Discordance between Prevalent Vertebral Fracture and Vertebral Strength Estimated by the Finite Element Method Based on Quantitative Computed Tomography in Patients with Type 2 Diabetes Mellitus

Background

Bone fragility is increased in patients with type 2 diabetes mellitus (T2DM), but a useful method to estimate bone fragility in T2DM patients is lacking because bone mineral density alone is not sufficient to assess the risk of fracture. This study investigated the association between prevalent vertebral fractures (VFs) and the vertebral strength index estimated by the quantitative computed tomography-based nonlinear finite element method (QCT-based nonlinear FEM) using multi-detector computed tomography (MDCT) for clinical practice use.

Research Design and Methods

A cross-sectional observational study was conducted on 54 postmenopausal women and 92 men over 50 years of age, all of whom had T2DM. The vertebral strength index was compared in patients with and without VFs confirmed by spinal radiographs. A standard FEM procedure was performed with the application of known parameters for the bone material properties obtained from nondiabetic subjects.

Results

A total of 20 women (37.0%) and 39 men (42.4%) with VFs were identified. The vertebral strength index was significantly higher in the men than in the women (P<0.01). Multiple regression analysis demonstrated that the vertebral strength index was significantly and positively correlated with the spinal bone mineral density (BMD) and inversely associated with age in both genders. There were no significant differences in the parameters, including the vertebral strength index, between patients with and without VFs. Logistic regression analysis adjusted for age, spine BMD, BMI, HbA1c, and duration of T2DM did not indicate a significant relationship between the vertebral strength index and the presence of VFs.

Conclusion

The vertebral strength index calculated by QCT-based nonlinear FEM using material property parameters obtained from nondiabetic subjects, whose risk of fracture is lower than that of T2DM patients, was not significantly associated with bone fragility in patients with T2DM. This discordance may indirectly suggest that patients with T2DM have deteriorated bone material compared with nondiabetic subjects, a potential cause of bone fragility in T2DM patients.     

Does type 2 diabetes predispose to osteoporotic bone fractures?

Chronic complications of diabetes are associated mainly with changes in major and small arterial vessels as well as in peripheral and autonomic fibers of the nervous system. For years it has been suggested that DM2 does not predispose to osteoporosis because bone mineral density (BMD) in DM2 patients is commonly normal or even increased. However, results of recent large cross-sectional studies have indicated that patients with DM2 have significantly increased risk of bone fractures, predominantly hip fractures (by 70%). Results of these studies suggest that the increased risk of fractures in DM2 is independent of BMD. In this group of patients is frequently associated the loss of vision caused by diabetic eye disease, peripheral neuropathy, arterial hypertension, orthostatic hypotonia (caused by autonomic neuropathy or/and by concomitant antihypertensive treatment), and ischemic disease of the brain, heart and lower extremities--conditions that predispose to falls. There are no specific methods of prophylaxis and treatment of osteoporosis associated with diabetes; therefore they should be based on widely accepted principles as in non-diabetic populations. It seems that in DM2 patients the most purposeful strategy could be the popularization of healthy attitudes aiming the elimination of unfavorable dietetic and environmental factors, such as low physical activity, smoking, and low vitamin D intake, as well as education against falls.     

