Cell division cyclin 25C knockdown inhibits hepatocellular carcinoma development by inducing endoplasmic reticulum stress.

BACKGROUND: Cell division cyclin 25C (CDC25C) is a protein that plays a critical role in the cell cycle, specifically in the transition from the G2 phase to the M phase. Recent research has shown that CDC25C could be a potential therapeutic target for cancers, particularly for hepatocellular carcinoma (HCC). However, the specific regulatory mechanisms underlying the role of CDC25C in HCC tumorigenesis and development remain incompletely understood. AIM: To explore the impact of CDC25C on cell proliferation and apoptosis, as well as its regulatory mechanisms in HCC development. METHODS: Hepa1-6 and B16 cells were transduced with a lentiviral vector containing shRNA interference sequences (LV-CDC25C shRNA) to knock down CDC25C. Subsequently, a xenograft mouse model was established by subcutaneously injecting transduced Hepa1-6 cells into C57BL/6 mice to assess the effects of CDC25C knockdown on HCC development in vivo. Cell proliferation and migration were evaluated using a Cell Counting Kit-8 cell proliferation assays and wound healing assays, respectively. The expression of endoplasmic reticulum (ER) stress-related molecules (glucose-regulated protein 78, X-box binding protein-1, and C/EBP homologous protein) was measured in both cells and subcutaneous xenografts using quantitative real-time PCR (qRT-PCR) and western blotting. Additionally, apoptosis was investigated using flow cytometry, qRT-PCR, and western blotting. RESULTS: CDC25C was stably suppressed in Hepa1-6 and B16 cells through LV-CDC25C shRNA transduction. A xenograft model with CDC25C knockdown was successfully established and that downregulation of CDC25C expression significantly inhibited HCC growth in mice. CDC25C knockdown not only inhibited cell proliferation and migration but also significantly increased the ER stress response, ultimately promoting ER stress-induced apoptosis in HCC cells. CONCLUSION: The regulatory mechanism of CDC25C in HCC development may involve the activation of ER stress and the ER stress-induced apoptosis signaling pathway.

Parathyroid carcinoma: Report of 10 patients and literature review.

OBJECTIVE: Parathyroid carcinoma (PC) is a rare disease with high rates of misdiagnosis and recurrence. This report summarized the clinical and pathological characteristics of 10 patients with PC at our hospital, to improve the early recognition and prognosis of PC. METHODS: The clinical manifestations, imaging findings, pathological features, treatments, and prognostic data of 10 patients diagnosed with PC at the First Medical Center, Chinese PLA General Hospital from 2003 to 2021 were analyzed. RESULTS: There were 7 male and 3 female patients with PC whose average age was 41.4 ± 9.4 years. All patients had bone involvement (bone pain and/or osteoporosis), meanwhile 6 patients had kidney stones and 7 patients had palpable neck masses. Five patients presented with tumor metastasis, invading lymph nodes, lung, liver, or bone. Laboratory examinations revealed elevated serum total calcium (4.15 ± 0.81 mmol/L), parathyroid hormone (PTH, 1236.1 ± 519.9 pg/mL) and alkaline phosphatase (405.8 ± 219.0 IU/L) levels. Especially, hypercalcemic crisis occurred in 9 patients. The diagnosis of PC depended on histopathological features of the parathyroid tumor, including capsular and/or vascular invasion. All patients underwent at least en bloc resection. In the follow-up, six patients with relatively high preoperative PTH levels (1519.5 ± 436.8 pg/mL) relapsed postoperatively. Two patients with the Ki-67 index ≥ 10% in parathyroid tumor tissue and distant metastasis died within 2 years after the operation. CONCLUSION: Severe bone pain, kidney stones, hypercalcemic crisis, and markedly elevated PTH usually indicate PC. A markedly elevated PTH level, tumor metastasis, and the Ki-67 index ≥ 10% may be indicators of poor prognosis.

The bidirectional association of C-peptide with cardiovascular risk in nondiabetic adults and patients with newly diagnosed type 2 diabetes mellitus: a retrospective cohort study.

