Molecular network of obesity: what does it promise for pharmacotherapy?

Estrogen Deficiency and the Origin of Obesity during Menopause

Sex hormones strongly influence body fat distribution and adipocyte differentiation. Estrogens and testosterone differentially affect adipocyte physiology, but the importance of estrogens in the development of metabolic diseases during menopause is disputed. Estrogens and estrogen receptors regulate various aspects of glucose and lipid metabolism. Disturbances of this metabolic signal lead to the development of metabolic syndrome and a higher cardiovascular risk in women. The absence of estrogens is a clue factor in the onset of cardiovascular disease during the menopausal period, which is characterized by lipid profile variations and predominant abdominal fat accumulation. However, influence of the absence of these hormones and its relationship to higher obesity in women during menopause are not clear. This systematic review discusses of the role of estrogens and estrogen receptors in adipocyte differentiation, and its control by the central nervous systemn and the possible role of estrogen-like compounds and endocrine disruptors chemicals are discussed. Finally, the interaction between the decrease in estrogen secretion and the prevalence of obesity in menopausal women is examined. We will consider if the absence of estrogens have a significant effect of obesity in menopausal women.

Ingestion-controlling network: what's language got to do with it?

The prevalence of obesity has increased dramatically worldwide, whereas the types of treatment and their efficacy have not substantially changed over the last two decades. Additionally, drugs used to control weight gain could occasionally create untoward effects in cardiovascular functions, as well as in behaviors, memory, sleep, and emotions because the molecular machinery responsible for ingestion control is interconnected with or shared by the above domains. How each group of drugs preserves the privacy of its message in the mutual network is not fully understood. In the present essay, the graph theory approach was used to explore some aspects of molecular signaling as though they were a 'language'. Its emphasis is on 'molecular polysemy', a term that refers to the ability of biomolecules to be used like words in natural languages more than one-way. This has physiological and clinical implications, in particular when planning drug designs with "specially engineered shotgun loads" that target a combination of biomolecules that assure a better therapeutic outcome without causing deficits in connected but patho-physiologically irrelevant bystanders.

Genetic variation in the hypothalamic pathways and its role on obesity

Over recent decades, the prevalence of obesity has increased dramatically worldwide. Although this epidemic is mainly attributable to modern (western) lifestyle, multiple twin and adoption studies indicate the significant role of genes in the individual's predisposition to becoming obese. As the hypothalamus plays a central role in controlling body weight, its regulatory circuits may represent a crucial system in the pathogenesis of the disorder. Genetic variations in genes in the hypothalamic pathways may therefore contribute to the susceptibility for obesity in humans and animals. We summarize current knowledge on the physiological role of the hypothalamus in body-weight regulation and review genetic studies on the hypothalamic candidate genes in relation to obesity. Together, data from functional and genetic studies as well as the new, common, obesity loci identified in genome-wide association scans support an important role for the hypothalamic genes in predisposing to obesity. However, findings are still inconclusive for many candidate genes. To improve our understanding of the genetic architecture of common obesity, we suggest that specific obesity phenotypes should be considered and different analytical approaches used. Such studies should consider multiple genes from the same physiological pathways, together with environmental risk factors.

The 'Tyranny of choices' in the ingestion-controlling network

BACKGROUND

Currently used antiobesity remedies offer only a modest weight reduction, and have untoward effects that can complicate treatment efforts. Motivated by the needs of the pharmacotherapy of obesity, the study explored the role of neuropeptide Y, leptin, and corticotrophin-releasing hormone.

METHOD

The study used Ingenuity Pathway Analysis which is a tool for automated discovery and visualization of molecular interactions.

RESULTS

In ingestion-controlling networks, neuropeptide Y, leptin, and corticotrophin-releasing hormone molecules are commonly combined into the units designated as 'maximal motifs'. The analysis of this triad allowed suggesting that maximal motifs are not more than a compendium of admission rules and transmission alternatives of their nodes catalogued in the dataset. Nonetheless, these options seem to endow them with the flexibility needed to respond dynamically as a functional unit to changing internal (metabolic) conditions or environmental challenges.

CONCLUSION

Thus far, each peptide represents a separate target for pharmaceutical interventions (as judged by US patents scanned). The study concludes with predictions regarding designs of 'multitargeted' antiobesity agents since only by hitting a combination of targets can an appropriate therapeutic effect be achieved.

Pharmacotherapy for eating disorders and obesity

Anorexia nervosa and bulimia nervosa are significant mental health problems in the adolescent population; however, there are no medications approved by the FDA for the treatment of adolescents with either of these disorders. Many medications are used off label for both the symptoms of eating disorders and their co-morbid conditions, particularly SSRIs and atypical anti-psychotics. The dosing, side effect profile, and long term effects of these medications in children and adolescents is unclear. Binge eating disorder, night eating syndrome, and sleep-related eating disorder often are associated with over-weight in adolescents. There are various pharmacological approaches to the treatment of obesity in the adolescent population some of which have FDA approval. In the article the authors discuss pharmacological approaches to guide the treatment of eating disorders and obesity in the pediatric population, including risks of treatment, monitoring of potential side effects, and recent outcomes in the literature.

Ingenuity pathway analysis of clozapine-induced obesity

BACKGROUND

Lipid accretion is one of the major side effects of clozapine pharmacotherapy of schizophrenia that made clozapine into an interesting obesity drug model.

METHOD

Ingenuity Pathway Analysis (IPA) engine was used for core analysis and building the networks of weight regulation.

RESULTS

The examination of molecules that were selected into 'clozapine neighborhood' identified them as multifunctional signals that appear to orchestrate vascular and tissue functions plausibly implicated in adiposity side effect.

CONCLUSIONS

It is hypothesized that clozapine unmasks the functional and morphological phenotype of microvascular deficit that facilitates shunting nutrients from utilization toward storage.