bluuebunny/crossref_metadata_2025 huggingface dataset:
Cysteinyl leukotriene receptor 2 (CysLT2R)‐mediated vascular permeability and ischemia/reperfusion injury
Authors: Ni Nathan , Ballantyne Laurel L , Mewburn Jeffrey D , Funk Colin D
Published: June 2021

Cysteinyl leukotrienes (CysLTs) are arachidonate‐derived lipid mediators of inflammation that act via CysLT receptors. Previously, we demonstrated that transgenic overexpression of the human CysLT2R in endothelium (hEC) exacerbates vascular permeability and inflammatory response activation. However, we could not delineate the relative contributions of endogenous mouse CysLT2R and the transgene‐derived receptor. Thus, we created a novel mouse strain (hECxKO) by crossing hEC mice with CysLT2R knockout mice in order to examine the specific roles of CysLT2R tissue‐localized expression niches in inflammation and tissue injury. Surprisingly, in contrast to our previous findings where myocardial ischemia/reperfusion injury was markedly enhanced in hEC mice compared to wildtype (WT) mice (47.3 ± 2.0% to 25.2 ± 3.5%), this was not the case with hECxKO mice, where injury was comparable to WT mice (24.0 ± 3.0%). Furthermore, in contrast to hEC and WT mice, hECxKO mice displayed altered leukotriene‐mediated vascular permeability responses, measured as FITC‐albumin leakage, in a cremaster muscle venule intravital imaging system. The data indicate that endothelial‐expressed CysLT2R mediates only part of the post‐injury inflammatory response to leukotrienes and that CysLT2R expressed in other uncharacterized sites is important. This work was supported by the CIHR and a Career Investigator award from the HSFO.
α‐TTP‐expressing astrocytes regulate α‐tocopherol homeostasis in the CNS
Authors: Ulatowski Lynn M , Atkinson Jeffrey , Manor Danny
Published: June 2021

Alpha‐tocopherol (Vitamin E) is a major lipid soluble antioxidant and is essential for the prevention of oxidative stress‐related diseases. The alpha tocopherol transfer protein (α‐TTP) is the principal regulator of whole‐body vitamin E status. Mutations in the TTPA gene lead to heritable vitamin E deficiency and neurological dysfunction. As very little is presently known about the mechanisms that govern α‐tocopherol's actions in the brain, we studied the expression of α‐TTP and the trafficking of vitamin E in the cerebellum. We found that α‐TTP is expressed in GFAP‐positive astrocytes, where it regulates the efflux of α‐tocopherol to neurons. Importantly, oxidative stress increases expression of TtpA mRNA in cerebellar astrocytes. Our data suggest that α‐TTP‐expressing astrocytes regulate the homeostasis of α‐tocopherol in the CNS, thereby ensuring protection of neurons from oxidative stress‐induced damage. This model is supported by our observations of atrophied cell bodies and decreased dendritic branching of cerebellar Purkinje neurons in vitamin E deficient mice. Our findings provide a mechanistic basis for the ataxic phenotype that accompanies vitamin E deficiency.

Work supported by awards T32DK07319 and RO1DK067494 from the NIH.
Level of anemia and deficiency of folic acid in blood mothers and children of younger age in Astana
Authors: Ospanova Feruza , Abduldayeva Aigul , Iskakova Saule , Syzdykova Saule
Published: June 2021

Survey of parent and children's health within the State Program for Public Health Development of Kazakhstan for 2011–2015 of “Salamatty Kazakhstan” was conducted, in the real research studying of level of Hb, folic acid was carried out to blood of women and their children at the age from 6 till 59 months on the basis of 4 city policlinics of the city of Astana.

Were taken on the analysis of serum of blood of mothers (n=82) and their children at the age from 6 till 59 months (n=82) the content of Hb and folic acid was defined by a method of an iimunnoelektrokhemilyuminestsentsiya. Indicators of slight anemia at children at the age from 6 till 59 months are similar to indicators of WHO and reaches 25% of the surveyed children, moderate anemia at children from 6,8 % reached 15,8 %. The general level of anemia decreased at women to 23,2 %, in particular indicators of slight anemia at mothers decreased from 19% to 9,7 %.

The best rates noted level increase folic acid in blood of mothers and their children, in comparison with WHO data for 2007 across the RK indicators of deficiency of folic acid considerably decreased at children from 18,7 % to 9,7 %, at mothers from 33 % to 9%.

Thus, the taken legislative and social measures in the RK first of all affected decrease in deficiency of folic acid in serum of blood of mothers and their children of younger age that will lead to reduction of number of congenital defects of a nervous tube at newborns.
A theory‐based nutrition newsletter education program reduces nutritional risk in community‐residing older adults
Authors: Francis Sarah L , Shelley Mack , MacNab Lindsay
Published: June 2021

The aging population merits the need for community nutrition education programs to promote healthy aging. Chef Charles (CC), a nutrition newsletter education program, advocates produce consumption, physical activity, food safety, and promotes food security. This study assessed the impact the traditional CC program (control) and a revised, theory‐based CC program (treatment) had on nutritional risk (NR), self‐efficacy for healthy eating (SE), food security (FS) and program satisfaction in adults age 60+. ANOVA was used to test for changes in NR, FS, and SE by CC participation status and marital status, and chi‐square to test for differences in program satisfaction between groups. Participants were mostly educated, single, food secure white females (n=34). Most (n=60 out of 73, 82.2%) completed CC. NR change (M=5.25) for the treatment group was significantly higher (p=0.042) than the control group. No differences were noted for SE or FS change and program satisfaction between groups. Over half (n=46, 76.7%) reported making dietary changes and the majority (n=52, 86.7%) rated CC as good to excellent. Results suggest the revised CC program is more effective in reducing NR than the traditional CC program.
Dietary B‐vitamin and C‐reactive protein in people with Human Immunodeficiency Virus Infection
Authors: Poudel Krishna C , Poudel‐Tandukar Kalpana
Published: June 2021

Background

C‐reactive protein (CRP) has been associated with survival of HIV‐positive people. B ‐vitamin such as B‐6, B‐12 and folic acid are known to be inversely associated to CRP in people without HIV‐infection. We tested the hypothesis that higher intakes of B‐vitamin are associated with lower levels of CRP in a HIV‐positive people.

