Identification of particular groups of microRNAs that positively or negatively impact on beta cell function in obese models of type 2 diabetes

Aims/hypothesis

MicroRNAs are key regulators of gene expression involved in health and disease. The goal of our study was to investigate the global changes in beta cell microRNA expression occurring in two models of obesity-associated type 2 diabetes and to assess their potential contribution to the development of the disease.

Methods

MicroRNA profiling of pancreatic islets isolated from prediabetic and diabetic db/db mice and from mice fed a high-fat diet was performed by microarray. The functional impact of the changes in microRNA expression was assessed by reproducing them in vitro in primary rat and human beta cells.

Results

MicroRNAs differentially expressed in both models of obesity-associated type 2 diabetes fall into two distinct categories. A group including miR-132, miR-184 and miR-338-3p displays expression changes occurring long before the onset of diabetes. Functional studies indicate that these expression changes have positive effects on beta cell activities and mass. In contrast, modifications in the levels of miR-34a, miR-146a, miR-199a-3p, miR-203, miR-210 and miR-383 primarily occur in diabetic mice and result in increased beta cell apoptosis. These results indicate that obesity and insulin resistance trigger adaptations in the levels of particular microRNAs to allow sustained beta cell function, and that additional microRNA deregulation negatively impacting on insulin-secreting cells may cause beta cell demise and diabetes manifestation.

Conclusions/interpretation

We propose that maintenance of blood glucose homeostasis or progression toward glucose intolerance and type 2 diabetes may be determined by the balance between expression changes of particular microRNAs.     

Identification of circulating microRNAs in HNF1A-MODY carriers

Aims/hypothesis

HNF1A-MODY is a monogenic form of diabetes caused by mutations in the HNF1A gene. Here we identify, for the first time, HNF1A-MODY-associated microRNAs (miRNAs) that can be detected in the serum of HNF1A-MODY carriers.

Methods

An miRNA array was carried out in rat INS-1 insulinoma cells inducibly expressing the common human Pro291fsinsC-HNF1A frame shift mutation. Differentially expressed miRNAs were validated by quantitative real-time PCR. Expression of miRNAs in the serum of HNF1A-MODY carriers (n?=?31), MODY-negative family members (n?=?10) and individuals with type 2 diabetes mellitus (n?=?17) was quantified by absolute real-time PCR analysis.

Results

Inducible expression of Pro291fsinsC-HNF1A in INS-1 cells caused a significant upregulation of three miRNAs (miR-103, miR-224, miR-292-3p). The differential expression of two miRNAs (miR-103 and miR-224) was validated in vitro. Strongly elevated levels of miR-103 and miR-224 could be detected in the serum of HNF1A-MODY carriers compared with MODY-negative family controls. Serum levels of miR-103 distinguished HNF1A-MODY carriers from HbA_1c-matched individuals with type 2 diabetes mellitus.

Conclusions/interpretation

Our study demonstrates that the pathophysiology of HNF1A-MODY is associated with the overexpression of miR-103 and miR-224. Furthermore, our study demonstrates that these miRNAs can be readily detected in the serum of HNF1A-MODY carriers.     

Association analysis of genetic variants in microRNA networks and gastric cancer risk in a Chinese Han population

Purpose

To investigate associations between genetic variants involved in microRNA networks (microRNA biogenesis, microRNA and microRNA binding sites) and risk of gastric cancer.

Methods

We genotyped 19 SNPs of the microRNA-related genes in a case–control study of 311 gastric cancers and 425 cancer-free controls in a Chinese Han population.

Results

We found that two of the SNPs were significantly associated with gastric cancer. Inhibitory effect of minor allele T of rs2071504 SNP within the exon of POLR2A gene was significantly associated with gastric carcinogenesis (p?=?0.033, aOR?=?0.742, 95%CI?=?0.564–0.977) and the SNP rs895819 in the miR-27a gene with the minor allele C presented significantly reduced risk to gastric cancer (p?=?0.037, aOR?=?0.771, 95%CI?=?0.604–0.985). Further stratified analysis with regard to clinical pathological parameters of the patients indicated that the SNP rs2071504 was associated with lymph node metastasis (p?=?0.021, aOR?=?0.529, 95%CI?=?0.307–0.910) and TMN stage (p?=?0.021, aOR?=?0.532, 95%CI?=?0.311–0.908), respectively.

