Insulin gene polymorphisms in type I diabetes, Addison's disease and the polyglandular autoimmune syndrome type II

Background: Polymorphisms within the insulin gene can influence insulin expression in the pancreas and especially in the thymus, where self-antigens are processed, shaping the T cell repertoire into selftolerance, a process that protects from ß-cell autoimmunity. Methods: We investigated the role of the -2221Msp(C/T) and -23HphI(A/T) polymorphisms within the insulin gene in patients with a monoglandular autoimmune endocrine disease [patients with isolated type 1 diabetes (T1D, n = 317), Addison´s disease (AD, n = 107) or Hashimoto´s thyroiditis (HT, n = 61)], those with a polyglandular autoimmune syndrome type II (combination of T1D and/or AD with HT or GD, n = 62) as well as in healthy controls (HC, n = 275). Results: T1D patients carried significantly more often the homozygous genotype "CC" -2221Msp(C/T) and "AA" -23HphI(A/T) polymorphisms than the HC (78.5% vs. 66.2%, p = 0.0027 and 75.4% vs. 52.4%, p = 3.7 × 10-8, respectively). The distribution of insulin gene polymorphisms did not show significant differences between patients with AD, HT, or APS-II and HC. Conclusion: We demonstrate that the allele "C" of the -2221Msp(C/T) and "A" -23HphI(A/T) insulin gene polymorphisms confer susceptibility to T1D but not to isolated AD, HT or as a part of the APS-II

DRhigh+CD45RA−-Tregs Potentially Affect the Suppressive Activity of the Total Treg Pool in Renal Transplant Patients

Recent studies show that regulatory T cells (Tregs) play an essential role in tolerance induction after organ transplantation. In order to examine whether there are differences in the composition of the total CD4+CD127low+/−FoxP3+- Treg cell pool between stable transplant patients and patients with biopsy proven rejection (BPR), we compared the percentages and the functional activity of the different Treg cell subsets (DRhigh+CD45RA−-Tregs, DRlow+CD45RA−-Tregs, DR−CD45RA−-Tregs, DR−CD45RA+-Tregs). All parameters were determined during the three different periods of time after transplantation (0–30 days, 31–1,000 days, >1,000 days). Among 156 transplant patients, 37 patients suffered from BPR. The most prominent differences between rejecting and non-rejecting patients were observed regarding the DRhigh+CD45RA−-Treg cell subset. Our data demonstrate that the suppressive activity of the total Treg pool strongly depends on the presence of these Treg cells. Their percentage within the total Treg pool strongly decreased after transplantation and remained relatively low during the first year after transplantation in all patients. Subsequently, the proportion of this Treg subset increased again in patients who accepted the transplant and reached a value of healthy non-transplanted subjects. By contrast, in patients with acute kidney rejection, the DRhigh+CD45RA−-Treg subset disappeared excessively, causing a reduction in the suppressive activity of the total Treg pool. Therefore, both the monitoring of its percentage within the total Treg pool and the monitoring of the HLA-DR MFI of the DR+CD45RA−-Treg subset may be useful tools for the prediction of graft rejection

Causal effect of plasminogen activator inhibitor type 1 on coronary heart disease

Background--Plasminogen activator inhibitor type 1 (PAI-1) plays an essential role in the fibrinolysis system and thrombosis. Population studies have reported that blood PAI-1 levels are associated with increased risk of coronary heart disease (CHD). However, it is unclear whether the association reflects a causal influence of PAI-1 on CHD risk. Methods and Results--To evaluate the association between PAI-1 and CHD, we applied a 3-step strategy. First, we investigated the observational association between PAI-1 and CHD incidence using a systematic review based on a literature search for PAI-1 and CHD studies. Second, we explored the causal association between PAI-1 and CHD using a Mendelian randomization approach using summary statistics from large genome-wide association studies. Finally, we explored the causal effect of PAI-1 on cardiovascular risk factors including metabolic and subclinical atherosclerosis measures. In the systematic meta-analysis, the highest quantile of blood PAI-1 level was associated with higher CHD risk comparing with the lowest quantile (odds ratio=2.17; 95% CI: 1.53, 3.07) in an age- and sex-adjusted model. The effect size was reduced in studies using a multivariable-adjusted model (odds ratio=1.46; 95% CI: 1.13, 1.88). The Mendelian randomization analyses suggested a causal effect of increased PAI-1 level on CHD risk (odds ratio=1.22 per unit increase of log-transformed PAI-1; 95% CI: 1.01, 1.47). In addition, we also detected a causal effect of PAI-1 on elevating blood glucose and high-density lipoprotein cholesterol. Conclusions--Our study indicates a causal effect of elevated PAI-1 level on CHD risk, which may be mediated by glucose dysfunction

Percentage of different Treg subsets of the total Treg pool obtained from healthy non-transplanted volunteers and kidney transplant patients in the presence or absence of BPR.

*<p>: p<0.05; no BPR versus BPR.</p>***<p>: p<0.001; no BPR versus BPR.</p

Positive selection and functional testing of four different Treg subsets within the total CD4⁺CD127^low+/−CD25⁺-Treg pool.

