Niacin-bound chromium increases life span in Zucker Fatty Rats

Repurposing effect of cardiovascular-metabolic drug to increase lifespan: a systematic review of animal studies and current clinical trial progress

With the increase in life expectancy, aging has emerged as a significant health concern. Due to its various mechanisms of action, cardiometabolic drugs are often repurposed for other indications, including aging. This systematic review analyzed and highlighted the repositioning potential of cardiometabolic drugs to increase lifespan as an aging parameter in animal studies and supplemented by information from current clinical trial registries. Systematic searching in animal studies was performed based on PICO: "animal," "cardiometabolic drug," and "lifespan." All clinical trial registries were also searched from the WHO International Clinical Trial Registry Platform (ICTRP). Analysis of 49 animal trials and 10 clinical trial registries show that various cardiovascular and metabolic drugs have the potential to target lifespan. Metformin, acarbose, and aspirin are the three most studied drugs in animal trials. Aspirin and acarbose are the promising ones, whereas metformin exhibits various results. In clinical trial registries, metformin, omega-3 fatty acid, acarbose, and atorvastatin are currently cardiometabolic drugs that are repurposed to target aging. Published clinical trial results show great potential for omega-3 and metformin in healthspan. Systematic Review Registration: crd.york.ac.uk/prospero/display_record.php?RecordID=457358, identifier: CRD42023457358.

Probing the Relationship Between Declining Renal Glomerular Filtration Over the Life Span and General Biological Aging: Does the Former Provide Means to Estimate the Latter?

While a consistent, gradual decline in the renal glomerular filtration rate (GFR) is a characteristic occurrence over the human life span, the exact pathophysiology behind this event remains unresolved. Evidence to date suggests that the endogenous glucose-insulin system could be involved at some level. Diabetic-induced nephropathy, one of the most prevalent chronic renal diseases, is closely linked to a severe form of insulin resistance (IR). Nevertheless, it is less certain that the ubiquitous milder forms of IR in nondiabetics ascribed customarily to routine, poor choices in diet and exercise management can over time diminish GFR and adversely influence other renal functions to any perceptible extent.

Baseline data for cross-sectional analyses were obtained from a cohort of healthy, nondiabetic volunteers (fasting blood glucose [FBG] ≤ 125 mg/dL) involved in prior clinical studies. Slope-based rather than threshold analyses were mainly employed. These measurements were applied for the most part to correlate age, FBG levels used as an estimate of IR activity, and systolic blood pressure (SBP) to a variety of metabolic parameters during aging with a primary focus on GFR.

Considering cause and effect, FBG and SBP correlate positively with the diminishing GFR over a major part of the life span. The decline in GFR begins somewhere around the mid-20s and coincides with key temporal increases in FBG and SBP levels.

A close time-based setting suggests that IR plays a prominent role in the declining GFR that occurs over the life span. This is perhaps due in part through deleterious effects of rising levels of insulin, glucose, and SBP individually or combined that are also popular proposed causative factors for human aging in general. On the philosophical side, the latter fact suggests that the declining GFR might provide a practical way to estimate the rate of overall human biological aging.

Correlating Circulating Vitamin D3 with Aspects of the Metabolic Syndrome and Nonalcoholic Fatty Liver Disease in Healthy Female Volunteers

Background: Significant inverse correlations between circulating vitamin D3 and the presence and strength of common clinical entities influenced by insulin resistance (IR) have been reported. Among these entities are common maladies such as the metabolic syndrome (MS) and nonalcoholic fatty liver disease (NAFLD). Since hypovitaminosis D3 is considered a common worldwide health disturbance, the consequences emanating from such relationships once soundly established might reasonably be ameliorated by vitamin replacement. Accordingly, a need exists for definitive confirmatory support for the existence of these linkages particularly in ordinary, relatively healthy individuals.Methodology: Many aspects of MS and NAFLD were examined in healthy females via linear regression analyses to determine significant correlations mainly using vitamin D3 and fasting blood glucose (FBG), the latter a surrogate for IR, as independent variables.Results: A descending linear regression between vitamin D3 and FBG did not reach full statistical significance, but a negative correlation of vitamin D3 with HbA1C was statistically significant and that with circulating insulin concentrations showed a downward statistical trend. These findings are consistent with previous ones by others suggesting an ameliorating effect of vitamin D3 on IR. Body weight, body mass index (BMI), and body fat correlated statistically significantly with vitamin D3 levels, as did systolic blood pressure. Again, these correlations were negative instead of positive unlike the case when FBG was the independent variable. The significant negative correlation of ALT with vitamin D3 was also consistent with previous reports that higher circulating vitamin D3 favorably influences the extent and intensity of NAFLD.Conclusions: Employing FBG as a surrogate for IR and ALT for status of NAFLD, linear correlations reasonably suggest that increasing circulating vitamin D3 can favorably influence the initial development of and/or strength of risk factors for MS including NAFLD in relatively fit females.

