Racial differences in association of elevated interleukin-18 levels with type 2 diabetes: the Atherosclerosis Risk in Communities study

Effects of anti-retroviral therapy on baseline serum interleukin-18 levels in HIV-I infected patients relative to viral suppression and CD4+ gain: A prospective pilot study

Background

In HIV infection, dysregulation of cytokines, including interleukin 18 (IL-18), has been linked to poor clinical outcomes in studies mainly conducted in resource-rich countries. This phenomenon has not been well-studied in resource-limited settings where outcomes could be confounded by exposure to endemic infections and genetic factors.

Objectives

Therefore, the influence of immunological and virological status of HIV-infected, antiretroviral therapy (ART)-naïve patients on serum IL-18 levels at baseline (pretreatment) and 24 weeks following initiation of combination ART (cART24) in a resource-limited setting was investigated.

Methods

Using the cross-sectional and longitudinal mixed method design, a total of Forty-four (44) newly diagnosed consenting HIV patients were consecutively recruited during routine clinic visits at the Nasara Treatment & Care Centre of the Ahmadu Bello University Teaching Hospital (ABUTH), Zaria, Nigeria between December 2016 to January 2018, and followed up for 24 weeks on initiation of first-line cART.

Results

Serum IL-18 concentrations, CD4+ T-cell counts (CD4+) counts, and HIV1 RNA levels were determined at baseline and cART24. There was little CD4+ count gain in both <200 and ≥ 200 cell/mm3subgroups despite the high proportion of subjects having virological suppression (n = 35, [80%]) at cART24. However, at cART24 there was a more than a threefold decrease in the level of IL-18 concentration compared to baseline in patients with <200 cells/mm3 and a significant decrease in the median plasma IL-18 concentration in patients with HIV1 RNA <1000 cp/mL at cART24. A multivariate logistic regression model shows IL-18 intermediate quartile to be more related to immunological poor gain as compared to the highest quartile.

Conclusion

Our study found high baseline and significantly low levels of IL-18 at cART24 in virologically suppressed subjects but not among virological non-suppressed responders despite comparable IL-18 levels by CD4+ T cell count strata at cART24. These findings have implications for risk stratification and treatment outcomes in HIV-positive persons.

Age- and Gender-Related Serum Level of Interleukin 18 in Iranian Fars Ethnic Group with Metabolic Syndrome

Background: The purpose of the present study was to investigate the age- and gender-related serum level of interleukin 18 (IL18) in male and female Iranian Fars ethnic group with metabolic syndrome components. Methods: The study included 226 native Iranian Fars ethnic groups. One hundred sixteen females and 110 men were selected. There were 60 females and 50 males with metabolic syndrome and 56 females and 60 males without metabolic syndrome. The serum fasting blood glucose (FBS), lipid profiles, and IL18 were measured. The National Cholesterol Education Program Adult treatment Panel III criteria were used to determine metabolic syndrome components. Results: There were significant differences between the males and females [except high-density lipoprotein (HDL)] with and without metabolic syndrome for the mean body mass index, FBS, HDL-cholesterol, waist circumference (WC), triglyceride (TG), and IL18 levels in all age groups. Serum IL18 was the highest in males and females in age groups 61-70 and 41-50 years with metabolic syndrome, respectively. Serum IL18 levels significantly correlated with TG and waist WC in males (and also correlated with HDL) and females with the metabolic syndrome. There were significant correlations between IL18 and TG and WC in males (and also correlated with HDL) in ages 61-70 years and females in ages 41-50 years with the metabolic syndrome. Conclusions: The increased IL18 level in both gender and different ages may have an important role in the alteration of some metabolic syndrome components. These alterations may be made to happen in different related metabolic diseases. IL18 seems to be a useful biomarker for the management of metabolic syndrome components and the risk factors of cardiovascular disease.

COVID-19: Mechanistic Model of the African Paradox Supports the Central Role of the NF-κB Pathway

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has expanded into a global pandemic, with more than 220 million affected persons and almost 4.6 million deaths by 8 September 2021. In particular, Europe and the Americas have been heavily affected by high infection and death rates. In contrast, much lower infection rates and mortality have been reported generally in Africa, particularly in the sub-Saharan region (with the exception of the Southern Africa region). There are different hypotheses for this African paradox, including less testing, the young age of the population, genetic disposition, and behavioral and epidemiological factors. In the present review, we address different immunological factors and their correlation with genetic factors, pre-existing immune status, and differences in cytokine induction patterns. We also focus on epidemiological factors, such as specific medication coverage, helminth distribution, and malaria endemics in the sub-Saharan region. An analysis combining different factors is presented that highlights the central role of the NF-κB signaling pathway in the African paradox. Importantly, insights into the interplay of different factors with the underlying immune pathological mechanisms for COVID-19 can provide a better understanding of the disease and the development of new targets for more efficient treatment strategies.