Bone densitometry: assessing the effects of growth hormone treatment in adults

Dual-energy X-ray absorptiometry (DXA) is the reference method for the measurement of bone mineral mass at different skeletal sites. It has been widely used in recent years to assess the effects of growth hormone (GH) treatment on bone metabolism. In normal individuals, bone mineral content (BMC) and density (BMD), as assessed using DXA, correlate with body size. Therefore, using DXA in patients with congenital GH deficiency (GHD), who have a smaller body frame, would be expected to result in lower bone mass. Thus, comparisons with reference data derived from populations of normal body size are invalid. The evaluation of the effects of GH administration should take into account the possible effects of GH on bone size, not only in children, but also in adults. The enlargement of bone, due to stimulation of the periosteal apposition, may partially mask an increase in BMC, resulting in little or no change in BMD. The ability of GH to affect bone area therefore requires analysis of the possible changes in bone area and BMC, as well as BMD. This issue has been poorly handled in the studies published to date. Lastly, the acceleration of bone turnover induced by GH leads to an increase in bone remodelling space, which in turn is associated with a reduction in BMC and BMD, independent of the net balance between breakdown and formation in each metabolic unit. This bone loss is completely reversible when the remodelling space returns to previous levels. This phenomenon must be taken into account when analysing the effects of GH treatment on bone mass, because a net gain in bone mass may be found in long-term GH treatment or after GH discontinuation, even if bone loss was evident during the first 6 months of treatment. In conclusion, the interpretation of bone density data in patients with GHD, and after GH administration, should take into account some of the methodological aspects of bone densitometry, as well as the specific actions of GH on bone metabolism and body composition.     

Influence of growth hormone on accretion of bone mass

Growth hormone (GH) exerts important influences on bone metabolism during lifespan. During childhood, GH is a major determinant of acquisition of bone mass and in adult life, GH partly determines the rate of bone remodelling and therefore influences maintenance of bone mineral density (BMD). Insights into the importance of GH in these respects may be obtained by studies of BMD and indices of bone remodelling in GH deficiency (GHD) of adult-onset and childhood-onset. Adult-onset GHD, usually accompanied by other features of hypopituitarism, may be associated with osteopenia and an increased fracture risk. Postulated mechanisms include GHD and gonadal steroid deficiency of unknown duration; glucocorticoid and thyroxine replacement do not appear to exert a major role. GH replacement in adult-onset GHD results in an early increment in indices of bone remodelling which persists for up to 5 years; BMD increases by 0.5-1.0 SD in males and stabilizes in females over this time period. In adolescents with GHD who traditionally discontinue GH at completion of linear growth, BMD is substantially lower than peak bone mass for a young adult population. Studies addressing the effects of continuation of GH after achievement of final height are currently underway and will provide insights into the possible need to continue GH into adult life. Such studies may confirm a role for GH in promoting continued accrual of bone mass and thereby demonstrate that cessation of GH at achievement of final height, by limiting peak bone mass, may predispose to clinically significant osteoporosis in later life. In addition to the potential importance of GH for achievement of peak bone mass, there may be a superimposed accelerated loss of BMD with advancing age similar to the situation observed in adult-onset GHD. To date, this has been difficult to assess in adult GHD of childhood-onset because the relative contributions of low peak bone mass and increased loss of bone in later life could not be distinguished.     

Axial BMD in Diabetic and Nondiabetic Southeast Asians with HIP Fractures: Do Race and Body Mass Index Matter?

Objective: Obesity is less prevalent in Asian subjects with type 2 diabetes mellitus (T2DM) in contrast to Caucasians. Whether higher axial bone mineral density (BMD) often reported in T2DM is independent of body mass index (BMI) has not been clearly shown. BMD characterization in T2DM patients with hip fractures has also not been performed. We compared the BMD of Asian diabetic and nondiabetic patients with new hip fractures and explored how BMD was influenced by BMI.Methods: We included 255 diabetic and 148 nondiabetic patients. BMD adjusted for age; BMI; race; sex; renal function; and use of statins, proton pump inhibitors, steroids, anticonvulsants, and calcium and/or vitamin D supplements were compared between the groups. We were particularly interested in the BMD comparison between underweight diabetics and nondiabetics with hip fractures.Results: The presence of T2DM was associated with higher BMD (g/cm²) at the femoral neck (0.527 ± 0.103 vs. 0.491 ± 0.102, P<.01) and lumbar spine [LS] (0.798 ± 0.147 vs. 0.723 ± 0.156, P<.01). This association persisted after adjustment for multiple confounding variables including BMI. The age-, BMI-, and sex-adjusted LS BMD was higher in underweight (BMI <18.5 kg/m²) diabetics compared to similar weight nondiabetics (0.733 ± 0.126 vs. 0.649 ± 0.131 g/cm², P = .014).Conclusion: T2DM is independently associated with higher axial BMD in patients with new hip fractures. The finding of higher BMD even in underweight diabetics with hip fractures compared to their nondiabetic counterparts suggests that higher BMD in subjects with T2DM is not due to higher BMI.Abbreviations:BMD = bone mineral densityBMI = body mass indexCV = coefficient of variationDXA = dual-energy X-ray absorptiometryHbA1c = glycated hemoglobinIGF-1 = insulin growth factor-1LS = lumbar spine25(OH)D = 25-hydroxyvitamin DT2DM = type 2 diabetes mellitus     