Methods

A cross‐sectional study was conducted among 250 HIV‐positive people aged 20–60 years residing in Nepal. Serum high‐sensitivity CRP concentrations were measured by the latex‐ agglutination‐nephelometry method. Dietary intake was assessed using two nonconsecutive 24‐hour dietary recalls. The relationship between B‐vitamin and CRP were assessed using multiple linear regression analysis.

Results

The mean intake of B‐vitamin were significantly higher in men than in women (P<0.001). Serum CRP concentration was inversely associated with B‐vitamin such as B‐1 (B=−1.5; P=0.003), B‐3 (B=−0.09; P=0.001), and B‐6 (B=−0.67; P=0.007) in men. CRP concentration was similarly associated with folic acid both in men (B=−0.002; P=0.09) and women (B=−0.003; P=0.06).

Conclusion

Higher intakes of B‐vitamin may have a beneficial role against inflammation in HIV‐positive people.

Support: Grant‐in‐Aid for Young Scientists (B), Japan.
Increase in skimmed milk intakes brings positive calcium balances during body weight reduction by exercise
Authors: Yamada Tetsuo , Kurasawa Shin‐ichi , Matsuzaki Masami , Tanaka Akira
Published: June 2021

Suitable diets during body weight‐loss programs are not understood in detail. We investigated the effects of increasing skimmed milk intakes on nutritional status and metabolism of calcium and magnesium.

Methods

Six adult male volunteers participated in crossover trial, i.e., two experiments over eight days. The first four days were an adjustment period consuming control diets (energy, 2,553 kcal; calcium, 1,028 mg; magnesium, 343 mg; mean intake levels per day). During the second four days, the participants exercised on a bicycle ergometer (mean additional energy, 511 kcal per day), and consumed either control diets or experimental diets which contained increased skimmed milk but the same energy levels as control diets.

Results

Although urinary and fecal calcium excretion levels were higher, calcium balances were significantly more positive during experimental period than during control period. Whereas magnesium balances during increased skimmed milk intakes are almost the same as during control diets. On the other hand, no significant differences in serum calcium, magnesium and intact parathyroid hormone (PTH) levels were observed between two diet methods.

Conclusions

Increase in skimmed milk intakes brings positive calcium balances during body weight reduction by exercise, but the regulation of calcium by PTH is not clear. This study was supported by a grant from Kanto Gakuin University.
Water intake and metabolic syndrome risk. A randomized clinical trial
Authors: Hernandez‐Cordero Sonia , Barquera Simon , Rodriguez‐Ramirez Sonia , de Los Angeles Villanueva Maria , de Cossio Teresita Gonzalez , Rivera Juan , Popkin Barry
Published: June 2021

Mexican adults consume extensive levels of sugar sweetened beverages (SSB). This randomized clinical trial examined the effect of substituting water with SSB's on cardio metabolic indicators over 9 m in overweight Mexican women. Conducted in Cuernavaca, Mexico from April 2009 – October 2011. Overweight and obese (BMI ≥ 25 and <39), 18–45 y women with self‐reported high intake of SSB (≥ 250 kcal/day) were randomly allocated to the water and education provision (WEP) (n=120) or Education provision only (EP) (n=120) group. Biweekly water deliveries and monthly education were provided. Repeated 24‐hour recalls, anthropometry and fasting blood were collected at baseline, 3, 6 and 9 months.

Results

Women in both groups lost weight, without being different among groups (p= 0.5). WEP women increased their water intake compared to EP women but over reported dietary reductions significantly more than EP women. Triglyceride levels decreased in the WEP, however this reduction did not differ among groups (p=0.2). This clinical trial water intervention did not result in a significant improvement in triglyceride levels, weight nor any other cardio metabolic risk factor. Our findings do not lead to conclude that SSB replacement with water does not support reduction of metabolic syndrome risk factors but rather that intervention provided was ineffective in reducing other sugary beverage intake
The Serum Glucose Response After a Dietary Treatment in Subjects with Metabolic Syndrome was predicted by a Genetic Predisposition Score that Integrated 11 Polymorphism
Authors: Guevara‐Cruz Martha , Tovar Armando R , Lai Chao Q , Parnell Laurence , Smith Caren E , Lee Yu‐Chi , Ordovas Jose M , Torres Nimbe
Published: June 2021

There is the need to develop genetic predisposition scores (GPS), that integrate the additive associations of a set of single nucleotide polymorphism (SNPs) with several phenotypes. Therefore, the aim of this work was to study how a GPS could be used as a predictive tool to infer the concentrations of glucose in response to a dietary treatment in subject with metabolic syndrome (MetS). We studied in 67 participants with MetS 11 SNPs at seven loci, and their serum glucose response after a dietary treatment. Subjects received either placebo or dietary portfolio (soy protein, nopal, chia seed and oat) for 2 months. To develop the GPS, we assigned a value to each polymorphism as follows: 1 unit (high beneficial‐response to glucose for allele homozygous), 0.5 unit (heterozygous) and 0 units (low beneficial‐response to glucose homozygous). The additive effect of each SNP on serum glucose was expressed as Δ mg/dL. Our results showed that subjects with a GPS >; 4 had a low response to a dietary treatment as observed by an increase of serum glucose, whereas subjects with a GPS< 4 had a high response to the dieatray treatment by reducing serum blood glucose. This response was independent of the consumption of placebo or dietary portfolio. Thus, a genetic score of 11 SNPs predicted the serum blood glucose response to a dietary treatment.

