bluuebunny/crossref_metadata_2025_split huggingface dataset:
17b‐Estradiol Rescues Low Force Potentiation in Ovariectomized Mice In Vivo
Authors: Le Gengyun , Warren Gordon L. , Lowe Dawn A. 
Published: November 2023

Post‐tetanic potentiation (PTP) of force is associated with phosphorylation of myosin regulatory light chain and increased Ca2+ sensitivity of the contractile apparatus. It has been previously reported that isolated muscles from ovariectomized mice have low PTP compared to that from ovary‐intact mice, and this decrement was reversed by acute estradiol treatment in vitro. However, there is no in vivo evidence supporting this estradiol effect.PurposeTo determine the effect of acute estradiol treatment on impairment of skeletal muscle PTP in ovariectomized mice in vivo.MethodsAdult female C57BL/6 mice (n = 9–15 per treatment) had a stimulating nerve cuff surgically implanted on the common peroneal nerve. Six weeks later these mice were ovariectomized or underwent a sham surgery. Four weeks later, the nerve cuff was used to electrically stimulate the anterior crural muscles immediately before and 1 h after treatment with either vehicle (OVX+vehicle) or 17β‐estradiol (OVX+E2; 0.15 mg estradiol per kg body weight) via tail vein injection. To measure PTP, baseline twitch torque production about the ankle was measured using a 0.1‐ms electrical stimulus pulse. Thirty seconds later, muscles were stimulated using 0.1‐ms pulses at 100 Hz for 1 s to produce a prolonged, isometric tetanic contraction. Starting 10 s later, two post‐tetanic twitches were elicited with 2 s between the two. PTP was calculated as the percent increase in torque from baseline to the highest torque of the post‐tetanic twitches. One‐way ANOVAs were used for data analysis. If a significant main effect was found, Holm‐Sidak post hoc tests were applied.ResultsPeak torque of the unpotentiated, baseline twitches were not different among OVX+vehicle, OVX+E2 and Sham mice (0.60 ± 0.06, 0.57 ± 0.05 and 0.51 ± 0.03 N*mm, respectively; p=0.30). Potentiated twitches generated 30–100% more torque than unpotentiated twitches. However, the extent of PTP depended on the presence of estradiol (main effect, p=0.03). PTP of Sham and OVX+E2 mice were not significantly different (53.7±5.0% vs 70.4±9.4% increase, respectively; p=0.11). PTP of OVX+E2 mice was greater than that of OVX+vehicle mice (70.4±9.4% vs 44.7±3.3% increase, respectively; p=0.01).ConclusionDeficiency of circulating ovarian hormones negatively impacts torque potentiation of the anterior crural muscles in anesthetized mice and acute estradiol treatment can rescue the low potentiation providing evidence estradiol can benefit skeletal muscle contractility in vivo. Supported by NIH grants R01‐AG031743 and T32‐AR050938.Support or Funding InformationSupported by NIH grants R01‐AG031743 and T32‐AR050938.
Impairment of osmotic challenge‐induced vasopressin secretion in sepsis survivor rats
Authors: Santos‐Junior Nilton Nascimento , Costa Luis Henrique Angenendt , Catalão Carlos Henrique Rocha , Kanashiro Alexandre , Sharshar Tarek , Rocha Maria José Alves 
Published: November 2023

Recent clinical and experimental studies report that sepsis survivors present long‐term immunosuppression and brain alterations. Neuroendocrine dysfunctions observed during sepsis have not yet been investigated in post‐sepsis condition. In the present study, we analysed the osmotic challenge‐induced arginine vasopressin (AVP) secretion in sepsis survivor rats. Wistar rats were subjected or not (naive) to cecal ligation and puncture (CLP). Five days after CLP surgery, the survivor animals were submitted to an osmotic challenge consisting of intraperitoneal injection of hypertonic saline. Thirty minutes after the osmotic challenge, the blood and brain were collected for determination of osmolality, nitrate, IL‐1β, IL‐6 and AVP levels and c‐fos expression analysis of hypothalamic supraoptic nuclei, respectively. All experiments were approved by the animal ethical committee of the Faculty (CEUA‐FORP). High levels of nitrate and IL‐1β, but not IL‐6, were found in the sepsis survivors plasma but this long‐term systemic inflammation was not altered by the osmotic challenge. AVP secretion (but not the osmolality) and c‐fos expression in SON were significantly attenuated in CLP survivor animals as compared with naive rats. We observed that AVP secretion dysfunction following an osmotic challenge in sepsis survivor rats is associated with hypothalamic dysfunction and this may be due to a persistent inflammatory response.Support or Funding InformationFAPESP (2015/12125‐5) and CNPq
Kinetics of Neurotransmitter Metabolism by Monoamine Oxidase in Porcine Heart Differs by Location and is Increased with Obesity/Metabolic Syndrome
Authors: Carter Kendal , Nelson Margaret , Robidoux Jacques , Lerman Lilach , Anderson Ethan 
Published: November 2023