Immune Responses and Risk of Triple-negative Breast Cancer: Implications for Higher Rates among African American Women

The etiology of triple-negative breast cancers (TNBC) is poorly understood. As many TNBCs develop prior to the initiation of breast cancer screening or at younger ages when the sensitivity of mammography is comparatively low, understanding the etiology of TNBCs is critical for discovering novel prevention approaches for these tumors. Furthermore, the higher incidence rate of estrogen receptor-negative breast cancers, and specifically, of TNBCs, among young African American women (AAW) versus white women is a source of racial disparities in breast cancer mortality. Whereas immune responses to TNBCs have received considerable attention in relation to prognosis and treatment, the concept that dysregulated immune responses may predispose to the development of TNBCs has received limited attention. We present evidence that dysregulated immune responses are critical in the pathogenesis of TNBCs, based on the molecular biology of the cancers and the mechanisms proposed to mediate TNBC risk factors. Furthermore, proposed risk factors for TNBC, especially childbearing without breastfeeding, high parity, and obesity, are more prevalent among AAW than white women. Limited data suggest genetic differences in immune responses by race, which favor a stronger Thr type 2 (Th2) immune response among AAW than white women. Th2 responses contribute to wound-healing processes, which are implicated in the pathogenesis of TNBCs. Accordingly, we review data on the link between immune responses and TNBC risk and consider whether the prevalence of risk factors that result in dysregulated immunity is higher among AAW than white women.

Association between C reactive protein and microvascular and macrovascular dysfunction in sub-Saharan Africans with and without diabetes: the RODAM study

INTRODUCTION

Although inflammation assessed by elevated C reactive protein (CRP) concentration is known to be associated with risk of cardiovascular disease, its association with microvascular and macrovascular dysfunction in diabetes and non-diabetes remains unclear. We examined the association between CRP and diabetes and associated microvascular and macrovascular dysfunction in sub-Saharan Africans with and without diabetes.

RESEARCH DESIGN AND METHODS

Cross-sectional analyses of baseline data from the multicenter RODAM study (Research on Obesity and Diabetes among African Migrants) including 5248 Ghanaians (583 with diabetes, 4665 without diabetes) aged 25-70 years were done. Logistic regression analyses were used to examine the associations between CRP Z-scores and diabetes and microvascular (nephropathy) and macrovascular (peripheral artery disease (PAD)) dysfunction, with adjustments for age, sex, site of residence, smoking, body mass index, systolic blood pressure, and low-density lipoprotein cholesterol.

RESULTS

In the fully adjusted models, higher CRP concentration was significantly associated with diabetes (adjusted OR 1.13; 95% CI 1.05 to 1.21, p=0.002). In participants with diabetes, higher CRP concentration was associated with PAD (1.19; 1.03 to 1.41, p=0.046) but not nephropathy (1.13; 0.97 to 1.31, p=0.120). Among participants without diabetes, higher CRP concentration was associated with higher odds of PAD (1.10; 1.01 to 1.21, p=0.029) and nephropathy (1.12; 1.04 to 1.22, p=0.004).

CONCLUSIONS

In this study, higher CRP concentration was associated with higher odds of diabetes in sub-Saharan Africans. Also, higher CRP concentration was associated with higher odds of nephropathy and PAD in non-diabetes and higher odds of PAD in diabetes. CRP may be an important marker for assessment of risk of diabetes and risk for PAD and nephropathy in sub-Saharan Africans with and without diabetes.

Interleukin-18 and testosterone levels in men with metabolic syndrome

OBJECTIVE

Interleukin 18 (IL-18) is an adipokine associated with obesity. Data about the relationship of IL-18 to the metabolic syndrome (MS) are still scarce. Low testosterone (T) levels are common in men with MS, but we did not find data about the levels of IL-18 in men with low T. The aim of this study was to determine the levels of IL-18 in men with MS with or without low T.

PATIENTS AND METHODS

A total of 251 men were included in the study. Of them 218 had MS (IDF 2005) and they were divided according to their morning total testosterone (TT) level (cutoff 10.4 nmol/l) into two groups: MS-low T (N = 84) and MS-normal T (N = 134). The control group consisted of 33 men without MS and low T. IL-18 was determined in serum using enzyme-linked immunosorbent assay. A small group of eight men with MS and low T levels received testosterone therapy for three months and physical and laboratory parameters were monitored at the end of that period.