(Grant: CONACyT 181685 to MGC)
Influence of apple pomace and its fractions on intestinal tumor development in APC Min/+ mice
Authors: Cao Loan , Walker Ryan , Bourquin Leslie D.
Published: June 2021

Consumption of apples has been demonstrated to lower the risk of chronic diseases due to the presence of bioactive components such as fiber and polyphenols. The aims of this study were to determine the effects of apple pomace, a major waste product of apple juice processing, and its fractions on tumor development in APCMin/+ mice. Mice were assigned to different treatment groups consisting of powdered AIN‐93G diet supplemented with apple pomace, apple juice, apple ethanol extract or apple residue. Mice consuming the apple juice‐containing diet had the fewest adenomas (P<0.05) in the small intestine and mice consuming apple residue the greatest number. No statistically significant differences in adenoma numbers were observed in the colon. However, male mice had significantly higher incidence of colonic adenomas (79.7%) than female mice (59.3%). In cecum, mice consuming diets containing apple juice had the smallest average adenoma size and mice consuming apple residue the greatest average adenoma size. These results demonstrate that fractions derived from apple pomace differentially influence intestinal adenoma development in APCMin/+ mice, but further research is required to determine the mechanisms for the observed effects. This research was supported in part by the Michigan Apple Committee.
Role for dusp4 in the pathogenesis of TNFa induced proinflammatory gene expression in adipocytes
Authors: Guo Wei , Ferguson Bradley S. , Nam Heesun , Hopkins Robin G. , Morrison Ron F.
Published: June 2021

Chronic adipose tissue (AT) inflammation is central to pathogenic mechanisms linking obesity and insulin resistance. There is strong evidence demonstrating that c‐Jun amino‐terminal kinases (JNKs) play compartmentalized roles in this process by phosphorylating inhibitory sites of insulin receptor substrates in the cytosol as well as by inducing the expression of AP‐1 pro‐inflammatory genes in the nucleus. To address a role for dual specificity phosphatases (DUSPs), we determined the expression profile of the 10 known DUSP family members in insulin‐responsive tissues of genetically‐obese (GO) and diet‐induced obese (DIO) mice. We demonstrated that dusp4 and dusp9 mRNAs were significantly more abundant in lean AT relative to liver, skeletal muscle and heart. Examining sequential stages of GO and DIO, we determined that dusp4 mRNA inversely correlated with the degree of inflammation associated with both models. Using 3T3‐L1 adipocytes, we further demonstrated that while dusp4 and dusp9 were abundantly induced with differentiation, dusp4 was significantly suppressed following TNFa stimulation. We hypothesized that once obesity reaches a stage involving chronic AT inflammation, the accompanying loss of dusp4 in the nucleus is expected to elevate JNK activity exacerbating the sequel of metabolic changes associated with AT dysfunction leading to insulin resistance. Support by NIH‐NIDDK (R15‐DK082799).
Value of fever versus hypothermia in severe sepsis
Authors: Liu Elaine , Corrigan Joshua J , Lewis Kevin , Al‐Saffar Hiba , Krall Catherine M , Singh Anju , Kulchitsky Vladimir A , Simons Christopher T , Petersen Scott R , Musteata Florin M , Bakshi Chandra S , Romanovsky Andrej A , Sellati Timothy J , Steiner Alexandre A
Published: June 2021

A switch from fever to hypothermia occurs in severe cases of systemic inflammation, but its impacts on the pathophysiology and outcome of this malady are unknown. This question was addressed in the present study. Following administration of LPS (5 or 18 mg/kg) or E. coli (5 × 109or 1 × 1010CFU/kg), hypothermia developed in rats exposed to a mildly cool environment, but not in rats exposed to a warm environment; only fever was revealed in the warm environment. Development of hypothermia instead of fever suppressed endotoxemia and the lung infiltration by neutrophils in E. coli‐infected rats, but not in LPS‐injected rats. These potentially beneficial effects came with costs, as hypothermia increased the liver bacterial burden. Furthermore, hypotensive responses to LPS or E. coli were exaggerated in hypothermic rats. This exaggeration, however, occurred independently of changes in inflammatory mediators and was not necessarily associated with tissue hypoxia. Despite possible costs, development of hypothermia lessened abdominal organ injury and reduced overall mortality rates in both the E. coli and LPS models. It is concluded that naturally occurring hypothermia may be more advantageous than fever in severe forms of aseptic (LPS‐induced) and septic (E. coli‐induced) systemic inflammation. Support: AHA, NIH, FAPESP.
Stimulation of the amyloid‐β precursor protein metabolism by cAMP
Authors: Ricciarelli Roberta , Canepa Elisa , Domenicotti Cinzia , Marengo Barbara , Gardella Elena , Marinari Umberto M , Pronzato Maria A , Fedele Ernesto
Published: June 2021

Besides playing a pathogenic role in Alzheimer disease, amyloid‐β (Aβ) peptides are normally produced in low amounts in the brain and several lines of evidence suggest that they can modulate synaptic plasticity and memory. As cyclic adenosine monophosphate (cAMP) is known to be involved in the same processes and the blockade of its degradation by phosphodiesterase‐4 inhibitors has consistently shown beneficial effects on cognition, we investigated the possible correlation between this second messenger and Aβ peptides in neuronal N2a cells overexpressing the amyloid‐β precursor protein (APP). We herein report that the elevation of endogenous cAMP by rolipram increased APP protein expression and both its amyloidogenic and non‐amyloidogenic processing. The effects of rolipram were reproduced by both the cAMP membrane‐permeant analogue 8Br‐cAMP and the forskolin‐induced activation of adenylyl cyclase, but were not affected by the PKA inhibitor H‐89.