胰岛素联合阿仑膦酸钠对2型糖尿病骨质疏松症患者骨代谢的影响

目的:研究胰岛素联合阿仑膦酸钠对2型糖尿病(T2DM)骨质疏松症患者骨代谢的影响。方法:选择从2010年1月到2015年7月在医院治疗的T2DM合并骨质疏松症患者208例纳入本次研究。依照随机数字表法将患者划分成单用胰岛素组(对照1组)、单用二甲双胍组(对照2组)、二甲双胍及阿仑膦酸钠组(对照3组)以及胰岛素及阿仑膦酸钠组(联合组)各52例,各组在常规补钙治疗的基础上分别给予对应治疗措施,比较各组治疗前后骨代谢相关指标,以及各组治疗过程中的不良反应。结果:组内相比,治疗后联合组的骨密度(BMD)、血清骨特异型碱性磷酸酶(BAP)及骨钙素(BGP)明显高于治疗前,人抗酒石酸酸性磷酸酶5b(TRAP-5b)明显低于治疗前,差异有统计学意义(P0.05);而其他三组治疗前后的BMD、BAP、TRAP-5b和BGP相比,差异均不显著(P0.05)。组间相比,治疗后联合组的BMD、BAP及BGP明显高于其他三组,TRAP-5b明显低于其他三组,差异有统计学意义(P0.05)。各组的不良反应总发生率比较,差异均无统计学意义(均P0.05)。结论:利用胰岛素以及阿仑膦酸钠联合治疗T2DM合并骨质疏松症患者,具有较好的疗效,同时还可有效改善其骨代谢指标水平,值得在临床上予以推广。     

Relationship of Dickkopf1 (DKK1) with Cardiovascular Disease and Bone Metabolism in Caucasian Type 2 Diabetes Mellitus

ObjectivesDickkopf-1 (DKK1) is a potent inhibitor of Wnt signalling, which exerts anabolic effects on bone and also takes part in the regulation of vascular cells. Our aims were to evaluate serum DKK1 in type 2 diabetes (T2DM) patients and to analyze its relationships with cardiovascular disease (CVD). We also evaluated the relationship between DKK1 and bone metabolism.DesignWe conducted a cross-sectional study in which we measured serum DKK1 (ELISA, Biomedica) in 126 subjects: 72 patients with T2DM and 54 non-diabetic subjects. We analysed its relationship with clinical CVD, preclinical CVD expressed as carotid intima media thickness (IMT), and bone metabolism.ResultsT2DM patients with CVD (P = 0,026) and abnormal carotid IMT (P = 0,038) had higher DKK1 concentrations. DKK1 was related to the presence of CVD in T2DM, independently of the presence of risk factors for atherosclerosis. Therefore, for each increase of 28 pg/ml of serum DKK1 there was a 6,2% increase in the risk of CVD in T2DM patients. The ROC curve analysis to evaluate the usefulness of DKK1 as a marker for high risk of CVD showed an area under the curve of 0,667 (95% CI: 0,538–0,795; P = 0,016). In addition, there was a positive correlation between serum DKK1 and spine bone mineral density in the total sample (r = 0,183; P = 0,048).ConclusionIn summary, circulating DKK1 levels are higher in T2DM with CVD and are associated with an abnormal carotid IMT in this cross-sectional study. DKK1 may be involved in vascular disease of T2DM patients.     

