bluuebunny/crossref_metadata_2025 huggingface dataset:
Acute Effects of Incremental Resistance Training on Muscle Function in Older Adults
Authors: Abdul Majid Mufaqam Syed , Mills‐Gray Susan L , Parks Elizabeth Jane , Ball Stephen Daniel
Published: November 2023

The population of older adults is growing significantly and is expected to reach 56.4 million by the year 2020. Aging reduces muscle mass that leads to decreases in muscle strength, flexibility, and balance in older adults and sedentary lifestyle increases the rate of progression of these conditions. Increased muscle mass and strength are associated with improved flexibility and balance, and resistance training (RT) may improve all of these aspects of aging.

PURPOSE

The purpose of this study was to determine whether an 8‐week program of incremental RT (iRT) improves muscle strength and function in older adults.

METHODS

Eighteen participants (men: n=2, women: n=16, age=61±4 y) performed iRT twice weekly for an hour for eight weeks. Dual‐x‐ray absorptiometry (DXA) scans, surface electromyography (S‐EMG, measured during bicep curl with progressive increases in weights, 0, 3, and 5 lbs.), a strength test (hand dynamometer), and plasma biochemical assays were performed at the beginning and end of the program.

RESULTS

iRT was associated with a reduction in BMI (32±6 vs. 31±5, P<0.001), body weight (90.0±18.1 kg vs. 87.5±17.4 kg, P<0.001) and %total body fat (40.3±5.7% vs. 39.2±5.2%, p<0.05). Lean mass increased (57.1±5.6% vs. 58.2±5.2%, P<0.05). Muscle strength tended to increase (63.5±13.5 kg vs. 64.7±12.2 kg, P<0.09), as did the efficiency of bicep EMG activity (P=0.07). Although the reduction in plasma creatinine kinase isozyme for muscle (CK‐MM) was not significant (107.6±66.1 U/L vs. 101.7±77.5 U/L, P=0.37), plasma aldolase was significantly reduced 35% (6.6±1.6 U/L vs. 4.2±1.9 U/L, P<0.001).

CONCLUSION

Post 8‐weeks of iRT, body weight was reduced by 3% even though weight loss was not a primary goal of the program. Furthermore, the loss in weight was attributed to a decrease in fat mass. Importantly, a significant decrease in plasma aldolase supported the effect of iRT to preserve muscle mass in older adults. Gains in muscle strength and EMG activity indicate enhanced muscle function which should improve overall quality of life during aging.

Support or Funding Information

University if Missouri Extension
Prostate Cancer Reduces Endurance Exercise Capacity in the Rat: Possible Roles of Reduced Cardiac Mass and Function
Authors: Rollins Korynne S , Esau Peter J , Gittemeier Elizabeth M , Opoku‐Acheampong Alexander B , Behnke Bradley J , Copp Steven W
Published: November 2023

Prostate cancer is the most commonly diagnosed non‐skin cancer in men. Exercise intolerance is common in prostate cancer patients; particularly those subject to androgen deprivation therapy. Whether prostate cancer itself reduces exercise capacity is unknown.

Objective

We used a preclinical rat prostate tumor model to test the hypothesis that untreated prostate cancer reduces endurance exercise capacity.

Methods

Sixteen male Copenhagen rats performed an initial treadmill test to exhaustion. The rats' prostates were subsequently injected with either prostate carcinoma cells (R‐3327 AT‐1 cell line) in Matrigel (cancer, n=9) or Matrigel only (sham, n=7) and the treadmill tests were repeated eight weeks post‐surgery. Following the final treadmill test, left ventricle contractility (left ventricle Δpressure/Δtime) was measured under anesthesia and the heart and gastrocnemius muscles were then dissected and weighed.

Results

Average prostate tumor mass in the cancer group was 9.8±2.6 g (range: 0.2 to 19.5 g). Initial times to exhaustion were not significantly different between groups (sham: 29.8±1.3, cancer: 28.6±2.5 min, p=0.710). Time to exhaustion at eight weeks post‐surgery was reduced compared to initial values for both groups but the eight‐week time to exhaustion was significantly lower in the cancer group (13.3±1.4 min) compared to the sham group (19.7±2.1 min, p=0.019). Left ventricle Δpressure/Δtime was not significantly different between groups, but within the cancer group prostate tumor mass was significantly inversely correlated to left ventricle Δpressure/Δtime (−0.71, p=0.047). Total body mass was not significantly different between groups (p=0.363) but heart (↓12%, p=0.021), left ventricle (↓16%, p=0.003) and gastrocnemius (↓9%, p=0.005) muscle mass were significantly lower in the cancer group compared to the sham group. Within the cancer group heart (r=−0.74, p=0.22) and left ventricle (r=−0.85, p=0.004) mass, but not gastrocnemius muscle mass (r=−0.15, p=0.696), were inversely correlated with prostate tumor mass. In other words, within the cancer group the rats with the largest prostate tumors had the lowest cardiac contractility, the smallest heart mass, and, more specifically, the smallest left ventricle mass.

Conclusion

We found that untreated prostate cancer reduced endurance exercise capacity in rats. Although multiple mechanisms likely contributed to the reduced exercise capacity in rats with prostate cancer, reductions in cardiac muscle function and mass, as well as reductions in gastrocnemius muscle mass, likely played an important role.