Our results demonstrate that, in neuronal cells, APP metabolism is physiologically modulated by cAMP and suggest that this might represent an additional mechanism through which the second messenger could influence memory functions. This work was supported by grants from the Alzheimer's Association and the Italian Ministry of University and Research (PRIN 2009M8FKBB_002).
IL‐6 mediates impaired motor coordination but not cognition in a murine model of mild traumatic brain injury (mTBI)
Authors: Yang Sung Huk , Gangidine Matthew , Pritts Timothy , Lentsch Alex
Published: June 2021

Mild traumatic brain injury (mTBI) affects more than 1.7 million people in the United States annually. mTBI is difficult to diagnose and is clinically associated with impaired motor coordination and cognition. To evaluate and define the deficits after TBI a murine model was used. mTBI was induced by weight drop (400g; 1.5cm). Mice were evaluated for motor coordination by rotarod and cognition by novel object recognition. Cytokine analysis on serum and brain samples was done by ELISA. Neuron specific enolase (NSE) and glial fibrillary acidic protein (GFAP) were brain injury markers. Blood brain barrier (BBB) disruption was evaluated using fluorescent micromolecular and macromolecular molecules. Experiments were repeated after giving anti‐IL‐6 antibody systemically after mTBI. mTBI induced deficits in motor coordination and cognition compared to controls. mTBI resulted in increased serum IL‐6, NSE and GFAP, decreased cognition, and decreased motor coordination. In addition, mTBI caused slight BBB breakdown; allowing micromolecular, but not macromolecular leakage. Neutralization of IL‐6 with antibody significantly improved motor coordination, but not cognition, after mTBI. The data suggest that IL‐6 is induced by mTBI and that blockade of IL‐6 mitigates mTBI‐induced motor coordination deficit.
Angiotensin‐(1–7) augments endothelium‐dependent relaxations of porcine coronary arteries to bradykinin by inhibiting ACE1
Authors: Vanhoutte Paul Michel , Wu Dongmei , Khang Gilson , Raffai Gabor
Published: June 2021

Angiotensin converting enzyme 2 (ACE2) converts angiotensin II to angiotensin‐(1–7) that activates Mas receptors, inhibits ACE, modulates bradykinin (BK) receptor sensitivity. The present study compared the direct and indirect (on the response to BK) effect(s) of the ACE2 activator diminazene aceturate (DIZE) and angiotensin‐(1–7) in rings of isolated porcine coronary arteries, with or without endothelium, suspended in conventional organ chambers for isometric tension recording. In preparations contracted with U46619 (10−7 M), increasing concentrations of DIZE, angiotensin‐(1–7) or of the ACE inhibitor captopril, did not cause significant changes in tension before or after desensitization of BK receptors. B K caused concentration‐dependent and endothelium‐dependent relaxations which were inhibited partially by L‐NAME or TRAM‐34 plus UCL‐1684, but not by indomethacin. The response to BK was not affected by DIZE, but significantly potentiated, to a similar extent, by angiotensin‐(1–7) and captopril. The two compounds augmented the response in the presence of either L‐NAME or TRAM‐34 plus UCL‐1684, indicating potentiation of NO bioavailability and endothelium‐dependent hyperpolarizations, respectively. These results indicate that in coronary arteries angiotensin‐(1–7) enhances both endothelium‐dependent relaxations and hyperpolarization to bradykinin solely by ACE inhibition.

Research support: World Class University program (R31–20029), Ministry of Education, Science and Technology, South Korea.
Investigation of the novel pharmacology of Neuropeptide Y (NPY) receptor dimers constrained by bimolecular fluorescence complementation (BiFC)
Authors: Kilpatrick Laura , Holliday Nicholas
Published: June 2021

Dimerisation of GPCRs potentially influences their pharmacology via binding site cooperativity or modified signalling. We have used bimolecular fluorescence complementation (BiFC; Kilpatrick et al. (2012) Methods Mol Biol 897) to constrain Neuropeptide Y (NPY) Y1 receptor (Y1R) homo and heterodimers of known composition. Using quantitative platereader imaging we measured the internalisation of BiFC receptor dimers simultaneously with endocytosis of SNAP tagged Y1R protomer to compare the pharmacology of Y1/Y1, Y1/Y4 or Y1/Y5 BiFC dimers.

Y1/Y1 and Y1/Y4 BiFC dimers internalised in response to NPY or PP (Y1/Y4), with potencies comparable to individually expressed YR subtypes. Endocytosis of Y1/Y1 or Y1/Y4 dimers to NPY was also inhibited by the Y1 antagonist BIBO3304, with expected pKb values ((8.2–8.5) from NPY concentration‐response curve shifts). However, the Y5 selective agonist PP(1–17)(Ala31, Aib32) NPY(18– 36) showed reduced potency for constrained Y1/Y5 BiFC dimers, compared to Y5‐GFP internalisation. BIBO3304 demonstrated a lower apparent affinity (pKb 7.4 ± 0.1) for Y1/Y5 BiFC dimers compared to the SNAP‐Y1 sub‐population (pKb 8.2 ± 0.4). This suggests an interaction between Y1 and Y5 orthosteric binding sites of Y1/Y5 BiFC dimers, with implications for selective targeting of this dimer as a mediator of central NPY appetite responses. LK is supported by the British Pharmacological Society.
Sphingosine‐1‐phosphate and the “albumin effect” on rat venular microvessels
Authors: Curry Fitz‐Roy E , Adamson Roger H
Published: June 2021

