Systemic immune mediators and lifestyle changes in the prevention of type 2 diabetes: results from the Finnish Diabetes Prevention Study.

The Finnish DPS (Diabetes Prevention Study) demonstrated that lifestyle intervention, aimed at increasing physical activity, improving diet, and decreasing body weight, reduced the incidence of type 2 diabetes in individuals with overweight and impaired glucose tolerance by 58%. Here, we studied which immunological markers at baseline predicted subsequent type 2 diabetes and whether there are immunologically defined subsets of subjects who are more or less responsive to the protective effects of lifestyle intervention. We randomly assigned 522 participants to a control group (n = 257) or a lifestyle intervention group (n = 265). Immunological parameters at baseline included high-sensitivity C-reactive protein (CRP), serum amyloid A, interleukin-6, regulated on activation normal T-cell expressed and secreted (RANTES), macrophage migration inhibitory factor (MIF), and soluble intercellular adhesion molecule. In the control group, CRP was the best immunological predictor for progression to overt type 2 diabetes. In the intervention group, progression to type 2 diabetes was significantly higher in subjects with the highest RANTES concentrations and was lower in subjects with the highest MIF levels. Ratios of RANTES to MIF in the upper tertile were highly predictive of incident type 2 diabetes in the intervention group (P = 0.006), whereas the association was less pronounced in the control group (P = 0.088). Thus, systemic concentrations of immune mediators appear to be associated with the progression to type 2 diabetes and the prevention of type 2 diabetes by lifestyle changes.

Differential expression of chemokines, risk of stable coronary heart disease, and correlation with established cardiovascular risk markers.

OBJECTIVE: We investigated the association of several chemokines with the risk of stable coronary heart disease (CHD) in a large case-control study after adjustment for other established risk factors. Furthermore, we analyzed their correlation with various acute-phase proteins, inflammation-associated cytokines, and an adhesion molecule. METHODS AND RESULTS: We included 312 patients aged 40 to 68 years with angiographically confirmed and stable CHD and 472 age- and gender-matched controls in this study. The main outcome measure was the odds ratio (OR) for CHD associated with increased levels of interferon (INF)-inducible protein of 10 kd (IP-10), interleukin (IL)-8, regulated on activation normal T-cell expressed and secreted (RANTES), monocyte chemoattractant protein 1 (MCP-1), macrophage inflammation protein 1alpha (MIP-1alpha), or eotaxin determined by rigidly evaluated sandwich ELISAs. Serum levels of IP-10 and IL-8 were higher, and serum levels of RANTES were lower in CHD patients when compared with age- and gender-matched controls. In addition, values in the second and top tertile of IP-10 and IL-8 were associated with an increased OR for CHD when compared with values in the bottom tertile [OR for IP-10 (top tertile) was 2.62 (95% CI, 1.79 to 3.85) in the age- and gender-adjusted model and 1.93 (95% CI, 1.23 to 3.04) in the fully adjusted model, and for IL-8, the OR was 1.77 (95% CI, 1.20 to 2.59) and 1.53 (95% CI, 0.98 to 2.39), respectively]; increased RANTES values were associated with a lower OR for CHD [OR, 0.67 (95% CI, 0.47 to 0.96) and 0.61 (95% CI, 0.40 to 0.94)]. Furthermore, positive correlations of IP-10 and IL-8 with several acute-phase proteins or inflammation-associated cytokines were evident, and positive correlations for IP-10 plasma viscosity and intercellular adhesion molecule 1 were also present. CONCLUSIONS: The current study suggests that there may be no universal upregulation of chemokines in CHD-associated inflammation but different upregulation of IP-10 and IL-8 versus downregulation of RANTES; there was no clear disease association for MCP-1, MIP-1alpha, or eotaxin.

Association of systemic concentrations of macrophage migration inhibitory factor with impaired glucose tolerance and type 2 diabetes: results from the Cooperative Health Research in the Region of Augsburg, Survey 4 (KORA S4).

OBJECTIVE: Macrophage migration inhibitory factor (MIF) is a central cytokine in innate immunity. MIF expression can be regulated by glucose and insulin, but data on the association with type 2 diabetes are sparse. The aim of this study was to test whether MIF is associated with impaired glucose tolerance (IGT) and type 2 diabetes and whether these associations are independent of metabolic and immunological risk factors and to compare the associations of MIF and IGT/type 2 diabetes with those of C-reactive protein (CRP) and interleukin-6 (IL-6) with IGT/type 2 diabetes. RESEARCH DESIGN AND METHODS: The Cooperative Health Research in the Region of Augsburg/Kooperative Gesundheitsforschung im Raum Augsburg, Survey 4 (KORA S4) is a population-based survey performed in Southern Germany (1999-2001). Of 1,653 participants aged 55-74 years, 236 patients with type 2 diabetes, 242 subjects with IGT, and 244 normoglycemic control subjects matched for age and sex were included in this cross-sectional study. Serum concentrations of MIF were measured by enzyme-linked immunosorbent assay. RESULTS: Serum MIF concentrations are highly increased in individuals with IGT and type 2 diabetes. The associations of MIF with IGT and type 2 diabetes were independent of classical risk factors and of CRP and IL-6 and were much stronger before and after multivariate adjustment than the associations of CRP and IL-6 with IGT and type 2 diabetes. CONCLUSIONS: Our data suggest that elevations of systemic MIF concentrations precede the onset of type 2 diabetes. This finding may be relevant because MIF has been reported to contribute to the development of type 2 diabetes-related diseases such as atherosclerosis and cancer.

