Associations of Innate and Adaptive Immune Cell Subsets With Incident Type 2 Diabetes Risk: The MESA Study

Investigating peripheral blood monocyte and T-cell subsets as non-invasive biomarkers for asymptomatic hepatic steatosis: results from the Multi-Ethnic Study of Atherosclerosis

Background

Circulating immune cells have gained interest as biomarkers of hepatic steatosis. Data on the relationships between immune cell subsets and early-stage steatosis in population-based cohorts are limited.

Methods

This study included 1,944 asymptomatic participants of the Multi-Ethnic Study of Atherosclerosis (MESA) with immune cell phenotyping and computed tomography measures of liver fat. Participants with heavy alcohol use were excluded. A liver-to-spleen ratio Hounsfield units (HU) <1.0 and liver attenuation <40 HU were used to diagnose liver fat presence and >30% liver fat content, respectively. Logistic regression estimated cross-sectional associations of immune cell subsets with liver fat parameters adjusted for risk factors. We hypothesized that higher proportions of non-classical monocytes, Th1, Th17, and memory CD4+ T cells, and lower proportions of classical monocytes and naive CD4+ T cells, were associated with liver fat. Exploratory analyses evaluated additional immune cell phenotypes (n = 19).

Results

None of the hypothesized cells were associated with presence of liver fat. Higher memory CD4+ T cells were associated with >30% liver fat content, but this was not significant after correction for multiple hypothesis testing (odds ratio (OR): 1.31, 95% confidence interval (CI): 1.03, 1.66). In exploratory analyses unadjusted for multiple testing, higher proportions of CD8+CD57+ T cells were associated with liver fat presence (OR: 1.21, 95% CI: 1.02, 1.44) and >30% liver fat content (OR: 1.34, 95% CI: 1.07, 1.69).

Conclusions

Higher circulating memory CD4+ T cells may reflect liver fat severity. CD8+CD57+ cells were associated with liver fat presence and severity, but replication of findings is required.

Age-related Differences in T-cell Subsets and Markers of Subclinical Inflammation in Aging Are Independently Associated With Type 2 Diabetes in the Health and Retirement Study

OBJECTIVES

Age-related changes in adaptive immunity and subclinical inflammation are both important risk factors for diabetes in older adults. We evaluated the independent association between T-cell subsets, subclinical inflammation, and diabetes risk in the Health and Retirement Study (HRS).

METHODS

We measured 11 T-cell subsets, 5 pro-inflammatory markers, and 2 anti-inflammatory markers from the 2016 wave of the HRS (baseline). Diabetes/prediabetes status was estimated at the 2016, 2018, and 2020 waves of HRS, based on levels of blood glucose/glycated hemoglobin in plasma or self-reported status. We used survey generalized logit models to evaluate the cross-sectional associations and Cox proportional hazard models to evaluate longitudinal associations.

RESULTS

Among 8,540 participants (56 to 107 years of age), 27.6% had prevalent type 2 diabetes and 31.1% had prediabetes in the 2016 survey. After adjusting for age, sex, race/ethnicity, education, obesity, smoking, comorbidity index, and cytomegalovirus seropositivity, individuals with type 2 diabetes had lower naive T cells and higher memory and terminal effector T cells as compared with normoglycemic individuals. Among 3,230 normoglycemic participants in the 2016 survey, the incidence of diabetes was 1.8% over 4 years of follow-up. The baseline percentage of CD4+ effector memory T cells was associated with a lower risk of incident diabetes (hazard ratio [HR]=0.63, 95% confidence interval [CI] 0.49 to 0.80, p=0.0003) after adjustment for covariates. Baseline level of interleukin-6 (IL-6) was associated with risk of incident diabetes (HR=1.52, 95% CI 1.18 to 1.97, p=0.002). The associations between age-related changes in CD4+ effector memory T cells and risk of incident diabetes remained unchanged after adjustment for subclinical inflammation, although adjusting for CD4+ effector memory T cells nullified the association between IL-6 and incident diabetes.

CONCLUSIONS

This study showed that the baseline percentage of CD4+ effector memory T cells was inversely associated with incident diabetes independent of subclinical inflammation, but CD4+ effector memory T-cell subsets affected the relationship between IL-6 and incident diabetes. Further studies are needed to confirm and investigate mechanisms by which T-cell immunity affects diabetes risk.