Sphingosine‐1‐phosphate (S1P) is carried in plasma bound to albumin (40%) and high density lipoprotein (60%). Because constant S1P is required to maintain a stable baseline endothelial barrier in individually perfused microvessels (Am J Physiol 303: H825, 2012), we tested the hypothesis that removal of albumin from a perfusate in rat venular microvessels would decrease available S1P and increase permeability. We measured the apparent solute permeability coefficient (Ps) of the vessel wall to fluorescently labeled albumin. Unlike the Landis‐Michel method to measure hydraulic conductivity, Ps measurement does not require the use of RBCs, a principal source of S1P, as flow markers. Perfusates used to measure Ps were initially conditioned by 20 min exposure to rat RBCs to provide a baseline level of S1P. Control perfusate was Ringer with fatty acid free albumin (10 mg/ml); test was Ringer alone. The control solution had a stable S1P concentration (0.34 ± 0.03 μM) close to normal plasma value and established a stable baseline Ps of 0.8 ± 0.2 × 10−6 cm/sec. The test solution with no albumin contained only 0.03 ± 0.01 μM S1P and increased permeability more than 10‐fold (n=4). We conclude that part of the well‐known “albumin effect” depends on the transport of S1P by albumin from RBCs to the endothelium. NIH HL28607.
Doxycycline Does Not Scavenge Reactive Oxygen Species During Inhibition of Shedding of the Endothelial Glycocalyx
Authors: Lipowsky Herbert H , Lescanic Anne
Published: June 2021

Shedding of the endothelial glycocalyx (GLYCLX ) has been shown to occur in response to inflammatory agents and may be inhibited by sub‐antimicrobial doses of doxycycline (0.5 uM). It has been suggested that doxy exerts its effect by inhibiting activation of matrix metalloproteases (MMPs). However, it has also been suggested that doxy may do this by scavenging reactive oxygen species (ROS). To determine if this occurs, GLYCLX shedding in response to ROS was studied with and without doxy present. ROS were generated by topical application of a mixture of xanthine oxidase (XO) and hypoxanthine (HX) on rat mesentery. GLYCLX shedding was quantified by the loss of lectin coated beads (0.1 um) bound to the EC of small venules following the rapid mixing of XO/HX on the tissue. XO and HX were rapidly pipetted onto the mesentery and allowed to mix for 2 min, following which it was removed by superfusion with Ringer's solution. With or without doxy present, exposure to HO/HX caused bead count in post‐capillary venules to fall significantly by 20% within 5 min and by 40% with 30 min. Thus, doxycycline did not inhibit the effects of ROS during shedding of the glycocalyx and it is concluded that its inhibition of shedding in response to inflammatory agents results from inhibition of MMP activation. Supported by R01‐HL39286–20
Chronic vasodilation increases collecting duct (CD) PDE5A and αENaC through independent renin‐angiotensin‐aldosterone system (RAAS) pathways
Authors: West Crystal A , Shaw Stefan , Sasser Jennifer M , Fekete Andrea , Alexander Tyler , Masilamani Shyama ME , Baylis Chris
Published: June 2021

We have previously observed that many of the renal and hemodynamic adaptations seen in normal pregnancy can be induced in virgin female rats (V) by chronic systemic vasodilation (VD). Fourteen‐day VD with NaNO2 or nifedipine (NIF) produced plasma volume expansion (PVE), hemodilution and increased renal medullary PDE5A protein. The present study examined the role of the RAAS in this mechanism. V were treated for 14 days with NIF; 10 mg/kg/day via diet, NIF with spironolactone (SPR; mineralocorticoid receptor (MR) blocker, 200–300 mg/kg/day via diet), enalapril (ENAL; ACE inhibitor, 62.5 mg/L via water), or vehicle (CON). Mean arterial pressure (MAP) was reduced 7.4±0.5% with NIF, 6.33±0.5% with NIF+SPR, and 12.0±0.4% with ENAL vs. baseline MAP. Compared to CON (3.6±0.3%) PV/BW was increased by NIF (5.2±0.4%) treatment but not by NIF+SPR (4.3±0.2%) or ENAL (4.0±0.3%). NIF increased PDE5A protein abundance only in the renal inner medulla (IM) and SPR did not prevent this increase (188±16% and 204±22% of CON respectively). NIF increased ∝ENaC protein in renal outer medulla (365±44%) and IM (526±83%) and SPR prevented these changes. With ENAL‐induced VD there was no change in either PDE5A or ∝ENaC abundance vs. CON. These data indicate that the PVE and CD adaptations in response to VD result from RAAS activation, with PDE5A being mediated through AII signaling and ∝ENaC through the MR. Funding: R01HD041571 and R01DK56843.
Thick Ascending Limb‐Specific NOS1 Knockout Reduces Urinary Osmolality in Type 1 Diabetes
Authors: Edenfield Leia A , De Miguel Carmen , Musall Benjamin C , Harrison David G , Carmines Pamela K , Pollock Jennifer S
Published: June 2021

Diabetic (T1D) animal models show upregulated nitric oxide (NO) production and NO synthase 1 (NOS1) activity in renal medullary thick ascending limb (TAL). Because NO reduces Na+ transport by the TAL, we hypothesized that TAL‐specific NOS1 knockout (KO) mice develop fluid‐electrolyte dysfunction with T1D. NOS1flox (n=10–12) and TAL NOS1 KO mice (n=6–9) were administered streptozotocin (STZ; 150 mg/kg, ip), and systolic blood pressure (SBP), electrolytes, and urine osmolality monitored. After 7 wks of T1D, NOS1flox and TAL NOS1 KO mice did not differ with regard to SBP (119±4 vs 120±3 mmHg), blood glucose (460±58 vs 511±42 mg/dl), body weight (25.0±1.6 vs 24.5±0.9 g), water consumption (8.3±3.5 vs 14.6±4.2 ml/day) or protein excretion (3.5±1.4 vs 4.12±0.8 mg protein/day). Post‐T1D urine flow was greater in TAL NOS1 KO than NOS1flox mice (9.5±3.3 vs 5.0±2.3 ml/day; p=0.04). T1D led to reduced urinary osmolality in TAL NOS1 KO mice (Baseline=2832±448 mOsm/kg; T1D=1287±195 mOsm/kg; p<0.05), an effect significantly different from NOS1flox mice (Baseline=2625±270 mOsm/kg; T1D=2117± 228 mOsm/kg; p(genotype x T1D)<0.05). T1D did not alter Na+ or K+ excretion in either group. In conclusion, the loss of NOS1 in the TAL altered TID‐induced urine output and osmolality suggesting that TAL NOS1‐derived NO is critical to maintain fluid‐electrolyte homeostasis during T1D.
Characterization of smooth muscle microRNA and mRNA genes that are regulated by actin polymerization
Authors: Albinsson Sebastian , Turczynska Karolina , Swärd Karl , Hellstrand Per
Published: June 2021

The phenotype of vascular smooth muscle cells is regulated by multiple environmental cues including mechanical stretch. We have previously demonstrated that stretch‐induced actin polymerization is an important event for the expression of smooth muscle markers.

