Increased ferritin concentrations correlate with insulin resistance in female type 2 diabetic patients

Aims: Iron overload identified by elevated ferritin concentrations has been implicated in risks of altered glucose metabolism and diabetic complications. The relationship between ferritin and insulin resistance in different gender and ethnicities remains uncertain; this study aimed to investigate it using homeostasis model assessment (HOMA-IR), and to explore whether it is gender-specific. Methods: A total of 524 type 2 diabetic patients were selected cross-sectionally from a cohort participating in a diabetic control study in Taiwan. Result: Overall, tertiles of ferritin were significantly and dose-dependently associated with elevated fasting plasma glucose, hemoglobin A1c, high-sensitivity C-reactive protein, HOMA-IR levels as well as Western dietary pattern scores generated by factor analysis (all p trend <0.05). Stratified by gender, a 1-tertile ferritin increase significantly correlated with a 0.241-unit increase in HOMA-IR (beta = 0.241, p = 0.001) in female diabetes, but not in male diabetes (beta = 0.072, p = 0.232), after adjusting for demographic, dietary, clinical and inflammatory factors. Conclusion: Iron overload, which produces elevated levels of ferritin, may augment insulin resistance in female but not in male type 2 diabetes. Longitudinal studies are warranted to establish relationships between iron stores and diabetes development in men and women of different ethnicities.     

Body iron stores in relation to the metabolic syndrome, glycemic control and complications in female patients with type 2 diabetes

Background and aimStudies suggest that iron plays a significant role in the development of diabetes and its complications. This study evaluates the associations of iron metabolism parameters with the metabolic syndrome (MS), control and complications in female patients with type 2 diabetes mellitus (T2DM).Methods and resultsFerritin, soluble Transferrin Receptor (sTfR), sTfR/Log ferritin ratio (sTfR-F index), iron, full blood count and high-sensitivity C-reactive protein (hs-CRP) were determined in 110 female patients with T2DM. Steady state beta cell function (%B), insulin sensitivity (%S) and insulin resistance were assessed with homeostasis model.Patients were divided into tertiles of ferritin and sTfR-F index and according to the presence or absence of the MS and diabetic complications. Patients within the lowest tertile of the sTfR-F index had significantly higher fasting insulin, percent B, low-density lipoprotein cholesterol and Apolipoprotein B than those in the highest tertile. Ferritin showed significant correlations with insulin, percent B and inverse correlations with adiponectin and percent S. The sTfR-F index was significantly correlated with insulin, percent B and lipid parameters. Correcting for hs-CRP abolished the correlations with ferritin but not the sTfR-F index. Higher indices of body iron were significantly associated with diabetes complications but no associations were found with MS, glucose or glycemic control. Multiple regression analysis with confounding variables showed ferritin and the sTfR-F index were not independently associated with diabetes complications.ConclusionsAssociation of ferritin with metabolic derangements and complications in diabetes is partly dependent on association with inflammation. Iron status, estimated with the sTfR-F index, is associated with metabolic derangements and complications but the associations are dependent on other risk factors. Prospective studies that use the sTfR-F index as a marker of iron status are required to confirm the role of iron in the etiopathogenesis of T2DM and its complications.     

Serum ferritin levels in poorly- and well-controlled diabetes mellitus

Serum ferritin level is related to body iron stores and is influenced by several diseases. We aimed to evaluate the association between serum ferritin concentration and the complications and nature of diabetes mellitus (DM). We examined association of ferritin concentration, fasting and post-prandial glucose levels and glycated hemoglobin in 329 patients with type 2 diabetes mellitus and 269 healthy controls. In the present study, 41 of 150 poorly controlled diabetic patients and 31 of 119 cases had hyperferritinemia. We confirmed that serum ferritin was increased in diabetic patients as long as glycemic control is not achieved. There was also a correlation between ferritin level and diabetic retinopathy. In conclusion, this study showed an independent positive association between serum ferritin concentration and markers of glucose homeostasis.     