BMAL1 regulates balance of osteogenic–osteoclastic function of bone marrow mesenchymal stem cells in type 2 diabetes mellitus through the NF-κB pathway

In bone marrow mesenchymal stem cell (BMSCs), type 2 diabetes mellitus (T2DM) induces metabolic and functional disorders, leading to imbalanced bone resorption and formation and bone loss. Brain and muscle ARNT-like protein 1 (BMAL1) is involved in regulating T2DM-related suppression of BMSCs osteogenesis and bone formation. However, the relationship between BMAL1 and bone remodelling, especially bone resorption in T2DM, is unclear. We investigated the antergic role played by BMAL1 in T2DM-prompted imbalance in BMSCs osteogenic–osteoclastic function. BMAL1 was inhibited and the receptor activator of nuclear factor-κB ligand/osteoprotegerin (RANKL/OPG) ratio was increased in diabetic BMSCs. Inhibitor κB (IκB) expression was decreased, whereas phosphorylated-p65 (p-p65), caspase-3, and p-IκB expression were increased in diabetic BMSCs. BMAL1 overexpression recovered the osteogenesis ability and suppressed osteoclastic induction capability of BMSCs to improve bone metabolism and function, which was partially due to NF-κB pathway activity inhibition. Our results provide evidence about the role of BMAL1 in T2DM-prompted BMSCs differentiation dysfunction, i.e. partially decreasing NF-κB pathway expression. In T2DM, it might be possible to use overexpressed BMAL1 to re-establish the homeostasis of bone metabolism.     

Serum BAP as the clinically useful marker for predicting BMD reduction in diabetic hemodialysis patients with low PTH

With decrease of serum PTH in hemodialysis (HD) patients, other factors besides parathyroid hormone (PTH) become important in regulating bone metabolism. We investigated which serum bone metabolic marker is the best to predict the bone mineral density (BMD) reduction in HD patients with serum PTH<180 pg/ml. The bone formation markers, bone alkaline phosphatase (BAP), intact osteocalcin (OC), and N-terminal propeptide of type I collagen (PINP), and the bone resorption markers, deoxypyridinoline (DPD), pyridinoline (PYD), and beta-crossLaps (beta-CTx) were measured in serum from 137 HD patients. BMD of all patients was measured twice, approximately 1.5 years before and 1.5 years after measurement of their markers of bone metabolism. In all 137 HD patients, serum BAP was the only marker significantly higher in those with BMD reduction than in those without. In 42 diabetes mellitus (DM) HD patients with serum PTH<180 pg/ml, hypothetically low bone turnover state, serum BAP was again the only marker to discriminate those with BMD reduction from those without. At serum PTH<60 pg/ml, serum BAP retained tendency toward higher value. These findings suggest that serum BAP might be the most sensitive to identify small changes of bone metabolism in low bone turnover state. Retrospective study confirmed the usefulness of serum BAP in clinical practice by significantly higher values in those with bone loss at PTH<180 pg/ml even in under routine sample handling. In conclusion, serum BAP is a clinically useful bone formation marker to predict the BMD reduction in DM HD patients with low level of PTH.     

Islet Autoimmunity Identifies a Unique Pattern of Impaired Pancreatic Beta-Cell Function,Markedly Reduced Pancreatic Beta Cell Mass and Insulin Resistance in Clinically Diagnosed Type 2 Diabetes