Support or Funding Information

American Cancer Society (RSG‐14‐150‐01‐CCE to BJB)
Multidimensional Factors Affecting Functional Outcomes After Amputation
Authors: Bachman Kaitlyn Lewis , Cox Lindsay , Venkataraman Muthuraman , Keyes Erin Elizabeth , Agazuma Keshia , Raynes Edilberto
Published: November 2023

For persons with amputations and for their healthcare providers, it is of critical importance to have a strong understanding of the multitude of factors that associate with positive functional outcomes. An understanding of these factors is necessary for optimal determination of prognosis, custom tailoring of interventions and resources provided, and overall improvement of quality of life. Additionally, an understanding of these factors aids both the developers and prescribers of prosthetic devices. Using the Oxford Level of Evidence Based Medicine, a systematic review was done in order to identify these factors. The study was limited to single, lower‐limb amputations between the levels of transpelvis and ankle mortis that resulted from combat‐associated trauma from either the Vietnam War or Operation Iraqi Freedom/Operation Enduring Freedom (OIF/OEF). From this literature, the emerging factors were identified and organized according to frequency of mention in the literature, degree, and relation to functional status. The most prominent factors discovered were psychological disorder, amputation level, cardiovascular comorbidities, soft tissue and/or systemic infection, residual limb pain, metabolic comorbidities, age, health of the intact leg, and phantom limb pain. Other factors discovered included Special Forces designation, low back pain, time of amputation, increased debridement at the time of amputation, sex, marriage status, skin condition on the residual limb, respiratory comorbidities, physical fitness, timing of amputation, and amputation secondary to salvage attempt. It is our hope that a better understanding of these factors will promote improved functional outcomes for persons with amputations.
INVESTIGATING INTERACTIONS BETWEEN POLYCHLORINATED BIPHENYLS, IMMUNE MARKERS AND EXERCISE
Authors: Pillai Mahesh R. , Keylock K. Todd , Meserve Lee A.
Published: November 2023

Polychlorinated biphenyls (PCBs) were chemicals produced in large quantities for wide ranging commercial applications. Their production was banned after discovery that their environmental pollution caused disruption of various systems including immunological, neurological, reproductive and endocrine. The immune system plays a vital role in wound healing and disrupting these responses can result in delayed healing. Benefits of exercise include accelerated wound healing and reduced harmful effects of physiological factors like stress and certain environmental toxins. This understanding led to our investigation of harmful effects of PCB on the immune system and exploration of possible moderation of some of those effects by exercise. Concentrations of cytokines involved in the inflammation phase of wound healing were analyzed to study this possible moderation. Interleukin‐6 (IL‐6) and granulocyte macrophage colony stimulating factor (GM‐CSF) concentration was measured in wounds created by punch biopsy in mice (female, C57/Bl6). Concentration of IL‐6 and GM‐CSF in not exercised mice was compared with mice exercised on a treadmill at moderate intensity (approx 70% VO2 max) for 30 min/day followed by intraperitoneal injection (in both not exercised and exercised mice) in doses of either 0, 100, 500 or 1000 ppm (wt/wt of mice) of an industrial mixture of PCB congeners (Aroclor 1254). Skin from the wound area was excised and homogenized for analysis of cytokine content in mice that were euthanized at Day 3 or Day 5 (n=3–6). Concentration of IL‐6 in Day 5 mice not exercised was 147% greater in 500 ppm PCB administered mice than mice adminitered no PCB. IL‐6 concentration in Day 5 mice administered 500 ppm PCB was 101% greater in mice not exercised than exercised mice, whereas IL‐6 concentration in Day 3 exercised mice was 61% less in 1000 ppm PCB administered mice than mice administered 100 ppm PCB. GM‐CSF concentration in Day 3 mice administered 100 ppm PCB was 31% greater in exercised mice than in mice not exercised. Concentration of GM‐CSF in Day 5 mice not exercised were 43% and 47% less in mice with 500 ppm and 1000 ppm PCB administration respectively as compared to mice administered no PCB. Wound size measurements were compared to the data obtained from the cytokine markers to help understand how exercise and PCBs affects the wound healing process.
Humanin skeletal muscle protein levels increase after resistance training in men with impaired glucose metabolism
Authors: von Walden Ferdinand , Gidlund Eva‐Karin , Venojärvi Mika , Heinonen Olli , Norrbom Jessica , Sundberg Carl‐Johan
Published: November 2023

Humanin (HN) is a mitochondrially encoded and secreted peptide linked to glucose metabolism and tissue protecting mechanisms. Plasma HN levels are lower in people with type 2 diabetes. Whether skeletal muscle HN expression is influenced by exercise is unknown. Therefore, the aim of this study was to investigate serum and skeletal muscle HN levels in men with impaired glucose control in response to 12 weeks of either resistance or aerobic (nordic walking) training.

Men (n=55) with impaired glucose regulation (IGR) were recruited and randomly assigned to resistance training (RT), Nordic walking (NW) or control (CON). Subjects trained three times per week for twelve weeks with progressively increased intensity during the intervention period. Biopsies from the vastus lateralis muscle and venous blood samples were taken before and after the intervention. A 2‐hr oral glucose tolerance test (OGTT) with 75 g of glucose loading was performed before and after the intervention period. Skeletal muscle and serum HN protein levels and skeletal muscle gene expression of MT‐NRN2 (the 16S gene), MT‐NRN1 (the 12S gene) and HNM1 were analyzed.

Skeletal muscle HN protein levels increased by 35 % after twelve weeks of resistance training (time × group interaction p=0.022). No significant interactions over time were seen in the NW or the C groups (ns). In the RT group, ΔHN serum protein concentration was correlated to the improvement of 2‐hr glucose loading test (R= 0.597, p=0.019). Twelve weeks of either RT or NW did not change mRNA levels of MT‐NRN2, MT‐NRN1 or of HNM1. There was a significant increase in citrate synthase activity in the RT group (1.8‐fold ± 0.47 p<0.05, time × group interaction p=0.027).

HN protein levels in skeletal muscle increase after regular resistance training in pre‐diabetic men. The significant correlation between ΔHN serum levels and improvements in the 2‐hr time point of the OGTT suggests a role for HN in the regulation of glucose metabolism. Given the preventative effect of exercise on diabetes type 2, the role of HN as a mitochondrially derived peptide and an exercise‐responsive mitokine warrants further investigation.