RESULTS

MS men were at mean age (±SD) = 53.77 ± 9.59 years; body mass index (BMI) = 34.0 ± 6.3 kg/m²; and TT = 12.59 ± 5.66 nmol/l. The control group was at age = 52.12 ± 5.2 years (NS); BMI = 25.6 ± 2.4 kg/m² (p < .001); and TT = 17.8 ± 5.68 nmol/l (p < .001), respectively. The levels of IL-18 were higher in the MS group - 345 pg/ml compared to the control one - 264 pg/ml (p < .01). There was no significant difference between MS-low T (330.6 pg/ml) and MS-normal T (350.2 pg/ml) subgroups. The MS-normal T differed more significantly from the control group (p < .001). Significant correlation of testosterone with IL-18 levels was not found. IL-18 correlated with parameters of obesity, lipids, fasting blood sugar (p < .05) and the number of criteria for MS (p < .001). Three months on T treatment showed improvement in obesity parameters and only in one patient IL-18 had clear reduction while the rest showed no change.

CONCLUSIONS

In this study, higher IL-18 levels were found in the presence of MS compared to healthy men, but they did not differ between men having MS with or without LOH.

Adiponectin, TNF-α and inflammatory cytokines and risk of type 2 diabetes: A systematic review and meta-analysis

AIMS

There has been growing evidence that adiponectin, tumor necrosis factor-α (TNF-α) and inflammatory cytokines involved in insulin resistance and may be attractive candidates for assessing risk of the incident type 2 diabetes (T2DM). A systematic review and meta-analysis of prospective studies was conducted to assess the associations of levels of serum adiponectin, TNF-α and inflammatory markers (Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), Interleukin-18 (IL-18), C-reactive protein (CRP)) with risk of T2DM.

MATERIALS/METHODS

We searched PubMed, ISI Web of Knowledge, EMBASE, and Cochrane Library databases up until February 1, 2016 for eligible studies which were matched to search subjects. Either fixed-effects or random-effects models were used to estimate the summary risk incorporated between study variations.

RESULTS

19 studies comprising a total of 39,136 participants and 7924 cases were included in the meta-analysis. Our findings showed that an obvious association of elevated CRP levels with T2DM risk (relative risk [RR] 1.48 [95% CI 1.26-1.71]), with the absence of publication bias. For IL-6, the meta-analysis involved 16 cohorts with a total of 24,929 participants and 4751 cases. Using data from all trials, a strong positive correlation (1.32 [1.14, 1.51]) was observed between basal plasma IL-6 and T2DM, whereas relatively lower relation between TNF-α (1.16 [0.87, 1.45]), IL-18 (1.45 [1.16, 1.73]), IL-1β (0.87, [0.59, 1.15]) and independently increased risk to occurrence of T2DM. Conversely, we also found that the level of adiponectin decreased significantly in patients with T2DM. Sensitivity analyses further supported the associations.

CONCLUSIONS

This meta-analysis indicates that T2DM risk as whole was strongly associated with elevated levels of inflammatory cytokines (IL-1β, IL-6, IL-18, CRP), TNF-α and low levels of adiponectin. Despite an overall detectable association in the meta-analysis, considerable heterogeneity existed between studies. Further work is needed, it seems clear that a complex interplay of inflammation and the development of DM. Moreover, these biomarkers are predictors of T2DM subjects and should take more attention to measure levels of these as well as to target therapy/interventions.

High-Sensitivity C-Reactive Protein Is Associated With Incident Type 2 Diabetes Among African Americans: The Jackson Heart Study

OBJECTIVE

Previous studies on the association between hs-CRP and incident type 2 diabetes among African Americans have been inconclusive. We examined the association between hs-CRP and incident diabetes in a large African American cohort (Jackson Heart Study).

RESEARCH DESIGN AND METHODS

hs-CRP was measured in 3,340 participants. Incident diabetes was defined by fasting glucose ≥126 mg/dL, physician diagnosis, use of diabetes drugs, or A1C ≥6.5% (48 mmol/mol) at follow-up. Cox regression was used to estimate hazard ratios (HRs) for incident diabetes, adjusting for age, sex, education, diabetes family history, alcohol, HDL, triglycerides, hypertension status, hypertension medications, physical activity, BMI, HOMA-insulin resistance (HOMAIR), and waist circumference.

RESULTS

Participants (63% women) were aged 53.3 ± 12.5 years. During a median follow-up of 7.5 years, 17.4% developed diabetes (23.1/1,000 person-years, 95% CI 21.3-25.1). After adjustment, the HR (hs-CRP third vs. first tertile) was 1.64 (95% CI 1.26-2.13). In separate models, further adjustment for BMI and waist circumference attenuated this association (HR 1.28 [95% CI 0.97-1.69] and 1.35 [95% CI 1.03-1.78, P < 0.05 for trend], respectively). Upon adding HOMAIR in the models, the association was no longer significant. In adjusted HOMAIR-stratified analysis, the hs-CRP-diabetes association appeared stronger in participants with HOMAIR <3.0 compared with HOMAIR ≥3.0 (P < 0.0001 for interaction). The association was also stronger among nonobese participants, although not significant when adjusted for HOMAIR.