Monoamine Oxidase (MAO), an outer mitochondrial enzyme, catalyzes the oxidative deamination of neurotransmitters and biological amines, and in the process, produces a reactive aldehyde and H2O2. Our lab has recently shown that MAO activity (i.e., H2O2 production) in human right atrial myocardium is associated with postoperative atrial fibrillation. Furthermore, our lab has shown that diabetic patients have higher MAO‐A and ‐B content and rates of activity in this tissue, compared to nondiabetics. While recent studies have explored the connection between MAO and cardiac dysfunction, the chamber‐specific content and activity of MAO within the heart is still unknown. Therefore, we characterized the regional enzymatic activity of MAO‐A and ‐B based upon the hypothesis that the atria would have the highest MAO activity due to the greater density of local sympathetic nerve innervation in this region. For this study, porcine hearts were isolated from domestic pigs, as this model closely recapitulates the physiology of the human heart. One group of pigs were fed a high fat, high sucrose diet for 16 weeks to induce obesity/metabolic syndrome (n=4). Three MAO substrates (dopamine, norepinephrine, serotonin) and two isoform‐selective inhibitors (clorgyline=MAO‐A, deprenyl=MAO‐B) were used to characterize MAO activities. Enzyme content was measured using ELISA and confirmed with immunoblots. Kinetic analysis showed that, across all substrates, when normalized to tissue protein, the left atrium has the highest maximal MAO‐A and –B activity while the other three chambers are similar. Furthermore, maximal MAO activity in the left ventricle of pigs with metabolic syndrome is significantly greater (P<0.05) than left ventricle of control group. Our findings suggest that MAO activity differs by location in the heart (i.e., chamber heterogeneity). This information will be useful to inform future experimental and clinical pharmacology applications where MAO inhibitors might be used. Moreover, increased MAO in left ventricle of pigs with obesity/metabolic syndrome is important as it provides a rationale for exploring MAO inhibitors as therapeutic strategy to mitigate cardiac complications of diabetes.Support or Funding InformationR01HL122863
Oral Glucose Tolerance Test in Insulin Resistant Adolescents Induces Regionally Different Macro‐ and Microvascular Responses in the Cerebral Circulation
Authors: Peltonen Garrett L. , Kellawan J. Mikhail , Ward Aaron T. , Carter Katrina J. , Carrel Aaron L. , Rehm Jennifer L. , Oh Jennifer M. , Bendlin Barbara B. , Schrage William G. 
Published: November 2023

