Interleukin-6 modulates plasma cholesterol and C-reactive protein concentrations in nonagenarians

The 90 plus: longevity and COVID-19 survival

The world population is getting older and studies aiming to enhance our comprehension of the underlying mechanisms responsible for health span are of utmost interest for longevity and as a measure for health care. In this review, we summarized previous genetic association studies (GWAS) and next-generation sequencing (NGS) of elderly cohorts. We also present the updated hypothesis for the aging process, together with the factors associated with healthy aging. We discuss the relevance of studying older individuals and build databanks to characterize the presence and resistance against late-onset disorders. The identification of about 2 million novel variants in our cohort of more than 1000 elderly Brazilians illustrates the importance of studying highly admixed populations of non-European ancestry. Finally, the ascertainment of nonagenarians and particularly of centenarians who were recovered from COVID-19 or remained asymptomatic opens new avenues of research aiming to enhance our comprehension of biological mechanisms associated with resistance against pathogens.

Paradoxical Suppression of Atherosclerosis in the Absence of microRNA-146a

RATIONALE

Inflammation is a key contributor to atherosclerosis. MicroRNA-146a (miR-146a) has been identified as a critical brake on proinflammatory nuclear factor κ light chain enhancer of activated B cells signaling in several cell types, including endothelial cells and bone marrow (BM)-derived cells. Importantly, miR-146a expression is elevated in human atherosclerotic plaques, and polymorphisms in the miR-146a precursor have been associated with risk of coronary artery disease.

OBJECTIVE

To define the role of endogenous miR-146a during atherogenesis.

METHODS AND RESULTS

Paradoxically, Ldlr^-/- (low-density lipoprotein receptor null) mice deficient in miR-146a develop less atherosclerosis, despite having highly elevated levels of circulating proinflammatory cytokines. In contrast, cytokine levels are normalized in Ldlr^-/-;miR-146a^-/- mice receiving wild-type BM transplantation, and these mice have enhanced endothelial cell activation and elevated atherosclerotic plaque burden compared with Ldlr^-/- mice receiving wild-type BM, demonstrating the atheroprotective role of miR-146a in the endothelium. We find that deficiency of miR-146a in BM-derived cells precipitates defects in hematopoietic stem cell function, contributing to extramedullary hematopoiesis, splenomegaly, BM failure, and decreased levels of circulating proatherogenic cells in mice fed an atherogenic diet. These hematopoietic phenotypes seem to be driven by unrestrained inflammatory signaling that leads to the expansion and eventual exhaustion of hematopoietic cells, and this occurs in the face of lower levels of circulating low-density lipoprotein cholesterol in mice lacking miR-146a in BM-derived cells. Furthermore, we identify sortilin-1(Sort1), a known regulator of circulating low-density lipoprotein levels in humans, as a novel target of miR-146a.

CONCLUSIONS

Our study reveals that miR-146a regulates cholesterol metabolism and tempers chronic inflammatory responses to atherogenic diet by restraining proinflammatory signaling in endothelial cells and BM-derived cells.

Interleukin-6 and C-reactive protein, successful aging, and mortality: the PolSenior study

BACKGROUND

In the elderly, chronic low-grade inflammation (inflammaging) is a risk factor for the development of aging-related diseases and frailty. Using data from several thousand Eastern Europeans aged 65 years and older, we investigated whether the serum levels of two proinflammatory factors, interleukin-6 (IL-6) and C-reactive protein (CRP), were associated with physical and cognitive performance, and could predict mortality in successfully aging elderly.

