Vivekanandhan Aravindhan

Increased Th1 and suppressed Th2 serum cytokine levels in subjects with diabetic coronary artery disease

BackgroundThe role played by T helper cytokines under chronic, low grade inflammation as seen in type-2 Diabetes Mellitus (T2DM) and Coronary Artery Disease (CAD) co-morbidity is less well studied. In the present study, we measured the serum levels of both Th1 and Th2 cytokines and correlated it with clinical risk factors for T2DM (Insulin Resistance (IR), Glycated haemoglobin (HbA1c)) and CAD (C-Reactive Protein (CRP), Intima Media Thickness (IMT) and Augmentation index (AGI)) in T2DM subjects with/without CAD.MethodologyThe study subjects were recruited from Chennai Urban Rural Epidemiology Study (CURES). Serum cytokine profile was determined by multiplex cytokine assay in Control (n = 61), T2DM (n = 60), CAD (n = 23) and T2DM-CAD (n = 21) subjects.ResultsT2DM subjects showed a mixed Th1-Th2 profile. CAD subjects presented a Th1 profile with modest Th2 suppression while T2DM-CAD subjects showed enhanced Th1 profile with strong suppression of Th2 cytokines. Both Th1 and Th2 cytokines showed a positive correlation with FPG, HbA1c, hsCRP, IMT and AGI. Logistic regression analysis revealed a significant association of IL-12 (OR = 9.3; 95% CI = 3.2-70.7; p = 0.016), IFN-γ (OR = 2.8; 95% CI = 2.7-2.9, p = 0.010), IL-4 (OR = 2.7; 95% CI 2.7-2.7, p = 0.010), IL-5 (OR = 1.1; 95% CI = 1.0-1.4; p = 0.003) and IL-13 (OR = 2; 95% CI = 1.7-2.6; p = 0.017) with T2DM-CAD.ConclusionIn conclusion, from the present study it appears that transition from T2DM or CAD to T2DM-CAD co-morbidity is associated with strong down regulation of Th2 cytokines and enhancement of Th1 responses.

Decreased prevalence of lymphatic filariasis among diabetic subjects associated with a diminished pro-inflammatory cytokine response (CURES 83).

Epidemiological studies have shown an inverse correlation between the incidence of lymphatic filariasis (LF) and the incidence of allergies and autoimmunity. However, the interrelationship between LF and type-2 diabetes is not known and hence, a cross sectional study to assess the baseline prevalence and the correlates of sero-positivity of LF among diabetic subjects was carried out (n = 1416) as part of the CURES study. There was a significant decrease in the prevalence of LF among diabetic subjects (both newly diagnosed [5.7%] and those under treatment [4.3%]) compared to pre-diabetic subjects [9.1%] (p = 0.0095) and non-diabetic subjects [10.4%] (p = 0.0463). A significant decrease in filarial antigen load (p = 0.04) was also seen among diabetic subjects. Serum cytokine levels of the pro-inflammatory cytokines—IL-6 and GM-CSF—were significantly lower in diabetic subjects who were LF positive, compared to those who were LF negative. There were, however, no significant differences in the levels of anti-inflammatory cytokines—IL-10, IL-13 and TGF-β—between the two groups. Although a direct causal link has yet to be shown, there appears to be a striking inverse relationship between the prevalence of LF and diabetes, which is reflected by a diminished pro-inflammatory cytokine response in Asian Indians with diabetes and concomitant LF.

Increased Levels of Both Th1 and Th2 Cytokines in Subjects with Metabolic Syndrome (CURES-103)

OBJECTIVE Metabolic syndrome (MS) is a cluster of metabolic abnormalities associated with obesity, insulin resistance (IR), dyslipidemia, and hypertension in which inflammation plays an important role. Few studies have addressed the role played by T cell-derived cytokines in MS. The aim of the study was to look at the T-helper (Th) 1 (interleukin [IL]-12, IL-2, and interferon-γ [IFN-γ]) and Th2 (IL-4, IL-5, and IL-13) cytokines in MS in the high-risk Asian Indian population. RESEARCH DESIGN AND METHODS Study subjects were recruited from the Chennai Urban Rural Epidemiology Study. MS was defined using National Cholesterol Education Program-Adult Treatment Panel III criteria modified for waist according to World Health Organization Asia Pacific guidelines. Serum cytokine profile was determined by multiplex cytokine assay in subjects with (n = 21) and without (n = 33) MS. RESULTS Both Th1 and Th2 cytokines showed up-regulation in MS. IL-12 (5.40 pg/mL in MS vs. 3.24 pg/mL in non-MS; P < 0.01), IFN-γ (6.8 pg/mL in MS vs. 4.7 pg/mL in non-MS; P < 0.05), IL-4 (0.61 pg/mL in MS vs. 0.34 pg/mL in non-MS; P < 0.001), IL-5 (4.39 pg/mL in MS vs. 2.36 pg/mL in non-MS; P < 0.001), and IL-13 (3.42 pg in MS vs. 2.72 pg/mL in non-MS; P < 0.01) were significantly increased in subjects with MS compared with those without. Both Th1 and Th2 cytokines showed a significant association with fasting plasma glucose level even after adjusting for age and gender. The Th1 and Th2 cytokines also showed a negative association with adiponectin and a positive association with the homeostasis model of assessment of IR and high-sensitivity C-reactive protein. CONCLUSIONS Apart from pro-inflammatory cytokines, Th cytokines might play an important role in inflammation, IR, and MS.

