Mesenchymal stem cells-based drug delivery systems for diabetic foot ulcer: A review.

The complication of diabetes, which is known as diabetic foot ulcer (DFU), is a significant concern due to its association with high rates of disability and mortality. It not only severely affects patients' quality of life, but also imposes a substantial burden on the healthcare system. In spite of efforts made in clinical practice, treating DFU remains a challenging task. While mesenchymal stem cell (MSC) therapy has been extensively studied in treating DFU, the current efficacy of DFU healing using this method is still inadequate. However, in recent years, several MSCs-based drug delivery systems have emerged, which have shown to increase the efficacy of MSC therapy, especially in treating DFU. This review summarized the application of diverse MSCs-based drug delivery systems in treating DFU and suggested potential prospects for the future research.

Effectiveness of drug interventions in nonalcoholic fatty liver disease: A network meta-analysis.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a major chronic liver disorder worldwide, and there is no established treatment for this disease. We conducted a network meta-analysis (NMA) to compare existing treatments, which include four classes of antidiabetic drugs, and examined the optimum treatments for NAFLD. AIM: To compare the effectiveness of different treatments for NAFLD. METHODS: An NMA was conducted using Stata 14.0 (Corporation LLC, College Station, United States) and R (X64 3.6.3 version) in this study. Eligible randomized controlled trials (RCTs) were searched in the PubMed, Cochrane Library, Embase, Medline and Web of Science databases from database inception to April 2021. Two researchers independently screened the available studies in strict accordance with inclusion and exclusion criteria. The Cochrane Risk of Bias tool was used to evaluate the risk of bias of the included studies. The variables with and without dimensional differences were calculated as the standardized mean difference and weighted mean difference, respectively. An inconsistency model and "node-splitting" technique were used to test for inconsistency. Funnel plots were used to evaluate publication bias. RESULTS: Twenty-two eligible RCTs involving 1377 participants were eventually included in our analysis. Data were pooled using a random-effects model. Our NMA results revealed that glucagon-like peptide-1 receptor agonists (GLP-1RAs) were the most effective treatment, yielding improvements in hepatic fat content (HFC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), serum γ-glutamyl transferase (GGT) and body weight [surface under the cumulative ranking curve (SUCRA) = 99.6%, 92.6%, 82.8%, 92.3% and 99.6%, respectively], while thiazolidinediones (TZDs) were the best intervention for reducing the NAFLD activity score (NAS; SUCRA = 98.9%). In addition, moderate performance was observed for the sodium glucose cotransporter-2 inhibitors groups (SUCRA = 25.1%, 66.2%, 63.5%, 58.2% and 71.9% for HFC, ALT, AST, GGT and body weight, respectively). However, metformin performed poorly according to most indicators (SUCRA = 54.5%, 0.3%, 19.5%, 33.7%, 57.7% and 44.3% for HFC, NAS, ALT, AST, GGT and body weight, respectively). CONCLUSION: GLP-1RAs may be the optimum choice for most patients with NAFLD. However, TZDs are considered the most effective therapies in NAFLD patients with histological disease activity.