Exploring shared pathways and the shared biomarker ERRFI1 in Obstructive sleep apnoea and atherosclerosis using integrated bioinformatics analysis

Obstructive sleep apnea (OSA) is an upper airway disorder occurring during sleep and is associated with atherosclerosis (AS). AS is a cardiovascular disease caused by environmental and genetic factors, with a high global mortality rate. This study investigated common pathways and potential biomarkers of OSA and AS. Microarray data were downloaded from the Gene Expression Omnibus (GEO) database and used to screen for differentially expressed genes (DEGs) in the OSA and AS datasets. A weighted gene co-expression network analysis (WGCNA) was used to identify the co-expression modules of OSA and AS. The least absolute shrinkage and selection operators (LASSO) were used to determine critical biomarkers. Immune cell infiltration analysis was used to investigate the correlation between immune cell infiltration and common biomarkers of OSA and AS. Results revealed that differentially expressed genes may be involved in inflammatory processes, chemokine signaling pathways, and molecular changes in cell adhesion. ERBB receptor feedback inhibitor 1 (ERRFI1) was the best-shared biomarker for OSA and AS. Immune infiltration analysis showed that ERRFI1 expression was correlated with immune cell changes. Changes in immune pathways, inflammatory processes, and cell adhesion molecules may underlie the pathogenesis of both diseases, and ERRFI1 may be a potential diagnostic marker for patients with OSA and AS.

What's the role of thymus in diabetes mellitus?

Diabetes mellitus is considered as an autoimmune inflammatory and age-related disease. As an important immune organ, the thymus is involved in the immune response and inflammatory response process. Therefore, there may be a link between changes in thymus function and diabetes. Based on previous studies, we hypothesized that thymus dysfunction due to aging and other reasons leads to changes in the generation of various inflammatory-immune cells and inflammatory cytokines that regulate insulin resistance, and then participates in the development of diabetes and its complications. Therefore, thymus may be a key factor in diabetes and complications, and it may be a promising therapeutic strategy to improve the thymus function for patients with diabetes. The purpose of this review is to summarize and discuss recent advances in the influence of thymus function on diabetes, especially its potential mechanisms.

Circulating differentiated and senescent lymphocyte subsets and incident diabetes risk in older adults: The Cardiovascular Health Study

INTRODUCTION

Cellular senescence is a feature of aging implicated in the pathophysiology of diabetes mellitus (DM). Whether senescent lymphocytes are associated with the future occurrence of DM is uncertain.

METHODS

We used cryopreserved peripheral blood mononuclear cells collected from 1860 Cardiovascular Health Study participants (average age 80.2 years) and flow cytometry immunophenotyping to evaluate the longitudinal relationships of naive (CD45RA⁺ ), memory (CD45RO⁺ ), senescent (CD28^- ), and T effector memory RA⁺ (TEMRA) (CD28^- CD57⁺ CD45RA⁺ ) CD4⁺ and CD8⁺ T cells, and memory B cells (CD19⁺ CD27⁺ ), with the risk of incident DM. In exploratory analyses we evaluated the relationships of 13 additional innate lymphocyte and CD4⁺ and CD8⁺ subsets with incident DM risk.

RESULTS

Over a median follow-up time of 8.9 years, 155 cases of incident DM occurred. In Cox models adjusted for demographic variables (age, sex, race, study site and flow cytometry analytical batch) or diabetes risk factors (demographic variables plus education, body mass index, smoking status, alcohol use, systolic blood pressure, hypertension medication use and physical activity), no significant associations were observed for any CD4⁺ , CD8⁺ or CD19⁺ cell phenotypes with incident DM.

CONCLUSIONS

These results suggest the frequencies of naive, memory and senescent T cells and memory B cells are not strongly associated with incident DM risk in older adults.

Association of immune cell subsets with incident heart failure in two population-based cohorts

AIMS

Circulating inflammatory markers are associated with incident heart failure (HF), but prospective data on associations of immune cell subsets with incident HF are lacking. We determined the associations of immune cell subsets with incident HF as well as HF subtypes [with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF)].

