High-molecular-weight adiponectin levels in healthy, community-dwelling, elderly Japanese volunteers: a 5-year prospective observational study

Mobility performance impacts mortality risk in community-dwelling healthy older adults in Japan: a prospective observational study

BACKGROUND

The timed up and go (TUG) test assesses balance and mobility performance.

AIM

This study aims to investigate the association between TUG time and mortality in Japanese older persons and to clarify possible moderation effects on mortality and TUG time.

METHODS

In all, 874 participants who were ≥ 65 years of age completed the TUG test and had their anthropometric parameters and physical functions measured. We investigated the association between all-cause mortality and TUG using a Cox regression model that included confounders, and explored the time associated with mortality using a restricted cubic spline. We also performed subgroup analyses to explore whether age, sex, and body mass index (BMI) affected the relationship between TUG time and mortality.

RESULTS

The median age and mean follow-up period were 74 and 8.5 years, respectively. Median TUG time was 7.4 s and the prevalence of mortality was 25.7%. TUG time in one second was positively associated with an increased risk of total mortality [hazard ratio (HR): 1.054 (1.016-1.093); P = 0.005] in the Cox regression model. The positive association of mortality and TUG time was present when the TUG was over 10.5 s in the restricted cubic spline curve. Older age (75 years or older) moderated the relationship between TUG time and mortality [P_interaction = 0.096].

CONCLUSION

This study demonstrates that TUG time is associated with all-cause mortality in Japanese older adults.

Adiponectin gene polymorphisms associated with diabetes mellitus: A descriptive review

Diabetes is currently a growing concern of the age. Prevention and treatment of diabetes is a global health priority. Adiponectin is an adipocyte derived protein hormone that enhances insulin sensitivity and ameliorates diabetes by enhancing fatty acid oxidation and glucose uptake in skeletal muscle and reducing glucose production in the liver. Low serum adiponectin concentrations are associated with diabetes, central obesity, insulin resistance and metabolic syndrome. Adiponectin gene is located on chromosome 3q27, where a locus of susceptibility to diabetes was mapped. Several cross-sectional studies showed that single nucleotide polymorphisms (SNPs) in adiponectin gene (ADIPOQ) were associated with diabetes. SNPs in ADIPOQ help in assessing the association of common variants with levels of adiponectin and the risk of diabetes. Two common SNPs, rs2241766 and rs1501299, have been linked significantly to type 1 diabetes mellitus which endow the world with a block of haplotypes. Experimental evidences also suggest that rs1501299, rs2241766, rs266729, rs17366743, rs17300539, rs182052, rs822396, rs17846866, rs3774261 and rs822393 are significantly associated with type 2 diabetes mellitus which is the predominant form of the disease. In addition, rs2241766 and rs266729 are extensively associated with gestational diabetes, a condition that develops in women during pregnancy. Therefore not a particular single mutation but a number of SNPs in adiponectin gene could be a risk factor for developing diabetes among the individuals worldwide. This study firmly suggests that adiponectin plays a crucial role in the pathogenesis of type 1, type 2 and gestational diabetes mellitus.

Obesity-induced cognitive impairment in older adults: a microvascular perspective

Over two-thirds of individuals aged 65 and older are obese or overweight in the United States. Epidemiological data show an association between the degree of adiposity and cognitive dysfunction in the elderly. In this review, the pathophysiological roles of microvascular mechanisms, including impaired endothelial function and neurovascular coupling responses, microvascular rarefaction, and blood-brain barrier disruption in the genesis of cognitive impairment in geriatric obesity are considered. The potential contribution of adipose-derived factors and fundamental cellular and molecular mechanisms of senescence to exacerbated obesity-induced cerebromicrovascular impairment and cognitive decline in aging are discussed.

Mobility performance among healthy older adults eligible for long-term care in Japan: a prospective observational study

BACKGROUND AND AIM

Disability is an important health problem among older individuals, prompting the need for long-term care. Age-related disability is usually associated with mobility; however, little is known about the association between mobility and long-term care. Therefore, this study aimed to clarify the association between the timed up and go (TUG) test measuring mobility and long-term care eligibility.

PATIENTS AND METHODS

We analyzed follow-up data of 489 community-dwelling healthy older adults (≥ 65 years) who participated in a prospective observational study. They were divided into certified (59 participants) and uncertified (430 participants) groups based on long-term care eligibility. Anthropometric and physical functioning measures included the TUG test and hand grip strength (HGS), among others. These measures were compared between groups and a multivariate logistic regression analysis evaluated the association between the TUG test times and long-term care eligibility.