Hypoadiponectinemia and proinflammatory state: two sides of the same coin?: results from the Cooperative Health Research in the Region of Augsburg Survey 4 (KORA S4).

OBJECTIVE: Previous studies have yielded conflicting results on the association of adiponectin levels and inflammation. Low systemic concentrations of adiponectin, as well as elevated levels of immune mediators, represent risk factors for the development of type 2 diabetes and coronary artery disease. The major aim of this cross-sectional study was to investigate the interdependence of hypoadiponectinemia and low-grade systemic inflammation. RESEARCH DESIGN AND METHODS: The study sample consisted of 606 participants aged 55-74 years (244 with normal glucose tolerance, 242 with impaired glucose tolerance, and 120 with newly diagnosed type 2 diabetes) of the population-based KORA S4 (Cooperative Health Research in the Region of Augsburg Survey 4; 1999-2001). Systemic concentrations of adiponectin and a wide range of anthropometric, metabolic, and inflammatory variables were available for analyses. The association of adiponectin with 15 immunological markers, including leukocyte count, acute-phase proteins, cytokines, cytokine receptors, and chemokines, was assessed using univariable and multivariable models. RESULTS: No evidence for a significant correlation between adiponectin and all immunological parameters except eotaxin could be found after multivariable adjustments, whereas multiple strong correlations with obesity and metabolic factors were present. CONCLUSIONS: From these data, we conclude that hypoadiponectinemia and a proinflammatory state are largely independent from each other.

Association of systemic chemokine concentrations with impaired glucose tolerance and type 2 diabetes: results from the Cooperative Health Research in the Region of Augsburg Survey S4 (KORA S4).

Chemokines are crucial immune mediators in many physiological and pathophysiological conditions. Chemokines have been hypothesized to be involved in macrophage infiltration into adipose tissue in obesity and might therefore play an important role in the development of obesity-related disorders like type 2 diabetes. Out of 1,653 individuals aged 55-74 years participating in a population-based survey in southern Germany (the Kooperative Gesundheitsforschung in der Region Augsburg [KORA] [Cooperative Health Research in the Region of Augsburg] Survey S4, 1999-2001), 236 individuals with type 2 diabetes, 242 subjects with impaired glucose tolerance (IGT), and 244 normoglycemic control subjects were studied for circulating concentrations of interleukin (IL)-8; RANTES (regulated on activation, normal T-cell expressed, and secreted); interferon-gamma-inducible protein-10 (IP-10), and eotaxin. Systemic concentrations of RANTES were higher in individuals with IGT or type 2 diabetes than in control subjects, whereas IL-8 levels were elevated in type 2 diabetic patients only (P < 0.001 for all comparisons). IP-10 and eotaxin were not significantly associated with IGT or type 2 diabetes. Adjustment for age, sex, BMI, hypertension, LDL cholesterol, HDL cholesterol, uric acid, C-reactive protein, and IL-6 did not alter these findings. Our findings indicate that RANTES and IL-8 may be involved in the development of type 2 diabetes independent of metabolic syndrome-related risk factors and of each other. There is no general upregulation of chemokine production in type 2 diabetes, but rather an association of the disease with specific members of the chemokine family.

Systemic monocyte chemoattractant protein-1 concentrations are independent of type 2 diabetes or parameters of obesity: results from the Cooperative Health Research in the Region of Augsburg Survey S4 (KORA S4).

OBJECTIVE: Data on the relevance of monocyte chemoattractant protein (MCP)-1 in the pathophysiology of type 2 diabetes (T2D) and obesity are inconsistent. Since MCP-1 is produced by adipocytes and has been postulated to be involved in macrophage infiltration into adipose tissue, we wanted to test whether serum MCP-1 levels were correlated with T2D or obesity. DESIGN AND METHODS: Out of 1653 individuals aged 55 to 74 years participating in the population-based KORA Survey S4 (KORA/Cooperative Health Research in the Region of Augsburg) in Southern Germany, 236 patients with T2D, 242 subjects with impaired glucose tolerance and 244 normoglycaemic controls matched for age and sex were analysed for circulating MCP-1 concentrations. RESULTS: MCP-1 serum concentrations were not associated with impaired glucose tolerance, type 2 diabetes or several parameters of obesity. Moreover, systemic MCP-1 levels were not significantly correlated with all but one (fasting triglycerides) of the biochemical markers tested. CONCLUSIONS: Our data indicate that MCP-1 levels are not associated with T2D and that the contribution of fat mass to systemic MCP-1 protein might be low, suggesting that the possible local pathogenic role of MCP-1 may not be reflected by increased systemic levels of MCP-1.

