Predictive value of multiple cytokines and chemokines for mortality in an admixed population: 15-year follow-up of the Bambui-Epigen (Brazil) cohort study of aging

Chemokine CXCL9, a marker of inflammaging, is associated with changes of muscle strength and mortality in older men

Our study examined associations of the CXC motif chemokine ligand 9 (CXCL9), a pro-inflammatory protein implicated in age-related inflammation, with musculoskeletal function in elderly men. We found in certain outcomes both cross-sectional and longitudinal significant associations of CXCL9 with poorer musculoskeletal function and increased mortality in older men. This requires further investigation.

PURPOSE

We aim to determine the relationship of (CXCL9), a pro-inflammatory protein implicated in age-related inflammation, with both cross-sectional and longitudinal musculoskeletal outcomes and mortality in older men.

METHODS

A random sample from the Osteoporotic Fractures in Men (MrOS) Study cohort (N = 300) was chosen for study subjects that had attended the third and fourth clinic visits, and data was available for major musculoskeletal outcomes (6 m walking speed, chair stands), hip bone mineral density (BMD), major osteoporotic fracture, mortality, and serum inflammatory markers. Serum levels of CXCL9 were measured by ELISA, and the associations with musculoskeletal outcomes were assessed by linear regression and fractures and mortality with Cox proportional hazards models.

RESULTS

The mean CXCL9 level of study participants (79.1 ± 5.3 years) was 196.9 ± 135.2 pg/ml. There were significant differences for 6 m walking speed, chair stands, physical activity scores, and history of falls in the past year across the quartiles of CXCL9. However, higher CXCL9 was only significantly associated with changes in chair stands (β =  - 1.098, p < 0.001) even after adjustment for multiple covariates. No significant associations were observed between CXCL9 and major osteoporotic fracture or hip BMD changes. The risk of mortality increased with increasing CXCL9 (hazard ratio quartile (Q)4 vs Q1 1.98, 95% confidence interval 1.25-3.14; p for trend < 0.001).

CONCLUSIONS

Greater serum levels of CXCL9 were significantly associated with a decline in chair stands and increased mortality. Additional studies with a larger sample size are needed to confirm our findings.

The ocular surface immune system through the eyes of aging

Since the last century, advances in healthcare, housing, and education have led to an increase in life expectancy. Longevity is accompanied by a higher prevalence of age-related diseases, such as cancer, autoimmunity, diabetes, and infection, and part of this increase in disease incidence relates to the significant changes that aging brings about in the immune system. The eye is not spared by aging either, presenting with age-related disorders of its own, and interestingly, many of these diseases have immune pathophysiology. Being delicate organs that must be exposed to the environment in order to capture light, the eyes are endowed with a mucosal environment that protects them, the so-called ocular surface. As in other mucosal sites, immune responses at the ocular surface need to be swift and potent to eliminate threats but are at the same time tightly controlled to prevent excessive inflammation and bystander damage. This review will detail how aging affects the mucosal immune response of the ocular surface as a whole and how this process relates to the higher incidence of ocular surface disease in the elderly.

Inflammaging in Endemic Areas for Infectious Diseases

Immunosenescence is marked by a systemic process named inflammaging along with a series of defects in the immunological activity that results in poor responses to infectious agents and to vaccination. Inflammaging, a state of low-grade chronic inflammation, usually leads to chronic inflammatory diseases and frailty in the elderly. However, some elderly escape from frailty and reach advanced age free of the consequences of inflammaging. This process has been called immunological remodeling, and it is the hallmark of healthy aging as described in the studies of centenarians in Italy. The biological markers of healthy aging are still a matter of debate, and the studies on the topic have focused on inflammatory versus remodeling processes and molecules. The sub-clinical inflammatory status associated with aging might be a deleterious event for populations living in countries where chronic infectious diseases are not prevalent. Nevertheless, in other parts of the world where they are, two possibilities may occur. Inflammatory responses may have a protective effect against these infectious agents. At the same time, the long-term consequences of protective immune responses during chronic infections may result in accelerated immunosenescence in these individuals. Therefore, the biological markers of healthy aging can vary according to environmental, cultural, and geographical settings that reflect worldwide, and in a non-biased, non-westernized perspective, the changes that we experience regarding our contacts with microorganisms and the outcomes of such contacts.

Inflammatory markers and occurrence of falls: Bambuí Cohort Study of Aging

OBJECTIVE

Analyze whether inflammatory markers are associated with falls among older adults living in Bambuí.

METHODS

Study that analyzed baseline data from a Bambuí Cohort Study of Aging, involving 1,250 participants. Data about falls were collected from previous 12 months, classified as single or multiple occurrence and severity (participant seeking health services). Information about sociodemographic characteristics, health behaviors and health condition was also collected and used as confounding factors. The exposures of interest included interleukins (IL-1β, IL-6, IL-8, IL-10, IL-12), tumor necrosis factor (TNF), ultra-sensitive C-reactive protein (us-CRP) and chemokines (CXCL9, CCL5, CCL10, MCP1). Data were processed through logistic regression, obtaining odds ratio and 95% confidence interval (95%CI).

RESULTS

The prevalence of falls was 27.1%; 40.1% of the older adults reported multiple falls and 33.3% sought health services. After adjustments, the following elevated levels were associated with falls: us-CRP (OR = 1.46, 95%CI 1.04–2.03), CCL5 (OR = 1.38, 95%CI 1.01–1.90) and CXCL9 (OR = 1.43, 95%CI 1.02–2.02). An association was observed between the number of elevated markers and the occurrence of falls: two (OR = 1.47, 95%CI 1.02–2.12) and three (OR = 2.08, 95%CI 1.12–3.87) elevated biomarkers indicated fall probability of 32.0% and 39.4%, respectively.

CONCLUSIONS

Elevated levels of us-CRP, CCL5 and CXCL9, which were associated with falls, may contribute to a proper understanding of the mechanism associated with the occurrence of falls among older people.