Mesencephalic astrocyte-derived neurotrophic factor ameliorates steatosis in HepG2 cells by regulating hepatic lipid metabolism.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a global metabolism-associated liver disease. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is a newly discovered secreted protein that is involved in metabolic homeostasis. However, much remains to be discovered about its function in hepatic lipid metabolism; thus, we assessed whether MANF could regulate hepatic metabolism. AIM: To establish in vivo and in vitro NAFLD models to explore the role of MANF in hepatic lipid metabolism. METHODS: HepG2 cells treated with free fatty acids (FFAs) and ob/ob mice were used as NAFLD models. Liver tissues collected from wild type and ob/ob mice were used to detect MANF expression. Cells were treated with FFAs for different durations. Moreover, we used lentiviral constructs to establish overexpression and knockdown cell models in order to interfere with MANF expression levels and observe whether MANF influences hepatic steatosis. Western blot analysis and quantitative real-time PCR were used to detect protein and gene expression, and oil red O staining was used to visualize intracellular lipid droplets. RESULTS: Hepatic MANF protein and mRNA expression in wild type mice were 10-fold and 2-fold higher, respectively, than those in ob/ob mice. The MANF protein was temporarily increased by 1.3-fold after stimulation with FFAs for 24 h and gradually decreased to 0.66-fold that of the control at the 72 h time point in HepG2 cells. MANF deficiency upregulated the expression of genes involved in fatty acid synthesis, cholesterol synthesis, and fatty acid uptake and aggravated HepG2 cell steatosis, while MANF overexpression inhibited fatty acid synthesis and uptake and cholesterol synthesis, and rescued HepG2 cells from FFAs-induced steatosis. Furthermore, a significant decrease in triglyceride levels was observed in the MANF overexpression group compared with the control group (0.4288 ± 0.0081 mmol/g vs 0.3746 ± 0.0121 mmol/g, P < 0.05) upon FFAs treatment. There was also a 17% decrease in intracellular total cholesterol levels between the MANF overexpression group and the control group (0.1301 ± 0.0059 mmol/g vs 0.1088 ± 0.0009 mmol/g, P < 0.05) upon FFAs treatment. Moreover, MANF suppressed lipid deposition in HepG2 cells. CONCLUSION: Our findings indicate that MANF improves the phenotype of liver cell steatosis and may be a potential therapeutic target in hepatic steatosis processes.

Initiating Characteristics of Early-onset Type 2 Diabetes Mellitus in Chinese Patients.

BACKGROUND: Type 2 diabetes mellitus (T2DM) has traditionally been considered to affect mainly the elderly; however, the age at diagnosis has gradually reduced in recent years. Although the incidence of young-onset T2DM is increasing, it is still not fully clear the onset characteristics and risk factors of early-onset T2DM. The aim of this study was to describe the initiating characteristics of early-onset T2DM in Chinese patients and evaluate the risk factors for diabetes mellitus. METHODS: This cross-sectional controlled study was performed using a questionnaire survey method in outpatients of multiple centers in China. A total of 1545 patients with T2DM with an age at onset of <40 years were included, and the control group consisted of subjects aged <40 years with normal blood glucose level. RESULTS: In patients with young-onset T2DM, the mean age and initial hemoglobin 1Ac at diagnosis were 32.96 ± 5.40 years and 9.59 ± 2.71%, respectively. Most of the patients were obese, followed irregular diet pattern and sedentary lifestyle, had life or work pressure, and had a family history of diabetes mellitus. Compared with subjects with normal blood glucose level, logistic regression analysis showed that waist-to-hip ratio (odds ratio [OR] 446.99, 95% confidence interval [CI] 42.37-4714.87), family history of diabetes mellitus (OR 23.46, CI 14.47-38.03), dyslipidemia (OR 2.65, CI 1.54-4.56), diastolic blood pressure (OR 1.02, CI 1.00-1.04), and body mass index (OR 0.95, CI 0.92-0.99) are independent factors for early-onset T2DM. CONCLUSIONS: We observed that abdominal obesity, family history of diabetes mellitus, and medical history of hypertension and dyslipidemia are independent risk factors for early-onset T2DM. It is, therefore, necessary to apply early lifestyle intervention in young people with risk of diabetes mellitus.

[Liraglutide protects against nonalcoholic fatty liver disease in ApoE knockout mice with high-fat diet and silenced Acrp30 by increasing AMPK].

