Adiponectin and Visceral Fat Tissue in Aging
Adiponectin is one of many signaling proteins generated by fat cells and has been showing up of late in research aimed at better understanding the ways in which the operation of metabolism determines the pace of aging. Visceral fat tissue is very active in terms of determining the operating state of your metabolism as a whole. Carrying more visceral fat is associated with worse long-term health and a shorter life expectancy, thought to be achieved through mechanisms such as raised levels of chronic inflammation. Studies in mice show that removing visceral fat extends life. Altered levels of adiponectin and related proteins may be one of the ways in which excess fat (adipose tissue) sabotages your health, but given the evidence from studies of the metabolism of long-lived individuals it's probably not a simple relationship:
Adipose tissue is an active metabolic organ secreting adipocytokines which are involved in the energy homeostasis and regulation of glucose and lipid metabolism. Aging is associated with fat redistribution, which is characterized by loss of peripheral subcutaneous fat and accumulation of visceral fat. Visceral adipose tissue is more involved in the development of metabolic diseases than subcutaneous adipose tissue.Aging also alters the function, proliferation, size, and number of adipose cells which leads to alterations in the secretion, synthesis and function of the adipocytokines. Adiponectin is an insulin sensitizing, anti-inflammatory, and antiathoregenic adipokine. Centenarians have higher adiponectin levels associated with longevity. However, in older individuals ‑ age 65 or more ‑ adiponectin is associated with higher mortality. Dysregulation of adiponectin in older individuals may be due to loss of function of circulating adiponectin or a response to increased inflammatory process. Longitudinal increase in adiponectin levels with aging rather than genetically high adiponectin levels may translate to increased mortality in older patients.
The adipocytokine leptin is traditionally viewed as a product of adipocytes that can exert endocrine effects. There have been conflicting reports of not only the effects of aging on leptin, but also the effects of leptin on age-related diseases including sarcopenia, Alzheimer's disease and cardiovascular diseases. Aging is also associated with resistance to leptin and/or to a decrease of receptors for this hormone.
"Studies in mice show that removing visceral fat extends life."
You mean rats. VF removal extended maximum lifespan in rats, as your links show.