METHODS AND RESULTS

Peripheral blood immune cell subsets were measured in adults from the Multi-Ethnic Study of Atherosclerosis (MESA) and Cardiovascular Health Study (CHS). Cox proportional hazard models adjusted for demographics, HF risk factors, and cytomegalovirus serostatus were used to evaluate the association of the immune cell subsets with incident HF. The average age of the MESA cohort at the time of immune cell measurements was 63.0 ± 10.4 years with 51% women, and in the CHS cohort, it was 79.6 ± 4.4 years with 62% women. In the meta-analysis of CHS and MESA, a higher proportion of CD4+ T helper (Th) 1 cells (per one standard deviation) was associated with a lower risk of incident HF [hazard ratio (HR) 0.91, (95% CI 0.83-0.99), P = 0.03]. Specifically, higher proportion of CD4+ Th1 cells was significantly associated with a lower risk of HFrEF [HR 0.73, (95% CI 0.62-0.85), <0.001] after correction for multiple testing. No association was observed with HFpEF. No other cell subsets were associated with incident HF.

CONCLUSIONS

We observed that higher proportions of CD4+ Th1 cells were associated with a lower risk of incident HFrEF in two distinct population-based cohorts, with similar effect sizes in both cohorts demonstrating replicability. Although unexpected, the consistency of this finding across cohorts merits further investigation.

Circulating CD4+ TEMRA and CD4+ CD28- T cells and incident diabetes among persons with and without HIV

OBJECTIVE

A higher proportion of circulating memory CD4+ T cells is associated with prevalent diabetes mellitus in persons with HIV (PWH) and HIV-negative persons. We assessed whether circulating T-cell subsets could also identify individuals who will subsequently develop diabetes.

DESIGN

This is a longitudinal follow-up study of PWH and similar HIV-negative individuals from the Veterans Aging Cohort Study who provided peripheral mononuclear blood cells between 2005 and 2007.

METHODS

We quantified T-cell subsets using flow cytometry and functional assays to identify CD4+ and CD8+ naive, activated, senescent, memory (central, effector, and effector RA+), and TH1, TH2, and TH17-phenotype cells. The occurrence of an incident diabetes diagnosis (i.e. after baseline blood draw) was adjudicated by a two-physician chart review. Cox proportional hazards models adjusted for traditional risk factors, cytomegalovirus serostatus, and plasma inflammatory biomarkers assessed the relationship between T-cell subsets and incident diabetes.

RESULTS

One thousand, eight hundred and thirty-seven participants (1259 PWH) without diabetes at baseline were included; 69% were black, 95% were men, and median follow-up was 8.6 years. Higher baseline frequencies of CD4+ T effector memory RA+ (TEMRA) cells defined as CD45RA+ CD27- (P = 0.04) and senescent T cells defined as CD4+ CD28- (P = 0.04) were associated with incident diabetes in PWH only.

CONCLUSIONS

Higher frequencies of CD4+ TEMRA and CD4+ CD28- T cells were associated with incident diabetes in PWH only after adjustment for other factors. Additional studies are necessary to assess whether these cells act in blood via inflammatory mediators or reflect T-cell populations in metabolically active tissues.

When a Friend Becomes Your Enemy: Natural Killer Cells in Atherosclerosis and Atherosclerosis-Associated Risk Factors

Atherosclerosis (ATS), the change in structure and function of arteries with associated lesion formation and altered blood flow, is the leading cause of cardiovascular disease, the number one killer worldwide. Beyond dyslipidemia, chronic inflammation, together with aberrant phenotype and function of cells of both the innate and adaptive immune system, are now recognized as relevant contributors to atherosclerosis onset and progression. While the role of macrophages and T cells in atherosclerosis has been addressed in several studies, Natural Killer cells (NKs) represent a poorly explored immune cell type, that deserves attention, due to NKs’ emerging contribution to vascular homeostasis. Furthermore, the possibility to re-polarize the immune system has emerged as a relevant tool to design new therapies, with some succesfull exmples in the field of cancer immunotherapy. Thus, a deeper knowledge of NK cell pathophysiology in the context of atherosclerosis and atherosclerosis-associated risk factors could help developing new preventive and treatment strategies, and decipher the complex scenario/history from “the risk factors for atherosclerosis” Here, we review the current knowledge about NK cell phenotype and activities in atherosclerosis and selected atherosclerosis risk factors, namely type-2 diabetes and obesity, and discuss the related NK-cell oriented environmental signals.