RESULTS

IL-6 and CRP levels systematically increased in an age-dependent manner in the entire study group (IL-6: n = 3496 individuals, p < 0.001 and CRP: n = 3632, p = 0.003), and in the subgroup of successfully aging individuals who had never been diagnosed with cardiovascular disease, myocardial infarction, stroke, type 2 diabetes, or cancer, and had a Mini Mental State Examination (MMSE) score ≥24 and a Katz Activities of Daily Living (ADL) score ≥5 (IL-6: n = 1258, p < 0.001 and CRP: n = 1312, p < 0.001). In the subgroup of individuals suffering from aging-related diseases/disability, only IL-6 increased with age (IL-6: n = 2238, p < 0.001 and CRP: n = 2320, p = 0.249). IL-6 and CRP levels were lower in successfully aging individuals than in the remaining study participants (both p < 0.001). Higher IL-6 and CRP levels were associated with poorer physical performance (lower ADL score) and poorer cognitive performance (lower MMSE score) (both p < 0.001). This association remained significant after adjusting for age, gender, BMI, lipids, estimated glomerular filtration rate, and smoking status. Longer survival was associated with lower concentrations of IL-6 and CRP not only in individuals with aging-related diseases/disability (HR = 1.063 per each pg/mL, 95 % CI: 1.052-1.074, p < 0.001 and HR = 1.020 per each mg/L, 95 % CI: 1.015-1.025, p < 0.001, respectively) but also in the successfully aging subgroup (HR = 1.163 per each pg/mL, 95 % CI: 1.128-1.199, p < 0.001 and HR = 1.074 per each mg/L, 95 % CI: 1.047-1.100, p < 0.001, respectively). These associations remained significant after adjusting for age, gender, BMI, lipids and smoking status. The Kaplan-Meier survival curves showed similar results (all p < 0.001).

CONCLUSIONS

Both IL-6 and CRP levels were good predictors of physical and cognitive performance and the risk of mortality in both the entire elderly population and in successfully aging individuals.

The importance of HDL-C and CRP in cardiovascular risk evaluation in longevous elderly individuals

The association between total mortality, lipoproteinS, and inflammatory markers, and their implications with aging and longevity are often controversial. Among the most often studied markers are low HDL cholesterol and high C-reactive protein. Particularly in octogenarians, it is expected that the impact of the inclusion of HDL cholesterol and C-reactive protein will improve the stratification of absolute cardiovascular risk. In the present study, we performed a literature review in PubMed about the relation between HDL cholesterol, inflammation and longevity. Applying the inclusion and exclusion criteria adopted, we selected 30 studies, among which one systematic review on the relation between HDL cholesterol and stroke, one meta-analysis on the relation between total cholesterol and HDL cholesterol with mortality, 22 longitudinal studies, and six cross-sectional studies. The results show an inverse association between HDL cholesterol and total mortality, and between cardiovascular mortality and C-reactive protein, as well as a positive association between C-reactive protein and mortality in longevous individuals. C-reactive protein and HDL cholesterol displayed promising characteristics as predictors of cardiovascular mortality in longevous elderly persons.

Association of interleukin-6-572C/G gene polymorphism and serum or cerebrospinal fluid interleukin-6 level with enterovirus 71 encephalitis in Chinese Han patients with hand, foot, and mouth disease

Interleukin-6 (IL-6), as one of pro-inflammatory cytokines, plays a key role in Enterovirus 71 (EV71) encephalitis. We investigated the association of IL-6-572C/G polymorphism and serum or cerebrospinal fluid (CSF) IL-6 level with EV71 encephalitis in patients with hand, foot, and mouth disease (HFMD). This study was carried out in 59 Chinese Han patients with EV71 encephalitis, 128 EV71-related HFMD without complications, and 232 controls. The IL-6-572C/G polymorphism was detected by polymerase chain reaction-restricted fragment length polymorphism gene analysis. Serum or CSF IL-6 levels were determined using a commercial enzyme-linked immunosorbent assay. The patients with EV71 encephalitis had a higher frequency of IL-6-572GG/GC genotype compared to the patients with EV71-related HFMD without encephalitis complications (40.7 vs. 15.6 %, odds ratio (OR)=3.70, 95 % confidence interval (CI)=1.83-7.50, p=0.001). Similarly, the frequency of IL-6-572 G allele among the patients with EV71 encephalitis was also higher than that of patients with EV71-related HFMD without encephalitis complications (23.7 vs. 8.6 %, OR=3.31, 95 % CI=1.80-6.08, p<0.001). Serum IL-6 levels in G carries (CG + GG) (195.1 ± 11.8 pg/ml) elevated significantly compared to CC homozygotes (167.7 ± 6.7 pg/ml) in EV71-infected patients (p<0.001), but no significant differences were observed in CSF IL-6 levels among different genotypes in patients with EV71 encephalitis. Furthermore, G carriers (GG + GC) (10.6 ±.29 mg/l) had significantly higher blood CRP levels compared to CC homozygotes (9.31 ± 1.93 mg/l) in patients with EV71 encephalitis (p=0.005). These findings suggested that IL-6-572 G allele was significantly associated with the susceptibility to EV71 encephalitis in Chinese Han patients, and IL-6-572 G allele might elevate the risk to EV71 encephalitis.

