–1020; Endocrine Rev: 21: 457–487). This cutaneous CRH/POMC system appears to be highly responsive to the common stressor ultraviolet radiation (UVR), cutaneous pathology or physiologic changes such as those associated with the hair cycle. Therefore, we have proposed that this system would be structurally analogous to the central HPA axis, with CRH, urocortin and CRH receptors playing a central role in the regulation of cutaneous reactions. Most recently, we found differential, spatiotemporal selectivity and species‐restricted expression of CRH‐Rs, suggesting that they may be evolutionary driven to adapt to the species predominant determinant of skin function: human, solar radiation and thermal energy; mice, hair cycle and production of chemical messengers.
The TRPV1: a possible role in GERD, asthma and migraine
Authors: Geppetti P.
Published: August 2010

The transient receptor potential vanilloid type 1 (TRPV1) is a non‐selective ion channel that belongs to the TRP family of channels that are activated by vanilloid molecules, including capsaicin. The cloned TRPV1 is a thermosensor, gated by temperature (43–52°C) and low pH. Additional putative endogenous activators of the TRPV1 are the cannabinoid receptor agonist, anandamide, N‐arachydonoil‐dopamine and certain lipoxigenase metabolites of arachidonic acid, as 12‐HPETE and LTB4. The TRPV1 is expressed selectively in a subpopulation of primary sensory neurons with C‐ and A‐delta fibres which also express NGF receptors, the neuropeptides, substance P (SP), neurokinin A and calcitonin gene‐related peptide (CGRP). These neurons being activated by different sensory (mechanichal, thermal and chemical) modalities are defined as polymodal nociceptors, and the peptides released from their peripheral terminals cause neurogenic inflammation. TRPV1 seems to be coupled with PLC and PIP2 hydrolysis results in channel activation. Additional modes of TRPV1 sensitization comprise PKC‐ and PKA‐dependent pathways. Activation of either G‐protein‐coupled receptors or tyrosine kinase receptors causes TRPV1 sensitization. Of pathophysiological interest is the finding that endogenous and exogenous molecules may also cause TRPV1. Recently, we found that exposure to 0.3–3% ethanol causes a remarkable increase in Ca2+ mobilization in capsaicin‐sensitive cultured DRG neurons of newborn rat, an effect that was inhibited by the TRPV1 antagonist capsazepine. Wild‐type human embryonic kidney (HEK) cells did not respond to ethanol, but transfection with the human TRPV1 conferred to these cells the ability to respond to ethanol (Ca2+ mobilization) in a capsazepine‐sensitive manner. Electrophysiological studies showed that ethanol dramatically potentiated currents activated by anandamide and protons, and that ethanol reduced the threshold temperature for TRPV1 activation by about 8°C. Thus, in the presence of ethanol, the physiological temperature of 37°C is a sufficient stimulus to activate TRPV1 on sensory neurons and activate their afferent and efferent functions. Ethanol can trigger attacks of asthma and migraine and aggravates the symptoms of GERD. Exposure to ethanol caused a Ca2+‐dependent release of neuropeptides (SP/CGRP) from slices of rat esophagus and dura mater and guinea‐pig airways and increased plasma extravasation in the rat oesophagus and dura mater and caused bronchoconstriction in vitro and in vivo in guinea pigs. All these responses were inhibited selectively by capsazepine. Activation of sensory neurons and neurogenic inflammatory responses via TRPV1 stimulation may contribute to the mechanism of attacks of migraine and to the worsening of GERD and asthma symptoms precipitated by alcohol ingestion.
Trafficking of neurokinin receptors: regulation, mechanism and function
Authors: Bunnett N.
Published: August 2010

Cellular responses to agonists of G‐protein‐coupled receptors (GPCRs) depend in large part on the trafficking of receptors between the plasma membrane and intracellular locations. Receptor activation usually triggers rapid endocytosis of receptors, which either recycle to the cell surface or are targeted for degradation, depending on the receptor in question and the nature of the stimulation. Activation of neurokinin receptors (NKRs) induces membrane translocation of G‐protein receptor kinases, which phosphorylate the receptors and β‐arrestins, which interact with phosphorylated receptors. β‐arrestins: 1) uncouple receptors from G‐proteins to mediate desensitization; 2) are adaptors for clathrin and AP‐2 and mediate clathrin and dynamin‐dependent endocytosis of receptors; and 3) interact with components of the MAP kinase pathway such as src, and thereby determine the subcellular location and function of activated MAP kinases. The fate of endocytosed NKRs depends on the receptor and the nature of the stimulus. Transient stimulation with low concentrations of SP (1 nm, 10 min) induces rapid recycling of the NK1R from superficially located endosomes by a mechanism that is mediated by rab4a and rab11a. Higher concentrations of SP (10 nm) induce rab5a‐dependent trafficking of the NK1R to perinuclear sorting endosomes and a gradual recycling to the plasma membrane. Continuous stimulation with high concentrations of SP (100 nm, 180 min) induces NK1R ubiquitination and trafficking for degradation. The fate of endocytosed receptors also depends on their interaction with β‐arrestins. The NK1R forms stable high‐affinity interactions with both β‐arrestins 1 and 2 at the plasma membrane and in endosomes, whereas the NK3R interacts transiently only with β‐arrestin 2 at the cell surface. The nature of these interactions is specified by domains in the intracellular loop 3 and the carboxyl terminus and determine the rate of recycling and resensitization of these receptors.
Antimicrobial actions of α‐MSH peptides – implications for mucocutaneous host defense
Authors: Catania A. , Grieco P. , Rossi C. , Colombo G. , Gatti S. , Lipton J. M.
Published: August 2010