Potential role of increased iron stores in diabetes

Diabetes mellitus (DM) is an important risk factor for the development of cardiovascular disease. Extensive clinical, epidemiologic, and basic studies suggest that excessive tissue iron stores may contribute to the occurrence and complications of DM. Secondary diabetes occurs in inherited pathologic iron overload syndromes of European- and African-derived populations and is an established complication of transfusional iron overload. Epidemiologic studies have repeatedly shown positive correlation between levels of serum ferritin and those of fasting glucose, insulin, and glycosylated hemoglobin. Iron reduction therapy in hereditary hemochromatosis and transfusional iron overload is associated with improved glucose tolerance and reduced incidence of secondary diabetes. Trials of iron reduction therapy in diabetes mellitus, although limited and inconclusive, have shown clinical improvement in some patients. The current article reviews evidence suggesting that tissue iron contributes to DM and its complications and presents preliminary data that emphasize the potential importance of iron overload in DM of African Americans.     

Relation between serum high molecular weight adiponectin and serum ferritin or prohepcidin in patients with type 2 diabetes

An increase of serum ferritin, an indicator of body iron store, is associated with insulin resistance and with an increased risk of type 2 diabetes in the general population. A low serum adiponectin is also associated with insulin resistance. Recently, hepcidin was identified as a regulator of iron metabolism. We investigated whether serum adiponectin was associated with serum ferritin or prohepcidin, a precursor of hepcidin, in healthy subjects and patients with type 2 diabetes. We studied 65 healthy subjects and 104 patients with type 2 diabetes. A serum ferritin concentration ≥ 300 ng/ml for men or ≥ 150 ng/ml for women was defined as hyperferritinemia. Serum ferritin was significantly higher and serum prohepcidin was significantly lower in diabetic patients than in control subjects. Serum total and high molecular weight (HMW) adiponectin correlated negatively with serum ferritin in control subjects or diabetic patients, while serum total and HMW adiponectin correlated positively with serum prohepcidin in diabetic patients, but not in control subjects. Serum total and HMW adiponectin were lower in patients with hyperferritinemia than in those without it. In conclusion, serum ferritin was increased in type 2 diabetic patients, while serum prohepcidin was decreased. A high serum ferritin was associated with insulin resistance, and with low serum total and HMW adiponectin in patients with type 2 diabetes.     

Hepatic iron accumulation may be associated with insulin resistance in patients with chronic hepatitis C

Background/Aim: Insulin resistance and hepatic iron overload are frequently demonstrated in hepatitis C virus (HCV)-related liver diseases. We investigated the relationship between insulin resistance and hepatic iron deposition in patients with chronic HCV infection. Methods: Insulin resistance was evaluated using the homeostasis model assessments for insulin resistance (HOMA-IR) in 56 non-diabetic non-obese patients with biopsy proven chronic hepatitis C. The relationship between insulin resistance and serum ferritin levels or the grade of hepatic iron deposition was assessed. Results: The levels of plasma immunoreactive insulin (IRI) and HOMA-IR were significantly correlated with serum ferritin levels and the grade of hepatic iron deposition (P = 0.003).Although IRI and HOMA-IR increased in parallel with the development of hepatic fibrosis, insulin resistance (HOMA-IR > 2) was observed in 11 (26.2%) of 42 patients even without severe fibrosis (F0-2). Among patients without severe fibrosis, IRI and HOMA-IR were significantly higher in patients with iron deposits than in those without iron deposits. Conclusion: Hepatic iron overload may be associated with insulin resistance in patients with chronic hepatitis C, especially in patients with mild to moderate fibrosis.     

Blood rheology in patients with diabetes mellitus

Blood rheology is now receiving increasing attention as an important potential contributory factor to diabetic angiopathy. This study was designed to provide evidence for and against early hemorheological abnormalities in diabetes mellitus (DM). For this purpose, blood viscosity, RBC aggregation, hematocrit, and plasma protein's levels of both fibrinogen and albumin were measured in 86 uncomplicated patients with DM (45 type 1 and 41 type 2). Patients with HbA1c < 7.5% were considered as having good glycemic control (GGC), while those with HbA1c > 8.5% as having poor glycemic control (PGC). Patients with type 1 DM showed normal blood viscosity at both shear rates high and low, while native hematocrit, fibrinogen, and RBC aggregation were significantly elevated and albumin significantly reduced when compared with healthy volunteers. Patients with type 2 DM showed more marked impairments associated with an increased low shear rate blood viscosity, when compared with patients with type 1 DM. Comparison between two subgroups of patients, both of which with type 1 DM and of similar disease duration of <5 yrs, with GGC or PGC showed that impaired blood rheology does depend on the quality of glycemic control. Differences were attenuated after a disease duration of >15 yrs. These findings suggest that early hemorheological impairments in patients with type 1 DM are dependent upon the glycemic control. In contrast, hemorheological impairments appear to be inevitable after a mean disease duration of 15 yrs even if there is a GGC. Aggravation of hemorheological abnormalities in patients with type 2 DM might depend upon the hemorheological effects of other metabolic abnormalities related to insulin resistance rather than the quality of glycemic control.     