Support or Funding Information

The study was supported by grants from the Research Council for Physical Education and Sports, of the Finnish Ministry of Education, of Turku University of Applied Sciences R&D program and from Karolinska Institutet, Department of Physiology & Pharmacology.
Oral administration of BGP‐15 significantly increases HSP72 expression and attenuates ventilator‐induced diaphragm dysfunction
Authors: Morton Aaron B , Smuder Ashley J , Hall Stephanie E , Wiggs Michael P , Powers Scott K
Published: November 2023

Mechanical ventilation (MV) is a life‐saving intervention for patients unable to sustain adequate pulmonary gas exchange on their own. Unfortunately, prolonged MV results in rapid atrophy and contractile dysfunction of the diaphragm, collectively termed ventilator‐induced diaphragm dysfunction (VIDD). Although the mechanisms responsible for VIDD remain elusive, it is established that increased mitochondrial production of reactive oxygen species (ROS) is required for the development of VIDD. Notably, recent evidence reveals that endurance exercise training performed prior to MV is sufficient to protect the diaphragm against VIDD. While the mechanisms responsible for exercise‐induced prevention of VIDD remain unknown, evidence suggests that endurance exercise training may reduce diaphragm oxidative damage by elevating heat shock protein 72 (HSP72) expression. Therefore, these experiments tested the hypothesis that oral administration of a pharmacological inducer of HSP72 expression (BGP‐15) would increase HSP72 expression and attenuate VIDD. Our data reveal that 5 days of oral administration of BGP‐15 prior to prolonged MV results in increased HSP72 expression in the diaphragm and protection against VIDD. Specifically, BGP‐15 administration resulted in the prevention of the MV‐induced decrease in diaphragm muscle cross sectional area. Further, treatment with BGP‐15 protected against both MV‐induced diaphragm contractile dysfunction and attenuated the increase in mitochondrial ROS production in the diaphragm. Collectively, these results reveal that oral administration of BGP‐15 provides protection against VIDD presumably through an increase in HSP72.

Support or Funding Information

Supported by NIH R01 AR064189 awarded to SKP
Overexpression of SIRT6 Suppresses TNFα‐induced Muscle Cell Atrophy via NFκB Inhibition
Authors: Yeo Dongwook , Kang Chounghun , Ji LiLi
Published: November 2023

Chronic inflammation is a primary cause of muscle atrophy partly due to nuclear factor (NF)κB‐mediated upregulation of pro‐inflammatory cytokines such as TNFα, IL‐6, and IL‐1β. SIRT6, a NAD+ dependent histone deacetylase has been shown to suppress inflammatory responses by inhibiting NFκB signaling in several mammalian cells, but its role in muscle atrophy has never been studied.

PURPOSE

The aim of this study was to investigate whether SIRT6 overexpression (OE) can prevent TNFα‐induced proteolysis and atrophy in skeletal muscle cells.

METHODS

C2C12 cells were cultured in DMEM supplemented with 10% FBS, 100 U/ml pen:strep in 37°C with 5% CO2 incubator. Transient transfections were performed with 2 ng of GFP or Flag‐SIRT6 DNA transfected with PEI transfection reagent in 70% confluency cells. After 24 h, various doses of TNFα were added and the cells were incubated for various times.

RESULTS

After 48 h TNFα‐treated cells decreased SIRT6 level in a dose‐dependent manner, whereas this effect was abolished in SIRT6 OE cells. GFP+TNFα decreased IκBα content and increased nuclear p65 level indicating NFκB activation; however, SIRT6+TNFα cells showed minimal effect compared to GFP+TNFα. P65 DNA binding was increased by 6.7, 3.5, 4.2, 3.9‐fold with GFP+TNFα at 10min, 1h, 2h, and 6h, respectively (P<0.01); however, SIRT6 OE cells showed 12, 20, and 31% less activation than GFP+TNFα at the above‐mentioned corresponding time points (P<0.05) IL‐6 levels in GFP increased with TNFα at 1h (P<0.05) but were reduced by 18, 13, and 14% (P<0.05) with SIRT6 OE at 1h, 3h, and 6h, respectively. IL‐1β level in GFP was increased by 28% with TNFα 3h (P<0.05), whereas this effect was abolished in SIRT6 OE cells. TNFα treatment increased reactive oxygen species (ROS) production in a dose‐dependent manner (P<0.05), but ROS showed no change with SIRT6 OE. E3 ubiquitin ligase Atrogin‐1 level increased in response to TNFα in GFP but not in SIRT6 OE cells. TNFα treatment increased MuRF‐1 levels in GFP+TNFα; however, the effect tends to be lower in SIRT6 OE cells. The cell viability was decreased in TNFα treatment (P<0.01), but not in SIRT6 OE cells.

CONCLUSION

Overexpression of SIRT6 reduced pro‐inflammatory cytokine transactivation and ROS production, and improved viabilities possibly due to inhibition of TNFα‐induced NFκB activation in C2C12 cells.
Norepinephrine exacerbates the suppressive action of intermittent hypoxia on synaptic transmission
Authors: Khuu Maggie A , Barnard Jasmine E , Garcia Alfredo J
Published: November 2023