Impaired cerebrovascular responsiveness to insulin may contribute to decreased cerebral blood flow (CBF) and cognitive decline associated with insulin resistance in adults. In insulin resistant adolescents (IR) however, the cerebrovascular response to insulin remains unknown. We tested the hypothesis that IR will display different cerebral macrovascular and microvascular responses to an oral glucose tolerance test (OGTT) compared to insulin sensitive adolescents (Ctrl). In 5 adolescents (15 ± 1 yrs), the Homeostatic Model Assessment of Insulin Resistance (HOMA‐IR) was used to quantify insulin resistance at baseline (2 Ctrl, HOMA‐IR = 3.3 ± 0.2; 3 IR, HOMA‐IR = 5.3 ± 0.2; P = 0.016). An OGTT (1.75g/kg, up to a maximum of 75g glucose solution) was administered to induce a physiologically relevant increase in circulating insulin. Prior to and at the 45‐minute time point of OGTT, CBF was measured with 4‐dimensional phase contrast‐vastly under sampled isotropic projection reconstruction (PC‐VIPR) MRI. Cerebral vascular conductance was calculated (CVC = CBF/mean arterial blood pressure [MAP] * 100mmHg) in 11 extracranial and intracranial cerebral arteries (Internal Carotid [ICA] x2, Middle Cerebral [MCA] x2, Anterior Cerebral [ACA] x2, Vertebral [VA] x2, Basilar [BA], and Posterior Cerebral [PCA] x2). Microvascular perfusion was measured prior to and at the 50‐minute time point of OGTT in 14 neuronal regions linked to cognition and learning, using pseudo‐continuous arterial spin labeling (pcASL) MRI. Heart rate, MAP, pulse oximetry oxygen saturation (SPO2), and end‐tidal CO2 (ETCO2) were measured at all time points. Changes in macrovascular CVC and microvascular perfusion were calculated as (ΔCVC = CVCOGTT − CVCbaseline and ΔASL = ASLOGTT − ASLbaseline). MAP (P = 0.029), and ETCO2 (P = 0.042) were higher in IR compared to Ctrl, but was unchanged with OGTT (P > 0.05). In agreement with our hypothesis, ΔCVC in response to OGTT was different in left MCA of IR compared to Ctrl (−39 ± 9 vs 6 ± 0 ml/min/100mmHg; P = 0.023). Likewise, ΔASL in response to OGTT was different in the left hippocampus (−8% ± 1% vs 6% ± 1%; P = 0.003) and right superior frontal medial gyrus (+5% ± 2% vs −4% ± 0%; P = 0.028) of IR compared to Ctrl. We conclude that IR demonstrate regionally different macrovascular and microvascular responses to an OGTT compared to Ctrl. These data are the first in IR to show alterations in the cerebrovascular responses to insulin in brain regions involved in learning, cognition, and executive function. Impaired insulin mediated perfusion of these regions may have important consequences for brain development and health as adolescents mature into adulthood.Support or Funding InformationUniversity of Wisconsin‐Madison Graduate School Pilot Funds
Fructose‐induced neurogenic hypertension is mediated by superoxide overexpression and stimulates p38 MAPK‐induced central insulin resistance in the central nervous system
Authors: Chen Hsin‐Hung , Cheng Pei‐Wen , Tseng Ching‐Jiunn 
Published: November 2023

Type 2 diabetes are at a high risk of complications related to hypertension, and reports have indicated that insulin levels may be associated with blood pressure (BP). Fructose intake has recently been reported to promote insulin resistance and superoxide formation. The aim of this study is to investigate whether fructose intake can enhance superoxide generation and impair insulin signaling in the nucleus tractus solitarii (NTS) and subsequently elevate BP in rats with fructose‐induced hypertension. Treatment with fructose for 4 weeks increased the BP, serum fasting insulin, glucose, homeostatic model assessment‐insulin resistance, and triglyceride levels and reduced the serum direct high‐density lipoprotein level in the fructose group. Treatment with tempol recovered the fructose‐induced decrease in nitric oxide production in the NTS. Immunoblotting and immunofluorescence analyses further showed that fructose increased the p38‐ and fructose‐induced phosphorylation of insulin receptor substrate 1 (IRS1S307) and suppressed AktS473 and neuronal nitric oxide synthase phosphorylation. Similarly, fructose was able to impair insulin sensitivity and increase insulin levels in the NTS. Fructose intake also increased the production of superoxide in the NTS. The results of this study suggest that fructose might induce central insulin resistance and elevate BP by enhancing superoxide production and activating p38 phosphorylation in the NTS.Support or Funding InformationMOST104‐2320‐B‐075B‐003‐MY3
General Characteristics of the 3 Groups of Rats

Control
Fructose
Fructose + Pioglitazone

Body weight (gm)
233 ± 6.6
227.5 ± 10.3
225 ± 6.7

Systolic blood pressure (mmHg)
128.4 ± 2.6
151.9 ± 2.3*
135.9 ± 5.3†

Mean blood pressure (mmHg)
113.7 ± 0.94
135.8 ± 1.7*
117.2 ± 3.2†

Fasting serum glucose (mg/dL)
110 ± 2.35
240.3 ± 12.7*
134.7 ± 18.2†

Fasting serum insulin (pmol/L)
9.38 ± 0.36
175.7 ± 24.5*
26.69 ± 1.9†

HOMA‐IR Index
0.38 ± 0.02
13.1 ± 2.9*
1.64 ± 0.23†

dHDL (mg/dL)
68.8 ± 0.67
55.0 ± 1.00*
69.7 ± 0.88†

Triglyceride (mg/dL)
56.4 ± 3.0
111.5 ± 8.96*
47.6 ± 9.2†

Cholesterol (mg/dL)
96.6 ± 1.78
100.63 ± 3.97
89.0 ± 1.2

NTS insulin (pmol/L/g protein)
7.97 ± 0.37
18.52 ± 1.73*
8.08 ± 0.32†

NTS insulin response (mmHg)
−24.62 ± 2.4
−8.86 ± 2.17*
−24.3 ± 2.2†
Antiaging Gene “Klotho” Deficiency Accelerates Stem Cells Aging by Impairing Telomere
Authors: Ullah Mujib , Sun Zhongjie 
Published: November 2023