Association of elevated serum ferritin concentration with insulin resistance and impaired glucose metabolism in Korean men and women

Increased serum ferritin concentrations in nonpathologic conditions, reflecting subclinical iron overload, have been reported to be associated with insulin resistance and an increased risk of type 2 diabetes mellitus (DM). However, serum ferritin concentrations differ significantly according to sex and ethnicity; and data concerning the relationship between serum ferritin concentrations and glucose metabolism abnormalities in Asian men and women are conflicting. This cross-sectional study investigated the association of serum ferritin concentrations with insulin resistance and impaired glucose metabolism in a large number of subjects with normal fasting glucose (NFG) level, impaired fasting glucose (IFG) level, or type 2 DM. We analyzed clinical and laboratory data from 12 090 subjects (6378 men and 5712 women; age, 20-89 years) who underwent general medical checkups. The study population included 1054 subjects with type 2 DM, 3783 subjects with IFG level, and 7253 subjects with NFG level. Serum ferritin, hemoglobin A_1c, fasting glucose, lipid, and insulin levels were measured. Insulin resistance and β-cell function indices were derived from a homeostasis model assessment. Serum ferritin concentrations were highest in the DM group, followed by the IFG group and the NFG group, in both men and women (186 ± 127, 176 ± 108, and 156 ± 92 ng/mL, respectively, in men; 85 ± 62, 75 ± 55, and 59 ± 47 ng/mL, respectively, in women). After adjustment for other variables using multiple regression analysis, homeostasis model assessment of insulin resistance was independently associated with serum ferritin concentration in men, but not in women. When the fourth quartile of ferritin was compared with the first quartile, the age-adjusted odds ratio (OR) for type 2 DM was 1.71 (95% confidence interval, 1.38-2.12) in men and 1.50 (1.05-2.13) in women. The OR in men was attenuated to 1.27 (1.01-1.60) but remained significant after adjustment for body mass index (BMI), waist circumference, blood pressure, serum lipids, liver enzymes, and high-sensitivity C-reactive protein (hsCRP). In nondiabetic subjects, the age-adjusted OR for IFG in the fourth quartile of ferritin was 1.82 (1.56-2.13) in men and 1.68 (1.40-2.02) in women. The OR was attenuated to 1.31 (1.11-1.55) in men and 1.45 (1.19-1.78) in women after adjustment for BMI, waist circumference, blood pressure, serum lipids, liver enzymes, and hsCRP. In NFG subjects, the age-adjusted OR for metabolic syndrome in the fourth quartile of ferritin concentration was 2.85 (1.99-4.07) in men and 1.21 (0.82-1.79) in women. In men, the OR was attenuated to 1.58 (1.06-2.37) after adjustment for BMI, liver enzymes, and hsCRP. Increased serum concentrations of ferritin are associated with insulin resistance, type 2 DM, IFG, and metabolic syndrome in men, but only with IFG in women. These results suggest that iron overload is associated with insulin resistance in men, but not in women.     

Insulin resistance/β‐cell function and serum ferritin level in non‐diabetic patients with hepatitis C virus infection