There is a paucity of literature describing metabolic and histological data in adult-onset autoimmune diabetes. This subgroup of diabetes mellitus affects at least 5% of clinically diagnosed type 2 diabetic patients (T2DM) and it is termed Latent Autoimmune Diabetes in Adults (LADA). We evaluated indexes of insulin secretion, metabolic assessment, and pancreatic pathology in clinically diagnosed T2DM patients with and without the presence of humoral islet autoimmunity (Ab). A total of 18 patients with at least 5-year duration of clinically diagnosed T2DM were evaluated in this study. In those subjects we assessed acute insulin responses to arginine, a glucose clamp study, whole-body fat mass and fat-free mass. We have also analyzed the pancreatic pathology of 15 T2DM and 43 control cadaveric donors, using pancreatic tissue obtained from all the T2DM organ donors available from the nPOD network through December 31, 2013. The presence of islet Ab correlated with severely impaired β-cell function as demonstrated by remarkably low acute insulin response to arginine (AIR) when compared to that of the Ab negative group. Glucose clamp studies indicated that both Ab positive and Ab negative patients exhibited peripheral insulin resistance in a similar fashion. Pathology data from T2DM donors with Ab or the autoimmune diabetes associated DR3/DR4 allelic class II combination showed reduction in beta cell mass as well as presence of autoimmune-associated pattern A pathology in subjects with either islet autoantibodies or the DR3/DR4 genotype. In conclusion, we provide compelling evidence indicating that islet Ab positive long-term T2DM patients exhibit profound impairment of insulin secretion as well as reduced beta cell mass seemingly determined by an immune-mediated injury of pancreatic β-cells. Deciphering the mechanisms underlying beta cell destruction in this subset of diabetic patients may lead to the development of novel immunologic therapies aimed at halting the disease progression in its early stage.     

A 1-year case-control study in patients with rheumatoid arthritis indicates prevention of loss of bone mineral density in both responders and nonresponders to infliximab

The goal of the present study was to record changes in bone mineral density (BMD) and markers of bone turnover in patients with rheumatoid arthritis (RA) who were treated with methotrexate combined (or not combined) with infliximab. Included were 90 patients with RA who required anti-TNF-α therapy with infliximab because of persistent active disease despite treatment with methotrexate. The historical control group included 99 patients with RA who were treated with methotrexate at a time when anti-TNF-α treatment was not yet available. Lumbar and femoral neck BMD was measured using dual energy X-ray absorptiometry at baseline and 1 year later. Osteocalcin, C-terminal cross-linked telopeptide of type I collagen, parathyroid hormone and 25-hydroxycholecalciferol were measured in plasma at baseline and 1 year later. At 1 year BMD had decreased in the control group at spine (P < 0.01) and femoral neck (P < 0.001). In contrast, BMD at spine and femoral neck did not change after 1 year of infliximab treatment. At the same time point, no change in bone remodelling markers was observed. No association was observed between clinical response and changes in BMD, indicating that even those who did not respond clinically did not lose bone over a 1-year period. These data confirm the BMD decrease observed in RA patients treated with methotrexate alone. This bone loss was prevented by infliximab therapy. Importantly, this beneficial effect was also observed in apparent nonresponders.     

ADRA2A is involved in neuro‐endocrine regulation of bone resorption

Adrenergic stimulation is important for osteoclast differentiation and bone resorption. Previous research shows that this happens through β2‐adrenergic receptor (AR), but there are conflicting evidence on presence and role of α2A‐AR in bone. The aim of this study was to investigate the presence of α2A‐AR and its involvement in neuro‐endocrine signalling of bone remodelling in humans. Real‐time polymerase chain reaction (PCR) and immunohistochemistry were used to investigate α2A‐AR receptor presence and localization in bone cells. Functionality of rs553668 and rs1800544 single nucleotide polymorphism SNPs located in α2A‐AR gene was analysed by qPCR expression on bone samples and luciferase reporter assay in human osteosarcoma HOS cells. Using real‐time PCR, genetic association study between rs553668 A>G and rs1800544 C>G SNPs and major bone markers was performed on 661 Slovenian patients with osteoporosis. α2A‐AR is expressed in osteoblasts and lining cells but not in osteocytes. SNP rs553668 has a significant influence on α2A‐AR mRNA level in human bone samples through the stability of mRNA. α2A‐AR gene locus associates with important bone remodelling markers (BMD, CTX, Cathepsin K and pOC). The results of this study are providing comprehensive new evidence that α2A‐AR is involved in neuro‐endocrine signalling of bone turnover and development of osteoporosis. As shown by our results the neurological signalling is mediated through osteoblasts and result in bone resorption. Genetic study showed association of SNPs in α2A‐AR gene locus with bone remodelling markers, identifying the individuals with higher risk of development of osteoporosis.     