Endogenous antimicrobial peptides are components of the innate host defense system that prevents microbial penetration before the time‐consuming adaptive immunity starts. We have recently demonstrated that α‐melanocyte‐stimulating hormone (α‐MSH) has antimicrobial effects. The antimicrobial influences of α‐MSH are exerted through a unique mechanism, which appears to be linked to the cAMP‐inducing activity of the peptide. This mechanism mimics the influence of α‐MSH in mammalian cells in which the peptide binds to G‐protein‐linked melanocortin receptors, activates adenylyl cyclase, and increases cAMP. In an attempt to improve the antimicrobial activity of α‐MSH and to better understand the peptide structure–activity relations, we designed and synthesized novel peptide analogs. In this structure–activity study, we discovered several compounds that have greater antimicrobial activity than α‐MSH. The peptide [DNal‐7, Phe‐12]‐α‐MSH (6–13) was the most potent of the analogs tested. This compound killed almost 100% of Candida cells and had substantial antimicrobial effects against Gram‐positive and Gram‐negative bacteria. Enhanced antimicrobial activity of the Phe‐12‐substituted peptides was the most distinctive feature relative to effects in mammalian cells. The results are very encouraging in that they show the great potential of α‐MSH peptides as a truly novel class of antimicrobial compounds.
Mast cells and their role in the neuro‐immune‐endocrine axis
Authors: Bienenstock J.
Published: August 2010

It has become clear that the immune and nervous systems communicate constantly to maintain homeostasis and a coordinated and continuing adaptive response to an ever‐changing environment. Evidence from mast cell nerve communication, as an example of this interaction, has been obtained in a variety of tissues and circumstances, most especially in the intestine and skin. Bidirectional communication has been shown in vivo, ex vivo, in vitro and in coculture experiments involving the two cell types. Examples will be given of these various situations and involve normal physiological situations and those involved in response to infection and inflammation as well as in response to ultraviolet light. More recent examples of the importance of mast cells in the regulation of central nervous activity including the secretion of hormones by the pituitary gland, and thereby the regulation of the HPA axis as well as involvement in behavioural change will be addressed. Through its potential communication with the nervous system, the mast cell can be regarded as a sentinel cell or receptor, especially located at surfaces exposed to the environment, which specifically and non‐specifically react to molecules and substances, foreign to the organism, so as to help orchestrate the complex and integrated responses required to maintain homeostasis.
Interaction between the immune and neuroendocrine system – focus on dendritic cells and skin
Authors: Butts C. L. , Sternberg E. M.
Published: August 2010

Autoimmune diseases present clinically with many differences in disease pattern and are characterized by dysregulation of the immune response to inflammation, pain, disease, and stiffness. Cells of the innate immune system, such as dendritic cells (DCs), have been shown to stimulate production of autoantibodies and self‐recognized T cells that induce autoimmune disease. DCs are considered amongst the most important of the antigen‐presenting cells because of their highly efficient ability to present antigenic peptides in the presence of MHC class II molecules that activates naïve lymphocytes. They also secrete cytokines and express costimulatory cell‐surface molecules that facilitate lymphocyte activation. These cells are responsive to regulation by the hypothalamic‐pituitary‐adrenal (HPA) axis, largely through the actions of the glucocorticoids. In addition to their long‐recognized usefulness in pharmacotherapy of autoimmune diseases, glucocorticoids secreted the adrenal glands play an important physiologic anti‐inflammatory role in regulating innate immunity. Interruption of this negative feedback loop by genetic, surgical, or pharmacological means leads to enhanced susceptibility to autoimmune/inflammatory disease. Evidence for the regulatory role of the HPA axis in autoimmune/inflammatory disease and its implications for treatment will be discussed.
Neurogenic modulation and vasoactive peptides in microvascular biology
Authors: Brain S. D. , Grant A. D. , Tam C. , Pintér E. , Starr A. , Keeble J. , Clark N.
Published: August 2010