Background & ObjectiveKlotho (anti‐aging gene) deficiency and telomere shortening occurs with aging. Mice with Klotho deficiency, show decreased lifespan with limited tissue renewal and short telomere, which suggests that telomerase is rate‐limiting step for stem cells which regenerate our bodies. It has become evident that telomere length and telomerase activity can directly affect the regenerative capabilities of stem cells. Here, we will explore the current evidence linking telomere shortening to aging and stem cell dysfunction in the light of klotho. Understanding the molecular pathways involved in this age‐dependent deterioration of stem cell function will be critical for developing new therapies.Methods & ResultsWe used adipose tissue‐derived stem cells (ADSC), as a model system, to identify the role of Klotho deficiency on stem cells and to assess their telomere length and activity. We identified the regulative and modulatory role of Klotho in the maintenance of ADSC population, their differentiation potential, pluripotency, proliferative index, and cells senescence. Klotho deficiency led to generation of reactive oxygen species and apoptosis. Further, we found the major targets, belong to TGFβ, insulin, and Wnt signaling pathways. These targets under the signaling of Klotho, takes part in the regulation of stem cells in a CD90 dependent way. Klotho knockout mice‐derived ADSC, exhibited altered osteogenic and chondrogenic differentiation. Klotho deficient ADSC showed an increased expression of TGFβ, SAMD2/3/4, BMP2, FGF2, Cdx, Cdk4, Leptin, Lpl, Crat, Asc‐1 and Apo‐A1. These targets probably play a role in stem cells aging. Klotho deficient ADSC exhibited significantly reduced expression for growth factors responsible for aging like FGF, IGF, SOX2, Pparγ, Irs1, Pgc1, Ucp‐1, and Pat2. The expression of all these targets notify the importance of Klotho in stem cells aging. Klotho deficient ADSC were also treated with telomerase activator Cycloastragenol (CAG) for telomere restoration. In result, we found that CAG stimulates telomerase activity, cell proliferation and partially rescued the regenerative abilities of ADSC.ConclusionKlotho gene deficiency impairs ADSC proliferation and differential potential which was markedly improved by activation of telomerase. Telomere shortening may be involved in klotho deficiency‐induced stem cell aging.
Characterizing A Rat Model to Study the Role Endo‐Immunology Plays in Diet‐Induced Non‐Alcoholic Fatty Liver Disease
Authors: Hinojosa Gabriella , Hamilton Alina , Lora Jessica , Short John D. , Dearth Robert K 
Published: November 2023

There is a rising epidemic of non‐alcoholic fatty liver disease (NAFLD) associated with the growing prevalence of obesity. NAFLD ranges from non‐progressive, steatosis, to a more aggressive disease, non‐alcoholic steatohepatitis (NASH). NASH, which is defined as an inflamed, fatty liver, contributes to liver cancer by causing chronic liver injury. A key event in the transitional progression from steatosis to NASH is the endocrine recruitment of monocytes to the liver. These infiltrating blood monocytes become polarized liver macrophages driving disease. There are currently no drugs specifically approved to treat NASH. One of the reasons is the availability of preclinical models that replicate disease pathophysiology in humans. A recent study showed that a specialized Amylin liver NASH Model (AMLN) diet (40% kcal from fat; fructose 22% by weight; cholesterol 2% by weight) caused NASH including immune cell infiltration in mice. However, the Sprague‐Dawley (SD) rat strain has been shown to be a more representative model to study human liver physiology and disease. Therefore, the objective of this study was to create a new model of diet‐induced NAFLD in the SD rat that more accurately maps the etiology of liver disease. Forty‐nine day old male Sprague Dawley rats were separated into groups and fed normal diet or AMLN diet for 4 weeks, 8 weeks, 12 weeks, or 19 weeks. AMLN diet rats showed a significant increase in weight gain and caloric intake weekly compared to controls. Histological analysis showed macrovesicular hepatic steatosis after four weeks on AMLN. Oil Red O staining confirmed an observable increase in lipid accumulation in the treated group after 4 weeks. After 19 weeks on AMLN, immunohistochemistry (IHC) revealed a significant increase in the macrophage markers CD68 and CC‐chemokine receptor 2 (CCR2) in the liver. CCR2 has been shown to be critical for the increased hepatic macrophage accumulation that accompanies NASH. We also observed notable clusters of hepatic macrophages indicative of advanced stages of NASH. Furthermore, we assessed changes in endo‐immuno markers known to be associated with liver disease progression. In conclusion, our rat model exhibited characteristics of diet‐induced liver injury that progresses from steatosis to NASH. This included the recruitment of blood borne monocytes that invaded the liver. This model may serve as a useful tool to elucidate the complex role endo‐immunology plays in the progression of diet‐induced NAFLD. Thus, allowing for a preclinical model that could be used to develop new drugs to treat NASH.Support or Funding InformationGH, AH, and JL were supported by the National Institute of General Medical Sciences‐award Number 1R25GM100866 (awarded to RKD and JGP).
Association of Vitamin‐D receptor polymorphisms with degenerative disc disease in Indian population
Authors: Doraiswamy Ravichandran , Ramaswami Karthikeyan , Subramanian Rashmi , Srinivasan Dinesh Kumar , Sivasankaran Balasubramanian 
Published: November 2023