Role of lipoproteins and inflammation in cognitive decline: do they interact?

The aim of this study was to examine the associations between high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, triglycerides, and cognition and focus on the modifying effect of inflammation. Data were collected in the population-based Longitudinal Aging Study Amsterdam and analyzed with mixed linear models. The sample comprised 1003 persons ≥ 65 years with cognitive data on at least 2 occasions over 6 years of follow-up. Cognition was measured with the Mini-Mental State Examination (general cognition), Auditory Verbal Learning Test (memory), and Coding Task (information processing speed). We found an independent association between high HDL cholesterol and better memory performance. In addition, low LDL cholesterol was predictive of worse general cognitive performance and faster decline on information processing speed. Furthermore, a significant modifying effect of inflammation (C-reactive protein, α-antichymotrypsin) was found. A negative additive effect of low LDL cholesterol and high inflammation was found on general cognition and memory performance. Also, high triglycerides were associated with lower memory performance in those with high inflammation. Thus, a combination of these factors may be used as markers of prolonged lower cognitive functioning.

Inflammatory markers and physical performance among nonagenarians

BACKGROUND

Recent studies have suggested that inflammation may play an important role in aging and the development of disabilities, but knowledge about its importance in the development of muscle weakness and functional disabilities in very old people is limited. This study examined associations between inflammatory markers and physical performance among nonagenarians.

METHODS

The population-based sample consisted of 197 women and 65 men aged 90 years. Physical performance was assessed according to the Barthel Index, the chair stand, and handgrip strength. Plasma levels of interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1Ra), and C-reactive protein (CRP) were determined.

RESULTS

A gender-adjusted linear regression model showed that high levels of CRP, IL-6, and IL-1Ra were significantly associated with poor handgrip strength (p = .041, p = .023, p < .001, respectively). After adjustment for diseases, smoking and physical exercise high levels of IL-6 and IL-1Ra were still significantly associated with poor hand grip strength (p = .048, p = .004, respectively). In the gender-adjusted model, high levels of CRP, IL-6, and IL-1Ra were significantly associated with a worse Barthel Index (p = .009, p = .004, p = .004, respectively). High levels of CRP and IL-6 were still significantly associated with a worse Barthel Index after adjusted for diseases, smoking and physical exercise (p = .034, p = .041, respectively). In the chair stand, no significant association with inflammatory markers was found.

CONCLUSIONS

Associations between high levels of inflammatory markers and worse handgrip strength as well as a worse Barthel Index result were evident among nonagenarians. However, the association with the chair stand was not significant.

Serum lipids and their association with mortality in the elderly: a prospective cohort study

BACKGROUND AND AIMS

To determine whether high levels of serum total cholesterol and low levels of high-density lipoprotein cholesterol (HDLc) are associated with increased mortality in the elderly.

METHODS

Prospective cohort study of 1032 non-institutionalized people aged 70 in the city of Turku, Southern Finland. The cohort population was recruited as part of a larger longitudinal aging study, the Turku Elderly Study. Fasting serum levels of total cholesterol, HDL-c and triglycerides were measured, and the amount of low-density lipoprotein cholesterol was calculated at baseline. The cohort was followed for mortality for 12 years, and the causes of death were recorded and further classified into cardiovascular and other causes of death. The hazard ratios of dying for subjects in various cholesterol quartiles were computed by the Cox proportional hazards model, adjusting for cardiovascular risk factors and pre-existing medical conditions.