Acute neurogenic inflammation is observed after topical application of the TrpV1 agonist capsaicin to the mouse ear. Inflammatory oedema is not detectable in the substance P NK1 receptor knockout mouse, indicating the importance of this receptor in mediating neurogenic oedema formation. However, neurogenic vasodilatation remains not only in the NK1 receptor knockout mouse but also in the CGRP knockout mouse after sensory nerve stimulation. Interestingly, it is abolished when both the CGRP and substance P dilator pathways are blocked. This has led us to suggest that there is a facilitatory interaction between endogenously released CGRP and substance P, such that when both are present there is redundancy in terms of dilator mechanisms. This could be relevant to the apparent maintenance of peripheral vasodilator tone, when either NK1 or CGRP receptor antagonists are given systemically for evaluation as novel therapeutic agents. The relative activity of CGRP and the structurally related non‐neuropeptide adrenomedullin have been compared. Adrenomedullin is less potent as a vasodilator, but functionally relevant concentrations can be induced in inflamed skin. Both peptides, as a consequence of their vasodilator activity, influence inflammatory processes (e.g. oedema and cell accumulation) acting through the CGRP receptor. Thus, adrenomedullin can act as a non‐neuronally derived CGRP agonist in skin.
Neurogenic inflammation of the airways and skin
Authors: Baluk P. , McDonald D. M.
Published: August 2010

According to its original definition, the main feature of neurogenic inflammation is plasma leakage induced by the stimulation of peripheral sensory nerves. The plasma leakage from postcapillary venules is accompanied by increased blood flow due to dilatation of upstream arterioles, and by other phenomena, including leukocyte adhesion and migration. Neurogenic inflammation occurs in the airways, skin, and parts of the intestinal, urinary, and reproductive tract of man and animals, but varies markedly in its magnitude and extent. In skin, neurogenic inflammation is manifested as wheal and flare. Both phenomena are mediated by neuropeptides released from unmyelinated sensory nerve fibers via stimulation of capsaicin‐sensitive vanilloid receptors. Substance P is mainly responsible for the plasma leakage, acting via NK‐1 receptors present on target blood vessels, whereas calcitonin gene‐related peptide and substance P both induce vasodilatation. Sensory neuropeptides also trigger release of histamine from mast cells, which contributes substantially to plasma leakage in the skin, but less so in the airways. The increase in vascular permeability is due to a focal, transient, and fully reversible formation of gaps located between endothelial cell junctions. Neurogenic inflammation can be inhibited by preventing the stimulation of sensory nerves, by depleting them of their neuropeptide transmitters, by presynaptic inhibition of transmitter release, or by blocking neuropeptide receptors. Anti‐inflammatory drugs such as β‐adrenergic agonists and steroids can reduce neurogenic inflammation by stabilizing endothelial cells.
Receptors for calcitonin gene‐related peptide and adrenomedullin: implications for skin cell biology
Authors: Fischer J. A. , Ittner L. M. , Born W.
Published: August 2010

The specificity of a G‐protein‐coupled calcitonin receptor (CTR) and a CT receptor‐like receptor (CLR) for calcitonin gene‐related peptide (CGRP), adrenomedullin (AM) and amylin is defined by the heterodimeric non‐covalent association with three receptor‐activity‐modifying proteins (RAMPs). Chemical cross‐linking of proteins at the cell surface and immunoprecipitation have identified [125I]CGRP/CLR/RAMP1, [125I]AM/CLR/RAMP2 and ‐3 as well as [125I]CGRP/CTR/RAMP1, [125I]amylin/CTR/RAMP1 and ‐RAMP3 complexes. CLR/RAMP1 defines a CGRP receptor. CLR/RAMP2 and ‐3 correspond to AM1 and AM2 receptor isotypes, respectively. The AM1 receptor cross‐reacts with CGRP at high and the AM2 receptor at low concentrations. With the N‐terminal deletion of amino acids 14–20 of the mouse, CLR‐selective inactivation of AM over CGRP receptor function was obtained. As a result, functional interaction with AM was no longer possible. Overexpression of the CLR in transgenic mice together with the endogenous RAMP2 results in thinning of the hairs during postnatal development (L. M. Ittner et al. conference poster). In conclusion, the extreme N‐terminus of the CLR and the extracellular N‐terminal domains of RAMP1 and ‐2 contain amino acid residues that provide AM‐ or CGRP‐binding selectivity of the CLR/RAMP complexes. Hair development is attenuated, resulting in the thinning of the hairs and eventually alopecia during postnatal development.
α‐MSH and fragments: potential therapeutic agents in inflammation
Authors: Brzoska T. , Kucharzik T. , Maaser C. , Scholzen T. E. , Böhm M. , Luger T. A.
Published: August 2010

