bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of Cardiac Progenitor Cells from Adult Murine Skeletal Muscle
Authors: Pacak Christina A , Alpatov Ivan , Fullen Shelby , Emmer Sawyer F , Cowan Douglas B
Published: June 2021

We have identified a cell population from the hind‐limb muscles of adult mice that possesses the potential to yield therapeutically‐relevant quantities of autologous cells for cardiac regenerative therapies. Using transgenic knock‐in mice, cells expressing the evolutionarily‐conserved transcription factors Islet‐1 and Nkx2–5, which direct cardiac specification during embryonic development, were selectively marked in post‐natal tissues. These non‐adherent, muscle‐derived cardiac progenitor (MDCP) cells spontaneously beat in culture, show a rapid growth potential, and express proteins essential in regulating cardiac lineage commitment. MDCPs were expanded in orbital bioreactors and characterized by a variety of gene expression, morphological and electrophysiological analyses. Our protocol yields cells that increasingly express cardiac‐specific genes over time. When attached to multi‐electrode arrays, MDCPs display action potential amplitudes resembling those of cardiomyocytes. Co‐culture experiments show electrical synchronization of MDCPs with neonatal cardiomyocytes and elongation of MDCP action potential duration along with slowing of conduction velocity. In conclusion, we are developing techniques to isolate, proliferate, and differentiate a population of cardiac progenitors in order to advance cell‐based therapies for the heart. Support ‐ NIH HL088206 and AHA 11910008.
Autonomic dysregulation and its prevention by voluntary exercise in a mouse model of chronic widespread pain (fibromyalgia)
Authors: Sabharwal Rasna , Rasmussen Lynn A. , Sluka Kathleen A. , Chapleau Mark W.
Published: June 2021

Chronic widespread pain (CWP) as occurs in fibromyalgia is relatively common and debilitating. Parasympathetic‐mediated heart rate variability (HRV) is decreased in people with fibromyalgia with reports of increased sympathetic activity that could contribute to pain by sensitizing nociceptors. Exercise training reduces pain in fibromyalgia. The aims of this study were to characterize autonomic dysregulation in an established mouse model of CWP (Yokoyama et al., J Pain, 2007); and determine if short duration (5‐day) exercise training (voluntary wheel‐running) abrogates the autonomic dysfunction. CWP was induced in young (10–12 wks) C57BL/6 male mice by repeated intramuscular injections of acidic saline (pH 5, 5 days apart) combined with 2 h of fatiguing exercise. Blood pressure (BP) and HR were measured by telemetry when mice were inactive. Induction of CWP decreased parasympathetic‐mediated HRV (RMSSD) without affecting mean BP or sympathetic vasomotor tone measured by the depressor response to the ganglionic blocker chlorisondamine (Table, *P<0.05, CWP vs. Control, n=4–6). Five days of exercise prior to induction of CWP prevented secondary mechanical hyperalgesia in the paw (n=4) and the decrease in HRV (†P<0.05, Exerc+CWP vs. CWP, n=4–8); and also decreased HR, BP and sympathetic tone in control and CWP mice (P<0.05). We conclude: 1) This mouse model of CWP exhibits selective impairment of parasympathetic modulation of HR with preserved sympathetic vasomotor tone; 2) Voluntary wheel‐running decreases sympathetic tone, HR and BP in both groups of mice, and prevents the secondary hyperalgesia and decreased HRV in CWP mice; and 3) The results suggest that exercise training would improve autonomic function as well as reduce pain in humans with CWP. (HL14388, AR061371)
Renal regeneration in diabetic nephropathy
Authors: Kelly Katherine J. , Dominguez Jesus
Published: June 2021

Diabetic nephropathy (DN) causes chronic kidney disease (CKD) and end‐stage renal disease (ESRD). We now introduce a method of renal regeneration by infusing cells expressing the tubulogenic protein SAA1. We tested in obese/diabetic Zucker diabetic/SHHF (ZS) rats the hypothesis that CKD can be abrogated by infusions of cells. We studied four groups, diabetic ischemic (subjected to bilateral renal ischemia for 20 min) and transplanted with cells expressing an empty vector (ADI, n = 9), diabetic ischemic transplanted with SAA expressing cells (BDI, n = 9), sham operated diabetic transplanted with SAA negative cells (ADS, n = 6), and diabetic sham transplanted with renal cells expressing SAA (BDS, n = 6). ZS rats were subjected to ischemia or sham surgery at 10 weeks of age, and given two infusions (1.5 × 106 cells per injection) at 15 and 20 weeks of age. The rats were terminated at 34 weeks of age. ADI had severe renal failure with creatinine clearance of 0.8 ± 0.1ml/min, 1.5 ±0.2, in BDI (p = 0.009), and unchanged in ADS 1.5 ± 0.2, and BDS 1.3 ± 0.3. Fractional interstitial fibrosis (IF) was 25 ± 2 % in ADI, 8 ± 1 in BDI (p <0.001). In ADS, IF was 12 ± 1 and 7 ± 1 in BDS, (p<0.01). Microvascular density was lowest in ADI, 7±1, and 16±2 in BDI, (p<0.05), 13±1 in ADS, and 18±1 in BDS (p<0.05). We conclude: infused primary kidney cells regenerate the vasculature and epithelial mass and stop renal decline in progressive CKD due to DN.
Effects of developmental hypoxia on alligator cardiac myocytes
Authors: Shiels Holly A , Moore Hailey , Hill Craig , Elsey Ruth , Warren Dan , Crossley Dane
Published: June 2021