While acute intermittent hypoxia (IH) has the potential to be harnessed for therapeutic rehabilitation, IH experienced with sleep apnea causes a deterioration in neurophysiology that contributes to cardiorespiratory dysfunction and cognitive decline. A previous investigation in respiratory control demonstrated that the impact of acute IH on neuronal activity is dependent on increased noradrenergic tone—a common feature in sleep apnea. This ongoing study tests the hypothesis that norepinephrine (NE) influences the impact of IH on synaptic transmission in the hippocampus. Electrophysiological recordings of the field excitatory postsynaptic potential (fEPSP) were made in the CA1 neuronal population of adult mouse hippocampal brain slices. Acute IH was achieved by exposing preparations to three hypoxic intervals (95% N2, duration=180 sec) separated by periods of recovery (95% O2, duration=180 sec). During acute IH, the initial hypoxic interval did not suppress synaptic transmission, yet subsequent intervals suppressed the fEPSP (second interval by 16%, third interval by 22%; n=5). 2 microM NE did not affect the fEPSP during baseline conditions or during the initial hypoxic interval (n=5). However, the increased noradrenergic tone augmented fEPSP suppression during the subsequent intervals of hypoxia (second interval by 46%, third interval by 65%; n=5). These findings suggest that the efficacy of IH to suppress glutamatergic synaptic transmission is dependent on the state of oxygenation and may contribute to disrupted neurophysiology observed with sleep apnea.
Manual Acupuncture, but not Electroacupuncture Stimulate Afferent Nerves through Activation of TRPV1 Receptors to Modulate Pressor Reflexes
Authors: Guo Zhiling , Fu Liang‐Wu , Su Hou‐Fen , Longhurst John C.
Published: November 2023

We have shown that manual acupuncture (MA) at the P6 acupoint and electroacupuncture at the P5‐6 acupoints stimulate afferent fibers in the median nerve (MN) to modulate sympathoexcitatory cardiovascular reflexes through central regulation of autonomic function. However, mechanisms underlying MA and EA activation of these sensory afferents and their cell bodies in the dorsal root ganglia (DRG) are unknown. A histological study demonstrated that, compared to non‐acupoints, TRPV1 receptors are expressed in greater quantities in sensory nerve fibers located in the area of the ST36 acupoint. It remains unclear if TRPV1 receptors at the P5‐6 areas and DRG neurons contribute to activation of sensory nerves by MA and EA, leading to modulation of pressor responses. Therefore, in the present study, we investigated sensory neural mechanisms by which acupuncture inhibited cardiovascular responses. We hypothesized that acupuncture stimulates afferent nerves through activation of TRPV1 receptors to modulate pressor reflexes. In rats, we found that phasic single‐unit MN activity evoked by MA at P6 was significantly attenuated (P<0.05) by local administration of Iodoresiniferatoxin (a selective TRPV1 receptor antagonist, n=12), but not 5% Dimethyl sulfoxide (DMSO; vehicle, n=12) into the acupoint. Administration of Iodoresiniferatoxin into P5‐6 did not reduce EA‐evoked single‐unit MN activity (n=8). We also observed that MA at P6 and EA at P5‐6 induced phosphorylation of extracellular signal‐regulated kinases (ERK; an intracellular signaling messenger involved in cellular excitation) in DRG neurons at spinal levels of C6‐T1 that receive MN inputs. After knocking‐down of DRG TRPV1 receptors at these spinal levels with intrathecal injection of siRNA, expression of phosphorylated ERK in DRG neurons was reduced by MA, but not EA. Moreover, local injection of Iodoresiniferatoxin (n=5), but not 5% DMSO (n=5) into P6 reversed the inhibitory action of MA at this acupoint on pressor reflexes induced by gastric distension. However, the inhibitory effect of EA at P5‐6 on pressor responses evoked by gastric distension was not reversed after administration of Iodoresiniferatoxin into P5‐6 in two separate rats. Thus, these data suggest that MA, but not EA activate sensory afferents through stimulation of TRPV1 receptors to inhibit reflex increases in blood pressure.

Support or Funding Information

NIH grant AT009347
Renal‐selective Snx5 gene silencing increases blood pressure and renal sodium transporters in mice
Authors: Wang Xiaoyan , Asico Laureano , Zheng Xiaoxu , Lin Hai , Jose Pedro A , Villar Van Anthony M
Published: November 2023

We have reported that sorting nexin 5 (SNX5) plays an important role in the positive regulation of the renal dopamine receptor subtype 1 (D1R). siRNA‐mediated gene silencing of renal Snx5 results in anti‐natriuresis and increases further the elevated blood pressure (BP) of spontaneously hypertensive rats. We tested the hypothesis that the increased renal sodium transport and increased BP following Snx5 gene silencing is accompanied by changes in the expression of renal transporters in C57BL6/J mice. We infused subcapsularly the Snx5‐specific siRNA (3 μg/kg/day), or non‐silencing “mock” siRNA as control, for 7 days in 8 1‐year old, previously uninephrectomized male C57BL6 mice. A 24‐hour urine was collected from the mice housed in metabolic cages a day prior to the end of the siRNA infusion. Renal SNX5 protein expression was decreased by 60% with Snx5‐siRNA relative to control group. Renal SNX5‐depleted mice had elevated systolic (119±5.2 mm Hg, measured under anesthesia) and diastolic BPs (91.8±7.3 mm Hg) relative to control mice (systolic BP=101.5±0.5 mm Hg, diastolic BP=72±2.3 mm Hg). Urine sodium excretion tended to decrease in SNX5‐depleted mice (0.68±0.22 mmol/Cr mg) relative to controls (1.08±0.30 mmol/ Cr mg). Moreover, renal SNX5 depletion shifted the pressure natriuresis curve to the right. Food and water intake, body weight, urine volume, and heart rate were similar in the two groups. SNX5 is mainly located at the apical membrane of proximal tubules (PT), thick ascending limbs of loop of Henle (TAL) and distal convoluted tubules (DCT). SNX5 was observed via confocal microscopy to colocalize with NHE3, NKCC2 and NCC in C57Bl/6J mice under basal conditions. However, the co‐staining is strongest with NHE3 in the PT, relative to NKCC 2 and NCC which are expressed in TAL and DCT, respectively. The expression of renal NHE3 (172±29 % of control), NaPi2 (223±12%), NKCC2 (440±12%) and NCC (177±23%) were greater in SNX5‐depleted mice than in control mice. Renal protein expressions of α,β,γ‐ENaCs, Na+K+ATPase and actin were similar in the 2 groups. These findings suggest that inhibition of SNX5 expression with siRNA increases sodium transporters in proximal and distal nephron segments. This may lead to the inability of renal D1R to inhibit renal sodium transport and may be responsible for the increased BP in Snx5‐siRNA‐ treated mice.