α‐Melanocyte‐stimulating hormone (α‐MSH) exerts numerous immunomodulatory and anti‐inflammatory activities, which at least partly are mediated through the melanocortin receptor‐1 (MC‐1R), expressed on monocytes, dermal fibroblasts, dendritic cells (DCs), endothelial, and epithelial cells. Accordingly, α‐MSH downregulates the production of proinflammatory cytokines and the expression of costimulatory molecules on antigen‐presenting cells (APCs) via inhibiting the activation of transcription factors such as NF‐κB, while upregulating the production of suppressor factors such as IL‐10. Besides α‐MSH, its C‐terminal‐tripeptide KPV and the IL‐1β‐derived tripeptide KPT are capable of modulating APC functions. Using a mouse model of contact hypersensitivity (CHS), systemic and epicutaneous application of α‐MSH, KPV, or KPT inhibited CHS induction and induced hapten‐specific tolerance. However, using MC‐1R‐deficient mice (MC‐1Re/e), tolerance induction was found to be independent of MC‐1R expression. To further investigate the mechanisms responsible for tolerance induction, adoptive transfer experiments were performed. α‐MSH‐treated haptenized DCs inhibited CHS and induced hapten‐specific tolerance, via induction of regulatory T lymphocytes (Treg). In contrast, using a murine model of intestinal inflammation [Dextransulfate (DSS)‐induced colitis], the expression of a functional MC‐1R was found to be crucial for α‐MSH to exert its anti‐inflammatory activity; in wt mice, weight loss was reduced and the survival rate significantly was improved upon treatment with α‐MSH or KPV. However, DSS colitis was significantly aggravated in MC1‐Re/e mice, resulting in the death of all animals. Bone marrow transplantation from wt mice did not alter the course of inflammation, indicating that MC‐1R expression on non‐hematopoietic cells is crucial for host defense. These findings further support the therapeutic potential of α‐MSH‐related peptides for the treatment of inflammatory, autoimmune, and allergic diseases.
Clinical trial design to study the effects of pharmacological intervention on different models of skin pain and inflammation – methodology and first results
Authors: Rother M. , Schmelz M. , Lehmann J. , Grossmann M.
Published: August 2010

Skin photodamage due to excessive ultraviolet (UV) light exposure is followed by a series of biochemical and immunologic events that cause inflammation including the release of prostaglandins, lipoxygenase products, cytokines (e.g. tumour necrosis factor‐α), adhesion molecule, reactive oxygen radicals and mast cell‐derived mediators, such as histamine and tryptase. In various inflammatory pain conditions, including UVB sunburn, nociceptors are sensitized to mechanical and thermal stimuli at the site of inflammation. This phenomenon, which leads to hyperalgesia, can be used to investigate pharmacological effects of different drugs and drug formulations in the model of UVB‐induced skin inflammation. Two additional models are useful for evaluating the direct, prostaglandin‐independent, modulatory effects on neuronal excitability of nociceptors (chemosensitivity): the chemically induced pain (capsaicin test) and itch (histamine test). IDEA‐070 is a novel carrier‐based topical dosage form of an analgesic drug that acts by inhibiting cyclooxygenase (COX‐1 and COX‐2) and lipoxygenase, thereby reducing prostaglandin‐ and leukotriene‐mediated inflammatory reactions. We used all three described models in the framework of a phase I clinical study to assess efficacy of IDEA‐070. The results of an interim analysis of the UVB model from the first 12 healthy volunteers indicate that IDEA‐070 as well as hydrocortisone‐21‐acetate (HC) reduces the UVB‐induced heat hyperalgesia if applied immediately after UV exposure. In contrast, only IDEA‐070 is effective when used 6 h after exposure to UVB. In addition, IDEA‐070, but not HC, suppressed erythema development if used immediately after UVB exposure as well as 6 h after UVB irradiation.
Clinical potential of Melanotan® (NDP‐α‐MSH) in skin protection – current status and future perspective
Authors: Humphrey S. M. , Oo T. K. T. , Barnetson St. C.
Published: August 2010