Pathophysiological hypoxia induces changes in the structure, function, and gene expression of the developing heart. Recent work in reptiles exposed to hypoxia during development revealed cardiac hypertrophy and a reduction in both resting heart rate and blood pressure. The purpose of the current study was to further investigate these responses at the level of the cardiac myocyte. America alligators (Alligator mississippiensis) were reared in normoxic and hypoxic conditions until 90% development. The heart was quickly excised and single ventricular myocytes were liberated via a modified langendorf perfusion using digestive enzymes. Ventricular myocytes were long and thin with clear sarcomeric striations. Sarcomeric shortening and calcium transients were simultaneously measured as contraction frequency was increased from 0.5 to 2.0 Hz. Data are presented as means ± SEM from n=7–15 cells under each condition from N=20 animals. There were no differences between normoxic and hypoxic resting sarcomere length (SL) (1.78±0.04 and 1.77±0.05 um, respectively) and resting SL decreased (~3%) in both treatments with increased frequency. SL shortening was significantly greater in the hypoxic (9.9±1.4%) than the normoxic (4.6±1.4%) myocytes at 0.5 Hz but the differences were reduced as frequency increased. Calcium transient amplitude data mirrored that of sarcomeric shortening.
Influence of regular endurance training on postexercise hemodynamic regulation to orthostatic challenge
Authors: Sugawara Jun , Komine Hidehiko , Miyazawa Taiki , Imai Tomoko , Ogoh Shigehiko
Published: June 2021

Although postexercise syncope in endurance athletes is well recognized, the underlying mechanism is unknown. To determine whether endurance athletes exhibit the substantial hypotension during postexercise orthostatic stimulation, we conducted 5‐min head‐up tilt (HUT) tests before and after the 1‐hour moderate intensity cycling in young sedentary (S: n=8), endurance‐trained (E: n=8), and resistance‐trained (R: n=8) men. After the exercise the HUT‐induced vasoconstriction was significantly blunted in S and E groups. Significantly larger increase in the HUT‐induced fall of stroke volume was seen in E and R groups. Contrast to our hypothesis, endurance trained men did not exhibit a substantial drop of mean arterial pressure and/or pre‐syncope symptom during postexercise HUT despite the accumulated factors which facilitates orthostatic hypotension. This phenomenon might be explained by the greater augmentation of HUT‐induced tachycardia: the postexercise increase in tachycardia response was significantly greater in the endurance‐trained (+118% from preexercise) than those in the other groups (+45–50%). Collectively, during postexercise orthostatic challenge (at least in an early phase), endurance athletes maintain arterial pressure mainly by the enhanced tachycardia response.

Grant: Nakatomi Foundation, Japan.
Obesity‐resistant rats demonstrate enhanced energy sensing and metabolism
Authors: Allerton Timothy Daniel , Primeaux Stefany D.
Published: June 2021

The propensity for some individuals to develop obesity has been linked to intake of a high fat diet (HFD) and physical inactivity. However, some individuals resist obesity through improved energy sensing and other compensatory measures to maintain a healthy body weight. The purpose of the current experiment was to evaluate various metabolic variables in obesity‐resistant and obesity‐prone rats consuming a HFD. S5B/Pl and Osborne‐Mendel (OM) rats were fed a HFD or a low fat diet (LFD) for 2 weeks. Rats were then placed in metabolic chambers for 5 days to evaluate the respiratory exchange ratio (RER), spontaneous physical activity (SPA), and energy expenditure (EE). Once removed from the metabolic chambers, OM and S5B rats underwent a glucose tolerance test. Blood glucose was measured every fifteen minutes for 135 minutes following a bolus of glucose. S5B/Pl and OM rats only differed in RER when eating a LFD, whereby S5B rats demonstrated a decreased RER during non‐active times, indicating increased fat oxidation. Overall, S5B rats were not more physically active than OM rats. In the glucose tolerance test, S5B rats, regardless of diet, had lower areas under curve (AUC) than OM rats. These results demonstrate that S5B rats consuming a HFD have a greater metabolic rate during active and non‐active times and more efficient glucose control than OM rats. Interestingly, S5B rats resist weight gain through, non‐locomotive means.
Low salt intake is associated with maternal obesity before and during pregnancy
Authors: Tresoldi Michelle Soto , Heimann Joel Claudio , Lopes Karen Lucasechi
Published: June 2021

Objective

To evaluate body weight, adipose tissue mass, serum leptin and mean blood pressure in females fed with different amounts of sodium chloride in three moments of the perinatal period: before (B) and at the end of pregnancy (P) and at the end of lactation (L).

Methods

Female Wistar rats were fed low (LS: 0.15%), normal (NS: 1.3%) or high (HS: 8%) salt diet since 8 weeks of age. Mating was induced at 12 weeks of age. The mass of white adipose tissue (WAT, g/100g), brown adipose tissue (BAT, g/100g), body weight (BW, g), serum leptin (SL, μg/mL) by radioimmunoassay, intra‐arterial mean blood pressure (BP, mmHg) and adiposity index (AI=WAT/BW × 100, %) were evaluated.

Results (p<0.05, values represented by mean±SEM, n=4 to 10/group):

In LS fed rats, BAT and SL were lower in L (BAT: 0.11±0.011; LS: 3.6±1.1) compared with B (BAT: 0.18±0.013; LS: 7.7±1.0) and P (BAT: 0.15±0.012; SL: 7.8±1.1). Also in LS fed rats, AI was lower in L (6.1±0.5) compared with B (8.1±0.6) and P (7.8±0.5). In L, BP was higher in HS (137.1±4.9) compared with NS (119.1±2.4) and LS (111.7±7.5). The BW was lower in HS (258.0±6.0) compared with NS (329.0±26.5) and LS (306.5±19.6) group.

Conclusions

The amount of dietary salt consumption during the perinatal period influences maternal energy metabolism and blood pressure.