Conclusions

Our findings provided evidence that the SNP rs2071504 in the exon of POLR2A gene would not only confer a decreased risk of gastric cancer, but also influence lymph node metastasis and TMN stage of gastric cancer in the Chinese population.     

Up-regulation of miR-182 expression in colorectal cancer tissues and its prognostic value

Purpose

Accumulating evidences indicate that dysregulated microRNAs (miRNA) are involved in cancer tumorigenesis and progression. In the present study, we evaluated the expression of miR-182 in colorectal cancer and adjacent noncancerous tissues and explored its associations with clinicopathological characteristics and prognosis.

Methods

Quantitative real-time PCR was used to analyze the expression of miR-182 in 148 pairs of colorectal cancer and adjacent noncancerous tissues. The relationship between miR-182 expression and clinicopathological characteristics in colorectal cancer tissues was estimated using Mann–Whitney U test or Kruskal–Wallis test, as appropriate. We calculated the survival curves and prognostic values of each variable by the Kaplan–Meier method and Cox proportional hazards regression analysis, respectively.

Results

The expression of miR-182 was found up-regulated in colorectal cancer tissues compared with adjacent noncancerous tissues (p?<?0.001), and its up-regulation was significantly correlated with large tumor size (p?=?0.016), positive regional lymph node metastasis (p?=?0.008), and advanced tumor–node–metastasis stage (p?=?0.020). Furthermore, Kaplan–Meier analysis demonstrated that high miR-182 expression predicted poor survival (p?=?0.001), and Cox proportional hazards risk analysis indicated that miR-182 was an independent prognostic factor for colorectal cancer.

Conclusions

MiR-182 was up-regulated in colorectal cancer tissues and correlated with adverse clinical characteristics and poor prognosis, indicating that miR-182 might be involved in colorectal cancer progression and could be used as a potential prognostic biomarker and therapeutic target in the management of colorectal cancer.     

Expression of anti-inflammatory macrophage genes within skeletal muscle correlates with insulin sensitivity in human obesity and type 2 diabetes

Aims/hypothesis

Low-grade systemic inflammation and adipose tissue inflammatory macrophages are frequently detected in patients with obesity and type 2 diabetes. Whether inflammatory macrophages also increase in skeletal muscle of individuals with metabolic disorders remains controversial. Here, we assess whether macrophage polarisation markers in skeletal muscle of humans correlate with insulin sensitivity in obesity and type 2 diabetes.

Methods

Skeletal muscle biopsies were obtained from individuals of normal weight and with normal glucose tolerance (NGT), and overweight/obese individuals with or without type 2 diabetes. Insulin sensitivity was determined by euglycaemic–hyperinsulinaemic clamps. Expression of macrophage genes was analysed by quantitative RT-PCR.

Results

Gene expression of the inflammatory macrophage phenotype marker cluster of differentiation (CD)11c was higher in muscle of type 2 diabetes patients (p?=?0.0069), and correlated with HbA_1c (p?=?0.0139, ρ?=?0.48) and fasting plasma glucose (p?=?0.0284, ρ?=?0.43), but not after correction for age. Expression of TGFB1, encoding the anti-inflammatory marker TGF-β1, correlated inversely with HbA_1c (p?=?0.0095, ρ?=??0.50; p?=?0.0484, ρ?=??0.50) and fasting plasma glucose (p?=?0.0471, ρ?=??0.39; p?=?0.0374, ρ?=??0.52) in two cohorts, as did HbA_1c with gene expression of macrophage galactose-binding lectin (MGL) (p?=?0.0425, ρ?=??0.51). TGFB1 expression was higher in NGT individuals than in individuals with type 2 diabetes (p?=?0.0303), and correlated with low fasting plasma insulin (p?=?0.0310, ρ?=??0.42). In exercised overweight/obese individuals, expression of genes for three anti-inflammatory macrophage markers, MGL (p?=?0.0031, ρ?=?0.71), CD163 (p?=?0.0268, ρ?=?0.57) and mannose receptor (p?=?0.0125, ρ?=?0.63), correlated with high glucose-disposal rate.