There is good epidemiological evidence that melanin in the skin protects against sunburn and skin cancer resulting from excessive ultraviolet radiation (UVR) exposure. Melanin is synthesized in a multistep biochemical pathway within specialized cell types in human skin called melanocytes situated in the epidermis. UV light causes an increase in melanocyte‐stimulating hormone (α‐MSH) receptor activity on cutaneous melanocytes (MC1‐R) that results in an increase of eumelanin within the epidermal melanocytes. Melanotan is a synthetic analogue of α‐MSH with potent melanogenic activity in animals and humans. We have recently completed a double‐blind, randomized controlled study in 80 healthy Caucasian adult subjects. A fixed dose of Melanotan (0.16 mg/kg/day) or placebo in a 3 : 1 ratio was given as three cycles of daily subcutaneous injections over 10 days each month for three consecutive months. Changes in skin pigmentation were quantified by serial skin reflectance measurements and UVR injury, as determined by ×3 MED exposure to broadband UVR, was assessed by measurement of apoptosis (sunburn cells). Results demonstrated that a highly significant increase in skin melanin was attained in all subjects on active treatment compared with placebo, and this was especially pronounced in subjects with lighter skin types (Fitzpatrick I and II; P < 0.0001). In these latter subjects, significant sunburn protection was also determined. The ability of Melanotan to stimulate melanin production without the associated UV‐induced skin damage may prove a useful adjunct to current photoprotective strategies to stem the marked rise in skin cancer incidence. Currently, we are studying the therapeutic efficacy of a slow‐release implant of Melanotan in skin disorders such as polymorphic light eruption and psoriasis.
Glutamine and glutamine synthetase immunoreactivities in Schwann cells of the rat glabrous skin
Authors: Miller K. E. , Jones K. , Wood A. E. , Kriebel R. M.
Published: August 2010

We have shown recently that glial cells of the peripheral nervous system contain substrates and enzymes related to the glutamine cycle, e.g. glutamine, glutamine synthetase, and glutamate dehydrogenase (Miller et al., Brain Res 2002: 945: 202–11). The present study used immunohistochemistry to determine the cellular distribution of glutamine and glutamine synthetase in the rat glabrous skin. Normal adult Sprague–Dawley rats were used for these studies. Glutamine and glutamine synthetase were localized with both immunoperoxidase and immunofluoresent techniques. Glutamine and glutamine synthetase immunoreactivities were abundant in Schwann cells of large dermal nerve bundles. An enrichment of glutamine and glutamine synthetase immunoreactivies occurred in terminal and near‐terminal Schwann cells in dermal papilla and at the dermal–epidermal interface. We hypothesize that the peripheral glial glutamine cycle is important for supplying neuronal energy demands in dermal nerve fibers. Furthermore, the peripheral glial glutamine cycle in terminal Schwann cells most likely produces glutamine for sensory terminal uptake. This glutamine would be converted to glutamate for release from sensory afferents. Glutamate released from sensory afferents may be important for the development of hyperalgesia and allodynia. Terminal Schwann cells, therefore, are potential targets for modulating sensory afferent sensitivity during acute and chronic pain.

Supported by NIH AR47410 (KEM).
New insights into the nerve end organ of human skin
Authors: Reinisch C. M. , Weninger W. , Mayer C. , Paiha K. , Lassmann H. , Tschachler E.
Published: August 2010

Bearing the sensory nerve end organ, the skin establishes contact to our environment. So far, the analysis of the cutaneous nervous system was dependent on the use of tissue serial sections. Because such samples inherently allow visualization of only a small part of the mainly horizontally oriented nervous system of the skin, we searched for possibilities enabling a more comprehensive view. Here, we present a method based on the immunostaining of dermal sheet preparations for subsequent analysis by electron microscopy and light, or laser scanning microscopy. We used antibodies against PgP9.5 and NCAM/CD56, both showing a regular network of fibers covering the entire superficial dermis. The bulk of free ending nerve fibers ramified within 25 µm of the dermo–epidermal junction, whereas below that only larger nerve bundles were present. Along the course of nerve fibers, we observed NCAM/CD56+ protrusions with diameters ranging from 5 to 15 µm. We further characterized these protrusions demonstrating the ultrastructural features of terminal non‐myelinating Schwann cells ensheathing nerve fibres. Depending on the body region, we detected between 140 and over 300 individual terminal Schwann cells/mm2 skin surface. In a double staining for NCAM/CD56 and vWF, we analyzed the topographical relationship of the nerve end organ to the blood vessels of the skin. In conclusion, this novel method allows for the first time a complex three‐dimensional depiction of the cutaneous nervous system over several cm2. Additionally, terminal Schwann cells can be studied in detail in situ for the first time. Furthermore, application of this method may provide new impetus in the investigation of the cutaneous nerve end organ under physiological and pathological conditions.
Docking and fusion sites in human endothelial cells imaged and measured by using atomic force microscopy
Authors: Schneider S. W. , Ossig R. , Görge T. , Matzke R. , Rogge P. , Niemeyer A. , Oberleithner H.
Published: August 2010