Supported by CAPES and FAPESP.
CaMKKα stimulates skeletal muscle glucose uptake independent of increases in glucose transporter expression
Authors: Hinkley J. Matthew , Witczak Carol A
Published: June 2021

Activation of Ca2+/calmodulin‐dependent protein kinase kinase α (CaMKKα) signaling in mouse skeletal muscle stimulates glucose uptake by ~2.5‐fold; yet the mechanism by which CaMKKα increases uptake is unknown. Muscle glucose uptake is increased by altering the expression and/or relocalization of sarcolemmal‐bound glucose transporters. The goal of this study was to determine whether CaMKKα stimulates glucose uptake by increasing the expression of glucose transporters found in muscle (i.e. GLUT1, GLUT4, GLUT8, and GLUT12). Plasmid DNA containing either constitutively active CaMKKα or empty vector were transfected into mouse tibialis anterior muscles by in vivo electroporation. Two weeks later, muscles were collected to assess CaMKKα and glucose transporter mRNA levels. Muscles transfected with active CaMKKα exhibited an 11.5‐fold increase in CaMKKα expression, a level previously shown to stimulate glucose uptake. Surprisingly, in muscles expressing active CaMKKα, there was a significant reduction in GLUT4 (24%) and GLUT12 (35%) expression, with no change in GLUT1 and GLUT8 expression. These results show that active CaMKKα stimulates muscle glucose uptake independent of increased glucose transporter mRNA expression, suggesting that CaMKKα may stimulate glucose uptake via a relocalization of glucose transporters on the sarcolemmal membrane. SUPPORT: NIH R00AR056298, ECU start‐up funds.
Improved satiety effect of leptin fusion proteins with prolonged plasma half‐life in mice
Authors: Bolze Florian , Morath Volker , Schneider Sarah , Mocek Sabine , Schlapschy Martin , Skerra Arne , Klingenspor Martin
Published: June 2021

Leptin, a 16 kDa hormone derived from adipocytes, plays a key role in energy balance regulation. Its clinical application in disorders associated with low plasma leptin levels, like genetically caused leptin deficiency, has been proposed. Due to its low hydrodynamic volume leptin is rapidly eliminated by renal clearance. Thus, daily injections would be needed to perpetuate a constant effect, which is not acceptable as therapy.

To improve leptin therapy, we have engineered leptin with an enlarged hydrodynamic volume using PASylation technology, which involves fusion with a disordered poly‐amino acid sequence comprising 200, 400 or 600 Pro, Ala and Ser residues (PAS). The expanded hydrodynamic volume reduces renal clearance in a length‐dependent manner. The affinity of the fusion proteins to the leptin receptor was almost fully retained as demonstrated by surface plasmon resonance analysis.

Cell culture assays revealed that PAS‐variants were nearly as potent in activating receptor signaling as native leptin. In C57BL/6J mice, PAS‐derivates were able to reduce food intake and body weight in a more effective manner than native leptin. The strongest effect was observed for PAS600‐leptin with a 10 % weight loss over 5 days.

Thus, PASylation is promising to maintain a lasting therapeutic effect without the need for daily injections.

Supported by National Genome Research Network plus to M. Klingenspor (01GS0822)
Targeting Diabetes with a Novel Small Molecule Activator of Sarco/endoplasmic Reticulum Ca2+‐ATPase (SERCA)
Authors: Kang Soojeong , Dhal Russell , Zsebo Krisztina , Thomas David , Cornea Razvan , Hajjar Roger , Lebeche Djamel
Published: June 2021

Diabetes represents an enormous burden due to the risk of complications and impact on mortality and morbidity. Endoplasmic reticulum (ER) stress has been shown to be a causative factor in diabetic pathophysiology. A major cause of ER stress is disturbed calcium homeostasis caused by dysfunctional Sarco/ER Ca2+‐ATPase (SERCA). Using novel screening methodology, we have developed a series of novel, drug‐like small molecules that activate SERCA and rescue various cell lines from ER stress‐induced cell death. Among our SERCA allosteric agonists, CDN1163 (CDN) significantly reduced the plasma levels of glucose and triglyceride in obese diabetic mice. Interestingly, the obese mice maintained a lower glucose level, identical to lean mice, for over 6 weeks after CDN has been administered. CDN also decreased hepatic steatosis and the expression of genes involved in gluconeogenesis and lipogenesis, and attenuated ER stress via PERK and IRE1a pathways independent of change in the expression of chaperones. Furthermore, CDN improved mitochondrial function through increased mitochondrial biogenesis and oxidative phosphorylation, upregulated the expression of antioxidant enzymes and attenuated ER stress‐induced apoptosis. Taken together, our data demonstrate that developing drug therapy that directly activates endogenous SERCA may constitute a novel therapeutic potential to treat diabetes. (NIH HL097357)
Steatosis Response To Curcumin In An Obese Mouse Model
Authors: Nookala Asha , Quinn Tim , Herndon Betty , Molteni Agostino , Alba Laura , Nachnani Jagdish , Bulchandani Deepti
Published: June 2021

Curcumin is a popular spice and part of the ancient medicinal system Ayurveda. It is known to have anti‐inflammatory, antimicrobial and antioxidant properties; research has shown prevention of liver damage induced by IL‐6. Here, we tested the hypothesis that the natural fatty livers in leptin k/o mice (OB/OB) would be improved by adding curcumin to food pellets, suggesting potential use in hepatic steatosis in general. Ten treated and ten control OB/OB mice were fed 2 months then studied for effects. Food pellets (Harlan) were prepared with and without 180 mg curcumin in the daily dietary intake (9 gm). Calories for both diets: protein 15.2%, carbs 62.5%, fat 22.3%.

Parameter evaluated
Curcumin diet
Control diet
P value

Body wt
55.14 ± 2.95
54.25 ± 1.84
>;0.05

Blood glucose
264.3 ± 124
171.7 ± 32
=0.046

Hepatic Superoxide
74.08%
76.73%
>;0.5

Liver, % fat (400×)
26.5%
38.27%
<0.001

Liver histopathology
8.125
17.5
<0.001

Insulin, serum
2.14 ± 1.8
3.37 ± 0.84
=0.2

IL‐6, serum
2.83 ± 2.5
5.89 ± 4.8
=0.2

Adiponectin, serum
7.96 ± 3.54
13.43 ± 3.6
=0.04

TNFα, serum
5.7 ± 1.21
10.69 ± 4.02
=0.03

We conclude that dietary curcumin in OB/OB mice produces significant improvement in general liver health by reduction of % hepatic fat and histopathology, improved cytokine values and reduced tissue superoxide. An increase in blood glucose by this treatment remains unexplained.

