Age-related changes in pancreatic islet cell gene expression

The age-dependent regulation of pancreatic islet landscape is fueled by a HNF1a-immune signaling loop

Animal longevity is a function of global vital organ functionality and, consequently, a complex polygenic trait. Yet, monogenic regulators controlling overall or organ-specific ageing exist, owing their conservation to their function in growth and development. Here, by using pathway analysis combined with wet-biology methods on several dynamic timelines, we identified Hnf1a as a novel master regulator of the maturation and ageing in the adult pancreatic islet during the first year of life. Conditional transgenic mice bearing suboptimal levels of this transcription factor in the pancreatic islets displayed age-dependent changes, with a profile echoing precocious maturation. Additionally, the comparative pathway analysis revealed a link between Hnf1a age-dependent regulation and immune signaling, which was confirmed in the ageing timeline of an overly immunodeficient mouse model. Last, the global proteome analysis of human islets spanning three decades of life largely backed the age-specific regulation observed in mice. Collectively, our results suggest a novel role of Hnf1a as a monogenic regulator of the maturation and ageing process in the pancreatic islet via a direct or indirect regulatory loop with immune signaling.

Management of Hyperglycemia in Older Adults with Type 2 Diabetes

The increasing incidence of type 2 diabetes in the general population as well as enhanced life expectancy has resulted in a rapid rise in the prevalence of diabetes in the older population. Diabetes causes significant morbidity and impairs quality of life. Managing diabetes in older adults is a daunting task due to unique health and psychosocial challenges. Medical management is complicated by polypharmacy, cognitive impairment, urinary incontinence, injurious falls, and persistent pain. Health care providers now have several traditional and contemporary pharmacologic agents to manage diabetes. Avoidance of hypoglycemia is critical; however, evidence-based guidelines are lacking due to the paucity of clinical trials in older adults. For many in this population, maintaining independence is more important than adherence to published guidelines to prevent diabetes complications. The goal of diabetes care in older adults is to enhance the quality of life without subjecting these patients to intrusive and complicated interventions. Recent technological advancements such as continuous glucose monitoring systems can have crucial supplementary benefits in the geriatric population.

Evidence-Based Management of Diabetes in Older Adults

The number of older adults with diabetes is rapidly increasing worldwide. A variety of factors contribute to the age-related increase in the incidence of diabetes. The lack of empiric evidence in the field has limited the management guidelines to mostly expert opinion. Given uncertainty over the rate at which to lower blood glucose levels and the optimal method of doing so, the goals of diabetes control in older people must be individualized. If the patient requires insulin therapy, the newer insulins, with their improved pharmacodynamic consistency and reduced risk of hypoglycemia, should be preferred. Several oral agents are preferable for people with sufficient endogenous insulin because they do not cause hypoglycemia when used as monotherapy. Some of these oral agents have been found to have cardioprotective effects. Older people with diabetes also require management of the other risk factors for cardiovascular disease, with antihypertensive drugs, cholesterol-lowering agents and low-dose aspirin. However, the precise targets for blood pressure control and low-density lipoprotein (LDL) cholesterol levels continue to evolve as more data become available. Diabetes care in older adults should focus on enhancing the individual's quality of life rather than trying to normalize blood glucose levels or reach predetermined blood pressure and LDL cholesterol targets.

Drug therapy of postprandial hyperglycaemia

It is widely accepted that the most challenging goal in the management of patients with diabetes mellitus is to achieve blood glucose levels as close to normal as possible. In general, normalising postprandial blood glucose levels is more difficult than normalising fasting hyperglycaemia. In addition, some epidemiological studies suggest that postprandial hyperglycaemia (PPHG) or hyperinsulinaemia are independent risk factors for the development of macrovascular complications of diabetes mellitus. Recently, several drugs with differing pharmacodynamic profiles have been developed which target PPHG. These include insulin lispro, amylin analogues, alpha-glucosidase inhibitors and meglitinide analogues. Insulin lispro has a more rapid onset of action and shorter duration of efficacy compared with regular human insulin. In clinical trials, the use of insulin lispro was associated with improved control of PPHG and a reduced incidence of hypoglycaemic episodes. Repaglinide, a meglitinide analogue, is a short-acting insulinotropic agent which. when given before meals, stimulates endogenous insulin secretions and lowers postprandial hyperglycaemic excursions. Both insulin lispro and repaglinide are associated with postprandial hyperinsulinaemia. In contrast, amylin analogues reduce PPHG by slowing gastric emptying and delivery of nutrients to the absorbing surface of the gut. Alpha-Glucosidase inhibitors such as acarbose, miglitol and voglibose also reduce PPHG primarily by interfering with the carbohydrate-digesting enzymes and delaying glucose absorption. With the availability of agents which preferentially reduce postprandial blood glucose excursions, it is now possible to achieve glycaemic goals in a larger proportion of individuals with diabetes mellitus.