OBJECTIVE: To investigate the mechanism of liraglutide-mediated protection against nonalcoholic fatty liver disease (NAFLD) using aApoE knockout (KO) mouse with high-fat diet (HFD) and Acrp30 knockdown. METHODS: Fifty-six male ApoE KO mice were divided into the following six modeling and experimental groups:regular chow fed (ApoE KO, n=10), HFD fed (HF, n=10), HFD+Adenovirus (Ad)-small hairpin (sh) Acrp30 (Ad-shAcrp30, n=10), HFD+Ad-shGreen Fluorescent Protein (GFP) (Ad-shGFP, n=6), HFD+Ad-shAcrp30+liraglutide (liraglutide, n=10), and HFD+Ad-shAcrp30+saline (saline, n=10). Weight-matched C57BL/6 mice on the regular chow diet were used as the control group (WT control, n=10).All mice were fed their assigned diet for 16 weeks.The Ad-shGFP or Ad-shAcrp30 was injected by tail vein at the end of 14 and 15 weeks.Mice in the liraglutide group received 1 mg/kg of the drug, twice daily, intraperitoneally for a total of 8 weeks (from the 9th to 16th week).Fasting blood samples were collected for testing levels of fasting plasma glucose (FPG), triglycerides (TGs), total cholesterol (TC), free fatty acid (FFA), alanine aminotransferase (ALT), Acrp30 and insulin.Liver tissue was procured for histological examination.Expression of mRNA was detected by real-time RT-PC and of protein was detected by western blot analysis. RESULTS: The Ad-shAcrp30 treated mice had reduced expression of Acrp30 at both the mRNA and protein levels in adipose tissues and plasma, as compared with the AdshGFP treated mice (all P < 0.01).Compared to the WT and ApoE KO groups, the HF group showed higher levels of FPG, FFA, TGs and TC (all P < 0.01); furthermore, the Ad-shAcrp30 treatment compounded these changes.The Ad-shAcrp30 treated group had markedly higher hepatic TC and TGs than the HF group (P < 0.01 and P < 0.05).Oil Red O staining showed that there was more lipid droplets in the liver tissue of the Ad-shAcrp30 treated group than in that of the HF group (P < 0.01), and hematoxylin-eosin staining confirmed these results.Liraglutide treatment prevented the increase in body weight, FPG, FFA, TGs, TC and ALT levels, as compared to the saline controls (all P < 0.01), but the plasma Acrp30 levels and the Acrp30 mRNA and protein expression in adipose tissues were elevated (all P < 0.01).Oil-Red O staining indicated that the liraglutide group had a significantly lower hepatic lipid content than the saline group, and total hepatic TG and TC were reduced in the former group (P < 0.01 and P < 0.05).The liraglutide treatment significantly attenuated the mRNA expression of ACC and FAS (both P < 0.01) but increased AMPK phosphorylation (P < 0.01). CONCLUSION: Administration of liraglutide prevented the development of HFD-and hypoadiponectinemia-induced metabolic disturbance and accumulation of hepatic lipids in this mouse model system of NAFLD.

Randomized, double blinded, placebo-controlled trial to evaluate the efficacy and safety of tolvaptan in Chinese patients with hyponatremia caused by SIADH.

To study the effect of tolvaptan on non-acute, non-hypovolemic hyponatremia in inappropriate secretion of antidiuretic hormone (SIADH) syndrome in Chinese patients. Hyponatremic SIADH patients received placebo (N = 18) or tolvaptan (N = 19) at an initial dose of 15 mg/day with further titration to 30 mg/day and 60 mg/day based on serum sodium concentrations. Randomized, double-blind, placebo-controlled trial. Primary endpoint was the change of the serum sodium from baseline to days 4 and 7. Analysis of covariance (ANCOVA) was used for statistical analysis. At day 4, average daily changes in serum sodium levels from baseline was 1.9 ± 2.9 mmol/L (1.9 ± 2.9 mEq/L) in the placebo group and 8.1 ± 3.6 mmol/L (8.1 ± 3.6 mEq/L) in the tolvaptan group; at day 7, the values were 2.5 ± 3.9 mmol/L (2.5 ± 3.9 mEq/L) and 8.6 ± 3.9 mmol/L (8.6 ± 3.9 mmEq/L) for the placebo and tolvaptan groups (ANCOVA, P < 0.001). At days 4 and 7, daily urine output and proportions of patients with normalized serum sodium were significantly superior in the tolvaptan group. The most common adverse events occurring in the tolvaptan group were dry mouth and thirst. Tolvaptan demonstrated superiority to placebo in the treatment of Chinese SIADH patients with hyponatremia by elevating serum sodium concentration with acceptable safety profile.

Comparison of parathyroid hormone (1-34) and elcatonin in postmenopausal women with osteoporosis: an 18-month randomized, multicenter controlled trial in China.