Funded: Sarah Morrison student grant (AN) & St. Luke's Foundation
Chlorpyriphos induces lung inflammation and alters response to E. coli lipopolysaccharide challenge
Authors: Chougule Amit Ajit , Sethi Ramsaran , Schneberger David , Brar Rajinder Singh , Gill Jatinder Paul Singh , Singh Baljit
Published: June 2021

Pesticided chlorpyriphos (CP), recently found in fodder and food in Punjab (India), has been linked to respiratory dysfunction. Because the effects of CP on lung immunity are not fully known, we studied that by exposing the mice to CP (3mg/kg/d orally for 60 d; N=20) followed by intranasal E. coli LPS (80μg) or normal saline (n=10 each). The mice were euthanized 12 hours post‐LPS treatment. Control mice (n=10 each) were given saline or the LPS alone. Mice treated both with CP and LPS had increase in total cell counts and leukocyte counts in broncho‐alveolar lavage (BAL) compared to other groups groups (P<0.05). Control mice showed normal lung histology compared to peribronchial and perivascular cell infiltration, loss of cilia, and congestion in 60d CP mice. While LPS induced acute inflammation in the lungs, combination of CP and LPS exacerbated histological signs of the inflammation. CP challenge increased lung staining of TNFα compared to control mice but not LPS or CP+LPS mice. TLR4, which ligates LPS, expression was increased in the airway epithelium, macrophages and alveolar septa of mice treated with CP or the LPS compared to the control. There were increased numbers of TLR9‐positive cells in lungs of CP‐treated mice compared to the control and the LPS groups but not CP+LPS mice (P<0.05). The data show CP caused lung inflammation and altered TLR expression which may have led to altered response to LPS challenge. Funding: GADVASU and UofSask
The prostaglandin F2alpha/calcineurin‐signaling pathway inhibits adipogenesis via the autocrine actions of an IL‐11/gp130/STAT1‐dependent signaling cascade
Authors: Annamalai Damodaran , Clipstone Neil A
Published: June 2021

Prostaglandin F2α (PGF2α) is a potent physiological inhibitor of adipocyte differentiation. In previous studies we have demonstrated that PGF2α inhibits adipogenesis via a signaling pathway that is dependent upon the activity of the calcium‐regulated protein phosphatase calcineurin. In the current study, we have extended these findings to further elucidate the mechanism by which the PGF2α/calcineurin‐pathway inhibits adipocyte differentiation. We now identify the IL‐11 cytokine, a member of the gp130 cytokine co‐receptor‐related family, as a downstream transcriptional target of this pathway in 3T3‐L1 preadipocytes. Using a combined shRNA and dominant‐negative mutant approach we provide evidence that IL‐11/gp130‐signaling is indeed required to mediate the inhibitory effects of PGF2α on adipogenesis. By taking advantage of a well‐characterized panel of chimeric gp130 mutant receptors, we demonstrate that gp130 signaling is sufficient to inhibit adipocyte differentiation and specifically requires the activation of the STAT1 transcription factor. Conversely, we find that depleting endogenous STAT1 levels rescues adipogenesis in the presence of both IL‐11 and PGF2α. Collectively, our findings support a model in which the PGF2α/calcineurin‐signaling pathway inhibits adipocyte differentiation via an autocrine IL‐11/gp130/STAT1‐dependent signaling cascade.
Cannabinoid Receptor Interacting Protein 1a (CRIP1a) Regulates CB1 Receptor Trafficking
Authors: Blume Lawrence C. , Dalton George D. , Selley Dana E. , Howlett Allyn C.
Published: June 2021

The CB1 receptor (CB1R) is a GPCR highly expressed in the CNS and has been targeted therapeutically for multiple diseases; however, CB1 compounds have limited clinical use due to their side effect profiles. GPCR interacting proteins provide a new avenue for modulating receptor activity. The Cannabinoid Receptor Interacting Protein (CRIP1a) is an accessory protein for CB1 that reversed CB1‐mediated tonic inhibition of voltage‐gated Ca2+ channels (Neihaus et al., 2008). The focus of this study was to investigate the cellular mechanisms underlying the CRIP1a‐CB1 interaction. CB1R was co‐immunoprecipitated from membranes and identified histochemically using antibodies developed against a non‐CB1R binding domain of CRIP1a. Stable over‐expression or knock‐down of CRIP1a in N18TG2 neuroblastomas did not alter CB1R mRNA or total protein levels. However, CB1R plasma membrane (PM) density was significantly reduced in CRIP1a over‐expressing clones, but increased in CRIP1a knock‐downs. The CB1R agonist WIN55212 led to CB1R internalization in WT and CRIP1a knock‐down cells, but a loss of internalization and a net increase in receptor externalization in CRIP1a over‐expressors. The CB1 antagonist rimonabant increased CB1R plasma membrane density in WT and CRIP1a over‐expressing and knock‐down clones. Thus, the function of CRIP1a may be to modulate trafficking and internalization‐associated CB1R mechanisms.
Acute doxorubicin treatment induces proteome lysine deacetylation, with no change in sirtuin expression, in the heart and liver of fasted animals
Authors: Dirks‐Naylor Amie Jeanette , Bero Joseph D. , Yang Sendra , Mabolo Raean , Tran Ngan T.K. , Kouzi Samir A.
Published: June 2021

