Association between serum interleukin-6 and frailty in older men: cross-sectional data

Aging-Related CYP3A Functional Changes in Chinese Older Patients: New Findings from Model-Based Assessment of Amlodipine

Aging-related alterations in hepatic enzyme activity, particularly of the CYP3A, significantly impact drug efficacy and safety in older adults, making it essential to understand how aging affects CYP function for optimal drug therapy. The exogenous probe substrate method, a minimally invasive approach to assess liver metabolic enzyme activity in vivo, is effective in studying these changes. Amlodipine being extensively metabolized (> 90%) in the liver, primarily via cytochrome P450 enzyme CYP3A was selected as a probe to investigate and quantify the factors affecting the aging-related changes of CYP3A in the Chinese older population. Amlodipine concentration data were collected from an ongoing noninterventional clinical study conducted at Peking University Third Hospital. A physiologically-based pharmacokinetic modeling approach, grounded in population pharmacokinetic (PPK) analysis, was employed to physiologically quantify the aging-related changes in CYP3A function. A total of 132 amlodipine concentrations from 69 patients were obtained from the clinical study. PPK analysis shows that frailty phenotype but not age is a significant influence and frail patients have 37% greater plasma amlodipine exposure than nonfrail patients. This difference in CYP3A function may be attributed to a 63.2% lower CYP3A relative abundance in the frail patients, compared with that in the nonfrail patients. In the context of dose selection for older adults, focusing on frailty rather than chronological age should be recognized as a more relevant approach, because frailty might more accurately reflect the individual's biological age. Our study suggested a need to shift the research focus from chronological age to biological age.

Nutritional and inflammation factors associated with current frailty level and effect of co-morbidities on the progression of frailty

AIM

Frailty is defined as extreme vulnerability, a syndrome that exposes the individual to a higher risk of disability. While risk factors for frailty have been gradually uncovered, the full identification of biochemical factors and co-morbidities influencing frailty remains incomplete.

METHODS

Cross-sectional and longitudinal analyses were performed to elucidate the risk factors for the prevalence and progression of frailty. The study included 1035 Japanese female outpatients. At baseline, biochemical markers were measured. Co-morbidities included diabetes mellitus, dyslipidemia, hypertension, vertebral osteoarthritis, and osteoporosis. Frailty levels were assessed using frailty scores ranging from 0 to 5. Prevalence of frailty was judged by a score of 3 or above, and progression was judged by an increase in the frailty score during the observation period. Multiple regression analysis was used for the cross-sectional analysis, and the Cox hazard model was used for the longitudinal analysis.

RESULTS

Of the 1035 selected participants, 212 were diagnosed with frailty. Advanced age and log IL-6 and branched-chain amino acids (BCAA) levels were significant independent risk factors for frailty. Subjects were followed for 7.7 ± 5.9 years and progression was observed in 130 subjects. Older age, the absence of hyperlipidemia, the presence of osteoporosis, and lower frailty scores were identified as significant risk factors for frailty progression.

CONCLUSIONS

Inflammatory and nutritional markers exhibited significant associations with the current frailty status, whereas co-morbidities such as osteoporosis or hyperlipidemia emerged as independent risk or protective factors of future frailty progression. Geriatr Gerontol Int 2024; 24: 523-528.

RhoA/rho kinase pathway activation in age-associated endothelial cell dysfunction and thrombosis

The small GTPase RhoA and the downstream Rho kinase (ROCK) regulate several cell functions and pathological processes in the vascular system that contribute to the age-dependent risk of cardiovascular disease, including endothelial dysfunction, excessive permeability, inflammation, impaired angiogenesis, abnormal vasoconstriction, decreased nitric oxide production and apoptosis. Frailty is a loss of physiological reserve and adaptive capacity with advanced age and is accompanied by a pro-inflammatory and pro-oxidative state that promotes vascular dysfunction and thrombosis. This review summarises the role of the RhoA/Rho kinase signalling pathway in endothelial dysfunction, the acquisition of the pro-thrombotic state and vascular ageing. We also discuss the possible role of RhoA/Rho kinase signalling as a promising therapeutic target for the prevention and treatment of age-related cardiovascular disease.

Inflammatory markers and physical frailty: towards clinical application

Global population aging poses a tremendous burden on the health care system worldwide. Frailty is associated with decreased physical reserve and is considered an important indicator of adverse events in the older population. Therefore, there is growing interest in the early diagnosis and intervention of frailty, but the cellular mechanisms responsible for frailty are still not completely understood. Chronic inflammation is related to decreased physical function and increased disease risk. Additionally, multiple human and animal studies suggest that inflammation probably plays the largest role in contributing to frailty. Some inflammatory markers have been proposed to predict physical frailty. However, there are still large gaps in knowledge related to the clinical application of these markers in frail patients. Therefore, understanding the biological processes and identifying recognized and reliable markers are urgent and pivotal tasks for geriatricians. In the present review, we broadly summarize the inflammatory markers that may have potential diagnostic and therapeutic use, thereby translating them into health care for older people with frailty in the near future.