Conclusions/interpretation

Muscle expression of macrophage genes reveals a link between inflammatory macrophage markers, age and high glycaemia, whereas anti-inflammatory markers correlate with low glycaemia and high glucose-disposal rate.     

Dysregulated microRNA expression in rheumatoid arthritis families—a comparison between rheumatoid arthritis patients,their first-degree relatives,and healthy controls

Objective

Recent studies have demonstrated an altered expression of certain microRNAs in patients with rheumatoid arthritis (RA) as well as their first-degree relatives (FDRs) compared to healthy controls (HCs), suggesting a role of microRNA in the progression of the disease. To corroborate this, a set of well-characterized RA families originating from northern Sweden were analyzed for differential expression of a selected set of microRNAs.

Method

MicroRNA was isolated from frozen peripheral blood cells obtained from 21 different families and included 26 RA patients, 22 FDRs, and 21 HCs. Expression of the selected microRNAs miR-22-3p, miR-26b-5p, miR-34a-3p, miR-103a-3p, miR-142-3p, miR-146a-5p, miR-155, miR-346, and miR-451a was determined by a two-step quantitative real-time polymerase chain reaction (qRT-PCR). Statistical analysis including clinical variables was applied.

Results

Out of the nine selected microRNAs that previously have been linked to RA, we confirmed four after adjusting for age and gender, i.e., miR-22-3p (p?=?0.020), miR-26b-5p (p?=?0.018), miR-142-3p (p?=?0.005), and miR-155 (p?=?0.033). Moreover, a significant trend with an intermediate microRNA expression in FDR was observed for the same four microRNAs. In addition, analysis of the effect of corticosteroid use showed modulation of miR-103a-3p expression.

Conclusions

We confirm that microRNAs seem to be involved in the development of RA, and that the expression pattern in FDR is partly overlapping with RA patients. The contribution of single microRNAs in relation to the complex network including all microRNAs and other molecules is still to be revealed.

Circulating miR-130b mediates metabolic crosstalk between fat and muscle in overweight/obesity

Aims/hypothesis

Adipose tissue is a dynamic endocrine organ that regulates whole-body energy homeostasis through the secretion of signalling molecules. Recent reports suggest that secreted microRNAs (miRNAs) may function as biologically active molecules for intercellular communication. This study aims to identify obesity-related circulating miRNA that could be secreted from adipocytes and to explore its possible role in the pathogenesis of metabolic diseases.

Methods

Real-time RT-PCR was used to evaluate the circulating level of miR-130b in mouse models of obesity as well as in humans. Luciferase assay and immunoblotting were used to verify the miRNA target. The effect of miR-130b on mouse peroxisome proliferator-activated receptor γ coactivator-1α was also investigated by electrogene transfer.

Results

The circulating level of miR-130b was elevated in mouse models of obesity as well as in obese Chinese individuals. More interestingly, the circulating level of miR-130b was positively correlated with BMI. Moreover, circulating miR-130b was a better predictor of the metabolic syndrome than was triacylglycerol level. Mechanistically, adipocytes secreted miR-130b during adipogenesis. TGF-β, which is proportionately increased with obesity, stimulated miR-130b secretion from adipocytes. Furthermore, miR-130b was able to target muscle cells and reduce the expression of its direct target gene, PGC-1α (also known as PPARGC1A), which plays a key role in lipid oxidation in muscle.

Conclusions/interpretation

Circulating miR-130b reflects the degree of obesity and could serve as a potential biomarker for hypertriacylglycerolaemia and metabolic syndrome. Circulating miR-130b could function as a metabolic mediator for adipose–muscle crosstalk and might be involved in the pathogenesis of obesity-associated metabolic diseases.     

Adipose tissue INSR splicing in humans associates with fasting insulin level and is regulated by weight loss

Aims/hypothesis

The insulin receptor (INSR) has two protein isoforms based on alternative splicing of exon 11. INSR-A promotes cell growth whereas INSR-B predominantly regulates glucose homeostasis. In this study we investigated whether weight loss regulates INSR alternative splicing and the expression of splicing factors in adipose tissue.