BACKGROUND: Recent literature reported the biological role of C-peptide, but this role is still controversial and unclear. The primary aim of this study was to investigate associations between C-peptide and cardiovascular biomarkers as well as events. METHODS: A total of 55636 participants who had a health examination from 2017 to 2021 were included. Of them, 6727 participants visited the hospital at least twice. Cardiovascular biomarkers like high-sensitivity C-reactive protein (hs-CRP) and high-sensitivity cardiac troponin T (hs-cTnT) were measured and their relationships with fasting C-peptide were evaluated for all participants. Cardiovascular events were obtained during the last visit and their associations with C-peptide were evaluated for those participants who visited the hospital at least twice. RESULTS: Among the included participants, 11.1% had a previous type 2 diabetes mellitus (T2DM). In the participants without previous T2DM, the relationships between fasting C-peptide and hs-CRP and hs-cTnT were negative if the value of fasting C-peptide was < 1.4 ng/mL and positive if the value was ≥ 1.4 ng/mL. These relationships remained significant after adjusting for hemoglobin A1c, insulin resistance index, and its interaction with C-peptide, even if the participants were stratified by glucose metabolism status or levels of insulin resistance index. Hazard ratios of cardiovascular events were first decreased and then increased with the increasing of baseline C-peptide levels, though these associations became unsignificant using the multivariate Cox regression model. Unlike the participants without previous T2DM, the associations of C-peptide with cardiovascular biomarkers and events were not significant in the patients with previous T2DM. CONCLUSIONS: The associations of C-peptide with cardiovascular biomarkers and events were different between the participants without previous T2DM and those with previous T2DM. The effect of C-peptide on cardiovascular risk may be bidirectional, play a benefit role at a low level, and play a harmful role at a high level in the nondiabetic adults and the patients with newly diagnosed T2DM.

Astragalus Polysaccharides Reduce High-glucose-induced Rat Aortic Endothelial Cell Senescence and Inflammasome Activation by Modulating the Mitochondrial Na+/Ca2+ Exchanger.

Vascular endothelial cells play a vital role in atherosclerotic changes and the progression of cardiovascular disease in older adults. Previous studies have indicated that Astragalus polysaccharides (APS), a main active component of the traditional Chinese medicine Astragalus, protect mitochondria and exert an antiaging effect in the mouse liver and brain. However, the effect of APS on rat aortic endothelial cell (RAEC) senescence and its underlying mechanism have not been investigated. In this study, we extracted RAECs from 2-month-old male Wistar rats by the tissue explant method and found that APS ameliorated the high-glucose-induced increase in the frequency of SA-ß-Gal positivity and the levels of the senescence-related proteins p16, p21, and p53. APS increased the tube formation capacity of RAECs under high-glucose conditions. Moreover, APS enhanced the expression of the mitochondrial Na+/Ca2+ exchanger NCLX, and knockdown of NCLX by small interfering RNA (siRNA) transfection suppressed the antiaging effect of APS under high-glucose conditions. Additionally, APS ameliorated RAEC mitochondrial dysfunction, including increasing ATP production, cytochrome C oxidase activity and the oxygen consumption rate (OCR), and inhibited high-glucose-induced NLRP3 inflammasome activation and IL-1ß release, which were reversed by siNCLX. These results indicate that APS reduces high-glucose-induced inflammasome activation and ameliorates mitochondrial dysfunction and senescence in RAECs by modulating NCLX. Additionally, APS enhanced the levels of autophagy-related proteins (LC3B-II/I, Atg7) and increased the quantity of autophagic vacuoles under high-glucose conditions. Therefore, these data demonstrate that APS may reduce vascular endothelial cell inflammation and senescence through NCLX.

Effects of a prolonged diet regimen on autophagic function in rat islets with aging.

The prevalence of type 2 diabetes increases with age-associated increased susceptibility of islet ß-cells and altered dietary patterns, in part because of insufficient compensation of ß-cell functional mass in the face of increasing insulin resistance. However, the underlying mechanisms have not been fully elucidated. In the present study, we investigated the effects of a long-term calorie-restricted (CR) or high-fat (HF) diet compared to a normal ad libitum diet on ß-cell structure-function relationships and autophagy in the islets of 3- and 24-month-old Fischer 344 rats. Aging and the HF diet decreased the ß-cell-to-islet area ratio, disorganized the islet structure, and increased the expression of senescence markers. Aging and the long-term HF diet also decreased autophagy-related proteins, which suggests compromised autophagic function. These findings were further corroborated by increased p62 accumulation and polyubiquitin aggregates observed with aging and the HF diet intervention; these are cardinal markers of attenuated autophagic function. It is important to note that the 24-month-old rats maintained on the CR diet closely mimicked the 3-month-old rats, which indicates that a long-term CR diet can delay islet aging and prevent the decline in the autophagic function of islets during the aging process. Taken together, our results indicate an autophagy-dependent mechanism responsible for islet function in older people or those with altered dietary patterns and lay the foundations for future research leading to novel therapeutic strategies for treating diabetes.