Doxorubicin (DOX) is an effective chemotherapeutic agent, but with known toxicity which limits its lifetime dosage. In various experimental models, cellular stress has been shown to alter proteome lysine acetylation status, causing deacetylation which was associated with a pro‐apoptotic environment. The effects of DOX on proteome lysine acetylation status and expression of related sirtuins is unknown, thus we aimed to determine these effects in heart and liver of treated animals. Male F344 rats were injected IP with 20 mg/kg of DOX or saline. Once treated, all animals were fasted with no food or water until sacrifice 24 hours later. DOX treatment caused significant deacetylation in heart and liver. DOX did not affect the expression of sirtuin 1 or 3 in either tissue. Western analysis of sirtuin 1 revealed a prominent band of ~40kDa in liver, but not heart. Further, DOX treatment increased the content of this species. It has been reported in chondrocytes that sirtuin 1 can be cleaved into a ~75kDa protein which can bind to cytochrome c and inhibit apoptosis. The ~40 kDa fragment may be the remaining cleaved fragment detected by the antibody used. In conclusion, DOX induces proteome lysine deacetylation, which may be due to other deacetylases. Further, liver, but not heart, may be another tissue type that produces a 75 kDa product of sirtuin 1 as a mechanism to protect against apoptosis and is responsive to DOX treatment.
Specific mitochondrial adaptation to chronic hypoxia counteracts effects of acute hypoxia in perfused rats beating hearts
Authors: Deschodt‐Arsac Veronique , Calmettes Guillaume , Vaillant Fanny , Chapolard Mathilde , Muller Bernard , Diolez Philippe
Published: June 2021

Hypoxic states of the cardiac system are associated with heart pathologies. Modifications of energetics induced by chronic hypoxia were studied under conditions of oxygen deprivation in order to understand the specific resistance encountered after adaptation to chronic hypoxia.

Swiss mice were exposed to a simulated altitude of 5500m for 21 days. The effects of a low PO2 (100/120 mmHg) on contractile performance (RPP), phosphocreatine concentration (assessed by 31P‐NMR) were studied to describe the integrative changes in cardiac energetics induced by acute hypoxia from the Modular Control Analysis (MoCA).

Hypoxic hearts were insensitive to the severe oxygen reduction unlike control hearts for which concomitant decreases in RPP (− 46%) and in [PCr] (−23%) were observed. This absence of change was explained by a higher sensitivity of energy supply for hypoxic hearts (p<0.01) measured under low oxygen perfusion resulting in the conservation of a healthy control pattern of contraction despite oxygen deprivation.

This positive adaptation to oxygen deprivation could participate in the improvement of cardiac energetics, specifically at the level of energy supply by mitochondria. Since alteration of the energetic system could induce severe organ dysfunction, adaptation to hypoxia may limit the damages induced by acute hypoxia observed in multiple pathologies.
Obesity leads to altered vasomotor function in juvenile Ossabaw pigs
Authors: Lee Sewon , Booth Frank W , Rector Scott R. , Hill Michael A
Published: June 2021

Obesity is known to impair endothelial cell‐dependent (ECD) vasodilation, but the effects on vasoconstriction have not been fully elucidated. Currently, there are conflicting reports as to whether agonist‐induced contractile force and kinetics are specifically altered in obesity. We hypothesized that juvenile obesity in Ossabaw pigs alters vasomotor function. Female Ossabaw pigs (5–6 wks of age, N=4–6 rings from 2–3 pigs) were fed with either a low fat diet (3.03 kcal/g, lean control) or a high‐fat/ high‐fructose/high cholesterol diet (4.14kcal/g, obese) for 16 wks and vasomotor function assessed by myography. In distal sections of left anterior descending (LAD) artery, contractile force in response to U‐46619 was impaired (20.0±6.4 vs. 56.9±2.4mN) in obese, despite ECD vasodilation to bradykinin, and EC‐independent vasodilation to sodium nitroprusside being unaffected. In regard to kinetics, time to reach max contraction following addition of U‐46616 was longer in LAD from obese pigs (2232.5±56.1 vs. 804±118.7sec). Furthermore, max contraction by 80mM KCl was reduced in obese pigs compared to lean controls (48.5±1.6 vs. 57.9±1.1mN). Collectively, diet‐induced obesity may lead to an early defect in contractile function as opposed to vasodilation in coronary circulation of juvenile Ossabaw pigs. (Supp: NIH HL085119, VHA‐CDA2IK2BX001299–01, Mizzou Advantage, and the Allen Foundation)
Cerebral artery distensibility is decreased in a rodent model of postmenopausal physiology, the aged SHR
Authors: Kilar Cody Robert , Dawson Jack Anthony , Ramirez Rolando JJ , Novak Jacqueline
Published: June 2021

After menopause, women are at an increased risk of stroke. Aged spontaneous hypertensive female rats (SHR) have hormonal and cardiovascular changes similar to what is observed in post‐menopausal women. However, the cerebral circulation has not been studied in this model. The aim of this study was to compare the vascular behavior of arteries isolated from young and aged SHR in an isobaric arteriograph. We examined cerebral and mesenteric arteries from aged and young female SHR over pressures ranging from 25 to 200 mmHg for cerebral and 20 to 120 mmHg for mesenteric arteries. In cerebral arteries we measured % tone (1‐(Dactive‐Dpassive)*100%) and since the mesenteric arteries were preconstricted with phenylephrine we evaluated myogenic reactivity (percent change in active diameter). We hypothesized that vascular reactivity would be increased in arteries isolated from aged SHR. Myogenic reactivity was increased in mesenteric arteries of aged SHR. The diameter changed less than 0.5% despite increased intraluminal pressure in aged SHR compared to a 5% change in the young SHR. In the cerebral arteries, percent tone was not increased in the aged SHR compared to the young SHR, but distensibility was decreased. Young SHR's showed distensibility at 100 mmHg of 18%, while aged SHR's show distensibility of 10%. This data likely represents vascular changes seen in post‐menopausal women. Funded by NIH R15HL097343
Restrictive diet during pregnancy‐induced vascular dysfunction and hypertension in mice is associated with insulin resistance
Authors: Rexhaj Emrush , Rimoldi Stefano , Pireva Agim , Brenner Roman , Bouillet Elisa , Sartori Claudio , Allemann Yves , Scherrer Urs
Published: June 2021

In mice, restrictive diet pregnancy (RDP), a model mimicking preeclampsia in humans, induces vascular dysfunction in the offspring that is related to decreased vascular nitric oxide (NO) bioavailability. There is abundant evidence that NO plays an important role in the regulation of insulin sensitivity in animals and humans. We speculated that offspring of RDP mice are insulin‐resistant.