Circulating ALT Levels in Healthy Volunteers Over Life-Span: Assessing Aging Paradox and Nutritional Implications

Background: Two facts are generally recognized: (1) development of nonalcoholic fatty liver disease (NAFLD) is consistently linked to insulin resistance which has dietary implications and (2) circulating alanine aminotransferase (ALT) levels are reasonable markers predicting NAFLD status. In a recent cross-sectional study employing nondiabetic subjects, ALT values rose steadily within a normal range early in the life cycle but begin decreasing steadily around age 65 years.Objectives: Because of important nutritional implications, the association between ALT levels and aging in a significantly larger population of healthy volunteers was examined for corroborative purposes. A secondary goal was to gain further knowledge concerning mechanisms behind any age-related decline in ALT activity.Methods: Baseline data from over 10,000 physician-approved, nondiabetic subjects (age 21-84 years) of both genders who had volunteered for previous clinical investigations were assessed.Results: In this cross-sectional examination, the line of best fit (weighted) for average yearly circulating ALT levels displayed an upward surge from ages 21 to 64 years with a discernible steady downward decline around 65 years-mimicking earlier results. Examining linear lines of correlation in the younger and older age groups, the following calculations were determined: a significant positive slope for 21 to 64 years, r = 0.42, n = 44, p < 0.005, and a trending negative slope for 65 and beyond, r = -0.43, n = 20, p < 0.057. Using this same datum base, the correlations between age and fasting blood glucose (FBG) mimicked the ALT results by once more showing a similar upward rise in the younger and a steady decline the older group of volunteers.Conclusions: A paradoxical downward age-related (≥ 65 years) decline of circulating ALT coinciding with a comparable steady decrease in FBG levels was replicated in a larger population of volunteers. The close association of these two chemistries along with other findings suggest that altered glucose-insulin metabolism may participate via "survivor bias" in the ubiquitously found age-related decline of serum ALT-suggesting that nutritional measures could advance optimal health over the life-span.

Reflecting on Concepts Relevant to Contemplating the Relationships Between Glucose-Insulin Perturbations, Nutrition, and Aging

Background: Medical professionals attribute a crucial role in the development of several age-related, chronic health maladies to glucose-insulin perturbations - particularly, discernible insulin resistance (IR). However, little information is available concerning the degree to which relatively minor changes in IR participate over time in overall aging population, e.g., when circulating glucose and/or insulin concentrations are consistently within the higher end of normally accepted ranges. Objective: Obtaining precise knowledge is important, because proper nutritional management has the distinct capability of ameliorating the consequences. Methods: Five key concepts are suggested to underpin current thinking as to the applicable mechanisms and these are (1) the practical use of fasting blood glucose (FBG) levels as an estimate of IR, (2) the potential role of even slightly aberrant insulin regulation over time in the aging process, (3) the implementation of "continuum of risks" rather than checkpoints in considering prevention, (4) the presence and meaning of an aging paradox discovered in a recent study, and (5) the importance nutritional considerations in the "deadly triangle" as key factors in aging. Conclusions: Maintaining relatively low levels of FBG representing IR during aging via nutritional means has the potential to deliver a longer, more healthful lifespan as well as ameliorate many adverse manifestations of aging.

Effects of nutritional components on aging

Nutrients including carbohydrates, proteins, lipids, vitamins, and minerals regulate various physiological processes and are essential for the survival of organisms. Reduced overall caloric intake delays aging in various organisms. However, the role of each nutritional component in the regulation of lifespan is not well established. In this review, we describe recent studies focused on the regulatory role of each type of nutrient in aging. Moreover, we will discuss how the amount or composition of each nutritional component may influence longevity or health in humans.

Is chromium pharmacologically relevant?

Recent research, combined with reanalysis of previous results, has revealed that chromium can no longer be considered an essential trace element. Clinical studies are ambiguous at best as to whether Cr has a pharmacological effect in humans. Observed effects of Cr on rodent models of insulin resistance and diabetes are best interpreted in terms of a pharmacological role for Cr. Studies on the effects of Cr on rat models of diabetes are reviewed herein and suggest Cr increases insulin sensitivity in peripheral tissues of the rodent models. The lack of effects in human studies may stem from humans receiving a comparably smaller dose than the rodent models. However, given the different responses to Cr in the rodent models, humans could potentially have different responses to Cr.