Decreased prevalence of lymphatic filariasis among subjects with type-1 diabetes

Several animal studies have shown a protective effect of helminth infections against type-1 diabetes mellitus (T1DM). However, epidemiologic studies demonstrating this protective relationship with T1DM are largely lacking, although an inverse correlation between the prevalence of lymphatic filariasis (LF) and prevalence of allergies and autoimmunity has been shown. A cross-sectional study was undertaken in southern India to assess the baseline prevalence of seropositivity of LF among persons with T1DM (n = 200) and normal glucose tolerant (NGT) persons (n = 562). The prevalence of LF was 0% among persons with T1DM and 2.6% among NGT persons (P = 0.026). The percentage of persons who were positive for filarial antigen-specific IgG4 (but not antigen-specific IgG) was also significantly lower in persons with T1DM (2%) compared with NGT persons (28%) (P < 0.001). Thus, there appears to be a striking inverse relationship between the prevalence of LF and T1DM in southern India.

Association of Cystatin-C with Metabolic Syndrome in Normal Glucose-Tolerant Subjects (CURES-97)

BACKGROUND This study looked at the association of cystatin-C (cys-C) with severity of metabolic syndrome in Asian Indians. METHODS Five sets of normal glucose tolerance subjects were recruited from the Chennai Urban Rural Epidemiology Study (CURES), a population-based study in southern India: 43 subjects with no metabolic risk factors, 44 subjects with one metabolic risk factor, 37 subjects with two risk factors, 40 subjects with three risk factors, and 40 subjects with four or five metabolic risk factors. Metabolic syndrome was defined using National Cholesterol Education Program criteria for adults modified for waist measured using the World Health Organization Asia Pacific guidelines. Serum cys-C was estimated by a high-sensitivity particle-enhancing nephelometry assay. RESULTS Subjects with four or five metabolic abnormalities had the highest cys-C levels, and with decreasing number of metabolic abnormalities, the cys-C levels decreased linearly (P for trend < 0.001). Regression analysis showed a linear increase in cys-C levels with increasing number of metabolic abnormalities. CONCLUSION Cys-C levels are highly correlated with the number of metabolic abnormalities in Asian Indians.

Increased Levels of Serum Granulocyte-Macrophage Colony-Stimulating Factor Is Associated with Activated Peripheral Dendritic Cells in Type 2 Diabetes Subjects (CURES-99)

BACKGROUND Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a pro-inflammatory cytokine with growth factor-like properties for monocytes and dendritic cells (DCs). In the present study, serum GM-CSF levels and the activation status of DCs were studied in type 2 diabetes mellitus (T2DM) subjects. METHODS Study subjects were recruited from the Chennai Urban Rural Epidemiology Study. Healthy controls (n=45) and T2DM patients (n=45) were included in the study. Serum levels of GM-CSF, interleukin-1β, interleukin-6, and tumor necrosis factor-α were measured. Enumeration of circulating DCs (myeloid [m] and plasmocytoid [p]) and its surface antigen expression were quantified by flow cytometry. RESULTS The serum GM-CSF levels were significantly higher among diabetes subjects compared with subjects without diabetes and showed a positive correlation with glycated hemoglobin (r=0.208, P=0.018). The serum GM-CSF levels were lower in subjects on combined insulin and oral hypoglycemic agents (OHA) treatment (1.09 pg/mL) compared with those taking OHA alone (1.9 pg/mL). The increased GM-CSF levels were associated with the activated phenotype of mDCs and pDCs, as determined by up-regulation of the lineage markers. CONCLUSION The activated state of mDCs and pDCs seen among diabetes subjects might be due to the increased levels of GM-CSF and other pro-inflammatory cytokines.

Decreased serum interleukin-17 and increased transforming growth factor-β levels in subjects with metabolic syndrome (Chennai Urban Rural Epidemiology Study-95).

The term metabolic syndrome (MS) refers to a conglomeration of many metabolic disorders. Recent studies suggest that inflammation plays a vital role in MS. There are however no data available on the recently characterized novel T-cell-derived cytokine interleukin (IL)-17 in MS; studies on the anti-inflammatory cytokine transforming growth factor (TGF)-β are also limited. The aim of the study was to look at IL-17 and TGF-β levels in subjects with and without MS. The study subjects were recruited from the Chennai Urban Rural Epidemiology Study (CURES), a population-based study in Chennai (formerly Madras) in southern India. Group 1 consisted of subjects without MS (non-MS) (n = 98) and group 2 consisted of subjects with MS (n = 156). MS was defined using the National Cholesterol Education Program Adult Treatment Panel III criteria modified for waist, according to the World Health Organization Asia Pacific guidelines. Serum IL-17 and TGF-β levels were estimated by enzyme-linked immunosorbent assay. Interleukin-17 levels were decreased (P < .001) and TGF-β levels (P < .001) were increased in subjects with MS compared to those without. With an increase in the number of metabolic risk factors, the IL-17 levels showed a decline, whereas the TGF-β levels showed an increase (P < .001). With respect to individual components of MS, TGF-β and IL-17 showed a significant association with blood pressure and blood glucose even after adjusting for age and sex. We report that IL-17 levels are decreased, whereas TGF-β levels are increased, among Asian Indians with MS.