RESULTS

Low levels of serum total cholesterol and HDL-c were associated with a greater risk of death over a follow-up of 12 years. After adjustment for several cardiovascular risk factors, the association between total cholesterol and survival changed. All-cause mortality seemed to be highest in the highest quartile of total cholesterol and nearly as high in the lowest quartile of total cholesterol, suggesting a U-shaped connection, but the differences were not statistically significant. However, cardiovascular mortality was significantly lowest in the lowest quartile of total cholesterol and significantly highest in the lowest quartile of HDL-c.

CONCLUSIONS

High levels of serum total cholesterol and particularly low levels of HDL-c seem to be risk factors for cardiovascular mortality even in the elderly population.

C-reactive protein and lipid parameters in older persons aged 80 years and older

OBJECTIVES

Aims of the study were 1) to investigate the association of C-reactive protein (CRP) with lipid (i.e. total, LDL, and HDL cholesterol, triglycerides) concentrations, and to evaluate their predictive value for mortality in very old subjects.

DESIGN

Cross-sectional and longitudinal analyses in a prospective cohort study.

SETTING

Participants. Data are from 336 community-dwelling subjects aged > or = 80 years old enrolled in the "Invecchiamento e Longevità nel Sirente" (ilSIRENTE) study.

MEASUREMENTS

High sensitivity CRP and lipid concentrations were measured at the baseline clinical visit. High sensitivity CRP concentrations were measured by ELISA assessment. Mortality outcome was evaluated over a 24-month follow-up.

RESULTS

Participants had a mean age of 85.8 (SD 4.8) years old. Spearman's correlations showed significant (p values < 0.01) inverse correlations between CRP and lipid parameters (except triglycerides). Adjusted linear regressions between CRP and lipid parameters concentrations showed no significant association in participants aged lower than 85 years old (all p values > 0.5). In the older age group, significant inverse associations of CRP with total (p=0.002), LDL (p=0.007), and HDL cholesterol (p=0.002) were found, even after adjustment for potential confounders. Adjusted Cox proportional hazard models demonstrated that CRP was the only biomarker significantly predictive of mortality, independently of age and lipid parameters.

CONCLUSION

An inverse relationship of total, LDL, and HDL cholesterol with CRP is present in very old persons. The prognostic value of CRP is particularly important among very old persons whereas lipid parameters tend to lose their capacity to predict events.

Effects of weight loss on visceral and abdominal subcutaneous adipose tissue blood-flow and insulin-mediated glucose uptake in healthy obese subjects

OBJECTIVE

Rapid weight loss with very-low-calorie diet (VLCD) is known to improve insulin sensitivity and decrease adipose tissue masses. The aim was to investigate the effects of VLCD on adipose tissue regional glucose uptake (rGU) and perfusion and their association with adipokines.

RESEARCH DESIGN AND METHODS

Sixteen healthy obese (body mass index 33+/-1.1 kg/m(2)) subjects underwent VLCD for 6 weeks. RGU and perfusion were measured using [(18)F]-fluoro-deoxy-glucose, [(15)O]H(2)O and positron emission tomography.

RESULTS

Blood-flow and rGU expressed per gram of adipose tissue were higher in visceral fat compared to abdominal subcutaneous fat (P<0.01 for both). Dieting decreased weight by 11+/-0.9 kg (P<0.0001). Visceral adipose fat decreased by 25% (P<0.001) and abdominal subcutaneous fat by 16% (P<0.001). Whole body insulin sensitivity increased by 33% (P<0.01). Perfusion of both fat depots decreased (P<0.001), while rGU remained unchanged. Among the adipokines, leptin and interleukin-6 levels seemed to be associated with abdominal subcutaneous and intra-abdominal adipose tissue insulin resistance but not with adipose tissue perfusion.

CONCLUSIONS

Abdominal adipose tissue perfusion and rGU are not related in obesity. Rapid weight loss decreases perfusion through adipose tissue depots but has no influence on rGU demonstrating the 'sink' role of adipose tissue.