BACKGROUND: Recombinant human parathyroid hormone (1-34) (rhPTH (1-34)) is the first agent in a unique class of anabolic therapies acting on the skeleton. The efficacy and safety of long-term administration of rhPTH (1-34) in Chinese postmenopausal women had not been evaluated. This study compared the clinical efficacy and safety of rhPTH (1-34) with elcatonin for treating postmenopausal women with osteoporosis in 11 urban areas of China. METHODS: A total of 453 postmenopausal women with osteoporosis were enrolled in an 18-month, multi-center, randomized, controlled study. They were randomized to receive either rhPTH (1-34) 20 µg (200 U) daily for 18 months, or elcatonin 20 U weekly for 12 months. Lumbar spine (L1-4) and femoral neck bone mineral density (BMD), fracture rate, back pain as well as biochemical markers of bone turnover were measured. Adverse events were recorded. RESULTS: rhPTH (1-34) increased lumbar BMD significantly more than did elcatonin after 6, 12, and 18 months of treatment (4.3% vs. 1.9%, 6.8% vs. 2.7%, 9.5% vs. 2.9%, P < 0.01). There was only a small but significant increase of femoral neck BMD after 18 months (2.6%, P < 0.01) in rhPTH groups. There were larger increases in bone turnover markers in the rhPTH (1-34) group than those in the elcatonin group after 6, 12, and 18 months (serum bone-specific alkaline phosphatase (BSAP) 93.7% vs. -3.6%; 117.8% vs. -4.1%; 49.2% vs. -5.8%, P < 0.01; urinary C-telopeptide/creatinine (CTX/Cr) 250.0% vs. -29.5%; 330.0% vs. -41.4%, 273.0% vs. -10.6%, P < 0.01). rhPTH (1-34) showed similar effect of pain relief as elcatonin. The incidence of clinical fractures was 5.36% (6/112) in elcatonin group and 3.2% (11/341) in rhPTH (1-34) group (P = 0.303). Both treatments were well tolerated. Hypercaluria (9.4%) and hypercalcemia (7.0%) in rhPTH (1-34) group were transient and caused no clinical symptoms. Pruritus (8.2% vs. 2.7%, P = 0.044) and redness of injection site (4.4% vs. 0, P = 0.024) were more frequent in rhPTH (1-34). Nausea/vomiting (16.1% vs. 6.2%, P = 0.001) and hot flushes (7.1% vs. 0.6%, P < 0.001) were more common in elcatonin group. CONCLUSIONS: rhPTH (1-34) was associated with greater increases in lumbar spine BMD and bone formation markers. It could increase femoral BMD after 18 months of treatment. rhPTH could improve back pain effectively. The results of the present study indicate that rhPTH (1-34) is an effective, safe agent in treating Chinese postmenopausal women with osteoporosis.

[The efficacy and safety of recombinant human insulin injection in the treatment of diabetic patients:a multicenter, randomized, controlled and open-labeled clinical trial].

OBJECTIVE: A multicenter, randomized, controlled and open-labeled clinical trial was performed to compare the efficacy and safety of recombinant human insulin injection (Yousilin R) and Novolin R in diabetic patients. METHODS: A total of 211 cases were randomized into two groups (1:1) treated with Yousilin R versus Novolin R for 12 weeks respectively. RESULTS: Compared with baseline, the levels of glycosylated hemoglobin A1c (HbA1c) at the end of 12 weeks treatment decreased from 10.77% to 7.72%(P < 0.05) in Yousilin R group and from 10.33% to 7.62% (P < 0.05) in Novolin R group, 2-hour postprandial plasma glucose (2hPG) decreased from 15.49 mmol/L to 9.72 mmol/L (P < 0.05) in Yousilin R group and from 15.33 mmol/L to 10.07 mmol/L (P < 0.05) in Novolin R group, and fasting plasma glucose (FPG) decreased from 10.90 mmol/L to 7.31 mmol/L (P < 0.05) in Yousilin R group and from 10.22 mmol/L to 7.21 mmol/L (P < 0.05) in Novolin R group. The changes of HbA1c, 2hPG and FPG from baseline to endpoint in Yousilin R group was similar to those in Novolin R group (P > 0.05). Furthermore, hypoglycemic events (26.42% vs 30.48%), other adverse events (13.21% vs 16.19%), and serious adverse events (1.89% vs 1.90%) were comparable between Yousilin R and Novolin R groups (P > 0.05). CONCLUSIONS: Yousilin R has similar efficacy, safety and compliance profiles to Novolin R group in the treatment of diabetic patients.