Background/Aims: Since impaired glucose tolerance and iron overload are frequently demonstrated in hepatitis C virus (HCV)‐related liver diseases, in this study we investigated insulin resistance, pancreatic β‐cell function, i.e., insulin secretion, and serum ferritin levels in patients with HCV infection, especially non‐diabetic patients. Methods: Homeostasis model assessments for insulin resistance (HOMA‐IR) and β‐cell function (HOMA‐β) were performed in 92 HCV‐infected patients. Results: The levels of plasma immunoreactive insulin (IRI), HOMA‐IR, and HOMA‐β were significantly correlated with fasting plasma glucose (FPG) levels. Among the 86 non‐diabetics (with an FPG of <126 mg/dl), IRI, HOMA‐IR, and HOMA‐β were significantly higher in patients with liver cirrhosis than in patients with persistently normal alanine aminotransferase levels. The IRI and HOMA‐IR values, but not the HOMA‐β values, were correlated with both serum transaminase and ferritin levels in the 65 non‐diabetic chronic hepatitis patients. Conclusion: Insulin resistance was connected with impaired glucose tolerance and the severity of liver diseases in non‐diabetic patients with HCV infection. Iron overload may be responsible for insulin resistance, or vice versa. Pancreatic β‐cell function was unrelated to the patients' serum ferritin levels.     

老年2型糖尿病和糖耐量受损患者血清铁蛋白与胰岛素抵抗和胰岛β细胞功能相关

目的 探讨60岁以上老年2型糖尿病和糖耐量受损(IGT)患者血清铁蛋白(SF)水平与胰岛素抵抗、胰岛β细胞功能之间的相关性.方法 入选2型糖尿病组患者1 143例,IGT组448例和正常糖耐量组(NGT)2 950名.测定身高、体重、血压、总胆固醇、甘油三酯(TG)、空腹血糖(FPG)、餐后2 h血糖(2hPG)、空腹胰岛素(FINS)和SF水平.采用稳态模型、QUICK来评估胰岛素抵抗,采用稳态模型和处置指数(DI)来评估胰岛β细胞功能.结果 2型糖尿病组SF水平高于NGT组(P<0.01);NGT、IGT和2型糖尿病组稳态模型评估的胰岛素抵抗指数(HOMA-IR)呈增高趋势(P<0.05),稳态模型评估的胰岛素β细胞功能指数(HOMA-β)、QUICK、DI呈递减趋势(均P<0.05).Spearman相关分析和偏相关分析显示,校正年龄和性别后,SF与FPG、2hPG、TG、FINS、HOMA-IR呈正相关,与HOMA-β、QUICK、DI呈负相关.多元逐步回归分析显示,QUICK、体重指数、TG是影响SF的独立危险因素.结论 老年2型糖尿病患者体内铁超负荷;随着SF的升高,胰岛素抵抗逐渐增加,而胰岛β细胞功能呈下降趋势.

Abstract：

Objective To investigate the relationship between serum ferritin and p-cell function,insulin resistance in elderly patients(age>60 years)with type 2 diabetes and impaired glucose tolerance.Methods Total 1143 patients with type 2 diabetes,448 patients with impaired glucose tolerance(IGT),and 2 950 subjects with normal glucose tolerance(NGT)were recruited for the measurments of height,weight,serum triglyceride(TG),total cholesterol,fasting plasma glucose(FPG),fasting insulin(FINS),postprandial 2 h plasma glucose(2hPG),and serum ferritin.Homeostasis model assessment of insulin resistance(HOMA-IR)and QUICK index were used to estimate insulin resistance,and homeostasis model assessment of β cell function(HOMA-p)and disposition index(DI)to evaluate p-cell function.Results The results showed that the level of serum ferritin was significantly higher in type2 diabetes mellitus group than NGT group(P<0.01).HOMA-IR was gradually increased,and HOMA-β,QUICK,and DI decreased from NGT to IGT,type 2 diabetes mellitus groups(all P < 0.05).Spearman and partial correlation analysis showed that partial adjustment for age and sex,serum ferritin was positively associated with FPG,2hPG,TG,FINS,and HOMA-IR,and negatively associated with HOMA-β,QUICK,and DI.Stepwise regression showed that serum ferritin was associated with QUICK,BMI,and TG.Conclusion The results suggest that iron overload exists in elderly patients with type 2 diabetes.With increasing serum ferritin level,insulin resistance increases and p-cell function decreases in the elderly patients with abnormal glucose metabolism.     