Paget's disease of bone: Report of 11 cases.

BACKGROUND: Paget's disease of bone (PDB) is a rare metabolic bone disease in China and is characterized by increased bone resorption and disorganized bone formation. The main clinical symptoms of PDB are focal or multiple bone pain and deformity with high disability. The disease has high missed diagnosis and misdiagnosis rates. This report summarizes the clinical manifestations, imaging and pathological features, and treatments of 11 patients with PDB at our hospital from 1993 to 2020 in order to improve the recognition and prognosis of PDB. CASE SUMMARY: There were eight male and three female patients whose average age was 48.7 ± 11.0 years with a PDB course of 1-16 years. Nine patients had bone pain and bone deformities in different parts of the body, the majority of which involved the long bones. Laboratory examinations revealed elevated serum alkaline phosphatase (ALP) in all patients with an average of 618 ± 460 IU/L (normal range 0-130 IU/L), and serum calcium and phosphorus levels were in the normal range. Imageology showed that osteolysis was usually combined with osteosclerosis and/or bone deformities in single or multiple bones. 99mTc-methylene diphosphonate bone scintigraphy revealed increased radionuclide uptake in the bone lesions. Six patients underwent bone tissue biopsy, and the typical pathological changes were a mosaic structure of the bone trabeculae with irregularly arranged cement lines and multinuclear osteoclasts. Ten of the 11 patients were effectively treated with bisphosphonates. CONCLUSION: Early diagnosis of the rare disease PDB can be made through elevated ALP levels and typical presentations on bone X-ray and from bone tissue biopsy.

System-Specific Complex Interactions Shape Soil Organic Carbon Distribution in Coastal Salt Marshes.

Coastal wetlands provide many critical ecosystem services including carbon storage. Soil organic carbon (SOC) is the most important component of carbon stock in coastal salt marshes. However, there are large uncertainties when estimating SOC stock in coastal salt marshes at large spatial scales. So far, information on the spatial heterogeneity of SOC distribution and determinants remains limited. Moreover, the role of complex ecological interactions in shaping SOC distribution is poorly understood. Here, we report detailed field surveys on plant, soil and crab burrowing activities in two inter-tidal salt marsh sites with similar habitat conditions in Eastern China. Our between-site comparison revealed slight differences in SOC storage and a similar vertical SOC distribution pattern across soil depths of 0-60 cm. Between the two study sites, we found substantially different effects of biotic and abiotic factors on SOC distribution. Complex interactions involving indirect effects between soil, plants and macrobenthos (crabs) may influence SOC distribution at a landscape scale. Marked differences in the SOC determinants between the study sites indicate that the underlying driving mechanisms of SOC distribution are strongly system-specific. Future work taking into account complex interactions and spatial heterogeneity is needed for better estimating of blue carbon stock and dynamics.

Glycemic control and comprehensive metabolic risk factors control in older adults with type 2 diabetes.

BACKGROUND: Older adults with type 2 diabetes are prone to multiple metabolic abnormalities. However, data from these patients on comprehensive metabolic risk factors control are limited. METHODS: The present study included 2736 older adults aged 60 to 90 years with type 2 diabetes from 114 hospitals across 22 provinces in China. Metabolic abnormalities, including hypertension, dyslipidemia, hyperuricemia, and obesity, were recorded. Comprehensive metabolic risk factors control included the control of hemoglobin A1c (HbA1c) level, blood pressure, serum lipids level, serum uric acid level, and body mass index. The target glycemic control was defined as HbA1c <7%. RESULTS: The proportion of older adults who achieved the HbA1c target was 23.0%. The glycemic control rate increased with the number of metabolic abnormalities increased. The patients who had all four metabolic abnormalities had 4.05 times (95% confidence interval: 2.16, 7.61) the odd to meet glycemic target than those with none of metabolic abnormalities. However, only 4.6% of patients met the targets for all 5 metabolic risk factors. The comprehensive rate of all 5 factors in control decreased from 13.4% to 0% with the number of metabolic abnormalities increased. CONCLUSION: The glycemic control rate and the comprehensive metabolic risk factors control rate were 23.0% and 4.6%, respectively. As the number of metabolic abnormalities increased, the number of risk factor targets achieved decreased. Our findings suggest that a strategy for comprehensive control is urgently needed in older adults with type 2 diabetes, especially in those with co-existing metabolic abnormalities.