[A randomized, multicenter, active-controlled trial to compare the efficacy of recombinant human parathyroid hormone (1-34) with that of elcatonin in postmenopausal women with osteoporosis in China].

OBJECTIVE: To compare the clinical efficacy and safety between recombinant human parathyroid hormone (rhPTH) (1-34) and elcatonin in the treatment of postmenopausal women with osteoporosis in China. METHODS: This 6 month, multicenter, randomized and controlled study enrolled 205 postmenopausal women with osteoporosis. They were randomized to receive either rhPTH (1-34) 20 µg (200 U) daily or elcatonin 20 U weekly. Lumbar spine (L1-4) and femoral neck bone mineral density (BMD) and biochemical markers of bone turnover were measured. In the meantime adverse events were recorded. RESULTS: The results showed that both rhPTH (1-34) and elcatonin increased L1-4 BMD significantly at the endpoint of the study, but femoral neck BMD did not change significantly. From baseline to endpoint, BMD of L1-4 and femoral neck in the rhPTH (1-34) group increased by 5.51% (P<0.01) and 0.65% (P>0.05), but BMD of L1-4 and femoral neck in elcatonin group increased by 1.55% (P<0.05) and 0.11% (P>0.05). Moreover, the rhPTH (1-34) group had better improvement in L1-4 BMD than the elcatonin group at 3, 6 months, but there was no difference of BMD in these two groups with regard to femoral neck. There were greater mean increases of the bone markers in the rhPTH (1-34) group than those in the elcatonin group at 3, 6 months [serum bone-specific alkaline phosphatase (BSAP) 36.79% vs 0.31%; 92.42% vs -0.17%; the ratio of urine N-telopeptide of type I collagen and creatinine (NTX/Cr) 48.91% vs -5.32%; 68.82% vs -10.86%]. Both kinds of treatment were well tolerated and there were no differences between the two groups in the rates of adverse events and serious adverse events. CONCLUSION: It is concluded that rhPTH (1-34) has more positive effects on bone formation than elcatonin as shown by the greater increments of L1-4 BMD and bone formation markers and the less occurrence of adverse events as well as no significant change in hepatic, renal or hemopoietic function.

A randomized, multicenter controlled trial to compare the efficacy of recombinant human parathyroid hormone (1-34) with elcatonin in postmenopausal women with osteoporosis in China.

BACKGROUND: Recombinant human parathyroid hormone (1-34) (rhPTH (1-34)) given by injection is a new seventh class drug of biological products, which is prepared by adopting gene recombination technique. rhPTH (1-34) is mainly used to treat osteoporosis, especially for postmenopausal women. This study compared the clinical efficacy and safety of rhPTH (1-34) with elcatonin for treating postmenopausal women with osteoporosis in 11 urban areas of China. METHODS: Two hundred and five women with osteoporosis were enrolled in a 6-month, multicenter, randomized, controlled study. They were randomized to receive either rhPTH (1-34) 20 microg (200 U) daily or elcatonin 20 U weekly. Lumbar spine (L1-4) and femoral neck bone mineral density (BMD), as well as biochemical markers of bone turnover were measured. Adverse events were recorded. RESULTS: rhPTH (1-34) increased lumbar BMD significantly more than did elcatonin at 3 months and 6 months (2.38% vs 0.59%, P < 0.05; 5.51% vs 1.55%, P < 0.01), but there were no significant increases of BMD in these two groups at femoral neck. There were larger mean increases in bone markers in the rhPTH (1-34) group than in the elcatonin group at 3 months and 6 months (serum bone-specific alkaline phosphatase (BSAP) 36.79% vs 0.31%; 92.42% vs -0.17%; urinary N-telopeptide/creatinine (NTX/Cr) 48.91% vs -5.32%; 68.82% vs -10.86%). Both treatments were well tolerated and there were no significant differences detected between the two groups in the proportion of any adverse events and any serious adverse events (67.0% vs 59.0%; 0 vs 0). CONCLUSIONS: rhPTH (1-34) has more positive effects on bone formation, as shown by the larger increments of lumbar BMD and bone formation markers, than elcatonin, with only mild adverse events and no significant change in the liver, kidney or hematological indices.