Efficacy and safety of imeglimin in patients with type 2 diabetes mellitus: A systematic review and meta-analysis of randomized clinical trials

Background and aimImeglimin is a novel tetrahydrotriazine-containing drug suggested as a safe drug for glycemic management in patients with type 2 diabetes mellitus (T2DM). We aimed to 1) evaluate the efficacy of imeglimin on glycemic control and insulin resistance improvement measured by homeostatic model assessment of insulin resistance (HOMA-IR). 2) assess whether the novel drug improves lipid parameters in diabetic patients. 3) compare between different doses regarding safety.MethodsWe searched PubMed, Cochrane Library, Scopus, Web of Science, Google Scholar, and Wiley through April 25, 2021, for relevant randomized controlled trials comparing different doses of imeglimin supplied as a monotherapy or as add-on therapy versus placebo for adult patients with type 2 diabetes mellitus. Data on glycemic and lipid parameters and adverse events were extracted and pooled in random-effect models using Review Manager version 5.3.ResultsEight studies comprising 1555 patients with T2DM were included in this study. The overall effect estimate of the meta-analysis showed that the imeglimin group was superior to the control group concerning glycated hemoglobin and fasting plasma glucose (P < 0.00001). However, it did not affect HOMA-IR or lipid parameters, including triglyceride, LDL-C, and HDL-C (all p > 0.05). Regarding safety profile, imeglimin was safe and tolerable with no treatment-emergent or serious adverse events.ConclusionsImeglimin safely improved glycemic control by reducing HbA1c and FPG. However, no beneficial effects regarding insulin resistance measured by HOMA-IR or lipid parameters were observed. Further high-quality RCTs with high dose imeglimin are encouraged to ensure HOMA-IR and lipid parameters results.     

Insulin resistance is a cardiovascular risk factor in humans

Diabetes is a common metabolic disorder associated to elevated cardiovascular morbidity and mortality that is not explained by hyperglycemia or traditional cardiovascular risk factors such as smoking or hypercholesterolemia. Intensive glycemic control with insulin that achieves near-normal glycemia does not reduce significantly macrovascular complications compared with conventional glycemic control. Cardiovascular disease continues to develop in patients with diabetes despite adequate glycemic control. In contrast, intensive control with metformin (leading to insulin resistance improvement) reduces diabetes complications, including cardiovascular events, suggesting that enhancement of insulin sensitivity rather than plasma glucose level has a major role improving diabetes outcomes. Accordingly, insulin resistance estimated by glucose tolerance tests is better predictor of future cardiovascular events than fasting glucose level in nondiabetic individuals. Insulin resistance precedes for decades the clinical onset of type 2 diabetes and deteriorates metabolic control of type 1 diabetes. Numerous investigations including cross-sectional and prospective studies, meta-analyses, and systematic reviews provide compelling evidence that insulin resistance by itself is a cardiovascular risk factor in a variety of population groups, including the general population and patients with diabetes. Several estimations of insulin resistance have been consistently associated with elevated rate of cardiovascular events independently of other cardiovascular risk factors and diabetes status. The clinical expression of insulin resistance (the metabolic syndrome or any of its components including obesity, hyperinsulinemia, hypertension, and dyslipemia) has been related to cardiovascular disease as well. An estimation conducted by the Archimedes model confirms that insulin resistance is the most important single cause of coronary artery disease.     

CD39: Interface Between Vascular Thrombosis and Inflammation

Obesity and type 2 diabetes mellitus (T2DM) are major drivers of cardiovascular disease (CVD). The link between environmental factors, obesity, and dysglycemia indicates that progression to diabetes with time occurs along a “continuum”, not necessarily linear, which involves different cellular mechanisms including alterations of insulin signaling, changes in glucose transport, pancreatic beta cell dysfunction, as well as the deregulation of key genes involved in oxidative stress and inflammation. The present review critically addresses key pathophysiological aspects including (i) hyperglycemia and insulin resistance as predictors of CV outcome, (ii) molecular mechanisms underpinning the progression of diabetic vascular complications despite intensive glycemic control, and (iii) stratification of CV risk, with particular emphasis on emerging biomarkers. Taken together, these important aspects may contribute to the development of promising diagnostic approaches as well as mechanism-based therapeutic strategies to reduce CVD burden in obese and diabetic subjects.     