The degenerative disc disease (DDD) in the lumbar spine refers to a syndrome that can lead to low back pain in elderly people. In the DDD, degeneration and herniation of disc are two main processes that contribute to low back pain. VDR is the first reported gene associated with DDD in a monozygotic twins study with Finnish population, which is located on chromosome 12q12–q14. Similar associations are later confirmed in various ethnic groups including Chinese and Japanese. There is a clear association between single nucleotide polymorphisms (SNP) and vitamin‐D receptor (VDR) gene (FokI and Taq1); however the pattern of genetic association with DDD in Indian population remains unknown. Thus, the present study was performed to validate the association of VDR polymorphisms and DDD in Indian population. In the present study, we have analyzed the polymorphisms of the VDR gene with an Indian population (48 cases and 47 controls). We identified a significant difference in the frequency of VDR gene alleles (FokI and TaqI) between cases and controls. In addition, there was a significant difference in genotypic distribution of FokI and TaqI alleles between these two groups. Overall, the distributions of VDR genotype frequencies FF, Ff, TT and Tt showed strong association with the DDD. To our knowledge, the present study reveals for the first time that polymorphism in the VDR gene is associated with disc degeneration and disc herniation in Indian population.Support or Funding InformationThis work was supported by research grant from the Karpagam Research Foundation, Karpagam Faculty of Medical Sciences and Research, Coimbatore, India.
HERG1 Expression Increases Calpain Activity in C2C12 Myotubes
Authors: Anderson Luke B. , Pratt Evan , Wang Wen‐Horng , Hockerman Gregory Howard , Pond Amber L. 
Published: November 2023

Skeletal muscle atrophy is the loss of muscle size and strength caused by an imbalance in protein degradation and protein synthesis. It occurs with normal aging, neural and skeletal muscle injuries, and with diseases such as diabetes, cancer cachexia, AIDS, Muscular Dystrophy, etc. If unabated, skeletal muscle atrophy can be very debilitating and even cause death. Three proteolytic systems are known to be upregulated in atrophic muscle: 1) ubiquitin proteasome proteolysis (UPP); 2) calcium activated calpains; and 3) lysosomal cathepsins. HERG1 is a K+ ion channel shown to be up‐regulated in atrophying skeletal muscle. We have shown that it transiently increases intracellular calcium concentration in cultured C2C12 myotubes. Thus our objective was to test our hypothesis that myotubes with increased levels of the HERG1 protein would have increased calpain activity. We transfected C2C12 myotubes with either an adenovirus encoding HERG1 or an appropriate control virus and, in both experimental groups, measured: 1) myotube size using ImageJ; 2) MuRF1 protein abundance using immunoblot; and 3) calpain activity in depolarized and non‐depolarized myotubes using a Calpain‐Glo Assay Kit (ProMega; Madison, WI). Indeed, our data reveal that, relative to controls, myotubes expressing HERG1 undergo atrophy, experiencing: 1) a 55% decrease in size; 2) an increased abundance of the UPP E3 ligase MuRF1; and 3) an 18% increase in calpain activity. We conclude that HERG1 increases proteolytic calpain activity in cultured myotubes.Support or Funding InformationThis research was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Number NIH NIAMS 1R03AR053706‐01A2 to ALP. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.