RESULTS

Participants' minimum follow-up period was 4 years. TUG times were significantly slower (median time: 7.4 vs. 8.3 s, p < 0.001) and HGS and knee-extension strength significantly lower in the certified group than in the uncertified group. The logistic regression analysis showed that TUG times were significantly associated with long-term care eligibility after adjusting for potential covariates. In addition, mediation analysis showed that 53.1% of the association between HGS and long-term care eligibility was mediated through TUG times.

CONCLUSION

The TUG test was associated with long-term care eligibility among healthy older adults, implying that the test may be helpful as a predictor for the early determination of dependence in old age.

Involvement of adiponectin in age-related increases in tear production in mice

Common age-related changes in the human eye contribute to the development of dry eye, including decreases in aqueous tear production. Although the infiltration of lymphocytes into the lacrimal glands occurs with age, age-related increases in tear production have also been observed in mice; however, the mechanisms underlying this increase remain unclear. We herein demonstrated that increases in tear production were not dependent on body weight gain or systemic conditions, such as insulin resistance, using aged mice and high-fat diet-fed mice. The results obtained also showed that senescence-associated T (SA-T) cells accumulated in the lacrimal glands of aged mice, particularly females. Expression levels of the nuclear transcription factor peroxisome proliferator-activated receptor-γ (PPARγ) in whole lacrimal glands and epithelial cells isolated from lacrimal glands were significantly higher in aged mice than in young mice. The expression levels of adiponectin and one of its receptors, AdipoR2, also increased in the lacrimal glands of aged mice, but not in those of high-fat diet-fed mice. Collectively, the present results indicate that PPARγ and adiponectin-mediated signaling contribute to age-related increases in tear production in mice and have potential as therapeutic targets for the treatment of dry eye in humans.

Adiponectin Receptor gene Polymorphisms are Associated with Kidney Function in Elderly Japanese Populations

Aim: Adiponectin exhibits its biological effects through adiponectin receptors (AdipoR1 and AdipoR2), which are distributed in the kidneys, and activation of those receptors could prevent or ameliorate diabetic nephropathy. This study aimed to evaluate the associations between AdipoR single nucleotide polymorphisms (SNPs) and kidney function in an elderly Japanese population.

Methods: A total of 271 elderly Japanese volunteers underwent anthropometric and laboratory tests (cystatin C-based eGFR and total and high molecular weight adiponectin levels at baseline and a follow-up visit). Genotype data were obtained for the selected 7 and 5 AdipoR1 and AdipoR2 SNPs, respectively.

Results: In a cross-sectional analysis at baseline, we found a significant association between the AdipoR2 SNP rs12230440 and kidney function; eGFRcys tended to increase as the number of carriers of T alleles increased after adjustment for covariates and Bonferroni correction, although the association of the SNP and annual eGFR decline could not be identified in the longitudinal data. Regarding the variants rs16850797, rs11061925, and rs10773983, each of the allele G, allele C, and allele G showed nominally significant associations with higher eGFRcys. However, this failed to reach significance after Bonferroni correction.

Conclusion: Here, an AdipoR2 SNP was associated with kidney function, suggesting that the effects of this polymorphism on adiponectin receptor may affect kidney function in the elderly Japanese population.

Adiponectin is not associated with renal function decline in community-dwelling elderly adults

Adiponectin secreted by adipocytes plays an important role in the regulation of glucose and fatty acid metabolism. Contrary to findings in patients with chronic kidney disease (CKD), no prospective data about the association of serum adiponectin with renal function decline in the general population have yet appeared. Our objective was to analyze the relationship of total and high molecular weight (HMW) adiponectin with renal function decline as measured by cystatin C in community-dwelling elderly adults without moderate or severe CKD.In a prospective observational analysis, a total of 216 healthy elderly volunteers with eGFRcys ≥60 mL/min/1.73 m underwent anthropometric and laboratory tests at baseline and at follow-up visits. A subgroup with serum samples collected 5 years apart was further analyzed.There were no differences in either total or HMW adiponectin level between subjects subsequently undergoing rapid renal function decline and subjects with normal physiologic renal function decline (P = .71, P = .81). On univariate linear regression, neither total nor HMW adiponectin were associated with annual renal function decline (β = -0.23; P = .71, β = -0.057; P = .90). Multivariate analysis did not show a significant contribution of either total or HMW adiponectin to annual renal function decline (β = -0.50; P = .46, β = 0.01; P = .98). In the logistic regression analysis, we did not observe any statistically significant association of serum adiponectin levels with rapid renal function decline or incidence of CKD.Contrary to findings in populations with CKD, neither total nor HMW adiponectin had a substantial association with renal function decline in an elderly population with eGFRcys ≥60 mL/min/1.73 m. Our results and conclusions should not be extrapolated to subjects with other characteristics.