The aim of this study was to characterize mRNA/proteins and microRNAs (miRNAs) that are regulated by actin polymerization to evaluate the role of this control mechanism for phenotypic modulation and vascular disease.

Affymetrix chip gene arrays as well as miScript pathway focused miRNA PCR arrays were performed on smooth muscle cells treated with jasplakinolide, which stabilizes actin filaments.

As expected a number of well‐known smooth muscle markers including calponin (Cnn1), myosin heavy chain (Myh11) and tropomyosin (Tpm2) were significantly up‐regulated by jasplakinolide treatment. We also confirmed that transcription of the newly identified smooth muscle markers Lmod1 and Kcnmb1 was induced by actin polymerization. In addition, our array data revealed a number of genes and miRNAs that were significantly affected by actin polymerization but which have not been previously identified as markers of the contractile smooth muscle phenotype.

In conclusion, this study will lead to a better understanding of the regulation and importance of contractile smooth muscle markers and phenotypic modulation in the vasculature.
IP3R‐dependent modulation of endothelial Ca2+ dynamics by CaMKII in mouse mesenteric arteries
Authors: Toussaint Fanny , Charbel Chimène , Blanchette Alexandre , Ledoux Jonathan
Published: June 2021

Local calcium dynamics such as Ca2+ pulsars appear to have a significant impact on endothelial function. These Ca2+ pulsars result from the spontaneous release of Ca2+ by IP3 receptors (IP3R) localized within the myoendothelial junction (MJ). We have recently shown that CaMKII, a Ca2+‐dependent kinase decoding Ca2+ oscillations, is activated by Ca2+ pulsars. However, CaMKII also regulates intracellular Ca2+ homeostasis in other cell types. CaMKII regulation of endothelial intracellular Ca2+ dynamics in native endothelium was then undertaken by confocal microscopy. Exposure to KN‐93, a CaMKII inhibitor, stimulated Ca2+ pulsar. In the absence of extracellular Ca2+, exposure to ionomycin provoked an increase in intracellular Ca2+, indicative of the endoplasmic reticulum (ER) content in Ca2+. Interestingly, preincubation with KN‐93 significantly impaired the ER Ca2+ content (−62%). However, SERCA inhibition by thapsigargin did not significantly alter the ionomycin‐induced Ca2+ increase in the presence of KN‐93. These results suggest that CaMKII regulates endothelial Ca2+ through the modulation of IP3R activity. Immunohistochemistry revealed a progressive intrusion of the different isoforms (IP3R2>;IP3R1>;IP3R3) within the MJ. Therefore, this study suggests that endothelial CaMKII inhibits Ca2+ pulsars through IP3R1/2 phosphorylation. Supported by FRQS, FICM, CFI and HSFC.
Assessment of cerebral autoregulation as a clinical prognostic tool in subarachnoid hemorrhage
Authors: Otite Fadar , Sorond Farzaneh A. , Tan Can Ozan
Published: June 2021

Subarachnoid hemorrhage (SAH) has a high case disability and fatality due to vasospasm (VSP), delayed cerebral ischemia (DCI), and subsequent neurological deficits. Thus, early prediction of these complications can be critical for favorable clinical outcomes. Data suggest that VSP and DCI may result if cerebrovasculature fails to compensate for changes in pressure (i.e., impaired autoregulation) after SAH. However, though linear indices of autoregulation relate to the clinical outcome at the population level, their predictive power is nil due to their inherent limitation to characterize a nonlinear phenomenon. To avoid this limitation, we have recently developed a method based on projection pursuit regression (PPR), and here we assess its prognostic utility. We recorded arterial pressure (Finapres) and cerebral blood flow velocity (Doppler) in 48 patients, explored the changes in autoregulation over the first 4 days via PPR, and applied a decision tree to see whether these changes can predict VSP (n=27) and DCI (n=9). The ability of cerebrovasculature to buffer against pressure falls was impaired, and the timing and extent of this impairment predicted the outcome with high specificity and sensitivity (AUC: 0.83 {VSP} and 0.76 {DCI}). This demonstrates the utility of PPR as a clinical prognostic tool for efficient targeting of interventions and monitoring after SAH. Support: NIH HL093113.
Hemodynamic alterations and myocardial mitochondrial respiration in diabetic spinal cord injured rats
Authors: Lopez Vanessa , Brito Alfonso , Yamazaki Katrina Go , de Leon Ray
Published: June 2021

Spinal cord injured (SCI) individuals are at high risk for cardiovascular disease (CVD). The more severe a spinal cord injury, the greater risk of all CVD. In addition, SCI also increases the prevalence of disorders such as type II diabetes due to metabolic abnormalities. While higher risk of both diabetes and CVD may be associated with the immobility and increased sympathetic activation of patients with SCI, mitochondrial function may be affected by these factors thereby playing a role in decreasing cardiac efficiency. Mitochondrial function has been found to decrease in the spinal cord after SCI, but mitochondrial function in the heart is unknown due to limited research in cardiac dysfunction after SCI. We will use a rat model of spinal cord injury and type II diabetes to examine changes in CVD function. We expect to see decreased mitochondrial function that could explain the altered hemodynamics in the damaged heart of SCI diabetic animals. Not only will this study serve to assess the unique physiologic characteristics of the heart in chronic SCI individuals, but it will provide a different SCI model that incorporates diabetes for the purpose of exacerbating the onset of cardiovascular disease.
Does endothelial peroxisome proliferator‐activated receptor gamma (ePPAR‐γ) protect baroreflex function during obesity?
Authors: McCully Belinda H. , Duffy Kevin D. , Sigmund Curt D. , Brooks Virginia L.
Published: June 2021