[Effects of urban nighttime light on the growth of Cinnamomum camphora]. / åŸŽå¸‚å¤œé—´ç¯å ‰å¯¹é¦™æ¨Ÿç”Ÿé•¿çš„å½±å“.

To understand the effects of urban artificial nighttime light on the growth of evergreen trees, we conducted a field investigation in a typical urban street planted with Cinnamomum camphora (a common evergreen street tree species in eastern China) in the Nanjing City, China. Along the street, trees from two types of growing locations with contrasting distances from the street lamp (just under the lamp vs. between two adjacent lamps) were selected. The growth-related plant functional traits were measured and compared. The results showed that trees grown under the lamp had a mean diameter at beast height (DBH) of 16.8 cm, current-year branch productivity (CBP) of 309.4 g·m-2, current-year leaf productivity (CLP) of 241.5 g·m-2, and leaf relative chlorophyll content (LCC) of 34.6 SPAD. Trees grown between lamps had a mean DBH of 15.5 cm, CBP of 273.4 g·m-2, CLP of 212.8 g·m-2, and LCC of 33.1 SPAD. DBH, CBP, CLP and LCC of the trees under the lamp were significantly higher than those between lamps. There was no significant difference in specific leaf area between trees from the two locations. Our results suggested that urban artificial nighttime light could promote the growth of C. camphora, and alter sunlight-determined characteristics of canopy growth vigor.

Isolation and culture of rat aortic endothelial cells in vitro: A novel approach without collagenase digestion.

To study cardiovascular diseases, the isolation and culture of functional endothelial cells are very important. This study uncovered a novel approach to isolate and culture endothelial cells. The thoracic aorta was collected from Wistar rats with the attached tissue clearly removed. These aorta segments were seeded onto a six-welled plate with the endothelium facing down and removed 2 days after endothelial sprouting started. The endothelial cells were harvested until 80% uneven confluence and cultured for another two passages for use in the following assays: immunofluorescence and flow cytometry assays for endothelial marker expression (CD31 and von Willebrand factor [vWF]), the Dil-labeled acetylated low-density lipoprotein (Dil-Ac-LDL) uptake assay, the tube formation assay, the Hoechst staining apoptosis assay, the ß-galactosidase staining assay for cell senescence, and the Cell Counting Kit-8 (CCK-8) assay for cell viability. Morphologically, the endothelial cells started to migrate away from the aorta after 50 to 72 hours of culture, showing a cobblestone-like structure. The cultured cells expressed high levels of CD31 and vWF, 94.65% of the cells were positive for CD31, and most of the cells showed low-density lipoprotein uptake. They were able to form tube-like structures in vitro and were negatively stained for ß-galactosidase or Hoechst staining. Importantly, the cells at passages 3 and 10 showed similar levels of CCK-8, ß-galactosidase, Hoechst staining, uptake of Dil-Ac-LDL, and capillary tube formation. This novel technique is useful to isolate and culture rat aortic endothelial cells for future studies of endothelial functions and biology. In addition, primary vascular endothelial cells at passages 3 to 10 are suitable for experiments.

Gas chromatography-mass spectrometry based metabolomics profile of hippocampus and cerebellum in mice after chronic arsenic exposure.

