Reproductive effects of irisin: Initial in vitro studies.

The recently discovered myo- and adipokine irisin affects insulin sensitivity in classical insulin target tissues (adipose tissue, skeletal muscle and liver), but the reproductive effects of this hormone, if any, remain largely unexplored. We hypothesized that irisin may have effects on the hypothalamic-pituitary-gonadal axis. To test this hypothesis, we used murine pituitary mPit12 and human ovarian granulosa cells. GnRH treatment resulted in significant (up to 2.5-fold, p<0.0005) and dose-dependent stimulation of LH production by the mPit12 cells. Treating these cells with irisin alone showed a significant stimulatory effect on LH synthesis only at irisin concentration of 100ng/ml. When used together with GnRH, irisin abolished the stimulatory effect of GnRH on LH production. Human ovarian granulosa cells were treated with insulin, irisin or a combination of both and the estradiol (E2) production was measured. Both insulin or irisin stimulated granulosa cell E2 production (1.4-fold, p<0.05 and 2.5-fold, p=0.0002, respectively), but when insulin and irisin were used in combination, this stimulatory effect on E2 production was abolished. We conclude that irisin may have reproductive axis effects in the pituitary and in the ovary. Further studies are needed to confirm these initial observations and to explore the mechanisms of irisin effects in the reproductive system.

A Case of Haemorrhagic Constrictive Pericarditis with Bilateral Pleural Effusions.

Presentation of pericardial disease is diverse, with the viral aetiology being the most common cause; however, when haemorrhagic pericardial effusion is present, these causes are narrowed to few aetiologies. We present a case of a young female of African descent who presented with diffuse abdominal pain and vomiting. Initial work-up showed pericardial effusion with impending echocardiographic findings of cardiac tamponade and bilateral pleural effusions. Procedures included a left video-assisted thoracoscopic surgery (VATS) with pericardial window. We consider that it is important for all physicians to be aware of not only typical presentation but also atypical and unusual clinical picture of pericardial disease.

Mechanisms of glucocorticoid-induced insulin resistance: focus on adipose tissue function and lipid metabolism.

Glucocorticoids (GCs) are critical in the regulation of the stress response, inflammation and energy homeostasis. Excessive GC exposure results in whole-body insulin resistance, obesity, cardiovascular disease, and ultimately decreased survival, despite their potent anti-inflammatory effects. This apparent paradox may be explained by the complex actions of GCs on adipose tissue functionality. The wide prevalence of oral GC therapy makes their adverse systemic effects an important yet incompletely understood clinical problem. This article reviews the mechanisms by which supraphysiologic GC exposure promotes insulin resistance, focusing in particular on the effects on adipose tissue function and lipid metabolism.