Association of immune cell subsets with cardiac mechanics in the Multi-Ethnic Study of Atherosclerosis

BackgroundImmunomodulatory therapy may help prevent heart failure (HF). Data on immune cells and myocardial remodeling in older adults with cardiovascular risk factors are limited.MethodsIn the Multi-Ethnic Study of Atherosclerosis cohort, 869 adults had 19 peripheral immune cell subsets measured and underwent cardiac MRI during the baseline exam, of which 321 had assessment of left ventricular global circumferential strain (LV-GCS). We used linear regression with adjustment for demographics, cardiovascular risk factors, and cytomegalovirus serostatus to evaluate the cross-sectional association of immune cell subsets with left ventricular mass index (LVMI) and LV-GCS.ResultsThe average age of the cohort was 61.6 ± 10.0 years and 53% were women. Higher proportions of γ/δ T cells were associated with lower absolute (worse) LV-GCS (-0.105% [95% CI -0.164%, -0.046%] per 1 SD higher proportion of γ/δ T cells, P = 0.0006). This association remained significant after Bonferroni's correction. Higher proportions of classical monocytes were associated with worse absolute LV-GCS (-0.04% [95% CI -0.07%, 0.00%] per 1 SD higher proportion of classical monocytes, P = 0.04). This did not meet significance after Bonferroni's correction. There were no other significant associations with LV-GCS or LVMI.ConclusionPathways associated with γ/δ T cells may be potential targets for immunomodulatory therapy targeted at HF prevention in populations at risk.FundingContracts 75N92020D00001, HHSN268201500003I, N01-HC-95159, 75N92020D00005, N01-HC-95160, 75N92020D00002, N01-HC-95161, 75N92020D00003, N01-HC-95162, 75N92020D00006, N01-HC-95163, 75N92020D00004, N01-HC-95164, 75N92020D00007, N01-HC-95165, N01-HC-95166, N01-HC-95167, N01-HC-95168, and N01-HC-95169 and grant R01 HL98077 from the National Heart, Lung, and Blood Institute/NIH and grants KL2TR001424, UL1-TR-000040, UL1-TR-001079, and UL1-TR-001420 from the National Center for Advancing Translational Sciences/NIH.

Natural killer cells, gamma delta T cells and classical monocytes are associated with systolic blood pressure in the multi-ethnic study of atherosclerosis (MESA)

Background

Hypertension is a major source of cardiovascular morbidity and mortality. Recent evidence from mouse models, genetic, and cross-sectional human studies suggest increased proportions of selected immune cell subsets may be associated with levels of systolic blood pressure (SBP).

Methods

We assayed immune cells from cryopreserved samples collected at the baseline examination (2000–2002) from 1195 participants from the multi-ethnic study of atherosclerosis (MESA). We used linear mixed models, with adjustment for age, sex, race/ethnicity, smoking, exercise, body mass index, education, diabetes, and cytomegalovirus titers, to estimate the associations between 30 immune cell subsets (4 of which were a priori hypotheses) and repeated measures of SBP (baseline and up to four follow-up measures) over 10 years. The analysis provides estimates of the association with blood pressure level.

Results

The mean age of the MESA participants at baseline was 64 ± 10 years and 53% were male. A one standard deviation (1-SD) increment in the proportion of γδ T cells was associated with 2.40 mmHg [95% confidence interval (CI) 1.34–3.42] higher average systolic blood pressure; and for natural killer cells, a 1-SD increment was associated with 1.88 mmHg (95% CI 0.82–2.94) higher average level of systolic blood pressure. A 1-SD increment in classical monocytes (CD14⁺⁺CD16⁻) was associated with 2.01 mmHG (95% CI 0.79–3.24) lower average systolic blood pressure. There were no associations of CD4⁺ T helper cell subsets with average systolic blood pressure.

Conclusion

These findings suggest that the innate immune system plays a role in levels of SBP whereas there were no associations with adaptive immune cells.