Methods

To determine the relative ratio of the INSR splice variants, we implemented the PCR-capillary electrophoresis method with adipose tissue samples from two weight-loss-intervention studies, the Kuopio Obesity Surgery study (KOBS, n?=?108) and a very low calorie diet (VLCD) intervention (n?=?32), and from the population-based Metabolic Syndrome in Men study (METSIM, n?=?49).

Results

Expression of INSR-B mRNA variant increased in response to weight loss induced by both bariatric surgery (p?=?1?×?10^?5) and the VLCD (p?=?1?×?10^?4). The adipose tissue expression of INSR-B correlated negatively with fasting insulin levels in the pooled data of the three studies (p?=?3?×?10^?22). Finally, expression of several splicing factors correlated negatively with the expression of the INSR-B variant. The strongest correlation was with HNRNPA1 (p?=?1?×?10^?5), a known regulator of INSR exon 11 splicing.

Conclusions/interpretation

INSR splicing is regulated by weight loss and associates with insulin levels. The effect of weight loss on INSR splicing could be mediated by changes in the expression of splicing factors.     

miR-874 Inhibits cell proliferation,migration and invasion through targeting aquaporin-3 in gastric cancer

Background

Aquaporin-3 (AQP3) is a water transporting protein which plays an oncogenic role in several malignant tumors. However, its regulatory mechanism remains elusive to date. In this study, we investigated the microRNA-mediated gene repression mechanism involved in AQP3's role.

Methods

The potential microRNAs targeting AQP3 were searched via bioinformatic methods and identified by luciferase reporter assays, microRNA RT–PCR and western blotting. The expression patterns of miR-874 and AQP3 in human gastric cancer (GC) specimens and cell lines were determined by microRNA RT-PCR and western blotting. 5-ethynyl-2′-deoxyuridine, cell migration and invasion assays and tumorigenicity in vivo were adopted to observe the effects of miR-874 depletion or ectopic miR-874 expression on GC cell phenotypes. Cell apoptosis was evaluated by FACS and TUNEL in vitro and in vivo respectively.

Results

miR-874 suppressed AQP3 expression by binding to the 3′UTR of AQP3 mRNA in GC cells. miR-874 was significantly down-regulated and reversely correlated with AQP3 protein levels in clinical samples. Analysis of the clinicopathological significance showed that miR-874 and AQP3 were closely correlated with GC characteristics. Functional analyses indicated that ectopic miR-874 expression suppressed the growth, migration, invasion and tumorigenicity of GC cells, whereas miR-874 knockdown promoted these phenotypes. Down-regulation of Bcl-2, MT1-MMP, MMP-2 and MMP-9 and upregulation of caspase-3 activity and Bax were involved in miR-874 inducing cell apoptosis, and inhibiting migration and invasion.

Conclusions

These results provide a mechanism by which AQP3 is upregulated, as well as highlight the importance of miR-874 in gastric cancer development and progression.     

Functional relevance of genes implicated by obesity genome-wide association study signals for human adipocyte biology

Aims/hypothesis

Genome-wide association studies (GWAS) have identified numerous single-nucleotide polymorphisms associated with obesity, consequently implying a role in adipocyte biology for many closely residing genes. We investigated the functional relevance of such genes in human adipocytes.

Methods

We selected eight genes (BDNF, MAF, MTCH2, NEGR1, NPC1, PTER, SH2B1 and TMEM18) from obesity GWAS and analysed their effect in human adipogenesis using small interfering (si)RNA-mediated knockdown, their regulation by metabolic agents in adipocytes and pre-adipocytes, and gene expression in paired samples of human fat biopsies (68 non-obese, 165 obese) by quantitative real-time PCR.