<p>A: Magnetically isolated CD4⁺CD127^low+/−CD25⁺-Treg cells were stained with anti-HLA-DR and anti-CD45RA specific monoclonal antibodies and sorted into a population of DR^high+CD45RA⁻-, DR^low+CD45RA⁻-, DR⁻CD45RA⁻-, and naïve DR⁻CD45RA⁺-Treg cells. Subsequently the different Treg populations obtained from six different healthy non-transplanted volunteers were analyzed concerning their maximum suppressive activity (Treg/Tresp = 1/1) (B) and the minimum ratio of Treg/Tresp (titer) up to which the purified Tregs could be diluted to achieve a minimum suppressive activity of at least 15% (C).</p

Detection of the changes in the composition of the total CD4⁺CD127^low+/−FoxP3⁺-Treg cell pool with four different Treg subsets during the time after transplantation.

<p>The percentage of the DR^high+CD45RA⁻- (A), the DR^low+CD45RA⁻- (B), the DR⁻CD45RA⁺- (C), and the DR⁻CD45RA⁻- (D) Treg subset within the total Treg cell pool was estimated in healthy non-transplanted volunteers (▴) and in non-rejecting (♦) and rejecting kidney transplant patients (•) at different time points after transplantation. In addition the HLA-DR MFI of the DR⁺CD45RA⁻-Treg subset was determined for all participants in all patient groups (E). Monitoring the HLA-DR MFI allowed a significant discrimination between rejecting and non-rejecting patients, due to a significantly reduced percentage of the DR^high+CD45RA⁻-Treg subset within the total Treg pool. MFI = mean fluorescence intensity.</p

Correlation between the HLA-DR MFI of the DR⁺CD45RA⁻-Treg subset and the ratio of Treg/Tresp (titer) up to which a significant suppression could be achieved.

<p>CD4⁺CD127^low+/−CD25⁺-Tregs were purified from healthy non-transplanted volunteers (▴), kidney transplant patients with stable transplant function (♦) and kidney transplant patients with BPR (•). Their suppressive activity concerning the ratio of Treg/Tresp (titer) up to which the purified Treg cells could be diluted to achieve a minimum suppressive activity of at least 15% was related to the HLA-DR MFI of the DR⁺CD45RA⁻-Treg subset. The figure shows the positive correlation (r = 0.546, p<0.001) between the HLA-DR MFI of the DR⁺CD45RA⁻-Treg subset and the ratio of Treg/Tresp (titer). MFI = mean fluorescence intensity.</p

Clinical characteristics of kidney transplant patients.

<p>Clinical characteristics of kidney transplant patients.</p

Gating strategy for five color flow cytometric detection of the total CD4⁺CD127^low+/−FoxP3⁺-Treg cell pool and its composition with four different Treg-subsets.

<p>A: CD4⁺-T cells (P1) were gated by fluorescence intensity of CD4 versus side light scatter (SSC). B: CD4⁺CD127^low+/−FoxP3⁺-Treg cells were gated by fluorescence intensity of FoxP3 versus CD127 (P2). C–D: The percentage of the DR^high+CD45RA⁻- (P6), the DR^low+CD45RA⁻- (P7), the DR⁻CD45RA⁻- (P4) and the naïve DR⁻CD45RA⁺- (P5) Treg subset was estimated by analyzing CD4⁺CD127^low+/−CD25⁺Foxp3⁺-Treg cells (P2) for their expression of HLA-DR and CD45RA. In addition, the MFI of HLA-DR expression of the DR⁺CD45RA⁻FoxP3⁺-Treg subset (P3) was estimated for all participants. MFI = mean fluorescence intensity.</p

Cushing's syndrome: a model for sarcopenic obesity

PURPOSE: Obesity and its metabolic impairments are discussed as major risk factors for sarcopenia leading to sarcopenic obesity. Cushing's syndrome is known to be associated with obesity and muscle atrophy. We compared Cushing's syndrome with matched obese controls regarding body composition, physical performance, and biochemical markers to test the hypothesis that Cushing's syndrome could be a model for sarcopenic obesity. METHODS: By propensity score matching, 47 controls were selected by body mass index and gender as obese controls. Fat mass and muscle mass were measured by bioelectrical impedance analysis. Muscle function was assessed by chair rising test and hand grip strength. Biochemical markers of glucose and lipid metabolism and inflammation (hsCRP) were measured in peripheral blood. RESULTS: Muscle mass did not differ between Cushing's syndrome and obese controls. However, Cushing's syndrome patients showed significantly greater chair rising time (9.5 s vs. 7.3 s, p = 0.008) and significantly lower hand grip strength (32.1 kg vs. 36.8 kg, p = 0.003). Cushing's syndrome patients with impaired fasting glucose have shown the highest limitations in hand grip strength and chair rising time. CONCLUSIONS: Similar to published data in ageing medicine, Cushing's syndrome patients show loss of muscle function that cannot be explained by loss of muscle mass. Impaired muscle quality due to fat infiltration may be the reason. This is supported by the observation that Cushing's syndrome patients with impaired glucose metabolism show strongest deterioration of muscle function. Research in sarcopenic obesity in elderly is hampered by confounding comorbidities and polypharmacy. As Cushing's syndrome patients are frequently free of comorbidities and as Cushing's syndrome is potentially curable we suggest Cushing's syndrome as a clinical model for further research in sarcopenic obesity