Intake of arsenic (As) via drinking water has been a serious threat to global public health. Though there are numerous reports of As neurotoxicity, its pathogenesis mechanisms remain vague especially its chronic effects on metabolic network. Hippocampus is a renowned area in relation to learning and memory, whilst recently, cerebellum is argued to be involved with process of cognition. Therefore, the study aimed to explore metabolomics alternations in these two areas after chronic As exposure, with the purpose of further illustrating details of As neurotoxicity. Twelve 3-week-old male C57BL/6J mice were divided into two groups, receiving deionized drinking water (control group) or 50 mg/L of sodium arsenite (via drinking water) for 24 weeks. Learning and memory abilities were tested by Morris water maze (MWM) test. Pathological and morphological changes of hippocampus and cerebellum were captured via transmission electron microscopy (TEM). Metabolic alterations were analyzed by gas chromatography-mass spectrometry (GC-MS). MWM test confirmed impairments of learning and memory abilities of mice after chronic As exposure. Metabolomics identifications indicated that tyrosine increased and aspartic acid (Asp) decreased simultaneously in both hippocampus and cerebellum. Intermediates (succinic acid) and indirect involved components of tricarboxylic acid cycle (proline, cysteine, and alanine) were found declined in cerebellum, indicating disordered energy metabolism. Our findings suggest that these metabolite alterations are related to As-induced disorders of amino acids and energy metabolism, which might therefore, play an important part in mechanisms of As neurotoxicity.

The mechanism of iron-compensation for manganese deficiency of Streptococcus pneumoniae.

Given their involvement in catalysis, infection, and biofilm formation, Fe and Mn are essential for bacterial survival and virulence. In this study, we found that Streptococcus pneumoniae (S. pneumoniae) could grow in the Mn-deficient medium (MDCM). Furthermore, findings showed that the Fe concentration in the bacterium increased when the Mn concentration decreased. In addition, it was noted that supplementing MDCM with Fe resulted in the recovery of bacterial growth. Quantitative proteomics using stable-isotope dimethyl labeling was performed to investigate the adaptive growth mechanism of S. pneumoniae under Mn-deficient conditions. It was found that the expression levels of 25 proteins were downregulated, whereas those of 54 proteins were upregulated in S. pneumoniae grown in MDCM. It was also noted that several of the downregulated proteins were involved in cell energy metabolism, amino acid synthesis, and reduction of oxidation products. More importantly, several ATP-binding cassette transporters related to Fe uptake, such as PiuA, PiaA, PitA, and SPD_1609, were overexpressed for increased Fe uptake from the MDCM. The results suggest that Mn deficiency disturbs multiple metabolic processes in S. pneumoniae. Furthermore, it causes a compensatory effect of Fe for Mn, which is beneficial for the survival of the bacterium in extreme environments. SIGNIFICANCE: The relationship between manganese and iron metabolism in S. pneumoniae has not been clearly revealed. In this paper, we suggest that Mn limitation disturbs multiple metabolic processes and evidently decreases the ATP level in the bacterium. In order to survive in this extreme environment, bacteria upregulated three type of Fe ion transporters PiuABC (heme), PiaABC (ferrichrome) and PitABC (Fe3+) to uptake enough Fe ions to response to Mn deficiency. Therefore, this study reveals a bacterial mechanism of Fe compensation for Mn, and provides new insight for investigating the relativeness of Fe and Mn metabolism of bacteria.

Evolution and molecular mechanism of PitAs in iron transport of Streptococcus species.

Iron is an essential element for almost all bacteria. The iron ATP-binding cassette (ABC) transporters located on the cell membrane affects bacterial virulence and infection. Although a variety of Fe3+-transporters have been found in bacteria, their evolutionary processes are rarely studied. Pneumococcal iron ABC transporter (PitA), a highly conserved Fe3+-transporter in most pathogenic bacteria, influences the capsule formation and virulence of bacteria. However, multiple sequence alignment revealed that PitA is expressed in four different variants in bacteria, and the structural complexity of these variants increases progressively. To more efficiently import Fe3+ ions into bacterial cells, bacteria have evolved a fused PitA from two separately expressed PitA-1 (SPD_0227) and PitA-2 (SPD_0226) proteins. Further biochemical characterization indicated that both PitA-1 and PitA-2 have weaker Fe3+-binding ability than their protein complex. More importantly, Glutathione S-Transferase (GST) pull-down and isothermal titration calorimetry (ITC) detection showed that PitA-1 and PitA-2 interact with each other via Tyr111-Leu37, Asn112-Gln38, Asn103-Leu33, and Asn103-Thr34. Further molecular dynamics (MD) simulations demonstrated that this interaction in full-length PitA is stronger than that in the two individual proteins. Deletion of PitA family genes could lead to decrease in the ability of iron acquisition and of adhesion and invasion of S. pneumoniae. Our study revealed the evolving state and molecular mechanism of Fe3+-transporter PitAs in bacteria and provided important information for understanding the iron transportation mechanism in bacteria and designing new antibacterial drugs.