Results

We show a two- to threefold upregulation of MAF, MTCH2 and NEGR1 and a two- to fourfold downregulation of BDNF and PTER during adipogenesis. Knockdown of BDNF (mean?±?SEM; 83.8?±?4.7% of control; p?=?0.0002), MTCH2 (72.7?±?9.5%; p?=?0.0006), NEGR1 (70.2?±?5.7%; p?<?0.0001) and TMEM18 (70.8?±?6.1%; p?<?0.0001) significantly inhibited adipocyte maturation, while knockdown of the other proteins had no effect. Insulin slightly induced MAF (1.65-fold; p?=?0.0009) and MTCH2 (1.72-fold; p?<?0.0001), while it suppressed BDNF (59.6%; p?=?0.0009), NEGR1 (58.0%; p?=?0.0085) and TMEM18 (69.3%; p?=?0.0377) in adipocytes. The synthetic glucocorticoid dexamethasone suppressed MAF (45.7%; p?=?0.0022), BDNF (66.6%; p?=?0.0012) and TMEM18 (63.5%; p?=?0.0181), but induced NEGR1 (3.2-fold; p?=?0.0117) expression. Furthermore, MTCH2, NEGR1 and TMEM18 were differentially expressed in subcutaneous and visceral adipose tissue. TMEM18 expression was decreased in the adipose tissue of obese patients, and negatively correlated with anthropometric variables and adipocyte size.

Conclusions/interpretation

Our results imply a regulatory role for TMEM18, BDNF, MTCH2 and NEGR1 in adipocyte differentiation and biology. In addition, we show a variation of MAF expression during adipogenesis, while NPC1, PTER and SH2B1 were not regulated.     

HLA-DRB1 reduces the risk of type 2 diabetes mellitus by increased insulin secretion

Aims/hypothesis

We sought to identify the physiological implications of genetic variation at the HLA-DRB1 region in full-heritage Pima Indians in Arizona.

Methods

Single-nucleotide polymorphisms from the HLA region on chromosome 6p were tested for association with skeletal muscle mRNA expression of HLA-DRB1 and HLA-DRA, and with type 2 diabetes mellitus and prediabetic traits.

Results

The A allele at rs9268852, which tags HLA-DRB1*02(1602), was associated both with higher HLA-DRB1 mRNA expression (n?=?133, p?=?4.27?×?10^?14) and decreased risk of type 2 diabetes (n?=?3,265, OR 0.723, p?=?0.002). Among persons with normal glucose tolerance (n?=?266) this allele was associated with a higher mean acute insulin response during an intravenous glucose tolerance test (p?=?0.005), higher mean 30?min insulin concentration during an oral glucose tolerance test (p?=?0.017) and higher body fat percentage (p?=?0.010). The polymorphism was not associated with HLA-DRA mRNA expression or insulin sensitivity.

Conclusions/interpretation

HLA-DRB1*02 is protective for type 2 diabetes, probably by enhancing self tolerance, thereby protecting against the autoimmune-mediated reduction of insulin secretion.     

Common variant in the HMGA2 gene increases susceptibility to nephropathy in patients with type 2 diabetes

Aims/hypothesis

Type 2 diabetes is a chronic metabolic disorder associated with devastating microvascular complications. Genome-wide association studies have identified more than 60 genetic variants associated with type 2 diabetes and/or glucose and insulin traits, but their role in the progression of diabetes is not established. The aim of this study was to explore whether these variants were also associated with the development of nephropathy in patients with type 2 diabetes.

Methods

We studied 28 genetic variants in 2,229 patients with type 2 diabetes from the local Malmö Scania Diabetes Registry (SDR) published during 2007–2010. Diabetic nephropathy (DN) was defined as micro- or macroalbuminuria and/or end-stage renal disease. Estimated glomerular filtration rate (eGFR) was assessed using the MDRD-4 formula. Replication genotyping of rs1531343 was performed in diabetic (Steno type 2 diabetes [n?=?345], Genetics of Diabetes Audit and Research in Tayside Scotland [Go-DARTS] [n?=?784]) and non-diabetic (Malmö Preventive Project [n?=?2,523], Botnia study [n?=?2,247]) cohorts.

Results

In the SDR, HMGA2 single-nucleotide polymorphism rs1531343 was associated with DN (OR 1.50, 95% CI 1.20, 1.87, p?=?0.00035). In the combined analysis totalling 3,358 patients with type 2 diabetes (n?=?1,233 cases, n?=?2,125 controls), carriers of the C-allele had a 1.45-fold increased risk of developing nephropathy (95% CI 1.20, 1.75, p?=?0.00010). Furthermore, the risk C-allele was associated with lower eGFR in patients with type 2 diabetes (n?=?2,499, β?±?SEM, ?3.7?±?1.2 ml/min, p?=?0.002) and also in non-diabetic individuals (n?=?17,602, β?±?SEM, ?0.008?±?0.003 ml/min (log _e ), p?=?0.006).