The vascular endothelium with its salient location at the interface between blood and tissue plays a pivotal role in the process of blood coagulation and inflammation. The transition into a procoagulatory and proinflammatory state upon stimulation (i.e. neuropeptides) is referred to as endothelial cell activation. One fundamental characteristic of this activation is the induction of von Willebrand factor (vWF), IL‐8, and P‐selectin exocytosis. These molecules are stored in large (up to 3 µm) cone‐like vesicles called Weibel Palade bodies (WPBs). By using atomic force microscopy (AFM), we are able to visualize the apical surface topography of human endothelial cells with nanometer resolution. In addition, AFM allows to measure local cell stiffness with a spatial resolution of 100 nm. In previous studies, we showed that endothelial cells have a readily releasable pool of WPBs. In resting cells, this intracellular docked vesicle pool can be imaged as plasma membrane protrusions with a height of 140 ± 50 nm (±SEM; n = 8) and a diameter of 275 ± 85 nm (±SEM; n = 8). Stiffness measurements revealed that humps are characterized by decreased cell membrane stiffness of 30% compared to surrounding cell membrane due to a reduced subapical actin network. After stimulation of the cells with hyperosmolaric solutions or histamine, these docked WPBs immediately fuse with the plasma membrane forming large (diameter: approximately 500 nm) exocytotic pores and release vWF into the supernatant (measured by ELISA) and expose P‐selectin. Immunostaining of vWF was found to be localized next to the exocytotic pores imaged by AFM. The data indicate that human endothelial cells have a readily releasable pool of WPBs that allows the instantaneous release of vWF, IL‐8, and exposure of P‐selectin. These distinct areas of exocytosis are characterized by cell membrane protrusions and decreased cell membrane stiffness due to a reduced actin cortical network.
Regulation of human hair follicle growth by neurokinin‐1 receptor ligands
Authors: Lachgar S. , Metenier S. , Quibeuf S. , Charveron M.
Published: August 2010

Recent reports revealed that neural mechanisms play a role in hair growth control. An induction of murine hair growth is obtained after treatment with substance P (SP). In this study, we examined the expression of a SP receptor: the neurokinin‐1 (NK1‐R) during: 1) the human hair cycle, 2) on isolated hair follicle, and 3) in cultured hair dermal papilla (HDPC) and the impact of NK1‐R ligands on the regulation of hair growth. We used immunohistochemistry, Western blot and RT‐PCR analysis to examine its expression. Anagen hair follicles showed a strong expression of NK1‐R in dermal papilla and in the outer root sheath. Weak expression of NK1‐R was observed in hair follicle at the catagen and telogen stages. Two isoforms of NK1‐R protein corresponding to 44 kDa and 54 kDa were identified in cultured HDPC. A fragment of 640 bp corresponding to NK1‐R was obtained by RT‐PCR. The nested PCR showed the expected band of NK1‐R at 395 bp. HDPC treatment with SP increases the level of NK1‐R gene and protein. The increase is stronger with NK1‐R‐selective agonist [Sar9, Met (O2) 11]‐SP. Ex vivo studies showed a significant dose‐dependent stimulation of hair growth by SP and by NK1‐R agonist. However, the NK1‐R antagonist (L‐732–138). showed a significant inhibition of hair follicle growth. These results demonstrate the presence of NK1‐R in the growing human hair follicle. NK1‐R is activated by SP and NK1‐R agonist. Ex vivo studies indicate that NK1‐R antagonist inhibited hair follicle growth.
Sex differences in morphine modulation of cutaneous inflammation: involvement of NK1 receptors
Authors: Elliott J. C. , Lysle D. T.
Published: August 2010

Morphine produces an exacerbation of DNFB‐induced cutaneous inflammation when administered prior to antigen challenge in a rat model of contact hypersensitivity (CHS). Recent evidence indicates that this exacerbation of inflammation is significantly greater in females than that in males. This sex difference in morphine modulation of CHS is due to the activation of central μ‐opioid receptor pathways and appears to be corticosterone independent. Furthermore, the presence of female gonadal hormones may account for observed the sex differences, because ovariectomy largely eliminates morphine's enhancement of CHS inflammation without affecting the basal CHS response. Given the involvement of substance P in the pathological exacerbation of CHS, we hypothesized that sex differences in NK1 receptor activation might account for morphine's greater effect on the expression of CHS in females. To that end, male and female CDF rats were treated with the selective NK1 receptor antagonist SR140 333 (1 mg/kg, subcutaneously) 150 min prior to and after DNFB challenge. SR140 333 treatment significantly reduced the magnitude of morphine's enhancement of CHS in female, but not male rats without affecting the baseline CHS response in either sex. Preliminary data suggest that neuropeptide depletion of the skin using capsaicin produces a similar pattern of sex‐dependent effects on morphine modulation of CHS. Taken together, these experiments support the hypothesis that greater activity of the peripheral NK1 receptor system in females may in part account for sex differences in the magnitude of CHS following morphine treatment.