Effects of body mass index and weight change on mortality in older men with impaired glucose regulation.

OBJECTIVES: To assess the effect of baseline body mass index (BMI) status and weight change on mortality in older men with impaired glucose regulation (IGR). METHODS: Eight hundred eighty-five men with IGR aged 60 to 90 were included. Baseline and endpoint weight were measured. All-cause and cardiovascular mortality were observed during a median follow-up period of 10years. Multivariate Cox regressions were used to estimate associations between BMI, weight change and mortality. RESULTS: Relative to normal weight, overweight was associated with lower all-cause mortality (hazard ratios, HRs [95% confidence interval, 95% CI]: 0.57 [0.41, 0.78]) and cardiovascular mortality (0.52 [0.29, 0.93]), whereas obesity did not significantly decrease or increase the mortality risk. Furthermore, compared to weight stability, all types of weight change led to increased mortality risk, except small weight gain. Specifically, after adjustment for covariates and the initial weight, the HRs (95% CI) of large weight loss were 1.64 (1.15, 2.34) for all-cause mortality and 1.85 (1.10, 3.14) for cardiovascular mortality, and the HRs (95% CI) of large weight gain were 1.55 (1.01, 2.40) for all-cause mortality and 2.11 (1.04, 4.30) for cardiovascular mortality. Similar associations were observed when weight change was redefined in sensitivity analyses. CONCLUSIONS: Both BMI at baseline and weight change have independent U-shaped associations with all-cause and cardiovascular mortality among older men with IGR. The present study suggests that older men with IGR may ensure their best survival by being overweight at baseline or by maintaining their weight regardless of their baseline weight status.

The cutoffs and performance of glycated hemoglobin for diagnosing diabetes and prediabetes in a young and middle-aged population and in an elderly population.

The aims were to compare the appropriate cutoffs of glycated hemoglobin (HbA1c) in a population of varying ages and to evaluate the performance of HbA1c for diagnosing diabetes and prediabetes. A total of 1064 participants in the young and middle-aged group and 1671 in the elderly group were included and underwent HbA1c testing and an oral glucose tolerance test (OGTT). Sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) were calculated to evaluate the optimal HbA1c cutoffs. Kappa coefficients were used to test for agreement between HbA1c categorization and OGTT-based diagnoses. The optimal HbA1c cutoffs for diagnosing diabetes were 5.7% (39 mmol/mol) in the young and middle-aged group with a sensitivity of 66.7%, specificity of 86.7%, and AUC of 0.821 (95% CI: 0.686, 0.955) and 5.9% (41 mmol/mol) in the elderly group with a sensitivity of 80.4%, specificity of 73.3%, and AUC of 0.831 (0.801, 0.861). The optimal cutoffs for diagnosing prediabetes were 5.6% (38 mmol/mol) and 5.7% (39 mmol/mol) in the young and middle-aged group and in the elderly group, respectively. Agreement between the OGTT-based diagnosis of diabetes or prediabetes and the optimal HbA1c cutoff was low (all kappa coefficients <0.4). The combination of HbA1c and fasting plasma glucose increased diagnostic sensitivities or specificities. In conclusion, age-specific HbA1c cutoffs for diagnosing diabetes or prediabetes were appropriate. Furthermore, the performance of HbA1c for diagnosing diabetes and prediabetes was poor. HbA1c should be used in combination with traditional glucose criteria when detecting and diagnosing diabetes or prediabetes.

Insulin resistance correlates with the arterial stiffness before glucose intolerance.

