Novel neuropeptide may hold clues to the risk of obesity and diabetes

Obesity is a chronic, multidimensional problem which is being increasingly seen in younger patients. Besides obesity is becoming an epidemic in industrialized countries and is continuing to increase in developing countries worldwide. And obesity is a major health epidemic that affects millions of people worldwide.

Diabetes is a chronic disease that occurs either when the pancreas does not produce enough insulin (a hormone that regulates blood sugar) or when the body cannot effectively utilize the insulin it produces. Diabetes mellitus can be classified into two main types: type 1 (previously known as insulin-dependent) and type 2 (formerly called non-insulin-dependent or adult-onset). Type 1 diabetes was characterized by absolutely lack of the production and secretion of insulin, due to destruction of the insulin producing pancreatic β-cells. Patients with type I diabetes require daily administration of insulin. Type 2 Diabetes, which was characterized by insulin resistance and the body’s inability to secrete enough insulin. 90% of diabetes cases belong to this type.

Obesity is associated with numerous co-morbidities and any treatment for obesity is likely to be required long term; the therapeutic window of any new pharmacotherapy must therefore be closely scrutinized before approval. The classical neurotransmitter and endocannabinoid systems are widespread within the CNS, reflecting multiple physiological roles, and manipulation of these systems carries the risk of unwanted effects. Neuropeptides can act in the CNS as neuromodulators of the classical neurotransmitter systems. Typically expressed by discrete clusters of neurons, they project diffusely throughout the CNS, and modulate postsynaptic neurons in a way that can alter their responses to classical neurotransmitters. All CNS neurons that produce neuromodulators also release classical neurotransmitters, for example, neuropeptide Y (NPY) and galanin regulate central adrenergic transmission within the hypothalamus.

Levels of circulating spexin, a newly identified neuropeptide, decrease with age and may predict risk for obesity and diabetes, according to findings from a cross-sectional study of healthy Chinese women. Research suggests that spexin is associated with satiety, gastrointestinal motility, energy metabolism, and glucose and lipid metabolism. Several animal studies have investigated the biological functions of spexin in fish and rodents; however, the clinical significance of the neuropeptide remains largely unknown.

Zhao-xiang Bian, MD, PhD, director of the Hong Kong Chinese Medicine Clinical Study Centre at Hong Kong Baptist University, China, and colleagues analyzed data from 68 women recruited from the clinical division at the School of Chinese Medicine at Hong Kong Baptist University (median age, 39 years; median BMI, 20.5 kg/m²). Researchers measured serum spexin levels via an enzyme-linked immunosorbent assay, as well as fasting glucose, total cholesterol, triglycerides, alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea and creatinine. Researchers stratified participants by spexin tertiles and performed two-way analysis of variance (ANOVA) to test the main and interaction effects of age and spexin on BMI, fasting glucose and triglycerides.

“In healthy women, circulating spexin levels decrease with age and negatively correlate with BMI, fasting glucose and triglycerides,” Bian said. “Meanwhile, no interaction effects of spexin and age on BMI and fasting glucose were found. Spexin may independently predict the risk of high BMI and high fasting glucose.” Bian said the close correlation between spexin and age suggests the possible role of the peptide in aging-related functions and disorders, which need to be further explored by additional clinical studies and mechanistic investigations to elucidate the role of spexin in aging.