Fengdi Lu

Cystatin C: a strong marker for lower limb ischemia in Chinese type 2 diabetic patients?

Objective Cystatin C is growing to be an ideal indicator for renal function and cardiovascular events. The aim of this study was to investigate the relationship between serum cystatin C levels and peripheral arterial disease and to explore its diagnostic value for lower limb ischemia (LLI) in type 2 diabetic population. Methods A total of 1609 T2DM patients were included in this cross-sectional study. Their clinical and biochemical characteristics, ankle-brachial index (ABI), carotid and lower extremity arterial ultrasound were detected. LLI was defined by ABI <0.9 and lower extremity arterial stenosis >50% by ultrasound examination. Patients were divided to two groups: with LLI and without. The risk factors of LLI were explored by binary logistic regression analysis. Results The serum concentrations of cystatin C were 1.53±0.60 and 1.08±0.30 mg/L in patients with and without LLI, respectively. Binary logistic regression analysis showed that the significant risk factors were cystatin C (P = 0.007, OR = 5.081), the presence of hypertension (P = 0.011, OR = 3.527), age (P<0.001, OR = 1.181), GA (P = 0.002, OR = 1.089) and diabetes duration (P = 0.008, OR = 1.074). The prevalence of coronary artery disease, cerebral infarction and LLI increased with cystatin C (P<0.01), and the prevalence of LLI in patients with cystatin C >1.2 mg/L was much higher than other three quartile groups. Receiver operating characteristic curve analysis revealed the cut point of cystatin C for LLI was 1.2 mg/L. The risk of LLI dramatically increased in patients with cystatin C >1.2 mg/L (OR = 21.793, 95% confidence interval 10.046−47.280, P<0.001). After adjusting for sex, age, duration, HbA1c, GA and hypertension, its OR still remained 3.395 (95% confidence interval 1.335–8.634). Conclusions There was a strong and independent association between cystatin C and limb arterial disease in diabetic population, and cystatin C >1.2 mg/L indicated a great increased risk of LLI.

Association between serum cystatin C and diabetic peripheral neuropathy: a cross-sectional study of a Chinese type 2 diabetic population.

OBJECTIVE Serum cystatin C (CysC) is a sensitive marker of kidney function and recent studies have shown that CysC plays a critical role in degenerative diseases in both the central and the peripheral nervous systems. The aim of this study was to explore the relationship between serum CysC and diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes. METHODS In total, 937 type 2 diabetic patients were enrolled in this cross-sectional study. Serum CysC concentration was measured by immunoturbidimetry. DPN was evaluated by neurological symptoms, neurological signs, neurothesiometer, and electromyogram. RESULTS Serum CysC levels were significantly higher in DPN patients (1.3 (1.1-1.5) mg/l) compared with patients with signs of DPN (1.1 (0.9-1.3) mg/l, P<0.001) and non-DPN patients (1.0 (0.9-1.3) mg/l, P<0.001). Multiple regression analysis revealed that DPN was associated with age, diabetes duration, HbA1c, and serum CysC. Spearmans correlation analysis showed that serum CysC was closely related with age, sex, diabetes duration, hypertension, glomerular infiltration rate, and serum creatinine (Cr) level. The patients were divided into quartiles according to the serum CysC levels. Compared with quartile 1 (referent), the risk of DPN was significantly higher in quartile 2 (odds ratio (OR), 1.753; 95% CI, 1.055-2.912; P<0.05), quartile 3 (OR, 2.463; 95% CI, 1.445-4.917; P<0.01), and quartile 4 (OR, 5.867; 95% CI, 2.075-16.589; P<0.01). Receiver-operating characteristic analysis revealed that the optimal cutoff point of serum CysC to indicate DPN was 1.25 mg/l in male patients and 1.05 mg/l in female patients. High serum CysC level indicated a onefold higher risk of DPN. CONCLUSIONS High serum CysC level is closely associated with DPN and may be a potential biomarker for DPN in type 2 diabetic patients.