Glucose abnormalities in non‐alcoholic fatty liver disease and chronic hepatitis C virus infection: the role of iron overload

Non‐alcoholic fatty liver disease (NAFLD) and chronic hepatitis C virus (HCV) infection are major causes of liver disease frequently described in outpatient patients with glucose abnormalities. Hyperferritinemia, which suggests that iron overload plays a decisive role in the pathophysiology of insulin resistance and hyperglycemia, is a common finding in both disorders. However, the role of the hepatic iron deposition differs from one to the other. In NAFLD, a moderate liver iron accumulation has been observed and molecular mechanisms, including the downregulation of the liver iron exporter ferroportin‐1, have been described. Iron overload will enhance intrahepatic oxidative stress that promotes hepatic fibrosis, interfere with insulin signalling at various levels and may hamper hepatic insulin extraction. Therefore, liver fibrosis, hyperglycemia and hyperinsulinemia will lead to increased levels of insulin resistance and the development of glucose abnormalities. Furthermore, iron depletion by phlebotomy removes liver iron content and reduces serum glucose and insulin resistance in NAFLD patients. Therefore, it seems that iron overload participates in those glucose abnormalities associated with NAFLD. Concerning chronic HCV infection, it has been classically assumed that iron overload contributes to insulin resistance associated with virus infection. However, recent evidence argues against the presence of iron overload in these patients and points to inflammation associated with diabetes as the main contributor to the elevated ferritin levels. Therefore, glucose abnormalities, and specially type 2 diabetes, should be taken into account when evaluating serum ferritin levels in patients with HCV infection. Copyright © 2009 John Wiley & Sons, Ltd.     

Management of elderly diabetic patients in the subacute care setting

Type 2 diabetes is a commonly encountered condition in the subacute care setting. The results of the landmark UK prospective studies have confirmed that aggressive glycemic and blood pressure control delayed diabetes-related microvascular and macrovascular complications and significantly improved diabetic outcomes. Within the past few years, new drugs have been developed to address both aspects of the type 2 diabetes syndrome: insulin resistance and insulin secretory defect. C-peptide analysis may be useful to predict a successful response to therapy with insulin sensitizers or the need to initiate therapy with insulin or insulin stimulators. The issues regarding the general approach to elderly diabetics and the strategies of dealing with diabetic complications encountered in the subacute care program are discussed and updated. It is hoped that diabetic management can be improved and that suggested alternate therapies can be used in the subacute care facilities.     

老年正常糖耐量代谢紊乱集簇铁蛋白水平与胰岛素抵抗和胰岛β功能相关性研究

目的 探讨老年正常糖耐量人群代谢紊乱集簇铁蛋白水平与胰岛素抵抗和胰岛β细胞功能之间的关系.方法 入选上海市江川社区＞60岁老年人4 330例,其中2型糖尿病组（T2DM）1 143例、糖尿病前期组（IGR） 237例及正常糖耐量组（NGT）2 950例.测定其血压、血脂、空腹血糖（FBG）、2小时血糖（2hBG）、空腹胰岛素（FINS）和血清铁蛋白（SF）水平.采用HOMA-IR、QUICK评估胰岛素抵抗;采用HOMA-β和处置指数（DI）评估胰岛β细胞功能.根据代谢综合征（MS）诊断标准将正常糖耐量组分为无代谢紊乱数目组（NMS0）、1种代谢紊乱数目组（NMS1）、2种代谢紊乱数目组（NMS2）、3种代谢紊乱数目组（NMS3）和4种代谢紊乱数目组（NMS4）.非正态资料进行自然对数（LN）转换.结果 老年正常糖耐量人群随着代谢紊乱数目集簇,LNHOMA-IR和LNSF呈逐渐升高趋势（P＜0.05）;LNQUICK和LNDI呈逐渐下降趋势（P＜0.05）.同时,随着SF水平升高,LNHOMA-IR逐渐加重,LNDI逐渐下降.Spearman相关分析显示老年正常糖耐量人群LNSF与HOMA-IR呈正相关,与LNQUICK和LNDI呈负相关（P＜0.05）.多元逐步回归分析显示,老年正常糖耐量LNSF与LNHOMA-IR呈独立正相关（P＜0.05）.结论 老年正常糖耐量人群随着代谢紊乱数目集簇,SF水平逐渐升高,胰岛素抵抗逐步加重,胰岛β细胞功能逐步减退.铁超载与胰岛素抵抗密切相关.     