We, therefore, assessed insulin sensitivity (euglycemic‐hyperinsulinemic clamp studies) in offspring of RDP and control mice fed with high‐fat diet (HFD) for 8 wks. The main new finding was that HFD induced much more severe insulin resistance in offspring of RDP than in control mice, as evidenced by a markedly smaller glucose infusion rate to maintain euglycemia (77.4±10.7 vs. 96.7±12.2, P<.001) in offspring of RDP than in control mice. Insulin resistance was not related to an intrinsic defect of skeletal muscle because muscle glucose uptake was comparable in the 2 groups. In analogy to other NO‐deficient states, this problem is probably related to vascular dysfunction resulting in impaired insulin stimulation of blood flow and substrate delivery to skeletal muscle tissue. Preeclampsia‐induced vascular dysfunction has also been found in humans. We speculate that preeclampsia represents a novel risk factor facilitating diet‐induced insulin resistance in humans.

Grant support: Swiss National Science Foundation and Swiss Society of Hypertension
Apocynin exerts dose‐dependent cardioprotective effects by attenuating reactive oxygen species (ROS) in ischemia/reperfusion (I/R)
Authors: Young Lindon , Parker Christopher , Barsotti Robert , Bartol Kyle , Habtamu Tsion , Tolson Jasmine , Koko Deima , Diaz Brian , Casey Brendan , Ondrasik Regina , Chen Qian
Published: June 2021

I/R results in cardiac contractile dysfunction in part due to increased ROS and decreased endothelial‐derived nitric oxide (NO) release. Thus, inhibiting NADPH oxidase and subsequent ROS release with apocynin may preserve cardiac function and reduce infarct size following I/R. In isolated rat hearts following I (30 min)/R (45 min), apocynin given at reperfusion significantly restored left ventricular developed pressure (LVDP) dose‐dependently by 57 ± 9% (40 μM, n=7) and 82 ± 5% (400 μM, n=9) (p<0.01) of baseline respectively, at 45 min postreperfusion compared to untreated control I/R hearts (n=9) that recovered to 46 ± 7% (n=9) of baseline values for LVDP. The dose‐dependent effect of apocynin on LVDP was also associated with a significant decrease in infarct size compared to untreated I/R hearts (p<0.05). To test whether these effects were caused by apocynin‐induced reduction in hydrogen peroxide (H2O2, index of ROS) and increased NO release, we studied ROS in real‐time in vivo during femoral artery/vein I/R. Apocynin (14 mg/kg, given i.v. at reperfusion, n=6) significantly decreased H2O2 and increased endothelial‐derived NO release in femoral I/R from 20 to 45 min postreperfusion compared to saline controls (n=7) (p<0.01). These results suggest that apocynin attenuates I/R‐induced cardiac contractile dysfunction and infarct size by inhibiting ROS release from NADPH oxidase in reperfused tissues.

This study was supported by the NIH Grant 2R15HL‐76235–02 and the Center for the Chronic Disorders of Aging at Philadelphia College of Osteopathic Medicine.
Circulating microRNA profiling and their association with hypoadiponectinemia
Authors: Hassan Furqan , Sammy Sanjay A , Trecartin Andrew , Alley Joshua B , Bovenzi Frank , Bohman Danna , Fitzgerald Laura , Prot Jean‐Matthieu , Schuler Michael L , Ariza‐Nieto Magnolia
Published: June 2021

Hypoadiponectinemia is frequently observed in individuals with cardiovascular disease, type 2 diabetes mellitus, obesity, and obesity related cancers among many other metabolic disorders. MicroRNAs appear to play a regulatory role in the expression of adiponectin, but this role remains unclear at this time. Consequently, the aim is to identify microRNAs involved in the regulation and expression of adiponectin. Replication of clinical in vivo observations will be attempted in vitro using the genotyped “body‐on‐a‐chip” BOAC systems. The goal is to have an in vitro model to identify nutritionally induced microRNA profiles. MicroRNA profile assays are performed in pools of 4 groups of donors. Group 1‐BMI >; 40 prior to bariatric surgery, 2‐BMI<30 after bariatric surgery; 3‐patients diagnosed with metabolic syndrome 4‐controls without metabolic syndrome. Circulating microRNAs are isolated from the plasma of patients corresponding to IRB approved clinical trial GHS # 1207–27. The assays are performed with the qiagen human plasma miRNA PCR array (MIHS‐106Z) with internal normalization control C. elegans miR‐39 spike. Circulating microRNA profiles are correlated with circulating levels of total adiponectin and other clinical markers of metabolism. Funding Cornell University Center on the Microenvironment and Metastasis (CMM) outreach pilot grant and Guthrie Foundation Investigator‐Initiated Research Grant.
High fat intake with monounsaturated fatty acids, but not n6 polyunsaturated fatty acid, increases activity of key mitochondrial oxidative enzymes in the heart
Authors: Cox James Wilburn , O'Connell Kelly , Xu Wenhong , Stanley William C.
Published: June 2021