This project was supported by NIH grants DA15709 (D.T.L.) and DA016836 (J.C.E). SR140 333 was generously provided by Sanofi‐Synthelabo.
Increased intraepidermal CGRP correlates with local immuno‐suppression after repeated broadband and narrowband UVB
Authors: Legat F. J. , Wolf P. , Jaiani L. T. , Lang R. , Wang M. S. , Armstrong C. A. , Ansel J. C. , Glass J. D.
Published: August 2010

We investigated the effects of repeated broadband UVB (UVB‐BB) and repeated narrowband UVB (UVB‐NB) on intraepidermal nerve fibers (ENF) immunoreactive (IR) for CGRP and on CHS to DNFB in hairless mice. Mice were exposed to equivalent subinflammatory UVB‐BB (Kodacel‐filtered FS20) or UVB‐NB (TL01) 3× per week for 4 weeks. One, 3, or 7 days after the last UV exposure, the number of CGRP‐IR ENF was determined in exposed back skin. At the same time points, other mice were sensitized to DNFB on exposed back skin, challenged on abdominal skin 5 days later, and skin swelling was determined at 24 h after challenge. UVB‐BB and UVB‐NB significantly increased the number of CGRP‐IR ENF in exposed back skin and significantly suppressed the sensitization of animals to DNFB. For both treatments, these effects were maximal 1 day after the last UV exposure. However, at 7 days after the last UV exposure, in UVB‐NB‐irradiated animals, the number of CGRP‐IR ENF was still significantly increased and the sensitization to DNFB significantly suppressed, while in UVB‐BB‐irradiated animals, these parameters were similar to that in non‐irradiated controls. Thus, while repeated exposure to UVB‐BB or UVB‐NB or both induced increase of CGRP‐IR ENF as well as local immunosuppression, the effects after repeated UVB‐NB were prolonged compared with that after repeated UVB‐BB. This may contribute to the higher phototherapeutic efficacy of UVB‐NB vs. UVB‐BB.
Calcitonin gene‐related peptide and adrenomedullin modulate cytokine‐induced microvascular endothelial cell cellular adhesion molecule expression and NF‐κB activation
Authors: Scholzen T. E. , Fastrich M. , Brzoska T. , Armstrong C. A. , Ansel J. C. , Muff R. , Born W. , Fischer J. A. , Luger T. A.
Published: August 2010

AM and the sensory neuropeptide CGRP are potent vasoactive mediators that activate high‐affinity G‐protein‐coupled receptors consisting of receptor‐activity modifying proteins (RAMPs) and a seven‐transmembrane domain calcitonin receptor‐like receptor (CRLR) with RAMP‐1/CRLR as CGRP and RAMP2 or ‐3/CRLR as AM receptors. In this study, we have examined the possibility that AM or CGRP modulate dermal microvascular EC adhesion molecule (ICAM‐1 and VCAM‐1) expression. Primary HDMEC or cells of the EC line HMEC‐1 were transfected with cDNA expression vectors for an EGFP control, RAMP‐1, RAMP‐2 and CRLR by electroporation, or left untransfected. Stimulation of EC‐overexpressing R1/CRLR or R2/CRLR with CGRP or AM (0.01–1000 nm) resulted in a dose‐dependent upregulation of intracellular cAMP. Importantly, when HDMEC transfected with R1/CRLR or R2/CRLR were treated with TNFα in combination with CGRP or AM, these peptides interfered with the TNF‐induced expression of ICAM‐1 and VCAM‐1 as well as the adhesion of lymphoblastoid cell lines to HDMEC monolayer in a biphasic manner. Likewise, AM and CGRP modulated the activation of nuclear factor κB (NF‐κB) partly by inhibiting the TNFα‐induced degradation of cytosolic IκBα. Neither transfection with the orphan CRLR nor RAMPs alone was capable of mediating a full reduction of TNFα‐induced ICAM‐1 or VCAM‐1 expression. In conclusion, CGRP and more pronounced AM are capable of modulating TNFα‐induced EC CAM expression, which may be of importance for the regulation of leucocyte–endothelial cell interaction during cutaneous neurogenic inflammation.