Low serum levels of the innate immune component ficolin-3 is associated with insulin resistance and predicts the development of type 2 diabetes

Dear Editor, Impaired insulin secretion and insulin resistance are the two main mechanisms that lead to type 2 diabetes mellitus (T2DM). Insulin resistance associated with innate immune system is known to be triggered by the activation of patternrecognition receptors (PRRs) (Olefsky and Glass, 2010). Recently, our research group showed that serum ficolin-3, a kind of soluble PRR within the lectin pathway varied significantly between individuals with normal glucose tolerance (NGT) and those with T2DM (Li et al., 2008). Here we performed a human crosssectional study and a prospective study to investigate whether serum ficolin-3 levels associate with insulin resistance and predict the incidence of T2DM. In the cross-sectional study, in which 170 had NGT and 95 had T2DM without any diabetic complications, we found that serum ficolin-3 in the T2DM group was significantly lower than that in the NGT group and multiple linear stepwise regression analyses revealed that serum ficolin-3 was independently correlated with high-density lipoprotein-cholesterol (HDL-c), homeostasis model assessment index of insulin resistance (HOMA-IR), hemoglobin A1c (HbA1c), and age (Supplementary Tables S1 and S2). The glucose disposal rate (GDR) used as a measurement of insulin sensitivity by euglycemic–hyperinsulinemic clamp technique was positively correlated with serum ficolin-3 in 51 NGT subjects (Figure 1A). Further logistic regression analyses showed that there was a significant correlation between serum ficolin-3 and T2DM, after adjustment for age and sex (model I), age, sex, HDL-c, HOMA-IR and HbA1c (model II), age, sex, HDL-c, HOMA-IR, HbA1c, triglycerides (TG), systolic blood pressure (SBP), C-reactive protein, creatinine and uric acid (model III) (Supplementary Table S3). To explore the role of serum ficolin-3 in the prediction of future risk of T2DM, we performed a prospective study in which 1951 subjects recruited from China communities for the Shanghai Diabetes Study (conducted in 1998–2001) and had returned for the follow-up assessment (an average of 3 years). Among them, 1742 had NGT and 209 had impaired glucose regulation at baseline. Serum ficolin-3 was significantly lower in subjects with impaired glucose regulation than in those with NGT (Supplementary Table S4). After the followup, 130 subjects had developed T2DM. The baseline level of serum ficolin-3 was significantly lower in subjects who developed T2DM than those who did not (Supplementary Table S5). Participants in the highest quartile of serum ficolin-3 had a significantly decreased risk of diabetes compared with those belonging to the lowest quartile even after the adjustment of age, sex, body mass index, and waist circumference (Figure 1B). The relative risk (RR) of T2DM for serum ficolin-3 was affected by further adjustment for HDL-c, TG, fasting plasma glucose, SBP, diastolic blood pressure (DBP), and HOMA-IR separately (Figure 1C). In subgroup analysis, a significant association was found between serum ficolin-3 and risk of diabetes among participants who were females, and those who had hyperglycemia, non-abdominal obesity, dyslipidemia, and hypertension (Figure 1D). Ficolin-3, a secreted PRR, was first identified as a serum glycoprotein that reacted with autoantibodies from patients with systemic lupus erythematosus (Epstein and Tan, 1973) and considered to have a primary role in the activation of the lectin pathway in the complement system and in the clearance of late apoptotic cells (Honore et al., 2007). Besides these specific effects on the immune response, a new phenomenon of ficolin-3 was detected in this study. Serum ficolin-3 was significantly lower in T2DM patients and was independently related to insulin resistance which was further confirmed by euglycemic– hyperinsulinemic clamp technique. The mechanism linking ficolin-3 with insulin resistance is not yet fully understood. Ficolin-3, containing the C-type carbohydrate recognition domain and the fibrinogen h/g (homology) domain, has evolved to recognize the surface sugar codes of microbes. Toll-like receptors, which are membrane-bound PRRs, have a similar function, in that they can bind to cell surface carbohydrate molecules in the same way as ficolin-3 does (Smith et al., 2011). Toll-like receptors have been shown to be associated with insulin resistance in T2DM (Raetzsch et al., 2009) through the activation of the innate immune response and subsequent inflammatory pathways in combination with free fatty acids. In addition, mannan-binding lectin, which shares many structural and functional similarities with ficolin-3, has previously been reported to be associated with the development of insulin resistance by increasing fatty acid oxidation in the rat soleus muscle (Fernandez-Real et al., 2006). However, it is unclear whether ficolin-3 affects the development of insulin resistance by similar mechanisms. The most important finding in the prospective study was that low serum ficolin-3 levels at baseline predicted the incidence of T2DM. Interestingly, an inverse association was observed among participants with elevated levels (within the non-diabetic range) of plasma glucose, 256 | Journal of Molecular Cell Biology (2012), 4, 256–257 doi:10.1093/jmcb/mjs032 Published online June 7, 2012