Retracted: Receptor for advanced glycation end products reveals a mechanism regulating thyroid hormone secretion through the SIRT1/Nrf2 pathway

Advanced glycation end products (AGEs) play a causative role in the complications involved with diabetes mellitus (DM). Nowadays, DM with hypothyroidism (DM-hypothyroidism) is indicative of an ascended tendency in the combined morbidity. In this study, we examine the role of the receptor (RAGE) played for AGEs in thyroid hormone (TH) secretion via the silent information regulator 1 (SIRT1)/nuclear factor erythroid-derived factor 2-related factor 2 (Nrf2) pathway. Blood samples were collected from patients with type 2 DM (T2DM)-hypothyroidism and from patients with T2DM, followed by detection of serum AGEs level. The underlying regulatory mechanisms of RAGE were analyzed in association with the treatment of high glucose, siRNA against RAGE, AGE, SIRT1, or Nrf2 vector in normal immortalized thyroid Nthy-ori 3-1 cells. Serum of patients with T2DM-hypothyroidism indicated promoted levels of AGEs vs those with just T2DM. Both AGEs and high glucose triggered cellular damage, increased oxidative stress, as well as displayed a decreased survival rate along with TH secretion in the Nthy-ori 3-1 cells. Moreover, AGEs and high glucose also led to RAGE upregulation, both SIRT1 and NRF2 downregulation, and the decreased expression of TH secretion–related proteins in Nthy-ori 3-1 cells. Notably, these alternations induced by the AGEs can be reserved by silencing RAGE or upregulating either SIRT1 or Nrf2, indicating a mechanism of regulating TH secretion through the SIRT1/Nrf2 pathway. Collectively, our data proposed that AGEs and high glucose exerted a potent effect on cellular damage and TH deficiency in Nthy-ori 3-1 cells through the RAGE upregulation as well as SIRT1/Nrf2 pathway inactivation. This mechanism may underlie the occurrence of DM-hypothyroidism.     

Effects of cyclical therapy for osteoporosis using an oral regimen of inorganic phosphate and sodium etidronate: a clinical and bone histomorphometric study

Cyclical therapy for osteoporosis has been proposed as a means to induce a coherently structured improvement in bone remodelling dynamics. This pilot study involved 37 osteoporotic patients with symptomatic vertebral compression fractures, treated with an oral protocol designed to activate endogenous bone turnover and selectively depress osteoclastic bone resorption, utilizing inorganic phosphate and sodium etidronate respectively in sequential 3 monthly cycles. Biochemical parameters were recorded during the first cycle, and quantitative bone histomorphometry was obtained from iliac crest biopsies before and after 23.4 ± 8.5 (SEM) months of treatment. In addition, fracture rates (expressed as new vertebral fractures/1000 patient years) were studied by sequential lateral spinal radiographs. Lumbar bone mineral density (BMD) was assessed by sequential dual-beam photon densitometry. The results demonstrated equivocal biochemical evidence of 2 ° hyperparathyroidism during the initial cycle of therapy with inorganic phosphate. However, fracture rates declined significantly from 640/1000 patient years during the first 15 months therapy to 242/1000 patient years during a further 20 months follow-up (P < 0.01). Lumbar BMD increased over baseline by 8.38 ± 2.87% after 12 months treatmen (P < 0.01). Bone histomorphometric analysis disclosed a modest increment in bone volume from 16.0 to 17.4% tissue volume, and a significant increase in eroded surface from 4.2 ± 0.6 to 6.0 ± 0.9% cancellous surface (P < 0.05). However, histomorphometric parameters of bone formation deteriorated. It is concluded that this cyclical protocol resulted in short-term improvement in trabecular bone mass, but there is no evidence at a cellular level that long-term improvements in bone remodelling occurred.     

