Effects of short-term treatment with orlistat on growth hormone/insulin-like growth factor-I axis in obese post-menopausal women

Strategies for Therapeutic Amelioration of Aberrant Plasma Zn2+ Handling in Thrombotic Disease: Targeting Fatty Acid/Serum Albumin-Mediated Effects

The initiation, maintenance and regulation of blood coagulation is inexorably linked to the actions of Zn²⁺ in blood plasma. Zn²⁺ interacts with a variety of haemostatic proteins in the bloodstream including fibrinogen, histidine-rich glycoprotein (HRG) and high molecular weight kininogen (HMWK) to regulate haemostasis. The availability of Zn²⁺ to bind such proteins is controlled by human serum albumin (HSA), which binds 70–85% of plasma Zn²⁺ under basal conditions. HSA also binds and transports non-esterified fatty acids (NEFAs). Upon NEFA binding, there is a change in the structure of HSA which leads to a reduction in its affinity for Zn²⁺. This enables other plasma proteins to better compete for binding of Zn²⁺. In diseases where elevated plasma NEFA concentrations are a feature, such as obesity and diabetes, there is a concurrent increase in hypercoagulability. Evidence indicates that NEFA-induced perturbation of Zn²⁺-binding by HSA may contribute to the thrombotic complications frequently observed in these pathophysiological conditions. This review highlights potential interventions, both pharmaceutical and non-pharmaceutical that may be employed to combat this dysregulation. Lifestyle and dietary changes have been shown to reduce plasma NEFA concentrations. Furthermore, drugs that influence NEFA levels such as statins and fibrates may be useful in this context. In severely obese patients, more invasive therapies such as bariatric surgery may be useful. Finally, other potential treatments such as chelation therapies, use of cholesteryl transfer protein (CETP) inhibitors, lipase inhibitors, fatty acid inhibitors and other treatments are highlighted, which with additional research and appropriate clinical trials, could prove useful in the treatment and management of thrombotic disease through amelioration of plasma Zn²⁺ dysregulation in high-risk individuals.

The complex relationship between obesity and the somatropic axis: the long and winding road

Despite the considerable body of evidence pointing to a possible relationship between the state of the adipose tissue depots and regulation of the somatotropic axis, to date the relationship between obesity and low growth hormone (GH) status remains incompletely understood. The low GH status in obesity is mainly considered as a functional condition, largely reversible after a sustained weight loss. Moreover, due to the effects of the adiposity on the regulation of the somatotropic axis, the application of GH stimulation tests in obesity may also lead to an incorrect diagnosis of GH deficieny (GHD). On the other hand, similar to patients with GHD unrelated to obesity, the reduced GH response to stimulation testing in obese individuals is associated with increased prevalence of cardiovascular risk factors and detrimental alterations of body composition, which contribute to worsening their cardio-metabolic risk profile. In addition, the reduced GH secretion may result in reduced serum insulin-like growth factor (IGF)-1 levels, and the concordance of low peak GH and low IGF-1 identifies a subset of obese individuals with high cardiovascular risk. Furthermore, after weight loss, the normalization of the GH response and IGF-1 levels may or may not occur, and in patients undergoing bariatric surgery the persistence of a low GH status may affect the post-operative outcomes. In this review, we will provide an overview on some clinically relevant aspects of the relationship between obesity axis and the somatotropic axis in the light of the recently published research.

Drug treatment of obesity in the cardiovascular patient

PURPOSE OF REVIEW

The incidence of obesity and its associated comorbidities have significantly increased over the years with adverse health and financial consequences for society. Lifestyle changes are essential for the prevention and treatment of obesity but their benefit appears limited as inadequate and nonsustained weight loss results have been reported. Pharmacotherapy is frequently advocated as part of a weight loss strategy. In this review, we will discuss the antiobesity drugs with Food and Drug Administration approval and their cardiovascular implications.

RECENT FINDINGS

Orlistat (Xenical) remains the single monotherapy that has approval in Europe. Topiramate (Topamax) and phentermine have long been approved in the United States, whereas lorcaserin and the extended release combination of phentermine with topiramate have recently gained approval. The development of single peptides targeting gut hormones or other host signals related to obesity may represent promising therapeutic options.

SUMMARY

Despite the recent failures of a number of antiobesity drugs, the pharmacotherapy of obesity is progressing rapidly. Treating the obese cardiovascular patient has proven challenging. Efficacy, safety and the sustainability of weight loss are key areas of focus in drug development strategies.