Support or Funding Information

This work was supported in part by grants from the National Institutes of Health, R37HL023081, R01DK039308, P01HL068686, P01HL074940, and R01HL092196. Dr. Xiaoyan Wang was supported, in part, by National Kidney Foundation of Maryland (Professional Development Award, 2014).
Imbalanced Plasma ACE and ACE2 ratio in the Uremic Patients with Cardiovascular Diseases and Its Change during a Single Hemodialysis Session
Authors: Cho Ching‐Chang , Lu Li‐Che , Chang Chia‐Chu , Lin Chung‐I , Wang Guan‐Hua , Yang Chung‐Wei , Lin Chih‐Sheng
Published: November 2023

Background

The renin‐angiotensin system (RAS) has significant influences on heart and renal disease progression. Angiotensin converting enzyme (ACE) and angiotensin converting enzyme II (ACE2) are major peptidases of RAS components and play counteracting functions through classical angiotensin II (Ang II)/ATIR and non‐classical angiotensin‐(1–7) (Ang‐(1–7))/Mas axis, respectively. Based on crucial roles of RAS in the pathogenic development of chronic kidney disease (CKD), we tested the hypothesis whether plasma ACE and ACE2 levels might be significantly changed in the patients with end‐stage CKD (ESRK), i.e., uremic patients or HD patients.

Methods

This study included 372 uremic patients (aged 66.0 ± 13.4; 184 women; the mean hemodialysis (HD) therapy time was 7.5 years) who were on regular HD treatment and 50 healthy controls. The HD patients were grouped by the clinical symptoms or previous history of CVD (n = 122) and without CVD (n = 250). Hematological and biochemical parameters were determined by routine procedures. The plasma ACE and ACE2 levels were detected using fluorogenic substrates assay, and plasma Ang II and Ang‐(1–7) concentrations were determined by ELISA assay.

Results

The clinical characteristics of the HD patients with CVD (n = 122) and without CVD (n = 250) were shown that few of the clinical determinants detected differs significantly between the HD patient subgroups. However, we compared pre‐HD levels of plasma ACE, ACE2, Ang II and Ang‐(1–7) in the HD patients with and without cardiovascular disease (CVD) to those of the controls. The HD patients, particularly those with CVD, showed a significant increase in the levels of plasma ACE and Ang II, whereas ACE2 and Ang‐(1–7) levels were lower than those in the healthy controls. Therefore, markedly loss of ACE and ACE2 correlation, i.e., imbalanced ACE/ACE2, was observed in the HD patients with CVD. In the course of a single HD session, the plasma ACE, ACE/ACE2 and Ang II levels in the HD patients with CVD were increased from pre‐HD to post‐HD. On the contrary, plasma ACE2 level were decreased after the HD session. These changes were not detected in the HD patients without CVD.

Conclusion

Pathogenically imbalanced circulating ACE/ACE2 was detected in the HD patients, particularly those with CVD. HD session could increase ACE/Ang II/AT1R axis and decrease ACE2/Ang‐(1–7)/Mas axis activity in the circulation of HD patients with CVD. The imbalanced ACE/ACE2 due to a single HD session in the HD patients with CVD is required to further validate on its mechanism.
Renal Nephron Segment‐Specific Gene Expression using Adeno‐Associated Viral (AAV) Vectors
Authors: Konkalmatt Prasad , Asico Larry D , Santiago Cuevas , Armando Ines , Jose Pedro A
Published: November 2023

AAV vectors provide sustained long‐term gene expression with minimal immunological consequences. Systemic administration of AAV9 vector transduces efficiently various organs, such as the liver, heart, lung and skeletal muscle but provides very low transduction in the kidney. We have reported that the administration of AAV9 vector by retrograde ureteral infusion provided efficient gene transfer to renal cells including proximal and distal tubule cells, and podocytes with minimum off‐target gene expression. In studies on the genetics of renal tubule function, it is important to restrict the expression of the transgene to the desired cell type within the kidney, so that the physiological parameters measured will represent the function of the transgene expressed in that specific renal cell type. We hypothesized that use of nephron segment‐specific promoters sodium‐glucose cotransporter‐2 (SGLT2), Na+‐K+‐Cl− cotransporter‐2 (NKCC2), E‐cadherin (ECAD), and kidney‐specific cadherin (KSPC) promoters will provide preferential gene expression in the proximal tubule, thick ascending limb of Henle (TALH), distal convoluted tubule, collecting duct, and entire nephron, respectively. We have constructed, and validated in appropriate cell lines, AAV vector encoding EGFP gene under the control of nephron segment‐specific promoters SGLT2, NKCC2, ECAD, or KSPC. AAV9 vector with SGLT2 promoter driving the expression of EGFP provided robust expression in mouse primary renal proximal tubule cells but not renal collecting duct cells. KSPC promoter provided AAV9‐mediated expression in primary mouse renal proximal tubule as well as renal collecting duct cells. NKCC2 promoter provided weak expression in primary mouse renal proximal tubule and collecting duct cells. Specificity and distribution of gene expression in the mouse kidney from each promoter was determined by immunofluorescence staining using antibody against the marker proteins for proximal tubule, TALH, distal convoluted tubule, and collecting duct cells. Preliminary results, using SGLT2, a proximal tubule‐specific promoter, showed expression of EGFP only in proximal tubules of the mouse kidney. These results demonstrate that AAV9 vectors carrying nephron segment‐specific promoters can provide expression in their respective segment of the nephron.
Isotopic labeling of multiple functional groups for improving the quantification of urine metebolome
Authors: Chen Xin‐Tian , Hsieh YA‐Ju , Fu Shu‐Hsuan , Chen Yi‐Ting , Hsu Ming‐Hua
Published: November 2023