Síndrome de apneas-hipopneas del sueño y diabetes tipo 2. ¿Una relación de ida y vuelta?

Epidemiological data suggest that sleep apnea-hypopnea syndrome (SAHS) is independently associated with the development of insulin resistance and glucose intolerance. Moreover, despite significant methodological limitations, some studies report a high prevalence of SAHS in patients with type 2 diabetes mellitus (DM2). A recent meta-analysis shows that moderate-severe SAHS is associated with an increased risk of DM2 (relative risk = 1.63 [1.09 to 2.45]), compared to the absence of apneas and hypopneas.Common alterations in various pathogenic pathways add biological plausibility to this relationship. Intermittent hypoxia and sleep fragmentation, caused by successive apnea-hypopnea episodes, induce several intermediate disorders, such as activation of the sympathetic nervous system, oxidative stress, systemic inflammation, alterations in appetite-regulating hormones and activation of the hypothalamic-pituitary-adrenal axis which, in turn, favor the development of insulin resistance, its progression to glucose intolerance and, ultimately, to DM2.Concomitant SAHS seems to increase DM2 severity, since it worsens glycemic control and enhances the effects of atherosclerosis on the development of macrovascular complications. Furthermore, SAHS may be associated with the development of microvascular complications: retinopathy, nephropathy or diabetic neuropathy in particular. Data are still scant, but it seems that DM2 may also worsen SAHS progression, by increasing the collapsibility of the upper airway and the development of central apneas and hypopneas.     

吸烟与糖尿病

近来的研究表明,吸烟是糖尿病发生的独立危险因子,两者之间存在剂量反应关系,而且,吸烟还可促进糖尿病患者心血管疾病、糖尿病、肾病、肺功能损害及足部溃疡的发生.其可能的机制是烟草成分增加胰岛素抵抗,由此影响血糖控制.临床医师应重视糖尿病患者的戒烟治疗,以提高患者的生活质量,改善远期预后.     

Thiazolidinedione therapy: the benefits of aggressive and early use in type 2 diabetes

Type 2 diabetes is now a global epidemic, with the number of people affected worldwide predicted to more than double to 300 million by the year 2025. While the importance of good glycemic control in countering the microvascular and macrovascular complications of diabetes is widely recognized, monotherapy with sulfonylureas or metformin achieves target blood glucose levels in only a minority of patients. Consequently, there is a pressing need for new treatment strategies that are more effective in providing sustained glycemic control and so reducing the burden of morbidity and mortality associated with diabetes and its complications. There is growing evidence of the benefits of early intervention with aggressive treatment strategies in improving glycemic control and reducing diabetic complications. To provide sustained control, such strategies need to address the combination of insulin resistance and beta-cell dysfunction that underlies most cases of type 2 diabetes. At the same time, treatment needs to address not only glycemic control but also the range of cardiovascular risk factors that are often found clustered together in patients with type 2 diabetes. This paper reviews the rationale and evidence for early combination therapy including a thiazolidinedione in improving glycemic control, and considers the potential for such aggressive therapy in reducing diabetic complications.     

Androgens activate mitogen-activated protein kinase via epidermal growth factor receptor/insulin-like growth factor 1 receptor in the mouse PC-1 cell line

Insulin replacement is the only effective therapy to manage hyperglycemia in type 1 diabetes mellitus (T1DM). Nevertheless, intensive insulin therapy has inadvertently led to insulin resistance. This study investigates mechanisms involved in the insulin resistance induced by hyperinsulinization. Wistar rats were rendered diabetic by alloxan injection, and 2 weeks later received saline or different doses of neutral protamine Hagedorn insulin (1.5, 3, 6, and 9?U/day) over 7 days. Insulinopenic-untreated rats and 6U- and 9U-treated rats developed insulin resistance, whereas 3U-treated rats revealed the highest grade of insulin sensitivity, but did not achieve good glycemic control as 6U- and 9U-treated rats did. This insulin sensitivity profile was in agreement with glucose transporter 4 expression and translocation in skeletal muscle, and insulin signaling, phosphoenolpyruvate carboxykinase/glucose-6-phosphatase expression and glycogen storage in the liver. Under the expectation that insulin resistance develops in hyperinsulinized diabetic patients, we believe insulin sensitizer approaches should be considered in treating T1DM.