β-Adrenergic stimulated lipolysis in pony adipocytes is exclusively via a β2-subtype and is not affected by lactation

Rutland C. Equine Stress: Neuroendocrine Physiology and Pathophysiology

This review presents new aspects to understanding the neuroendocrine regulation of equine stress responses, and their influences on the physiological, pathophysiological, and behavioral processes. Horse management, in essence, is more frequently confirmed by external and internal stress factors, than in other domestic animals. Regardless of the nature of the stimulus, the equine stress response is an effective and highly conservative set of interconnected relationships designed to maintain physiological integrity even in the most challenging circumstances (e.g., orthopedic injuries, abdominal pain, transport, competitions, weaning, surgery, and inflammation). The equine stress response is commonly a complementary homeostatic mechanism that provides protection (not an adaptation) when the body is disturbed or threatened. It activates numerous neural and hormonal networks to optimize metabolic, cardiovascular, musculoskeletal, and immunological functions. This review looks into the various mechanisms involved in stress responses, stress-related diseases, and assessment, prevention or control, and management of these diseases and stress. Stress-related diseases can not only be identified and assessed better, given the latest research and techniques but also prevented or controlled.

Retrospective evaluation of the association between admission blood glucose and l-lactate concentrations in ponies and horses with gastrointestinal disease (2008-2016): 545 cases

OBJECTIVES

A recent study described increased l-lactate concentrations in ponies with gastrointestinal disease compared to horses, but blood glucose (BG) concentrations were not considered. The study tested the hypothesis that BG and l-lactate concentrations are correlated in horses and ponies with gastrointestinal disease and that BG concentrations, not equid type (pony vs horse), are an independent predictor of L-lactate concentrations. It was further hypothesized that equid type was an independent predictor of BG concentrations.

DESIGN

Retrospective study 2008-2016.

SETTING

University teaching hospital.

ANIMALS

Admission data from 545 animals (384 horses and 161 ponies) with gastrointestinal disease.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data collected included signalment, clinicopathological findings on admission, and nature and location of the gastrointestinal lesion (strangulating vs non-strangulating and large vs small intestinal lesion). The association between admission blood l-lactate concentrations, equid type (pony or horse) and BG concentrations was investigated in a multivariable model. Admission l-lactate and BG concentrations were strongly correlated (n = 522; r = 0.63; P < 0.001). Ponies had significantly higher l-lactate (2.7 mmol/L (0.5-18.0 mmol/L) vs 1.4 mmol/L (0.3-19 mmol/L); P < 0.001) and BG concentrations than horses (8.4 mmol/L (4.2-24.4 mmol/L); 151 mg/dL (76-439 mg/dL) vs 6.9 mmol/L (3.4-26.8 mmol/L); 124 mg/dL (61-482 mg/dL); P < 0.001). In the multivariable analysis, l-lactate concentrations were significantly and positively associated with admission BG concentrations in all animals and also with equid type. For each millimole per liter (18 mg/dL) increase in BG, l-lactate concentrations increased by 7.9% (5.9, 9.9); P < 0.001. In comparison to ponies, l-lactate concentrations were decreased by 27.7% (37.4, 16.5); P < 0.001 in horses. Admission BG concentrations were significantly and positively associated with l-lactate concentrations in all animals. For each millimole per liter increase in l-lactate concentration, BG concentration increased by 6.2% (4.7, 7.6; P < 0.001). Admission BG concentrations were not associated with equid type.

CONCLUSION

Admission BG concentrations and equid type are independent predictors of blood l-lactate concentrations in equids with gastrointestinal disease, but their relationship requires further investigation.

Characteristics and multipotency of equine dedifferentiated fat cells

Dedifferentiated fat (DFAT) cells have been shown to be multipotent, similar to mesenchymal stem cells (MSCs). In this study, we aimed to establish and characterize equine DFAT cells. Equine adipocytes were ceiling cultured, and then dedifferentiated into DFAT cells by the seventh day of culture. The number of DFAT cells was increased to over 10 million by the fourth passage. Flow cytometry of DFAT cells showed that the cells were strongly positive for CD44, CD90, and major histocompatibility complex (MHC) class I; moderately positive for CD11a/18, CD105, and MHC class II; and negative for CD34 and CD45. Moreover, DFAT cells were positive for the expression of sex determining region Y-box 2 as a marker of multipotency. Finally, we found that DFAT cells could differentiate into osteogenic, chondrogenic, and adipogenic lineages under specific nutrient conditions. Thus, DFAT cells could have clinical applications in tissue regeneration, similar to MSCs derived from adipose tissue.