A high proportion of metabolites in human urine possess hydroxy and amino groups. Dangly chloride has been widely used in chemical isotope labeling to detect the compounds with phenol and amines by liquid chromatography‐mass spectrometry (LC‐MS), but not for alcohols. Therefore, we carried out the chemical isotope labeling with two kinds of catalysts (DMAP and DIPEA) for labeling both amino group and hydroxy group simultaneously using 12C or 13C‐dansyl chloride. After labeling, the products were extracted with water for three times and collected the organic layer. We dried the extracted sample, separated as two aliquots which were labeled separated with 12C / 13C‐dansyl chloride. The mixtures of 12C / 13C‐labeled metabolites were analyzed by LC‐MS for metabolite identification and quantification. Using penal and cholesterol as standards, this new dansylation method is proved be able to label the compounds with phenol and hydroxyl groups. To optimize the whole work flow, we optimized the variables including reaction solvent ratio, reaction time, reaction volume and compared this technique with other dansylation methods in the peak pairs, retention time and the functional group of labeled metabolites. In summary, this technique improves the detection of many metabolites in LC‐MS analysis, particularly hydroxy group and amino group.
Acute Cyclooxygenase Inhibition and Baroreflex Sensitivity in Lean and Obese Adults
Authors: Al‐Khateeb Abdulrahman A , Limberg Jacqueline K , Barnes Jill N , Joyner Michael J , Charkoudian Nisha , Curry Timothy B
Published: November 2023

Purpose

Obese adults exhibit increased levels of inflammation which may negatively affect blood pressure regulation. Based on existing literature, we hypothesized: 1) baroreflex sensitivity would be lower in obese adults when compared to lean adults and 2) acute ibuprofen (IBU, a cyclooxygenase inhibitor and nonsteroidal anti‐inflammatory agent) administration would increase baroreflex sensitivity in obese adults, with no effect in lean adults.

Methods

Seven lean (4M, 3F; 25±2 yrs; 23±1 kg/m2) and six obese (5M, 1F; 30±3 yrs; 36±1 kg/m2) adults completed two visits randomized to control (CON) or IBU (800 mg oral). On each visit, blood pressure (intra‐arterial catheter), heart rate (electrocardiogram), and muscle sympathetic nerve activity (MSNA, microneurography) were measured continuously and venous blood was sampled for measures of systemic inflammation [C‐Reactive protein (CRP) and Interleukin‐6 (IL‐6)]. Sympathetic and cardiac baroreflex sensitivity were assessed using the modified Oxford technique, which consisted of a 5‐min resting period, followed by a 100 μg intravenous bolus of sodium nitroprusside. One minute later, subjects were administered a 150 μg intravenous bolus of phenylephrine HCl and data were collected for an additional 2‐min.

Results

CRP and IL‐6 were higher in obese adults when compared to lean adults, and tended to decrease with IBU (IL‐6: p<0.05; CRP: p=0.14). Cardiac baroreflex sensitivity was lower in obese adults (14±2 vs 24±2 ms/mmHg, p=0.02), whereas sympathetic baroreflex sensitivity was higher in obese adults (−3.6±0.5 vs −2.1±0.5 bursts/100 beats/mmHg, p=0.03) when compared to lean. There was no effect of IBU on cardiac or sympathetic baroreflex sensitivity in either group (p‐value range 0.20 – 0.71).

Conclusion

In our present group of relatively healthy individuals with obesity, we observed lower cardiovagal baroreflex sensitivity but higher sympathetic baroreflex sensitivity in the obese group compared to lean controls. We found no effect of an acute dose of 800 mg ibuprofen on cardiac or sympathetic baroreflex sensitivity, suggesting that chronic effects of obesity‐related inflammation on baroreflex sensitivity may not be reversed by a single acute pharmacological anti‐inflammatory intervention.

Support or Funding Information

NIH HL083947 (NC, MJJ), DK082424 (TBC), AG038067 (JNB), and UL1 TR000135 from the National Center for Advancing Translational Sciences (NCATS). AHA 0750036Z (NC) from the American Heart Association.
Lipid Homeostasis and Function
Authors: Riezman Howard , Hannich J. Thomas , Galih Agustinus , Santos Aline X.S. , Riezman Isabelle , Martinou Jean‐Claude , Gentina Sebastien
Published: November 2023

We have developed a new approach to study lipid homeostasis and function which we call systematic lipidomics. It shows that the determined lipidome allows inferences about genetic background and has shown the tight relationship between the nutrient environment and lipid homeostasis. It represents therefore a new, rich source of biological information and has potential applications in medicine. We have recently focused on the role of ceramides in the response to anoxia after having isolated mutants in ceramide synthases that cause hypersensitivity or resistance to anoxia in worms. Using high resolution mass spectrometry we have shown that deoxyvceramides accumulate during anoxia and they seem to play a crucial role in determining the hypersensitivity to anoxia. Their mode of action seems to be through effects on mitochondria and the actin cytoskeleton. Our results would suggest that death after treatment under anoxic conditions involves generation of reactive oxygen species and therefore occurs during reoxygenation rather than during oxygen deprivation.