Vitamin D deficiency increases the risk of peripheral neuropathy in Chinese patients with Type 2 diabetes

Vitamin D deficiency was reported to be associated with diabetic peripheral neuropathy. But the association in Chinese population and the screening value of vitamin D deficiency for diabetic peripheral neuropathy were unknown.

The Gonadal Hormone Regulates the Plasma Lactate Levels in Type 2 Diabetes Treated With and Without Metformin

OBJECTIVE Our previous study showed there was a gender difference in plasma lactate concentrations in subjects with type 2 diabetes. This study investigated the effect of sex hormone levels on plasma lactic acid (LA) levels in type 2 diabetes with and without metformin therapy. SUBJECTS AND METHODS Fasting whole blood specimens of 392 type 2 diabetes patients treated with metformin (n=199) or not (n=193) were collected. LA was measured with an enzyme-electrode assay. Levels of sex hormones, including testosterone (T) and estradiol (E(2)), were measured with a chemiluminescence microparticle immunoassay. Spearmans or Pearsons correlation and logistic regression analysis were performed for the factors associated with LA. RESULTS The LA level in the metformin group was significantly higher than that in the non-metformin group (1.26±0.43 vs. 1.14±0.49 mmol/L, P<0.001), and LA levels of females were significantly higher than those of males (P<0.001). LA concentrations were positively correlated with E(2) level but negatively correlated with metformin and T levels (P<0.01). The logistic regression analysis showed that gender, creatinine, E(2), metformin, and T were independent factors influencing lactate levels. Analysis of subgroups demonstrated that the LA concentrations increased with the elevation of E(2) level (P<0.05) but decreased with the rising of T level (P<0.05). CONCLUSIONS Sex hormones play an important role on regulating plasma lactate levels in diabetes patients treated with metformin. E(2) up-regulates but T tend to down-regulate lactate levels.

Assessment of the Performance of A1CNow+ and Development of an Error Grid Analysis Graph for Comparative Hemoglobin A1c Measurements

BACKGROUND This study investigated the performance of the A1CNow(+®) test (Bayer Diabetes Care, Sunnyvale, CA) in a large population of Chinese patients with diabetes. SUBJECTS AND METHODS Hemoglobin A1c (HbA1c) levels in 1,618 Chinese patients with diabetes 10-94 years of age were measured with both the A1CNow(+) test, from a fingerstick blood sample, and the high-performance liquid chromatography (HPLC) test, using a venous blood sample, within 24 h. The reportable ranges of the HbA1c values were 4.0-13.0% (A1CNow(+)) and 4.1-16.8% (HPLC). An error grid analysis (EGA) method was developed to quantify the accuracy of the A1CNow(+) results against the HPLC reference results. RESULTS The A1CNow(+) results were highly correlated with the HPLC reference results (r=0.945, P<0.01). Passing-Bablok regression analysis showed a good linear agreement between the two variables, and the linear regression equation fitted as y=-0.10+1.00x (P=0.21). The Bland-Altman difference plot presented that the mean bias of the A1CNow(+) results minus the HPLC reference results was -0.09% (P<0.001); the 95% confidence intervals for the limits of agreement were -1.28% to 1.09%, with 96.5% of the data points lying within this zone. The results of the EGA showed that 80.2% of the A1CNow(+) results were accurate, 17.7% were acceptable, 1.9% may lead to inappropriate treatment, and 0.3% may lead to severe clinical consequence. CONCLUSIONS The A1CNow(+) test values demonstrated a slight negative bias from the HPLC values. The majority of A1CNow(+) test values were accurate when compared with results from the reference method.

Vibration perception threshold for sight- threatening retinopathy screening in type 2 diabetic outpatients

We investigated the relationship between vibration perception threshold and diabetic retinopathy and verified the screening value of vibration perception threshold for severe diabetic retinopathy.