Conclusions/interpretation

These data demonstrate that the HMGA2 variant seems to be associated with increased risk of developing nephropathy in patients with type 2 diabetes and lower eGFR in both diabetic and non-diabetic individuals and could thus be a common denominator in the pathogenesis of type 2 diabetes and kidney complications.     

Differential expression of Lp-PLA2 in obesity and type 2 diabetes and the influence of lipids

Aims/hypothesis

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a circulatory macrophage-derived factor that increases with obesity and leads to a higher risk of cardiovascular disease (CVD). Despite this, its role in adipose tissue and the adipocyte is unknown. Therefore, the aims of this study were to clarify the expression of Lp-PLA2 in relation to different adipose tissue depots and type 2 diabetes, and ascertain whether markers of obesity and type 2 diabetes correlate with circulating Lp-PLA2. A final aim was to evaluate the effect of cholesterol on cellular Lp-PLA2 in an in vitro adipocyte model.

Methods

Analysis of anthropometric and biochemical variables from a cohort of lean (age 44.4?±?6.2 years; BMI 22.15?±?1.8 kg/m², n?=?23), overweight (age 45.4?±?12.3 years; BMI 26.99?±?1.5 kg/m², n?=?24), obese (age 49.0?±?9.1 years; BMI 33.74?±?3.3 kg/m², n?=?32) and type 2 diabetic women (age 53.0?±?6.13 years; BMI 35.08?±?8.6 kg/m², n?=?35), as part of an ethically approved study. Gene and protein expression of PLA2 and its isoforms were assessed in adipose tissue samples, with serum analysis undertaken to assess circulating Lp-PLA2 and its association with cardiometabolic risk markers. A human adipocyte cell model, Chub-S7, was used to address the intracellular change in Lp-PLA2 in adipocytes.

Results

Lp-PLA2 and calcium-independent PLA2 (iPLA2) isoforms were altered by adiposity, as shown by microarray analysis (p?<?0.05). Type 2 diabetes status was also observed to significantly alter gene and protein levels of Lp-PLA2 in abdominal subcutaneous (AbdSc) (p?<?0.01), but not omental, adipose tissue. Furthermore, multivariate stepwise regression analysis of circulating Lp-PLA2 and metabolic markers revealed that the greatest predictor of Lp-PLA2 in non-diabetic individuals was LDL-cholesterol (p?=?0.004). Additionally, in people with type 2 diabetes, oxidised LDL (oxLDL), triacylglycerols and HDL-cholesterol appeared important predictors, accounting for 59.7% of the variance (p?<?0.001). Subsequent in vitro studies determined human adipocytes to be a source of Lp-PLA2, as confirmed by mRNA expression, protein levels and immunochemistry. Further in vitro experiments revealed that treatment with LDL-cholesterol or oxLDL resulted in significant upregulation of Lp-PLA2, while inhibition of Lp-PLA2 reduced oxLDL production by 19.8% (p?<?0.05).

Conclusions/interpretation

Our study suggests adipose tissue and adipocytes are active sources of Lp-PLA2, with differential regulation by fat depot and metabolic state. Moreover, levels of circulating Lp-PLA2 appear to be influenced by unfavourable lipid profiles in type 2 diabetes, which may occur in part through regulation of LDL-cholesterol and oxLDL metabolism in adipocytes.

     

An increased frequency of NK cell receptor and HLA-C group 1 combinations in early-onset type 1 diabetes

Aims/hypothesis

Natural killer (NK) cells serve as primary immune surveillance and are partially regulated by combinations of killer immunoglobulin-like receptor (KIR) genes and their HLA class I ligands. Alterations in NK cell activity have been associated with type 1 diabetes. The aim of this study was to determine whether KIR?CHLA class I gene frequency: (1) is altered in a current population with type 1 diabetes compared with healthy controls; and (2) has changed over the half century in which the incidence of type 1 diabetes has increased rapidly.

Methods

KIR?CHLA class I gene frequencies were compared in 551 individuals diagnosed with type 1 diabetes ??15?years of age (394 in a current cohort and 157 from the historical ??Golden Years?? cohort) and 168 healthy controls. The overall balance of activation and inhibition was analysed using KIR?CHLA genotype models.