We tested the hypothesis that ePPAR‐γ protects baroreflex function during obesity by determining whether a long term (10–12 weeks, LT) or short term (1–2 weeks, ST) high fat diet (HFD, 45% kcal fat) impairs baroreflex gain (BRG) in mice with a dominant‐negative mutation of ePPAR‐γ (E‐V290M) more than wild‐type mice (WT). Arterial pressure and HR were measured by telemetry for 24hrs in mice on a 12:12 dark (D): light (L) cycle. Spontaneous BRG (sBRG; msec/mmHg) was derived using the sequence method. sBRG was lower in lean E‐V290M compared to WT during L, but not D. The LT‐HFD attenuated sBRG in WT and E‐V290M during both L and D, with no difference between groups. During L, the ST‐HFD also blunted sBRG in WT, and sBRG remained lower in E‐V290M mice. During D, ST‐HFD only lowered sBRG in E‐V290M. However, the ST‐HFD‐induced decreases in sBRG were not greater in E‐V290M compared to WT mice during L (WT: −0.30±0.05 vs E‐V290M: −0.17±0.04) or D (WT: −0.06±0.05 vs E‐V290M: −0.17±0.04), indicating that there was not an interactive effect between obesity and the ePPAR‐γ mutation on sBRG. These data suggest that while ePPAR‐γ supports BRG in lean mice, it does not protect the baroreflex during obesity.

sBRG (msec/mmHg)

Lean
L
D

WT (n=11)
1.63 ± 0.08
1.18 ± 0.06

E‐V290M (n=11)
1.28 ± 0.07†
1.08 ± 0.07

LT‐HFD

WT (n=5)
0.96 ± 0.18 #
0.84± 0.10 #

E‐V290M (n=3)
0.88 ± 0.19 #
0.69 ± 0.08 #

ST‐HFD

WT HFD (n=5)
1.36 ± 0.05#
1.10 ± 0.06

E‐V290M HFD (n=7)
1.12 ± 0.05†
0.89 ± 0.06†#

Data are mean ± SE.

P<0.05 group within diet,

P<0.05 diet within group
Child MTHFR C677T genotype and HPA stress regulation at 6 years of age
Authors: Hookenson Kaia Vivian , Weinberg Joanne , Brain Ursula , Devlin Angela M , Oberlander Tim F
Published: June 2021

Major depression is often characterized by elevated daily cortisol concentrations reflecting altered hypothalamic pituitary adrenal (HPA) regulation. A dysregulated maternal HPA axis may exert early programming effects on fetal HPA activity. The methylenetetrahydrofolate reductase (MTHFR) gene, an enzyme required for folate metabolism, has a variant (C677T) associated with depression. It remains unknown whether the C677T variant moderates the effect of antenatal maternal depression in shaping HPA function during early childhood. To study if an association between antenatal maternal mood and offspring HPA regulation may be moderated by C677T genotype, salivary cortisol concentrations were obtained from children (n=59) over four days [early morning awakening (mean 7:42 ± 0.91 h), 15 min later (8:02 ± .96 h), and evening (18:40 ± 2.35 h)]. Using a linear regression model, prenatal SRI antidepressant exposure, and maternal mood (Hamilton Depression Rating Scale) at 33 weeks and 6 years, did not predict cortisol concentrations. However, children with 677TT genotype (n=9) had higher evening cortisol concentrations (β=−0.384, P=0.004), and a smaller change from early morning to evening (β=0.292, P=0.037), compared to children with 677CC and CT. These data suggest that children with a MTHFR 677TT genotype have both elevated and altered diurnal cortisol patterns, possibly indicating HPA axis dysregulation.

Supported by Canadian Institutes of Health Research, and the Human Early Learning Partnership.
Changes in Toll‐Like Receptor‐5 Expression in the Small Intestine During Hibernation
Authors: Kurtz Courtney
Published: June 2021

Hibernation is associated with dramatic changes in intestinal physiology. Among these are a lack of enteral nutrition, mucosal atrophy and significant increases in the number of immune cells. One possible reason for the increase in intestinal immune cells is changes in microbial sensing and composition of the gut microbiota. In this study, we used immunoblotting to examine the expression of Toll‐like receptor (TLR)‐5, a receptor for bacterial flagellin that is normally expressed in mammalian small intestine. TLR5 expression increased in the jejunum of torpid hibernators compared to summer but decreased during arousal. In the ileum, TLR5 levels were slightly higher in torpid squirrels compared to summer but significantly decreased upon arousal. Immunohistochemistry was used to identify the subcellular location of TLR5 and revealed expression primarily on the basolateral side of the epithelium in all activity states. In summary, these results suggest a specific upregulation of TLR5 in the small intestinal epithelium as the animal enters into torpor potentially leading to increased bacterial sensing and promotion of immune tolerance. Supported by UW‐Oshkosh Faculty Development Program.
Short‐term intermittent hypoxia enhances ventilatory chemoreflex sensitivity in humans
Authors: Leuenberger Urs A. , Li Stephanie , Drew Rachel C. , Muller Matthew D. , Heffernan Matthew J.
Published: June 2021