Inflammation and Oxidative Stress in Frailty and Metabolic Syndromes-Two Sides of the Same Coin

In developed countries, aging is often seen as typical, but it is made complicated by many disorders and co-morbidities. Insulin resistance seems to be an underlying pathomechanism in frailty and metabolic syndromes. The decline in insulin sensitivity leads to changes in the oxidant-antioxidant balance and an accelerated inflammatory response, especially by adipocytes and macrophages in adipose tissue, as well as muscle mass density. Thus, in the pathophysiology of syndemic disorders-the metabolic syndrome and frailty syndrome-an extremely important role may be played by increased oxidative stress and pro-inflammatory state. Papers included in this review explored available full texts and the reference lists of relevant studies from the last 20 years, before the end of 2022; we also investigated the PubMed and Google Scholar electronic databases. The online resources describing an elderly population (≥65 years old) published as full texts were searched for the following terms: "oxidative stress and/or inflammation", "frailty and/or metabolic syndrome". Then, all resources were analyzed and narratively described in the context of oxidative stress and/or inflammation markers which underlie pathomechanisms of frailty and/or metabolic syndromes in elderly patients. So far, different metabolic pathways discussed in this review show that a similar pathogenesis underlies the development of the metabolic as well as frailty syndromes in the context of increased oxidative stress and acceleration of inflammation. Thus, we argue that the syndemia of the syndromes represents two sides of the same coin.

Are Skeletal Muscle Changes during Prolonged Space Flights Similar to Those Experienced by Frail and Sarcopenic Older Adults?

Microgravity exposure causes several physiological and psychosocial alterations that challenge astronauts' health during space flight. Notably, many of these changes are mostly related to physical inactivity influencing different functional systems and organ biology, in particular the musculoskeletal system, dramatically resulting in aging-like phenotypes, such as those occurring in older persons on Earth. In this sense, sarcopenia, a syndrome characterized by the loss in muscle mass and strength due to skeletal muscle unloading, is undoubtedly one of the most critical aging-like adverse effects of microgravity and a prevalent problem in the geriatric population, still awaiting effective countermeasures. Therefore, there is an urgent demand to identify clinically relevant biological markers and to underline molecular mechanisms behind these effects that are still poorly understood. From this perspective, a lesson from Geroscience may help tailor interventions to counteract the adverse effects of microgravity. For instance, decades of studies in the field have demonstrated that in the older people, the clinical picture of sarcopenia remarkably overlaps (from a clinical and biological point of view) with that of frailty, primarily when referred to the physical function domain. Based on this premise, here we provide a deeper understanding of the biological mechanisms of sarcopenia and frailty, which in aging are often considered together, and how these converge with those observed in astronauts after space flight.

Frailty and cytokines in preclinical models: Comparisons with humans

Chronic low-grade elevations of blood-borne cytokines/chemokines in older age tend to associate with frailty in humans. This persistent inflammation is often called "inflammageing" and likely contributes to frailty progression. Preclinical models such as ageing and/or genetically modified mice offer a unique opportunity to mechanistically study how these inflammatory mediators affect frailty. In this review, we summarize and contrast evidence relating cytokines/chemokines to frailty in humans and in mouse models of frailty. In humans and mice, higher levels of the pro-inflammatory cytokine interleukin-6 regularly increased in proportion to the degree of frailty. Evidence linking other cytokines/chemokines to frailty in humans and mice is less certain. The chemokines CXCL-10 and monocyte chemoattractant protein-1 related to frailty across both species, but evidence is limited and inconsistent. Several other cytokines/chemokines, including tumour necrosis factor-α relate to frailty in humans or in mice, but evidence to date is species- and tissue-dependent. It is important for future studies to validate common mechanistic inflammatory biomarkers of frailty between humans and mice. Achieving this goal will accelerate the search for drugs to treat frailty.

Salivary IL-6 Concentration Is Associated with Frailty Syndrome in Older Individuals

Background: One of the physiological changes that is most closely associated with frailty is the increase in pro-inflammatory cytokines, and IL-6 in particular. Most studies have demonstrated this association using blood samples. We analyzed the relationship between frailty syndrome, individual frailty criteria, and IL-6 levels obtained by saliva tests. Methods: A cross-sectional pilot study was performed among women institutionalized in nursing homes. Frailty was defined as having three or more of the following components: low lean mass, weakness, self-reported exhaustion, low activity level, and slow walking speed; prefrailty was defined as having one or two of those components. Results: There was a significant and positive correlation between the frailty score and salivary IL-6 concentration. Regarding the associations between IL-6 and individual dichotomized frailty criteria, there were significant differences in salivary IL-6 concentration in two frailty criteria: weight loss (p = 0.002) and low physical activity (p = 0.007). Receiver operating characteristic curve analysis showed that IL-6 concentration significantly (p < 0.05) (although moderately) discriminated patients that progressed in the frailty syndrome (the area under the curve value was 0.697 with 95% CI 0.566–0.827). Conclusions: Salivary IL-6 concentration can be used as potential biomarker of frailty syndrome and as a tool to monitor the effects of interventions in frail individuals.