Results

Children with type 1 diabetes who were positive for KIR2DS2/KIR2DL2 and KIR2DL3 were more often homozygous for HLA-C group 1 and this effect was strongest in children diagnosed with diabetes before the age of 5?years (p?=?0.003, corrected p [p _corr]?=?0.012) and (p?=?0.001, p _corr?=?0.004), respectively. Children with type 1 diabetes have fewer inhibitory KIRs with their corresponding ligands compared with healthy controls (p?=?1.9?×?10^?4). This pattern of NK activation has not changed significantly in individuals with type 1 diabetes over the last half century.

Conclusions/interpretation

Activating combinations of KIR?CHLA genes are more frequent in young children with type 1 diabetes diagnosed in the first 5?years of life, suggesting that NK cell responses may be altered in this group.     

Downregulation of microRNA-124 is an independent prognostic factor in patients with colorectal cancer

Purpose

Recently, microRNA-124 (miR-124) has been demonstrated as a potential tumor suppressor in several types of cancers. However, the role of miR-124 in colorectal cancer remains unclear. This study was aimed at investigating the clinicopathological significance of miR-124 expression in colorectal cancer.

Methods

Quantitative real-time PCR was used to analyze miR-124 expression in 96 colorectal cancers and individual-matched normal mucosa samples. The expression of miR-124 was assessed for associations with clinicopathological characteristics using chi-square test. The survival curves were calculated by the Kaplan–Meier method. The influence of each variable on survival was examined by the Cox multivariate regression analysis.

Results

The miR-124 expression was significantly downregulated in colorectal cancer compared to normal mucosa (P?=?0.001). In colorectal cancer, miR-124 decreased expression correlated significantly with the grade of differentiation (P?=?0.021). Univariate survival analysis showed that the downregulated miR-124 was significantly correlated with worse prognosis, both in terms of overall survival (P?=?0.017) and disease-free survival (DFS) (P?=?0.014). Further, the downregulated miR-124 was demonstrated as a prognostic factor for overall survival (hazard ratio, HR?=?4.634; 95 % confidence interval, CI, 1.731–12.404; P?=?0.002) and DFS (HR?=?4.533, 95 % CI 1.733–11.856, P?=?0.002), independently of gender, age, location, maximum tumor size, depth of invasion, differentiation, and TNM stage.

Conclusions

MiR-124 may play a certain role in the development of colorectal cancer. The downregulation expression of miR-124 is an independent prognostic factor in patients with colorectal cancer.     

Impact of diabetes and glycaemic control on peripheral artery disease in Japanese patients with end-stage renal disease: long-term follow-up study from the beginning of haemodialysis

Aims/hypothesis

End-stage renal disease (ESRD) patients with diabetes have been regarded as being at the highest risk of cardiovascular disease. We therefore investigated the relationship between diabetes and the incidence of peripheral artery disease (PAD) in new haemodialysis patients.

Methods

We enrolled 1,513 ESRD patients who had just begun haemodialysis therapy. They were divided into two groups: those with (n?=?739) and those without diabetes (n?=?774). The endpoint was the development of PAD, defined as ankle brachial pressure index ≤0.9 or toe brachial pressure index <0.7 in patients with an ankle brachial pressure index >0.9.

Results

According to the Kaplan–Meier method, the 10?year event-free rate for development of PAD and lower limb amputation was significantly lower in the diabetes group than in the non-diabetes group (60.3% vs 82.8%, HR 2.99, 95% CI 2.27, 3.92, p?p?=?0.0005 for PAD and lower limb amputation, respectively). In patients with diabetes, quartile analysis of HbA_1c levels showed that the highest quartile group (≥6.8% [51?mmol/mol]) had significant development of PAD and lower limb amputation compared with lower quartile groups (PAD HR 1.63, 95% CI 1.17, 2.28, p?=?0.0038; lower limb amputation HR 2.99, 95% CI 1.17, 7.70, p?=?0.023).

Conclusions/interpretation

Diabetes was a strong predictor of PAD after initiation of haemodialysis therapy in patients with ESRD. In addition, higher HbA_1c levels were associated with increased risk of developing PAD and requiring limb amputation in such diabetic populations.