[Effects of tumor necrosis factor-alpha induced insulin resistance on adipose triglyceride lipase in mice].

OBJECTIVE: To investigate the effects of tumor necrosis factor (TNF)-alpha induced insulin resistance (IR) on glucose and lipid metabolism and adipose triglyceride lipase (ATGL). METHODS: Forty male C57BL/6J mice were randomly divided into 2 equal groups: TNF-alpha group with undergoing intraperitoneal injection of TNF-alpha 6 microg x kg(-1) x d(-1) for 7 days and normal control (NC) group with saline injection. Hyperinsulinemic-euglycemic clamp technique combined with 2-deoxy-[(3)H] glucose as a tracer was used on 20 mice, 10 from each group, to examine the fasting blood glucose (FBG), plasma insulin (INS), total cholesterol (TC), triglyceride (TG), and free fatty acid (FFA). The glucose infusion rate (GIR) was recorded. Other 20 mice, 10 in each group, were killed with their adipose and/or muscle tissues taken out. RT-PCR was used to detect the mRNA expression of ATGL, hormone-sensitive lipase (HSL), carnitine palmitoyl transferase-1 (CPT-1), and peroxisome proliferator activated receptor-gamma (PPARgamma). Western blotting was used to measure the protein expression of ATGL. Muscle glucose uptake (MGU) was measured. RESULTS: After TNF-alpha treatment, the FBG, plasma INS, and FFA were significantly elevated in the TNF group compared with the NC group (all P < 0.05). During the steady-state of clamp test, the plasma INS level of the TNF group was (341.7 +/- 17.7) mU/L, significantly higher than that of the NC group [(84.7 +/- 5.5) mU/L, P < 0.01]. The FFA level of the TNF group was (0.82 +/- 0.03) mmol/L, significantly higher than that of the NC group [(0.43 +/- 0.07) mmol/L, P < 0.01]. The GIR of the TNF group was (39.1 +/- 2.3) mg x kg(-1)x min(-1), significantly lower than that of the NC group [(54.2 +/- 2.2) mg x kg(-1) x min(-1), P < 0.01]. The MGU level of the TNF group was (15.8 +/- 1.7) micromol.100 g(-1) x min(-1), significantly lower than that of the NC group [(20.9 +/- 2.5) micromol.100 g(-1) x min(-1), P < 0.01]. The ATGL mRNA expression level in adipose tissues of the TNF group was (0.85 +/- 0.09), significantly lower than that of the NC group (1.37 +/- 0.12, P < 0.01). The ATGL protein expression level of the TNF group was 0.53 +/- 0.03, significantly lower than that of the NC group (0.65 +/- 0.05, P < 0.05). The PPARgamma mRNA expression level in adipose tissues of the TNF group was 0.83 +/- 0.07, significantly lower than that of the NC group (1.07 +/- 0.07, P < 0.05). CONCLUSION: In TNF-alpha induced insulin resistance, AGTL may be involved in the pathways of lipid metabolism.

[Effects of visfatin gene overexpression on insulin sensitivity in the insulin-resistant rats induced by high-fat diet].