Support or Funding Information

Swiss National Science Foundation, Swiss National Center of Competence in Research i (NCCR) n Chemical Biology
Determination of thermosensory pathways required for behavioural thermoregulation
Authors: Yahiro Takaki , Kataoka Naoya , Nakamura Yoshiko , Nakamura Kazuhiro
Published: November 2023

Thermoregulatory behavior, represented by cold‐ and warm‐seeking behaviors in hot and cold environments, respectively, is utilized by animals to choose an optimal thermal environment. This voluntary behavior helps involuntary autonomous thermoregulatory mechanisms efficiently maintain body core temperature. Although many thermoregulatory behaviors are dependent on environmental temperature information transmitted from skin thermoreceptors to the brain, the afferent mechanism of the thermosensory transmission for behavioral thermoregulation has been unknown. In this study, we first examined the involvement of the well‐known spinothalamocortical thermosensory pathway in behavioral thermoregulation. The rat spinothalamocortical pathway was ablated by bilateral lesions of the ventral posteromedial and ventral posterolateral thalamic nuclei (VPM/VPL), a thalamic area receiving most thermal somatosensory signals from the spinal cord. The functional ablation of this pathway was confirmed with elimination of skin temperature‐dependent electroencephalographic responses recorded from the primary somatosensory cortex. To measure behavioral thermoregulation, we performed a two‐floor thermal plate preference test, in which control rats preferred a 28°C plate to a 15°C (cold) or 38°C (hot) plate, displaying cold‐ and heat‐avoidance thermoregulatory behaviors. Of note, the lesions of the VPM/VPL did not affect the thermoregulatory behaviors, indicating that the spinothalamocortical pathway is not involved in behavioral thermoregulation. We next investigated whether the lateral parabrachial nucleus (LPB), which mediates thermosensory signaling for autonomous thermoregulation, plays a role in behavioral thermoregulation. Inhibition of neurons in the LPB with bilateral nanoinjections of muscimol eliminated the cold‐ and heat‐avoidance thermoregulatory behaviors. These results indicate that an LPB‐mediated afferent pathway, but not the spinothalamocortical pathway, transmits the cutaneous thermosensory neural signals required for behavioral thermoregulation. This finding may contribute to future understanding of the central circuit mechanisms for the generation of thermal comfort and discomfort underlying thermoregulatory behavior.

Support or Funding Information

Funding from Nagoya University School of Medicine (TY); KAKENHI, MEXT of Japan 16H05128 & 15H05932 (KN)
Necrotizing enterocolitis is associated with recruitment of Lysozyme M positive myeloid cells in the intestinal submucosa via NF‐κB‐dependent upregulation of adhesion molecules
Authors: Managlia Elizabeth , Yan Xiaocai , Liu Xueli , De Plaen Isabelle
Published: November 2023

Necrotizing enterocolitis (NEC) is a devastating disease of the neonatal intestine. It predominantly affects premature infants and results in high mortality and morbidity. The pathogenesis of NEC is incompletely understood. We previously found that NEC is associated with a macrophage‐rich infiltrate and that blocking NF‐κB in LysM‐myeloid cells protects against experimental NEC. Furthermore, our previous data suggest that LysM‐myeloid cells are mainly present in intestinal monocytes in dam fed pups, but present in both monocytes and inflammatory macrophages in pups exposed to a NEC protocol in an NF‐κB‐dependent manner. Here, we sought to investigate whether Lysozyme (Lys) M‐myeloid cells infiltrate the intestine during NEC using our well‐established neonatal mouse model. To do so, we quantified by immunohistochemistry LysM+ cells present in the villi and submucosa of IKKβ floxed or WT mice with LysM expressing cre‐recombinase crossed with GFP cre‐reporter (mT/mG) mice. We found that NEC induction was associated with an increase in LysM+ (= GFP +) cells in the submucosa (14.78±1.1 vs controls 9.47±0.07 cells/HPF; p<0.01) but not the villi ((10.03±1.03 vs controls 6.5±0.88) in NF‐κB‐sufficient pups, but not in NF‐κB‐deficient pups. Furthermore, many of the GFP+ cells were located outside the intestinal vasculature, while they were located predominantly intravascularly in the NF‐κB‐deficient pups. Interestingly, we found that expression of L‐selectin and alpha 4‐integrin of isolated intestinal inflammatory myeloid cells, which were significantly increased during NEC when assessed by PCR, was significantly attenuated in NF‐κB‐deficient pups. This suggests, that, in NEC, inflammatory macrophages are recruited into intestinal tissue via expression of adhesion molecules, which is dependent on NF‐κB activation in myeloid cells.

Support or Funding Information

Supported by NIH grant RO1HD060876 and Ann & Robert H. Lurie Children's Hospital of Chicago Foundation
The role of HIF‐1α in a single bout of heavy exercise induced intestinal barrier dysfunction
Authors: Wu Die , Luo Beibei , Chen Peijie , Xiang Dao , Shi Yue
Published: November 2023

Intestinal epithelial cells are positioned between an anaerobic lumen and a highly metabolic lamina propria, affected by reduced blood flow and tissue hypoxia. Heavy exercise induces tissue blood flow redistribution by which the blood flow is decreased in the splanchnic circulation. The redistribution significantly reduces blood flow to the gut, leading to hypoperfusion and GI compromise. The hypoxia‐inducible factor (HIF) 1α is pivotal in the transcriptional response to oxygen flux. Therefore, we hypothesize that HIF‐1α plays an important role in heavy exercise induced intestinal barrier dysfunction. Two heavy exercise models were used in this study. (1) Long‐time exercise: mice voluntarily swam for 3 hours (or till exhaustion) in warm water (37 ± 1°C). (2) High‐intensity exercise: mice were subjected to weight‐loaded forced swim (7.5% of the body weight) for 1 hour. The noninvasive in vivo bioluminescence imaging was applied to monitor HIF‐1α expression after exercise in ROSA26 ODD‐Luc/+ mouse model (ODD‐Luc) that ubiquitously expresses a bioluminescent reporter consisting of firefly luciferase fused to a region of HIF‐1α. We found that one session of heavy swimming exercise markedly increases in vivo HIF‐1α in the gastrointestinal system. Next, we developed Vil‐Cre mediated, intestinal specific deletions of HIF‐1α (Vil‐Hif1a−/−) mouse model to verify the role of HIF‐1α in heavy exercise induced intestinal barrier dysfunction. Intestine segments were excised and stained with hematoxylin and eosin (HE) and alcian blue‐periodic acid Schiff (AB‐PAS). Intestinal permeability was quantified with FITC‐dextran. Bacterial translocation was determined by quantification of colony forming units (CFU) in cultured mesenteric lymph nodes, livers, kidneys and spleens. Gene expression profiling experiments were performed on mouse intestine cDNA samples from each group using RT2 Profiler PCR Arrays including over 84 genes related to antimicrobial responses. We found no significant differences between Vil‐Hif1a−/− and control Hif1aloxp mice in intestinal histology and mucus layer structure. However, the antimicrobial responses related genes expression were significantly different (P<0.001) between Vil‐Hif1a−/− and Hif1aloxp mice, including Il12a, Irak3, Irf5, Lbp, Lyz2, Nlrp1a, Ticam2, Tlr4, Tlr9 and Tnf. In conclusion, these results demonstrate an important role of HIF‐1α in the regulation of intestinal barrier functions related genes expression after one session of heavy exercise.