Evaluation of C-Reactive Protein and Total Serum Cholesterol in Adult Patients with Bipolar Disorder

The aim of the present study is to evaluate the role of CRP and Total Cholesterol (TC) in patients suffering from type I Bipolar Disorder (BD-I). Moreover, the goal is to elucidate possible CRP and TC differences in different phases of BD-I: acute mania, euthymia and bipolar depression. Medical records of 90 BD-I patients (30 patients with acute mania, 30 in euthymic state, full remission, and 30 in depressive phase) were reviewed to evaluate serum CRP and TC levels. Laboratory data of 30 healthy controls were also obtained. The scores of Young Mania Rating Scale (YMRS), Bech-Rafaelsen Manic Rating Scale (BRMRS) and Hamilton Rating Scale for Depression (HAM-D) were evaluated. CRP levels were higher in acute mania and depressive phase subgroups when compared to healthy controls. CRP was positively associated with BRMRS and YMRS scores in acute mania and with HAM-D in depressive phase subgroups. TC levels were lower in all clinical groups compared to controls. TC levels were negatively correlated to BRMRS, YMRS and HAM-D. In conclusion, the results of the present study support the notion that CRP and TC may be altered in patients with BP-I.

Interleukin-1 receptor antagonist, interleukin-6, and C-reactive protein as predictors of mortality in nonagenarians: the vitality 90+ study

BACKGROUND

Inflammation plays a major role in both aging and chronic disease. Longitudinal studies in very old people can improve our understanding of these processes. We investigated blood levels of C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1ra), and their combinations as predictors of mortality in nonagenarians.

METHODS

This is a prospective population-based study including both community-dwelling and institutionalized nonagenarians enrolled in the Vitality 90+ Study. Altogether 285 persons participated in the baseline interview and gave blood. Information on chronic disease was drawn from health center registers. Data on mortality over 4 years were obtained from the Population Register Center. In Cox proportional hazards models, chronic disease and major risk factors were adjusted for.

RESULTS

Plasma levels of IL-1ra, IL-6, and CRP were higher in persons who died during the follow-up than in those who survived. When sex, education, cardiovascular disease, diabetes, cancer, history of infections, high density lipoprotein cholesterol, Mini-Mental State Examination, body mass index, smoking status, and exercise were adjusted for, only IL-1ra was a significant predictor of mortality (hazard ratio [HR] 2.12; 95% confidence interval [CI], 1.24-3.62). Persons in the upper tertiles of both CRP and IL-1ra (HR 2.72; 95% CI, 1.25-6.00), or in the upper tertile of all three markers (HR 2.34; 95% CI, 1.23-4.61), had higher mortality than those who were not in the upper tertile in any of the markers.

CONCLUSIONS

IL-1ra is a powerful prognostic marker in very old people. Our results implicate its role in the complex interaction between inflammatory markers in aging and disease.

Total cholesterol and oxysterols: early markers for cognitive decline in elderly?

In this prospective study we examined whether total cholesterol and the oxysterols 24S- and 27-hydroxycholesterol were related to cognitive performance and rate of cognitive decline in elderly, and whether these associations were modified by ApoE epsilon 4. Data were collected during 6 years of follow-up as part of the Longitudinal Aging Study Amsterdam (N=1181, age >or=65 years), and analyzed using generalized estimating equations. Cognitive performance was measured with the mini-mental state examination (general cognition), the auditory verbal learning test (memory) and the coding task (information processing speed). Lower cholesterol at baseline was negatively associated with both general cognition (p=.012) and information processing speed (p=.045). ApoE modified the association between cholesterol and cognitive decline, and the association between the ratio of 27-hydroxycholesterol to cholesterol and cognitive functioning. In ApoE epsilon 4 carriers, lower cholesterol was related to a higher rate of decline on information processing speed (p=.006), and a higher ratio of 27-hydroxycholesterol to cholesterol was related to a lower level of general performance (p=.002) and memory functioning (p=.045). The results implicate that lower total cholesterol may be considered as a frailty marker, predictive of lower cognitive functioning in elderly.