Low-intensity interval exercise training attenuates coronary vascular dysfunction and preserves Ca²⁺-sensitive K⁺ current in miniature swine with LV hypertrophy.

Coronary vascular dysfunction has been observed in several models of heart failure (HF). Recent evidence indicates that exercise training is beneficial for patients with HF, but the precise intensity and underlying mechanisms are unknown. Left ventricular (LV) hypertrophy can play a significant role in the development of HF; therefore, the purpose of this study was to assess the effects of low-intensity interval exercise training on coronary vascular function in sedentary (HF) and exercise trained (HF-TR) aortic-banded miniature swine displaying LV hypertrophy.

Medical implications of obesity in horses--lessons for human obesity.

There is growing recognition that obesity is common and represents a significant detriment to the health of companion animals in a manner similar to that by which it is affecting the human population. As is the case for other species, obesity appears to promote insulin resistance in horses and it is through this pathophysiological process that many of the adverse medical consequences of obesity are being characterized. Equine medical conditions that have been described in the context of obesity and insulin resistance differ from those in humans.

Endogenous testosterone attenuates neointima formation after moderate coronary balloon injury in male swine.

Aims: Previous studies from our laboratory have demonstrated that testosterone increases coronary smooth muscle protein kinase C delta (PKC delta) both in vivo and in vitro and inhibits coronary smooth muscle proliferation by inducing G(0)/G(1) cell cycle arrest in a PKC delta-dependent manner. The purpose of the present study was to determine whether endogenous testosterone limits coronary neointima (NI) formation in a porcine model of post-angioplasty restenosis.

Methods And Results: Sexually mature, male Yucatan miniature swine were either left intact (IM), castrated (CM), or castrated with testosterone replacement (CMT; Androgel, 10 mg/day).

Chronic inhibition of nitric oxide synthase augments the ACTH response to exercise.

Exercise can activate the hypothalamo-pituitary-adrenocortical (HPA) axis, and regular exercise training can impact how the HPA axis responds to stress. The mechanism by which acute exercise induces HPA activity is unclear. Therefore, the purpose of this study was to test the hypothesis that nitric oxide modulates the neuroendocrine component of the HPA axis during exercise.

Exercise training alters effect of high-fat feeding on the ACTH stress response in pigs.

Eating and physical activity behaviors influence neuroendocrine output. The purpose of this study was to test, in an animal model of diet-induced cardiovascular disease, the effects of high-fat feeding and exercise training on hypothalamo-pituitary-adrenocortical (HPA) axis activity. We hypothesized that a high-fat diet would increase circulating free fatty acids (FFAs) and decrease the adrenocorticotropic hormone (ACTH) and cortisol response to an acute stressor.

Sex difference in link between interleukin-6 and stress.

Inflammation contributes to disease development, and the neuroimmunoendocrine interface is a potential site of action for inflammatory products like IL-6 to affect health. Although plasma IL-6 can stimulate the activity of the hypothalamo-pituitary-adrenocortical (HPA) axis, the precise role, if any, for IL-6 in the HPA response to nonimmunological stressors is unclear. The purpose of this study was to test the hypothesis that IL-6 in the stalk median eminence (SME) can be directly involved in stimulating ACTH secretion in response to acute stress in female swine.

Induction of pulsatile secretion of leptin in horses following thyroidectomy.

Endocrine characteristics of Quarter Horse-type mares were determined during a 68 h feed deprivation and again in the same mares following surgical thyroidectomy (THX). A crossover experimental design was implemented, in which mares received brome hay available ad libitum (FED) or were food deprived (RES) for 68 h. Blood samples were collected every 20 min for 48 h, beginning 20 h after the onset of food deprivation.

Serial alterations in digital hemodynamics and endothelin-1 immunoreactivity, platelet-neutrophil aggregation, and concentrations of nitric oxide, insulin, and glucose in blood obtained from horses following carbohydrate overload.

Objective: To quantify changes in endothelium-derived factors and relate those changes to various aspects of digital hemodynamics during the prodromal stages of carbohydrate overload (CHO)-induced laminitis in horses.

Animals: 20 adult horses without abnormalities of the digit.

Procedures: Digital and jugular venous blood samples were collected at 1-hour intervals (for assessment of endothelin-1 [ET-1] immunoreactivity and measurement of glucose, insulin, and nitric oxide [NO] concentrations) or 4-hour intervals (CBC and platelet-neutrophil aggregate assessment) for 8 hours or 16 hours after induction of CHO-associated laminitis in horses treated with an ET-1 antagonist.

Modulation of leptin, insulin, and growth hormone in obese pony mares under chronic nutritional restriction and supplementation with ractopamine hydrochloride.

Horses fed beyond their nutritional requirement and that are physically inactive will develop obesity, which is often accompanied by insulin resistance and heightened risk of laminitis. The use of pharmacologic agents in combination with nutritional restriction may promote weight loss in obese horses unable to exercise because of laminitic pain. This study shows that reducing feed intake of brome grass hay to 75% of ad libitum intake in obese pony mares reduces body weight without induced exercise.

Glucocorticoids and laminitis in the horse.

The administration of exogenously administered GCs and syndromes associated with GC excess are both attended by increased risk for the development of laminitis in adult horses. However, there exists substantial controversy as to whether excess GCs cause laminitis de novo. If true, the pathogenesis of laminitis arising from the effects of GC excess is probably different from that associated with diseases of the gastrointestinal tract and endotoxemia.

Estrogen receptor-independent catechol estrogen binding activity: protein binding studies in wild-type, Estrogen receptor-alpha KO, and aromatase KO mice tissues.

Primary evidence for novel estrogen signaling pathways is based upon well-documented estrogenic responses not inhibited by estrogen receptor antagonists. In addition to 17beta-E2, the catechol estrogen 4-hydroxyestradiol (4OHE2) has been shown to elicit biological responses independent of classical estrogen receptors in estrogen receptor-alpha knockout (ERalphaKO) mice. Consequently, our research was designed to biochemically characterize the protein(s) that could be mediating the biological effects of catechol estrogens using enzymatically synthesized, radiolabeled 4-hydroxyestrone (4OHE1) and 4OHE2.

Factors regulating collagen synthesis and degradation during second-intention healing of wounds in the thoracic region and the distal aspect of the forelimb of horses.

Objective: To determine significant molecular and cellular factors responsible for differences in second-intention healing in thoracic and metacarpal wounds of horses.

Animals: 6 adult mixed-breed horses.

Procedure: A full-thickness skin wound on the metacarpus and another such wound on the pectoral region were created, photographed, and measured, and tissue was harvested from these sites weekly for 4 weeks.