Vibrating Perception Threshold and Body Mass Index Are Associated with Abnormal Foot Plantar Pressure in Type 2 Diabetes Outpatients

AIMS This study investigated the influencing factors of foot plantar pressure and attempted to find practical indicators to predict abnormal foot pressure in patients with type 2 diabetes mellitus (T2DM). SUBJECTS AND METHODS Vibration perception threshold (VPT) and foot plantar pressure in 1,126 T2DM outpatients were examined. Patients were assigned to Group A (n=599), Group B (n=312), and Group C (n=215) according to VPT values and to Group I (n=555), Group II (n=436), and Group III (n=135) based on body mass index (BMI). The clinical characteristics and pressure-time integral (PTI) were compared among the three groups, and the associated factors of the total PTI in the entire foot (T-PTI) were analyzed. RESULTS PTI of Group C in heel medial and heel lateral was significantly higher than that of Group A (all P<0.01). PTI of Group B in the right fifth metatarsal and heel medial was significantly higher than that of Group A (all P<0.05). T-PTI of Group C was significantly higher than those of Groups A and B, and that of Group B was higher than that of Group A (all P<0.01). PTI of Groups II and III in the second, third, and fourth metatarsal, midfoot, heel medial, and heel lateral was significantly higher than that of Group I (all P<0.05). T-PTI of Groups II and III was significantly higher than that of Group I (all P<0.01). Pearson correlation analysis showed that T-PTI was positively associated with age, VPT, waist circumference, waist-to-hip ratio, and BMI (P<0.05). In multiple stepwise regression analysis, VPT (P=0.004) and BMI (P=0.000) were independent risk factors of T-PTI, and each 1 unit increase in BMI increased the T-PTI by 5.962 kPa•s. Receiver operator characteristic curve analysis further revealed that the optimal cutpoint of VPT and BMI to predict the abnormal PTI was 21 V (odds ratio=2.33, 95% confidence interval 1.67-3.25) and 24.9 kg/m(2) (odds ratio=2.12, 95% confidence interval 1.55-2.90), respectively. CONCLUSIONS Having a VPT higher than 21 V and a BMI above 24.9 kg/m(2) increases the risk of excessive foot plantar pressure in Chinese T2DM.

Contribution of structured self-monitoring of blood glucose to self-efficacy in poorly controlled diabetes patients in China

To investigate the association between structured self‐monitoring of blood glucose (SMBG) and diabetes self‐efficacy in Chinese patients.

Different effect of testosterone and oestrogen on urinary excretion of metformin via regulating OCTs and MATEs expression in the kidney of mice.

The aim of this study was to investigate the effect of testosterone and oestrogen on regulating organic cation transporters (Octs) and multidrug and toxin extrusions (Mates) expression in the kidney of mice and urinary excretion of metformin. 8 week‐old male db/db mice were treated with estradiol (5 mg/kg), testosterone (50 mg/kg) or olive oil with same volume. Metformin (150 mg/kg) was injected in daily for successive 7 days. Plasma, urine and tissue concentrations of metformin were determined by liquid chromatography‐tandem mass spectrometry (LCMS) assay. Western blotting and Real‐time PCR analysis were successively used to evaluate the renal protein and mRNA expression of Octs and MATEs. After treatment, the protein expression of Mate1 and Oct2 in testosterone group was significantly increased than those in control group (both P < 0.05). The protein expression of Mate1 and Oct2 in estradiol group was significantly reduced by 29.4% and 43.3%, respectively, compared to those in control group (all P < 0.05). These data showed a good agreement with the change in mRNA level (all P < 0.05). The plasma metformin concentration (ng/ml) in mice treated with estradiol was significantly higher than control and testosterone group (677.56 ± 72.49 versus 293.92 ± 83.27 and 261.46 ± 79.45; P < 0.01). Moreover, testosterone increased the metformin urine excretion of mice while estradiol decreasing (both P < 0.01). Spearman correlation analysis showed that gonadal hormone was closely associated with Mate1 and Oct2 expression and metformin urine excretion in db/db mice (all P < 0.05). Testosterone and oestrogen exerted reverse effect on metformin urinary excretion via regulating Octs and Mates expression in the kidney of mice.