OBJECTIVE: To investigate the effects of visfatin gene overexpression on insulin sensitivity in insulin-resistant (IR) rats induced by high-fat diet. METHODS: The recombinant visfatin plasmid was constructed and transfected into IR rats induced by high-fat diet. The euglycemic-hyperinsulinemic clamp experiments were performed for evaluation the change of insulin sensitivity before and after administration. RESULTS: The expression plasmid of visfatin were successfully constructed. After 3 days for plasmid injecting, plasma visfatin levels and glucose infusion rates were significantly increased (2.19 +/- 0.36 vs 0.98 +/- 0.27 and 32.6 +/- 1.2 vs 24.0 +/- 1.2 mg x kg(-1) x min(-1), respectively, all P < 0.01), and total cholesterol and high-density lipoprotein cholesterol (HDL-C) were significantly decreased (2.36 +/- 0.22 vs 1.60 +/- 0.21 mmol/L and 1.41 +/- 0.24 vs 0.88 +/- 0.11 mmol/L, respectively, all P < 0.05) in high-fat diet rats. CONCLUSION: The transfection of visfatin plasmid enhanced plasma visfatin level and improved insulin sensitivity in IR rats induced by high-fat diet.

[Changes of bone density and insulin-like growth factor-1 level in elders with type 2 diabetes mellitus].

OBJECTIVE: To investigate the changes of bone mineral density(BMD) and the relationship of BMD to serum Insulin-like growth factor-1 concentrations, body mass index (BMI), waist hip ratio (WHR), estradiol (E2), testosterone (T), biochemical markers of bone turnover as well as other factors in the elderly individuals with Type 2 diabetes mellitus (T2DM). METHODS: BMDs of spine were measured by quantitative CT for patients with T2DM (n=53) and health controls (n=40). The relationships of BMD related to serum Insulin-like growth factor-1 concentrations, BMI, WHR, E2, T, bone Gla'protein, bone alkaline phosphatase, tartrate resistant acid phosphatase 5b levels were also analyzed. RESULTS: The spine BMD values for the T2DM patients were significantly reduced when compared with controls [(74.75 +/- 22.70) mg/cc vs. (88.04 +/- 28.29) mg/cc, P < 0.05], and the concentration of serum Insulin-like growth factor-1 in T2DM group was significantly lower than that in control [(27.63 +/- 5.74) ng/mL vs. (32.51 +/- 9.68) ng/mL, P < 0.05]. The level of serum Insulin-like growth factor-1 was positive correlation to bone-specific alkaline phosphatase (B-ALP) in the T2DM patients (r = 0.46, P < 0.01). CONCLUSION: The spine BMD in elderly T2DM patients is lower than that in control group. The circulating serum Insulin-like growth factor-1 does not have a significant influence on bone mass in elderly T2DM patients.

[Effect of free fatty acid-induced insulin resistance on plasma ghrelin level: an experimental study with rats].