This study was supported by the “Medizinische Forschungsgesellschaft Salzburg” and a grant of the Austrian Science Foundation (P14906).
Expression of vanilloid receptor subtype 1 (VR1/TRPV1) in the skin – implications for neurogenic inflammation and nociceptive sensations
Authors: Ständer S. , Moormann C. , Schumacher M. , Artuc M. , Luger T. A. , Metze D. , Steinhoff M.
Published: August 2010

The vanilloid receptor subtype 1 (VR1/TRPV1) is a non‐selective cation channel that binds the vanilloid capsaicin and endogenous cannabinoids. In human skin, VR1 has recently been shown to be expressed by keratinocytes in vitro and in vivo. To determine a precise localization of VR1 in other cutaneous compartments in particular cutaneous nerve fibres, we investigated VR1 immunoreactivity as well as mRNA and protein expression in a series of normal and capsaicin‐treated human skin. VR1 immunoreactivity could be observed in cutaneous sensory nerve fibres, mast cells, epidermal keratinocytes, dermal blood vessels, the inner root sheet and infundibulum of hair follicles, differentiated sebocytes, sweat gland ducts and the secretory portion of eccrine sweat glands. Upon RT‐PCR and Western blot, the expression of VR1 was confirmed in primary mast cells and keratinocytes from human skin. During capsaicin therapy, VR1‐receptor distribution was unchanged, while a reduction of neuropeptides (substance P, calcitonin gene‐related peptide) was observed in nerve fibres. After cessation of capsaicin therapy, neuropeptides re‐accumulated in skin nerves. In conclusion, VR1 is widely distributed in the skin, suggesting a central role for this receptor, e.g. in nociception and inflammation.
Role of nerve growth factor in nerve cells/skin cells physio‐pathology
Authors: Coassin M. , Costa N. , Stampachiacchiere B. , Lambiase A. , Bonini S. , Aloe L.
Published: August 2010

Studies carried out in our laboratory showed that NGF has a primary role in wound healing, induces healing in the skin of farm animals and promotes healing of human pressure ulcers. More recently, it has been demonstrated that NGF has a role in eye physiology and promotes healing of corneal ulcers in humans. In the present study, we evaluated the efficacy of topical NGF treatment in a dog model of eye chronic disease to promote epithelial healing, reduction of corneal scarring, increase sensory innervation and goblet cells density. English Bulldogs who had undergone the surgical removal of the lachrymal gland developed chronic keratoconjunctivitis sicca. One eye of each dog was treated twice daily with 100 ml of NGF ointment for 1 month, while the fellow eye was used as control. Eyes were evaluated at baseline and after 1 month of NGF. NGF treatment significantly recovered epithelial keratopathy, reduced corneal haze, improved corneal sensitivity and strongly increased the tear production as well as the conjunctival goblet cell density. This study shows that topical application of NGF improves ocular surface signs in dogs with dry eye. Overall, our findings suggest a crucial role of NGF in nerve cells/skin cells physiopathology.
Processing of POMC peptides by dermal microvascular endo‐thelial cells: implication for EC biologic functions and skin inflammation
Authors: Scholzen T. E. , Koenig S. , Fastrich M. , Böhm M. , Luger T. A.
Published: August 2010

Dermal microvascular endothelial cells (ECs) are both source and target of the pro‐opiomelanocortin (POMC) peptides ACTH and α‐melanocyte‐stimulating hormone (α‐MSH). The availability of neuropeptides as important modulators of innate and adaptive immune responses is controlled by neuropeptide‐specific peptidases such as neutral endopeptidase (NEP) or angiotensin‐converting enzyme (ACE). In this study, we have tested the possibility that NEP or ACE expressed by ECs may influence the local bioavailability of POMC peptides. Incubation of ACTH1−39 with cell membranes prepared from the high NEP‐/low ACE‐expressing microvascular EC line 1 (HMEC‐1) or from low NEP‐/high ACE‐expressing primary human dermal ECs (HDMECs) for 30–480 min resulted in a decrease in ACTH immunoreactivity (IR) over time in membrane supernatants that could be partially blocked with NEP inhibitors as detected by radioimmunoassay. In parallel, α‐MSH IR increased peaking after 60 min. Fragments generated by incubation of HMEC‐1 or HDMEC membranes with ACTH1−39, ACHT1−24 or α‐MSH for 1–120 min were further analysed by mass spectroscopy. HMEC‐1 membranes generated peptide products which could be altered by inhibition of NEP, but not ACE. Likewise, HDMEC membranes fragmented ACTH similar to HMEC‐1 membranes in the presence of NEP inhibitors. Some of the proteins can be assigned to regular proteolytic cleavage, while others seem to be modified. Importantly, HMEC‐1 and HDMEC membranes also slowly degraded α‐MSH, suggesting that EC proteolytic peptidases locally control ACTH/α‐MSH bioavailability, which may be important in controlling cutaneous inflammation.