Support or Funding Information

The National Natural Science Foundation of China (31471135).
α2‐Adrenergic Blockade as a Novel Drug Therapy for Obstructive Sleep Apnea
Authors: Song Gang , Poon Chi‐Sang
Published: November 2023

Rationale

Decreased noradrenergic excitation of hypoglossal motoneurons during sleep causing atonia of pharyngeal dilator muscles is a major contributor to the pathogenesis of obstructive sleep apnea (OSA), a widespread disease for which effective drug treatment is currently lacking. Previous drug candidates for OSA aiming to restore hypoglossal motoneuron excitability and upper airway dilator muscle tone have proved largely ineffective in animal studies and clinical trials. Episodic airway obstruction is known to induce a long‐lasting noradrenergic‐dependent increase in hypoglossal activity called hypoglossal long‐term facilitation (hLTF) in animal models. We hypothesized that (1) the pathogenesis of OSA may involve not only decreased hypoglossal motoneuron excitability but also impaired hLTF during sleep; (2) therapeutic drugs targeting endogenous noradrenergic drive rather than hypoglossal motoneurons per se may prove more effective in restoring baseline hypoglossal activity and hLTF in defense against OSA.

Objectives

To examine the efficacy and mechanism of action (MOA) of a clinically well‐tested α2‐adrenoceptor antagonist (yohimbine) as a potential drug candidate for OSA in an animal model.

Methods

hLTF was induced by episodic airway occlusion simulating obstructive apnea and by episodic optogenetic stimulation of central noradrenergic neurons in urethane‐anesthetized rats. Efficacy of yohimbine therapy in restoring baseline hypoglossal activity and hLTF was studied during spontaneous or cholinergic‐induced REM sleep.

Measurements and Main Results

(1) Baseline hypoglossal activity and hLTF were markedly depressed during spontaneous or cholinergic‐induced REM sleep in urethane‐anesthetized rats. (2) These adverse effects of REM sleep on the first‐and second‐line motor defenses against OSA were promptly reversed by systemic (i.v.) administration of yohimbine. (3) Rats exposed to episodic airway occlusion demonstrated increased c‐Fos expression in pontine A7 and A5 neurons but not A6 (locus coeruleus and sub‐coeruleus) neurons, suggesting possible involvement of these noradrenergic neurons in the induction of hLTF. (4) Episodic optogenetic activation of pontine A7 or A5 noradrenergic neurons effectively induced hLTF post‐stimulation. (5) Microinjection of yohimbine into bilateral A7 and A5 regions resulted in significant augmentations of baseline hypoglossal activity and hLTF similar to systemic yohimbine administration, whereas microinjection of clonidine (an α2‐adrenoceptor agonist) into these regions produced the opposite effects.

Conclusion

Results suggest that disinhibition of A7 and A5 noradrenergic neurons by α2‐adrenergic blockade with yohimbine constitutes a viable drug therapy for OSA.

Support or Funding Information

HL093225, HL127258 and NS094178
Diaphragm Muscle Activity Following High Cervical Spinal Cord Injury (SCI) in Rats
Authors: Bezdudnaya Tatiana , DeFinis Jaclyn , Marchenko Vitaliy , Lane Michael A
Published: November 2023

Diaphragm dysfunction occurs following high cervicall spinal cord injury (SCI). As the diaphragm is a primary respiratory muscle its dysfunction often necessitates assited‐ventiation, dramatically impacting quality of life and increasing risk of mortality in injured individuals. Despite these devastating outcomes, functional plasticity and recovery of diaphragm activity, albeit limited, can occur spontaneously over the time. Understanding of the mechanisms underlying this recovery will facilitate developing new therapeutic strategies to treat respiratory impairment post‐SCI. In the current study, a C2 cervical spinal cord hemisection (C2Hx) was used to explore spontaneous plasticity ‐ known as the spontaneous crossed phrenic phenomenon – in awake behaving animals. While previous studies have assessed functional under anesthesia, the present study monitored changes in diaphragm activity using chronically implanted diaphragm EMG electrodes in behaving rats up to 8 weeks. Our EMG recording data show that recovery of diaphragm activity in awake animal occurs in one‐two weeks post injury, but inspiratory bursts on the injured side differ from the contralateral. Even when the amplitude of ipsilateral bursts is comparable with uninjured side, intraburst spike frequency is significantly lower especially during quiet breathing. Recording diaphragm EMG activity under anesthesia (isoflurane or ketamine) can eliminate ipsilateral diaphragm activity up to 100% indicating that recovery seen in behaving rats is mostly attributed to NMDA receptor activation. Ongoing studies are assessing this progressive functional recovery in more detail.

Support or Funding Information

Supported by Conquer Paralysis Now (CPN) and the Edward Jekkal Muscular Dystrophy Association Fellowship (Drexel).