Evidence suggests that a high fat intake may be beneficial for cardiovascular health, though optimal dietary fatty acid composition is unclear. In this study, we compare the effects of a standard low fat diet (STD, 15% energy from fat) to high fat diets (40% energy from fat) comprised of monounsaturated fat (MUFA, oleate (18:1)), n6 polyunsaturated fat (PUFA, linoleic acid (18:2n6)), or saturated fat (SAT, palmitate and stearate (16:0 and 18:0)). Male rats (n=13–14/group) were fed the STD diet until 16 weeks of age and then assigned to dietary treatment for 15 weeks. Cardiac function was assessed by echocardiography and left ventricle (LV) pressure measurements and was unaffected by diet. Mitochondria were isolated from the LV and show no impact of dietary treatment on mitochondrial yield or respiration with lipid and nonlipid substrates. Mitochondrial oxidative enzyme activity in whole tissue dramatically increased with MUFA compared to STD. Citrate synthase activity increased from 105±15 μmol/g/min in STD to 157±14 in MUFA (P<0.05 vs STD and PUFA), with no significant effect in PUFA (107±9) or SAT (130±11). Similar changes occurred with aconitase and long chain acyl‐CoA dehydrogenase activities. In summary, a high fat diet did not adversely impact cardiac function, increased activity of mitochondrial oxidative enzymes of the TCA cycle and fatty acid oxidation, and did not affect mitochondrial function.
Morphological Changes Underlying High Fat Diet‐Associated Arterial Stiffening Differ with Advancing Age
Authors: Henson Grant D , Reihl Kelly D , Walker Ashley E , Bramwell R Colton , Donato Anthony J , Lesniewski Lisa A
Published: June 2021

Although it is not known how these risk factors interact, aging and obesity independently increase arterial stiffness and contribute to cardiovascular morbidity/mortality. We studied normal chow (NC) or high (40%) fat (HF) fed young (5–7mo) and old (28–31mo) male B6D2F1 mice to determine the effect of aging on obesity‐associated increases in arterial stiffness and morphology. Aortic stiffness, measured by pulse wave velocity (PWV), was greater in old compared to young (369±8 v 245±14 cm/s, P=0.04) NC fed mice and was concurrent with a ~3‐fold increase (P=0.015) in aortic collagen content (Picrosirius Red) and a ~50% reduction (P<0.05) in medial elastin (Van Gieson). In young mice, HF increased stiffness (359±18 cm/s, P<0.05) and was associated with increased collagen (59±9 v 19±8%, P=0.04) and reduced elastin (54±7 v 88±3%, P<0.05), similar to aging alone. Although aortic stiffness was higher in old mice after HF (385±47 cm/s, P=0.02) there was no effect on collagen content or medial elastin in old mice. In conclusion, age‐related arterial stiffening is associated with altered collagen and elastin content and, although HF feeding increases arterial stiffness across age, the associated morphological changes differ between young and old mice. Thus, the underlying mechanisms and effective therapeutic strategies used to combat obesity –associated arterial stiffness may differ with advancing age.

AG040297, AG033755, AG033196
CTP synthase, a smooth muscle‐sensitive therapeutic target for effective vascular repair after injury
Authors: Tang Rui , Chen Shiyou
Published: June 2021

Neointima formation due to smooth muscle cell (SMC) proliferation following injury is a major medical challenge in cardiovascular intervention. However, anti–neointimal drugs often block re‐endothelialization as a side effect. Identification of SMC‐sensitive therapeutic targets will potentially conquer this medical barrier. In the present study, we identified CTP synthase (CTPS) as one of these potential targets. Blockade of CTPS function by shRNA or its specific inhibitor suppressed SMC proliferation and neointima formation. In contrast, targeting CTPS treatments had no side effects on endothelial cell (EC) in vitro, and promoted re‐endothelialization in vivo. Mechanistically, blockade of CTPS pathway activated CTP synthesis salvage pathway in ECs but not in SMCs, which sustained EC proliferation. Meanwhile, blockade of CTPS function induced SMC phenotypic modulation into the contractile phenotype, which characterized by the expression of pro‐angiogenic factors while inhibiting anti‐angiogenic factors in SMCs, leading to enhanced EC proliferation. In summary, for the first time, our study discovered a fundamental difference between SMC and EC in their CTP biosynthesis during pathological proliferation which provided a novel strategy to selectively block SMC proliferation while not disturbing or even promoting re‐endothelialization for effective vascular repair after injury.
Influence of long‐term exposure of obesity on protein expression of myocardial calcium handling
Authors: Lima‐Leopoldo Ana Paula , Leopoldo André , Sugizaki Mário , Nascimento André , Campos Dijon , Silva Danielle , Luvizotto Renata , Alves Carlos , Freire Paula , Deus Adriana , Cicogna Antonio Carlos
Published: June 2021

Several structural and functional changes of the heart have often been associated with human obesity and experimental models. Myocardial calcium (Ca2+) handling has been extensively studied in several experimental models and has often been shown to be related to cardiac dysfunction. The objective was to test the hypothesis that the increased duration of exposure to obesity leads to a reduction in the expression and/or phosphorylation of proteins levels related to myocardial Ca2+ handling. The adiposity index used to characterize animals as obese was 79.5%, 82%, and 69.5% higher than controls after 15, 30, and 45 weeks, respectively. Obesity promoted comorbities such as glucose intolerance, insulin resistance, hyperinsulinemia, hyperleptinemia, and dyslipidemia; however, were not associated with changes in systolic blood pressure. The cardiac structure results post‐death showed that obesity caused cardiac hypertrophy at the 3 evaluation times. The obesity was not accompanied by changes in protein expression of L‐type Ca2+ channels, SERCA and CSQ. The protein levels of PLB, PLB phosphorylation at threonine‐17 (pPLB thr17), and the ratio between pPLB thr17 and PLB was not changed due to obesity. The main finding of this study was that obesity, after 15 and 30 weeks, resulted in decreased levels of PLB phosphorylation at serine‐16 (pPPLB ser16).
Associations between dietary/serum carotenoids and cardiovascular disease risk factors
Authors: Wang Ying , Chung Sang‐Jin , Vance Terrence M. , Fernandez Maria‐Luz , Chun Ock K.
Published: June 2021