Influence of cardiovascular disease risk factors on the relationship between low bone mineral density and type 2 diabetes mellitus in a multiethnic us population of women and men: A cross-sectional study

Introduction: Higher bone mineral density (BMD) has been reported among white women and men with type 2 diabetes mellitus (DM) compared with nondiabetic white individuals, but there is scant evidence for nonwhite persons. It is also not known whether cardiovascular disease (CVD) risk factors may confound any association between BMD and type 2 DM.Objective: The present study examined the relationship between low BMD and type 2 DM in a multiethnic population of women and men while controlling for the influence of osteoporosis and CVD risk factors including body mass index (BMI), cigarette smoking, physical inactivity, total cholesterol and its components, blood pressure, and C-reactive protein.Methods: Data collected from 4929 African American, Mexican American, and white women and men aged 50 to 79 years who participated in the household interview and clinical examinations during the Third National Health and Nutrition Examination Survey were analyzed. CVD risk factors associated with type 2 DM in this study population were included as covariates in gender-specific multiple logistic regression models assessing the relationship between type 2 DM and low BMD while controlling for osteoporosis risk factors. Gender- and race/ethnicity-specific mean BMD values at the total hip for young adults aged 20 to 29 years were used to establish race/ethnicity and gender-specific low BMD T-scores.Results: The final study population included 2505 women and 2424 men. More women and men with type 2 DM than women and men without type 2 DM were nonwhite and had high BMI. Osteoporosis risk factors but not CVD risk factors were associated with low BMD in both women and men. Type 2 DM was not associated with low BMD among women (odds ratio [OR] = 0.77; 95% CI, 0.56-1.08). Based on a statistically significant interaction between type 2 DM status and race/ethnicity, white men with type 2 DM were less likely to have low BMD than were white men without type 2 DM (OR = 0.56; 95% CI, 0.37-0.86; P = 0.01). There was no significant BMD difference between diabetic and nondiabetic nonwhite men.Conclusion: CVD risk factors did not appear to influence the relationship between low BMD and type 2 DM in this study     

Abnormal NF-kappa B function characterizes human type 1 diabetes dendritic cells and monocytes

Dendritic cell (DC) differentiation is abnormal in type 1 diabetes mellitus (T1DM). However, the nature of the relationship between this abnormality and disease pathogenesis is unknown. We studied the LPS response in monocytes and monocyte-derived DCs isolated from T1DM patients and from non-T1DM controls. In T1DM patients, late LPS-mediated nuclear DNA binding by RelA, p50, c-Rel, and RelB was impaired as compared with type 2 DM, rheumatoid arthritis, and healthy subjects, associated with impaired DC CD40 and MHC class I induction but normal cytokine production. In TIDM monocytes, RelA and RelB were constitutively activated, and the src homology 2 domain-containing protein tyrosine phosphatase (SHP-1), a negative regulator of NF-kappaB, was overexpressed. Addition of sodium stibogluconate, a SHP-1 inhibitor, to DCs differentiating from monocyte precursors restored their capacity to respond to LPS in approximately 60% of patients. The monocyte and DC NF-kappaB response to LPS is thus a novel phenotypic and likely pathogenetic marker for human T1DM. SHP-1 is at least one NF-kappaB regulatory mechanism which might be induced as a result of abnormal inflammatory signaling responses in T1DM monocytes.     

脂联素基因单核苷酸多态性与Ⅱ型糖尿病合并肥胖及胰岛素抵抗相关联

脂联素是近年新发现的脂肪组织特异性的细胞因子,其mRNA是脂肪组织中含量最丰富的基因转录产物,该因子可通过多种途径影响个体对胰岛素的敏感性。脂联素基因多态性与肥胖、胰岛素抵抗和2型糖尿病密切相关,而与冠心病相关性研究的报道较少。本研究以中国汉族人群1,098例为对象,其中304例冠心病(CHD)患者,389例糖尿病患者(T2DM),及405例性别年龄相匹配的正常对照,采用PCR-RFLP技术对脂联素基因-4522C/T进行基因分型,并分别对血脂水平、胰岛素抵抗、体重指数等临床数据进行分析比较。研究结果显示,脂联素基因-4522C/T各基因型及等位基因在CHD组与对照组、T2DM组与对照组中的分布差异无显著性;经分组分析发现,T2DM合并肥胖患者BMI≥25kg/m2TT基因型及T等位基因明显多于对照组,差异有显著性,P=0.014和P=0.034;TT基因型T2DM患者胰岛素抵抗指数(HOMA-IR)显著高于携带有C等位基因的T2DM患者,P=0.0069。本研究提示脂联素基因-4522C/T与中国汉族人群T2DM合并肥胖的发生及T2DM患者胰岛素抵抗相关,是引发糖尿病患者肥胖和胰岛素抵抗的重要候选基因,而与冠心病的发生无关联。     