Production and release of macrophage migration inhibitory factor from human adipocytes.

BACKGROUND AND AIM OF THE STUDY: Macrophage migration inhibitory factor (MIF) has been identified as a critical mediator of inflammatory responses. Because of its potent migration inhibition activity, it regulates macrophage accumulation in tissues. We therefore analyzed whether human adipocytes produce MIF, in the search of candidate mediators of macrophage infiltration of obese adipose tissue. METHODS: Human adipose tissue samples were obtained from various depots. The precursor cells were allowed to differentiate under defined adipogenic culture conditions. MIF expression was analyzed by RT-PCR, ELISA, and immunocytochemistry. RESULTS: Human preadipocytes secreted MIF in a differentiation-dependent fashion with maximum concentrations at d 12, whereas MIF mRNA was detected in both undifferentiated and differentiated cells at relatively constant levels. Immunocytochemical analysis showed that MIF protein was present in preadipocytes and more pronounced in differentiated adipocytes. Freshly isolated mature adipocytes from sc, omental, and mammary depots released MIF at rates of up to 10,000 pg/ml.24 h. Most importantly, MIF production was positively correlated with donor body mass index. Secretion of MIF was not influenced by lipopolysaccharide, interferon-gamma, or IL-4. The rates of MIF release from sc and omental adipocytes were similar but approximately 10 times higher compared with mammary adipocytes. CONCLUSIONS: Human preadipocytes and mature adipocytes from different depots spontaneously release substantial amounts of MIF. Expression levels were positively associated with donor body mass index. Hence, MIF may be an obesity-dependent mediator of macrophage infiltration of adipose tissue.

The proatherogenic cytokine interleukin-18 is secreted by human adipocytes.

OBJECTIVE: Interleukin (IL)-18, an important mediator of innate immunity and strong risk factor for the development of cardiovascular disease, was shown recently to be elevated in obesity. The aim of our study was to investigate whether human adipocytes produce IL-18. METHODS: Human adipose tissue was obtained from lean women undergoing elective plastic surgery and from obese individuals undergoing laparoscopic surgery (gastric banding). Preadipocytes from mammary adipose tissue were isolated and differentiated under defined adipogenic conditions. IL-18 expression was analyzed by real-time reverse transcriptase PCR, ELISA and immunocytochemistry. RESULTS: Human preadipocytes of all differentiation stages spontaneously secreted IL-18. In parallel significant amounts of IL-18 mRNA were detected. Freshly isolated mature adipocytes from subcutaneous and omental depots also released IL-18. IL-18 release from adipocytes from obese donors was about 3-fold higher compared to adipocytes from non-obese donors. CONCLUSIONS: We conclude that human adipose tissue produces IL-18 and thereby contributes to systemic IL-18 concentrations. This finding supports the concepts that adipocytes behave as primitive immune cells and that IL-18 may mediate some of the detrimental complications of obesity such as cardiovascular disease and type 2 diabetes.

Evaluation of diagnostic relevance of mRNA levels in peripheral blood: predictive value for mortality in hemodialysis patients.

In clinical practice, diagnosis and risk prediction are usually based on the analysis of serum or plasma proteins whereas gene expression analysis is not used on a routine basis. In order to compare the diagnostic and predictive relevance of serum protein and peripheral blood mRNA levels, we determined cytokine levels of end-stage renal failure patients undergoing hemodialysis. These patients face a high mortality mainly due to acceleration of atherosclerosis and subsequent severe vascular events. mRNA expression of the pro-inflammatory cytokine TNF alpha was significantly elevated in hemodialysis patients and further increased after 2 h of dialysis treatment. In contrast, gene expression of the anti-inflammatory cytokine TGF beta was significantly decreased. Patients who died during the observation period of 36 months had significantly increased mRNA levels of TNF alpha and decreased TGF beta mRNA expression at baseline. Survival analysis indicated that increased TNF alpha mRNA levels (P < 0.02) and TNF alpha/TGF beta mRNA ratios (P < 0.001) predict mortality. The corresponding cytokines in serum showed some association with disease, but serum concentrations neither changed during hemodialysis nor predicted mortality. This study shows that gene expression patterns of circulating leukocytes may present an important new diagnostic tool to predict clinical outcome in patients with inflammatory vascular diseases.