Serum IL-9, IL-17, and TGF-β levels in subjects with diabetic kidney disease (CURES-134).

The role of inflammation in both diabetes and diabetic kidney disease (DKD) is becoming more widely accepted. However, the role of recently characterized T cell cytokines interleukin (IL)-9 and IL-17 in diabetes and especially DKD is less well studied. Transforming growth factor beta (TGF-β) controls the secretion of both of these cytokines. In this study, we estimated the levels of IL-9, IL-17, and TGF-β in the serum of subjects with normal glucose tolerance (NGT = 88) and subjects with type 2 diabetes without (diabetes mellitus (DM) = 65) and with DKD (DKD = 97) using enzyme-linked immunosorbent assay (ELISA), and we correlated these levels with the clinical risk factors of diabetes and DKD. IL-17 levels showed a serial decline and TGF-β levels showed a serial increase from NGT to DM to DKD (p < 0.001). However, the IL-9 levels were significantly reduced in the DM group compared to the NGT and DKD group (p < 0.001). While TGF-β and IL-17 showed a positive and negative correlation, respectively, with fasting and postprandial glucose levels and glycated hemoglobin (HbA1c), IL-9 showed positive correlation with urea and microalbuminuria. Apart from pro-inflammatory cytokines, T helper (Th) cytokines might play an important role in insulin resistance and DKD.

Chronic Endotoxemia in Subjects with Type-1 Diabetes Is Seen Much before the Onset of Microvascular Complications

Background Lipopolysaccharide (LPS)/Endotoxin is hypothesized to play an important role in chronic inflammation associated with Type-1 diabetes (T1DM) and its complications. Endotoxin core antibodies (EndoCAb), LPS binding protein (LBP) and soluble CD14 (sCD14) act as modulators of LPS induced activation of innate immune system in vivo. For the present study we estimated the levels of LPS and its translocation markers in T1DM subjects with and without microvascular complications (MVC) and correlate them with clinical parameters of T1DM and serum inflammatory cytokine levels (TNF-α, IL-6, IL-1β and GM-CSF). Methods A total of 197 subjects (64 normal glucose tolerance (NGT) subjects, 97 T1DM subjects without MVC and 36 with MVC) were included in this study and the levels of serum LPS, its translocation markers and cytokines measured by immunoassays. Results Compared to NGT, T1DM subjects (both with and without MVC) had significantly higher levels of LPS, reduced levels of LBP and EndoCAb along with significant increase in the levels of IL-1β, IL-6, TNF-α and GM-CSF (p<0.05). No significant change was seen in the levels of these biomarkers between T1DM subjects with and without MVC. Conclusions Decreased levels of EndoCAb and LBP suggest sustained endotoxin activity in T1DM subjects even before the onset of microvascular complications.

Circulating Levels of High Molecular Weight (HMW) Adiponectin and Total Adiponectin in Relation to Fat Distribution, Oxidative Stress and Inflammation in Asian Indians

Aim: To look at the association of total and high molecular weight (HMW) adiponectin with markers of fat distribution, oxidative stress and inflammation in Asian Indians. Methods: A total of 120 subjects were chosen randomly from Chennai Urban Rural Epidemiological Study. Fasting HMW adiponectin levels, TNF-alpha and oxidized LDL were measured using ELISA. High sensitivity C reactive protein (hsCRP) was measured by a high sensitive nephelometric assay. Lipid peroxidation was measured by Tbars assay and protein carbonyl content was assessed by DNPH assay. Visceral and subcutaneous fat areas were assessed by computed tomography (CT) scan. When stratified based on the tertiles of visceral fat, the levels of total (p = 0.03) and HMW adiponectin (p = 0.007) were highest in the first tertile followed by tertiles 2 and 3 whereas in tertiles of subcutaneous fat, there was no such trend. With increasing tertiles of Tbars, the levels of total (p = 0.03) and HMW adiponectin decreased (p = 0.002). The levels of HMW (p < 0.001) but not total adiponectin was also found to decrease with increasing tertiles of Protein carbonyl content. The levels of Total (p = 0.02) and HMW adiponectin (p = 0.004) were highest in the first tertile of oxidized LDL followed by tertile 2 and tertile 3. With increasing tertiles of TNF-alpha total (p = 0.01) and HMW adiponectin (p = 0.004) was found to decrease. With increasing tertiles of hs-CRP, Total (p = 0.005) and HMWadiponectin (p = 0.007)was found to decrease. Conclusion: Oxidative stress markers, visceral but not subcutaneous fat and inflammation are associated with total and HMW adiponectin levles in Asian Indians.