Short‐term intermittent hypoxia (IH, one episode/min for 30 min) raises basal sympathetic nerve activity and blood pressure, and enhances sympathetic vasoconstrictor nerve responses to acute hypoxia. We investigated whether the enhanced sympathetic activation in response to acute hypoxia following IH is also accompanied by enhanced ventilatory chemosensitivity. To this end we examined the effects of IH (30 episodes, SaO2 nadir 80–85%) on sympathetic vasoconstrictor nerve activity and ventilation in young healthy humans (5 male, 6 female). Muscle sympathetic nerve activity (MSNA, peroneal microneurography) and ventilatory responses to inhalation of 100% N2 (2–8 breaths) pre‐and post‐IH were compared. In addition, the effects of IH on the blood pressure and MSNA responses to static handgrip to fatigue (HG, at 30% of maximal voluntary contraction) and post‐HG circulatory arrest (CA) were also assessed. Compared to pre‐IH, post‐IH mean blood pressure (89±4 vs. 92±3 mmHg; n=11), MSNA (12.1±1.9 vs. 16.8±2.6 bursts/min; n=9), and ventilatory chemoreflex sensitivity (−0.184±0.032 vs. −0.285±0.051 L/min/%SaO2; n=11) were all increased (P<0.05) whereas the blood pressure and MSNA responses to HG and post‐HG CA were unaffected (n=9; P=NS). These data suggest that short‐term IH in healthy humans selectively enhances ventilatory chemoreflex sensitivity. (Supported by P01 HL09670 and UL1 TR000127)
Expression of sestrins in skeletal muscle with acute exercise and aging
Authors: Carter Heather N , Saleem Ayesha , O'Leary Michael F.N. , Ostojic Olga , Hood David A.
Published: June 2021

Regular exercise can maintain skeletal muscle mass as we age. However, the molecular mechanisms that contribute to muscle health with exercise are incompletely defined. Recently, a group of three p53‐regulated proteins called Sestrins (Sesn1–3) have been identified. Whether these proteins are altered with age, or are induced by acute exercise in muscle is currently unknown. Thus, the purposes of our investigation were to determine: 1) if Sesns are expressed in the presence or absence of p53 after acute exercise, and 2) whether the expression of Sesns is altered in aging muscle. p53 wild‐type (WT) and knock‐out (KO) mice were run on a treadmill for 90mins and either sacrificed immediately or allowed to recover for 3hrs. Basally, muscle from p53 KO animals had 27% lower mRNA expression of Sesn2, while Sesn1 mRNA was increased by 2.3‐fold compared to WT animals. Acute exercise had no effect on Sesn2 expression, but resulted in a 1.9‐fold increase in Sesn1 which was evident in the recovery phase, but only in WT animals. To examine the effect of age, muscle from 6‐ and 36‐month old rats was analyzed. Aged animals displayed 71% and 26% reductions in Sesn1 and Sesn2 mRNA, respectively, compared to younger animals. Similar trends were observed at the protein level. Our results suggest that Sesn expression is reduced with age, and that Sesn1 can be induced by acute exercise in a p53‐dependent manner. Supported by NSERC.
Akirin‐1 expression blocks dexmethosone induced satellite cell dysfunction
Authors: Dong Yanjun , Pan Jenny , Dong Yanlan , Mitch William E , Zhang Liping
Published: June 2021

Glucocorticoids are elevated in many pathological conditions and are associated with muscle loss, but the mechanisms are not fully understood. Defects in satellite cell function contribute to the development of muscle atrophy. Here, we demonstrated a new mechanism of dexamethasone‐induced muscle atrophy by suppression of satellite cell function. Dexamethasone decreased satellite cell proliferation and differentiation in vitro and in vivo. This was associated with upregulation of myostatin and suppression of Akirin1, a promyogenic gene. Myostatin inhibition in dexamethasone‐treated mice increased Akirin1 expression, satellite cell activity, muscle regeneration and muscle growth. Silencing myostatin in satellite cells prevented dexamethasone suppression of Akirin1 expression and satellite cells proliferation and differentiation. Finally, overexpression of Akirin1 in satellite cells increased the expression of MyoD and myogenin and improved cell proliferation and differentiation even in the presence of dexamethasone. We conclude that glucocorticoids stimulate myostatin which inhibits Akirin1 expression causing satellite cell dysfunction and muscle atrophy. Thus, inhibition of myostatin or increasing Akirin1 expression could be therapeutic strategies to improve satellite cell activation and enhance muscle growth in diseases associated with increased glucocorticoid production.
Inhibition of the phosphotidylinositol 3‐kinase (PI3K) pathway attenuates post‐exercise increases in soleus muscle satellite cells in estrogen supplemented ovariectomized rats
Authors: Mangan Gary , Bombardier Eric , Tiidus Peter
Published: June 2021

17β‐Estradiol (E2) enhances the activation, proliferation and differentiation of muscle satellite cells (SC) following eccentric exercise via activation of estrogen receptor‐α. Insulin‐like Growth Factor‐1 (IGF‐1) is known to cause SC proliferation and differentiation via phosphatidylinositol 3‐kinase (PI3K) signaling. To determine if E2 regulates SC activity via the PI3K pathway, 64, nine‐week old, ovariectomized Sprague‐Dawley rats were divided into eight treatments groups based on: estrogen status (0.25 mg estrogen pellet or sham), exercise status (90 min run @ 17 m/min, −13.5° or unexercised), PI3K signaling inhibition (0.7 mg Wortmannin/kg Body Weight or saline control). Significant increases in total SCs in soleus muscle (immunofluorescent colocalization of nuclei with Pax7) were seen at 72 hr post‐exercise in rats who were E2‐supplemented (t(62) = 1.89, p = 0.063), exercised (t(62) = 5.723, p < 0.001), and whose PI3K pathway was not inhibited (t(62) = 3.460, p = 0.001). PI3K pathway inhibited animals, regardless of estrogen or exercise status showed no significant enhancement of SC number. Preliminary data suggests that an increase in SC population following exercise in estrogen supplemented females may be mediated via PI3K pathway signaling.