OBJECTIVE: To investigate the effect of free fatty acid-induced insulin resistance on plasma ghrelin level. METHODS: A venous catheter was inserted through the right jugular vein into the right atrium, and an arterial catheter was inserted through the left carotid in 24 SD rats. After at least 5 days the rats underwent clamping of pancreas after fasting of 12-14 hours. Then the rats were divided into 2 equal groups: lipid-infused group (lipid/heparin were infused during the clamping through the arterial catheter for 4 hours, 60 minutes after the beginning of clamping Ci 3-3H-glucose was infused through the venous catheter till the end of clamping, 120 minutes after the beginning of clamping insulin and 25% glucose were infused for 2 hours with the blood sugar remaining at about 5 mmol/L) and control group (normal saline were infused). Before and after clamping venous blood was collected to detect the concentration of ghrelin. At the time points 0, 120, 200, 230, and 240 min specimens of plasma were collected to detect the concentrations of blood sugar, insulin, free fatty acid, and 3-3H glucose activity. RESULTS: 120 minutes after the beginning of hyperinsulinaemic-euglycaemic clamping the plasma FFA was significant increased from 742 micromol/L +/- 51 micromol/L to 2346 micromol/L +/- 238 micromol/L (P < 0.01) in the lipid-infused group. The glucose infusion rate (GIR) in the lipid-infused rats, compared to the control rats, was significantly reduced by 35% (200-240 min after, with an average value of 12.6 mg.kg(-1).min(-1) +/- 1.5 mg.kg(-1).min(-1) vs. 34.0 mg.kg(-1).min(-1) +/- 1.6 mg.kg(-1).min(-1), P < 0.01). By the end of clamping (240 min after) the GIR in the lipid-infused group was 12.0 mg.kg(-1).min(-1) +/- 1.9 mg.kg(-1).min(-1), significantly lower than that in the control group (34.7 mg.kg(-1).min(-1) +/- 1.7 mg.kg(-1).min(-1), P < 0.01). At the end of clamping, the hepatic glucose production (HGP) in the controls rats was significantly suppressed by 88% (from 19.0 mg.kg(-1).min(-1) +/- 4.5 mg.kg(-1).min(-1) to 2.3 mg.kg(-1).min(-1) +/- 0.9 mg.kg(-1).min(-1), P < 0.01). The suppressive effect of insulin on HGP was significantly blunted in the lipid-infused rats (200 - 240 min: from 18.7 mg.kg(-1).min(-1) +/- 3.0 mg.kg(-1).min(-1) to 23.2 mg.kg(-1).min(-1) +/- 3.1 mg.kg(-1).min(-1), P < 0.05). At the end of euglycemic-hyperinsulinemic clamping the plasma ghrelin levels in the controls was significantly decreased as compared with the basal level (584 ng/L +/- 67 ng/L vs. 892 ng/L +/- 90 ng/L, P < 0.05). Lipid infusion of 4 hours also caused a significant decrease in plasma ghrelin concentration in comparison with the basal levels (548 ng/L +/- 82 ng/L vs. 936 ng/L +/- 78 ng/L, P < 0.05). At the end of euglycemic-hyperinsulinemic clamping, there was no significant difference in the plasma ghrelin levels between the control and lipid-infused rats (584 ng/L +/- 67 ng/L vs. 548 ng/L +/- 82 ng/L, P > 0.05). Pearson analysis showed that fasting plasma ghrelin concentration was negatively correlated with fasting plasma insulin levels (r = -0.52, P < 0.05)and blood glucose (r = -0.61, P < 0.05). CONCLUSION: Lipid-infusion impairs the ability of insulin to suppress lipolysis and hepatic glucose output, as well as insulin-mediated glucose utilization in peripheral tissue. Euglycemic-hyperinsulinemic clamping decreases the circulating ghrelin level in rats, but an acute insulin resistance induced by lipid-infusion in vivo has no effect on circulating ghrelin level.

Effect of hepatic glucose production on acute insulin resistance induced by lipid-infusion in awake rats.

AIM: To explore the influence of hepatic glucose production on acute insulin resistance induced by a lipid infusion in awake rats. METHODS: A hyperinsulinaemic-euglycaemic clamp was established in awake chronically catheterized rats. Two groups of rats were studied either with a 4-h intraarterial infusion of lipid/heparin or saline. Insulin-mediated peripheral and hepatic glucose metabolism was assessed by hyperinsulinaemic-euglycaemic clamp combined with [3-(3)H]-glucose infusion. RESULTS: During hyperinsulinaemic-euglycaemic clamp, there was a significant increase in plasma free fatty acid (FFA, from 741.9+/-50.6 to 2 346.4+/-238.5 micromol/L, P<0.01) in lipid-infused group. The glucose infusion rates (GIR) in the lipid infusion rats, compared to control rats, were significantly reduced (200-240 min average: lipid infusion; 12.6+/-1.5 vs control; 34.0+/-1.6 mg/kg.min, P<0.01), declining to - 35% of the corresponding control values during the last time of the clamp (240 min: lipid infusion; 12.0+/-1.9 vs control; 34.7+/-1.7 mg/kg.min, P<0.0001). At the end of clamp study, the hepatic glucose production (HGP) in control rats was significantly suppressed (88%) from 19.0+/-4.5 (basal) to 2.3+/-0.9 mg/kg.min (P<0.01). The suppressive effect of insulin on HGP was significantly blunted in the lipid-infused rats (200-240 min: from 18.7+/-3.0 to 23.2+/-3.1 mg/kg.min (P<0.05). The rate of glucose disappearance (GRd) was a slight decrease in the lipid-infused rats compared with controls during the clamp. CONCLUSION: These data suggest that lipid infusion could induces suppression of hepatic glucose production, impairs the abilities of insulin to suppress lipolysis and mediate glucose utilization in peripheral tissue. Therefore, we conclude that lipid-infusion induces an acute insulin resistance in vivo.