Although cohort studies have found inverse associations between dietary/serum carotenoids and incidence of CVD, little is known about the association between dietary/serum carotenoids and CVD risk factors. A cross‐sectional study was conducted to examine the associations of dietary/serum carotenoids with plasma lipids, homocysteine (Hcy), and C‐reactive protein (CRP). A total of 7,398 participants aged over 19 y free of CVD or cancer in the NHANES 2003–2006 were utilized. After adjusting for covariates, the odds ratios for CRP >; 2.4 mg/L (ref: CRP ≤ 2.4 mg/L) were 0.14 (95% CI: 0.04–0.47), 0.29 (CI: 0.17–0.77), 0.32 (CI: 0.12–0.85) and 0.39 (CI: 0.15–0.97) for participants in the highest quartile vs. the lowest of β‐cryptoxanthin, lycopene, lutein+zeaxanthin, and total carotenoid intakes, respectively. Serum carotenoids, except α‐carotene, were positively associated with plasma total cholesterol (p<0.05). Serum α‐carotene, cis β‐carotene, and lutein+zeaxanthin were positively associated with HDL (p<0.05) but not with LDL. The odds ratios for Hcy >; 12 μmol/L (ref: Hcy ≤ 12 μmol/L) were 0.29 (CI: 0.12–0.72), 0.36 (CI: 0.14–0.95), and 0.24 (CI: 0.11–0.56) for participants in the highest quartile vs. the lowest of serum α‐carotene, cis β‐carotene, and lycopene, respectively. Serum carotenoids were better predictors than dietary carotenoids in terms of their protective effects against CVD.

Grant Funding Source: NA
Heat shock factor‐1 regulates IL‐6 promoter activity in C2C12 muscle myotubes
Authors: Welc Steven S , Chen Daniel L , Judge Andrew R , Clanton Thomas L
Published: June 2021

Hyperthermia stimulates interleukin‐6 (IL‐6) mRNA and protein production and also potentiates the IL‐6 response to epinephrine (EPI) and lipopolysaccharide (LPS), but the signaling pathways are not known. In this study we specifically tested the role of heat shock factor‐1 (HSF‐1) in these responses using a mouse IL‐6 promoter reporter construct (mIL‐6.Luc) in C2C12 myotubes. IL‐6 promoter activity was inhibited by co‐transfection of dominant negative (d.n.) HSF‐1 or stimulated using a constitutively active (c.a.) HSF‐1 construct. The d.n. HSF‐1 significantly diminished IL‐6 promoter activity at both 37°C and 42°C (P < 0.05). Furthermore, the d.n. HSF‐1 significantly reduced the IL‐6 transcriptional responses to EPI (100 ng/ml) and LPS (1 ug/ml) at both 37°C and 42°C (P < 0.05). In contrast, co‐transfection with c.a. HSF‐1 significantly elevated IL‐6. Luc reporter activity at 37°C and amplified the response to LPS (P< 0.05); however, it had no influence on the response to EPI. Results demonstrate that hyperthermia is an important functional stimulus for IL‐6 promoter activity, which employs HSF‐1 activation. In addition, the interactions of overexpressed HSF‐1 with stress signals (from EPI or LPS) and the IL‐6 promoter have different regulatory outcomes. The overexpression of HSF‐1 does not amplify the IL‐6 promoter's response to EPI. The results confirm the important role of HSF‐1 in IL‐6 regulation and suggest that hyperthermia may also recruit other parallel signaling pathways besides HSF‐1 that influence IL‐6 regulation. Supported by: AHA #11GRNT7990119
Voluntary control of breathing and cerebral blood flow during prolonged exercise in the heat
Authors: Tsuji Bun , Honda Yasushi , Ikebe Yusuke , Fujii Naoto , Kondo Narihiko , Nishiyasu Takeshi
Published: June 2021

Hyperthermia during prolonged exercise leads to hyperventilation (hyperthermic hyperventilation), which causes a decrease in arterial CO2 pressure (PaCO2), resulting in reduced cerebral blood flow. Here we examined whether humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise and, if so, are reductions in PaCO2 and cerebral blood flow attenuated by this suppression. Eight male subjects performed two exercise trials at 50% of peak oxygen uptake in the heat (37°C). The subjects breathed normally (normal breathing) and tried to control respiratory frequency and tidal volume to their levels of 5 min of exercise (controlled breathing). Minute ventilation increased with rising esophageal temperature (Tes) in normal breathing, whereas controlled breathing attenuated the increased ventilation (increase from the onset of controlled breathing: 11.5 vs. 3.6 L/min at +1.3°C Tes, P < 0.05). Normal breathing resulted in a decrease in end‐tidal CO2 pressure (PETCO2) and middle cerebral artery mean blood velocity (MCAVmean) with rising Tes, whereas controlled breathing attenuated the reductions (PETCO2 −4.8 vs. −1.4 mmHg; MCAVmean −15.7 vs. −6.6 cm/s at +1.3°C Tes, P < 0.05, respectively). Our results indicate that humans can voluntarily suppress hyperthermic hyperventilation during prolonged exercise, and this suppression leads to smaller changes in PaCO2 and cerebral blood flow.
Monocarboxylate Transporters and Creatine Kinase Protein Content in McArdle's Disease
Authors: Kitaoka Yu , Ogborn Daniel I , Mocellin Nicholas J , Schlattner Uwe , Tarnopolsky Mark A
Published: June 2021

McArdle's disease (MD) is well known as a metabolic myopathy due to myophosphorylase deficiency. We examined monocarboxylate transporters (MCT) and creatine kinase (CK) protein content in skeletal muscle from 12 patients with MD and 12 age‐matched controls, to evaluate potential cellular adaptations to compensate for the loss of glycogenolysis. MD muscle had higher protein content of MCT1 and mitochondrial CK (mt‐CK), with no changes in the activities of citrate synthase (CS) and cytochrome c oxidase (COX) and voltage‐dependent anion channel (VDAC) protein, as compared to controls. These results suggest that lactate uptake via MCT1 could be important to increase the pyruvate availability, and that mt‐CK could be important to maintain phosphocreatine concentration and thus local ATP availability for MD patients, under conditions of reduced energy flux due to inborn errors of metabolism. Collectively, the above data suggest that the proteins related to extra‐muscular fuel uptake and intra‐muscular energy transduction are up‐regulated without change in mitochondrial mass in MD muscle. Additionally, our findings support the effectiveness of carbohydrate for MD patients, and also highlight a potential role for creatine supplementation in the treatment of this population.