CONCLUSIONS

Low-grade inflammation, as measured by hs-CRP level, may have an important role in the development of diabetes among African Americans with a lesser degree of insulin resistance.

Sleep apnea and retinal signs in cardiovascular disease: the Multi-Ethnic Study of Atherosclerosis

PURPOSE

The aim of the study was to examine the relationship between sleep apnea, retinal vascular caliber and retinopathy, and their impact on cardiovascular disease (CVD) risk.

METHODS

A multi-ethnic cohort of 5,803 participants was examined based on standardized grading of retinal vascular caliber and retinopathy from digital fundus photographs, self-reported physician-diagnosed sleep apnea (PDSA), and incident cardiovascular events.

RESULTS

In women, PDSA was associated with narrower arterioles (regression coefficient [β] -5.76; 95 % confidence Interval [CI] -8.51, -3.02) after adjusting for cardio-metabolic risk factors. The incident rate ratio (IRR) of CVD was also associated with narrower arterioles (IRR for highest versus lowest tertile 1.91; 95 % CI 1.08, 3.38). In men, PDSA was not associated with arteriolar caliber. However, incident CVD was associated with narrower arterioles (IRR 1.67; 95 % CI 1.10, 2.52), wider venules (IRR 1.71; 95 % CI 1.13, 2.59) and PDSA (IRR 2.03, 95 % CI 1.17, 3.51). The IRR of CVD in men with PDSA increased minimally to 2.06 (95 % CI 1.18, 3.56) after adjustment for retinal arteriolar and venular caliber. Combining women and men, the IRR of CVD was 3.41 (95 % CI 1.79, 6.50) in those with both PDSA and narrower retinal arterioles.

CONCLUSIONS

Sleep apnea was associated with narrower retinal arterioles in women but not in men. However, sleep apnea was also associated with incident CVD in men. These suggest potential gender differences in susceptibility to microvascular disease in association with sleep apnea.

Effects of statins on TH1 modulating cytokines in human subjects

Background. Activation of the innate immune system by cholesterol accelerates atherosclerosis. High levels or modified forms of cholesterol stimulate release of the inflammatory cytokines IL-12 and IL-18 that synergistically stimulate T lymphocytes to produce the atherogenic cytokine interferon-γ. While activation of the innate immune system by cholesterol is well-described in animal models and human subjects with high cholesterol levels or known atherosclerotic disease, the interaction of cholesterol and lipoproteins with the innate immune system in human subjects without known atherosclerosis is less well-described. The goal of our study was to assess the T_H1 modulating cytokines IL-12 p40 and IL-18, and their counter regulatory cytokines IL-18 binding protein and IL-27, to determine if their levels are linked to cholesterol levels or other factors.

Methods. We performed a blinded, randomized hypothesis-generating study in human subjects without known atherosclerotic disease. We measured serum lipids, lipoprotein levels, and collected plasma samples at baseline. Subjects were randomized to two weeks of therapy with atorvastatin, pravastatin, or rosuvastatin. Lipids and cytokine levels were measured after two weeks of statin treatment. Subjects were given a four-week statin-free period. At the end of the four-week statin-free period, venous blood was sampled again to determine if serum lipids returned to within 5% of their pre-statin levels. When lipid levels returned to baseline, subjects were again treated with the next statin in the randomization scheme. IL-12, IL-18, IL-18 binding protein, and IL-27 were measured at baseline and after each statin treatment to determine effects of statin treatment on their blood levels, and identify correlations with lipids and lipoproteins.

Results. Therapy with statins revealed no significant change in the levels of IL-12, IL-18, IL-18 binding protein or IL-27 levels. We found that IL-18 levels positively correlate with total cholesterol levels (r² = 0.15, p < 0.03), but not HDL or LDL cholesterol. In contrast, IL-12 p40 levels inversely correlated with total cholesterol (r² = −0.17, p < 0.008), HDL cholesterol (r² = −0.22, p < 0.002), and apolipoprotein A1 (r² = −0.21, p < 0.002). Similarly, IL-18 binding protein levels inversely correlated with apolipoprotein A1 levels (r² = −0.13, p < 0.02).

Conclusions. Our findings suggest that total cholesterol levels positively regulate IL-18, while HDL cholesterol and apolipoprotein A1 may reduce IL-12 p40 and IL-18 binding protein levels. Additional studies in a larger patient population are needed to confirm these findings, and verify mechanistically whether HDL cholesterol can directly suppress IL-12 p40 and IL-18 binding protein levels in human subjects.