TNF-α is upregulated in T2DM patients with fracture and promotes the apoptosis of osteoblast cells in vitro in the presence of high glucose

Fracture healing is regulated by proinflammatory mediators such as tumor necrosis factor-α (TNF-α), which poses influence on the balance between bone formation and remodeling. And the diabetes is thought to contribute to the delayed diabetic fracture healing. In the present study, we examined the promotion to proinflammatory cytokines and chemokines in type 2 diabetes mellitus (T2DM) patients with bone fractures, and then evaluated the promotion to TNF-α by the high glucose treatment in human osteoblast-like MG-63 cells and the regulatory role of the promoted TNF-α on the MG-63 cell apoptosis. It was demonstrated that there were significantly-upregulated high-sensitivity C-reactive protein (hsCRP) TNF-α, IL-1β, IL-6, IFN-γ-inducible protein 10 (IP-10) and RANTES in T2DM patients with bone fracture. And the promotion to TNF-α and IL-1β was confirmed in vitro in both mRNA and protein levels in high glucose-treated MG-63 cells. And either TNF-α or high glucose reduced the viability of MG-63 cells, promoted apoptosis and upregulated apoptosis-associated markers, such as released cytochrome c, cleaved caspase 3 and lyzed PARP. Moreover, there was a synergistic effect between TNF-α and high glucose. The viability reduction and the apoptosis induction of MG-63 cells were significantly higher in the group with both TNF-α and high glucose treatments, than in the group with singular TNF-α treatment. In conclusion, our study demonstrated that proinflammatory cytokines and chemokines were promoted in T2DM patients with bone fracture or in osteoblasts by the high glucose stimulation. TNF-α and high glucose synergistically reduced the viability and induced the apoptosis in the osteoblast-like MG-63 cells in vitro. It implies the significant regulatory role of TNF-α in the delayed fracture healing in T2DM.     

TH1/TH2 cytokine balance in patients with both type 1 diabetes mellitus and asthma

BACKGROUND AND OBJECTIVE: T1DM and asthma are mediated by opposite arms of the cellular immune system namely T helper (Th)1 and Th2 CD4(+) cells, respectively. Our aim was to characterize the Th1/Th2 cytokine balance in patients with both T1DM and asthma. METHODS: Forty-four patients, mean age 19 years were matched by gender and age, to 4 paired groups: T1DM and asthma, asthma only, T1DM only and healthy controls. Peripheral blood mononuclear cells (PBMC) were stimulated in vitro with disease-specific recombinant antigens; glutamic acid decarboxylase and house dust mite (Der p1 antigen) for T1DM and asthma, respectively, and non-specific mitogens; phytohemaglutinin (PHA), tetanus toxin and anti-CD3 mAb. ELISPOT and ELISA technique were used to determine INF-gamma, IL-2, IL-4, IL-13 and IL-10 expression. RESULTS: Patients with T1DM and asthma demonstrated a similar cytokine pattern but lower Th1/Th2 ratio compared to patients with T1DM only. The Th2 cytokines response to Der p1 was enhanced in patients with both diseases compared to controls. The IL-10 overall secretion was higher in patients with both diseases compared to one disease only. CONCLUSION: The Th1 and Th2 secretory pattern of patients with T1DM and asthma combines features of both diseases suggesting a unique Th1/Th2 balance.