OBJECTIVE: The elevated plasma glucose level and/or insulin resistance in diabetes or impaired glucose tolerance play important roles in the pathogenesis of arterial stiffness. The present study investigated whether insulin resistance correlated with arterial stiffness before the development of glucose intolerance. METHODS: We conducted a cross-sectional analysis in 872 young to middle-age individuals with normal glucose tolerance (aged 36.2±8.5 years, BMI 24.6±3.1 kg/m2 [mean±SD]). The homeostasis model assessment (HOMA) index was used as a quantitative assessment of the fasting insulin resistance (FIR), and the plasma insulin level after glucose loading was adopted as an index of the post-challenge insulin resistance (PIR). The Matsuda index [ISI (composite)] was used as a measurement of the insulin sensitivity. The arterial stiffness assessed by the brachial-ankle pulse wave velocity (baPWV) was adopted to quantify its independent associations with insulin resistance. RESULTS: The univariate linear regression analysis indicated that the fasting plasma glucose level (FPG, ß = 68.2; 95% CI 40.9, 95.6; p<0.001), post-challenge plasma glucose level (PPG, ß = 25.3; 95% CI 15.6, 35.0; p<0.001), FIR (ß = 24.5; 95% CI 14.1, 35.0; p<0.001), PIR (ß=1.30; 95% CI 0.87, 1.73; p<0.001) and ISI (composite) (ß = -3.55; 95% CI -5.02, -2.07; p<0.001) were all significantly correlated with the baPWV. After adjustment for sex, age, BMI, heart rate, smoking, systolic blood pressure, total cholesterol, LDL-cholesterol and family history of diabetes, the multivariate linear regression analysis demonstrated that the PIR (model 1, ß = 0.39, p=0.038; model 2, ß = 0.39, p=0.035; model 3, ß = 0.39, p=0.035) was an independent contributor to the baPWV, while the FIR, FPG, PPG and ISI (composite) failed to show any significant contribution. CONCLUSION: The insulin resistance correlated with the arterial stiffness before glucose intolerance.

The human glucagon-like peptide-1 analogue liraglutide regulates pancreatic beta-cell proliferation and apoptosis via an AMPK/mTOR/P70S6K signaling pathway.

Glucagon-like peptide-1 (GLP-1), an effective therapeutic agent for the treatment of diabetes, has been proven to protect pancreatic beta cells through many pathways. Recent evidence demonstrates that AMP-activated protein kinase (AMPK), as a metabolic regulator, coordinates beta-cell protein synthesis through regulation of the mammalian target of rapamycin (mTOR) signaling pathway. The purpose of the present study was to explore whether liraglutide, a human GLP-1 analogue, protects beta cells via AMPK/mTOR signaling. We evaluated INS-1 beta-cell line proliferation using the Cell Counting Kit-8, and examined the effect of GLP-1 on cellular ATP levels using an ATP assay kit. mTOR pathway protein expression levels were tested by Western blotting and glucolipotoxicity-induced cell apoptosis was evaluated by flow cytometry. Liraglutide increased beta-cell viability at an optimum concentration of 100 nmol/L in the presence of 11.1 or 30 mmol/L glucose. Liraglutide (100 nmol/L) activated mTOR and its downstream effectors, 70-kDa ribosomal protein S6 kinase and eIF4E-binding protein-1, in INS-1 cells. This effect was abated by pathway blockers: the AMPK activator AICAR and the mTOR inhibitor rapamycin. Furthermore, the effect of liraglutide on beta-cell proliferation was inhibited by AICAR and rapamycin. Liraglutide increased cellular ATP levels. In addition, liraglutide protected beta cells from glucolipotoxicity-induced apoptosis. This response was also prevented by rapamycin treatment. These results suggest that the enhancement of beta-cell proliferation by that GLP-1 receptor agonist liraglutide is mediated, at least in part, by AMPK/mTOR signaling. Liraglutide also prevents beta-cell glucolipotoxicity by activating mTOR.

[The effects and mechanisms of BTBD10 on the proliferation of islet beta cell].

OBJECTIVE: To explore the role of BTBD10 overexpression in the proliferation of insulinoma cell line INS-1 and its mechanism. METHODS: The recombined expression plasmid of pcDNA4.0-BTBD10 was constructed by gene cloning technique and was transfected into INS-1 cell by lipofectamine 2000. The stable overexpression BTBD10 of INS-1 cell was selected at 48(th) hour after transfection. INS-1 cell proliferation activity was measured by MTT method. The expression of BTBD10, protein kinase B (Akt), phospho-Akt (p-Akt), mammal target of rapamycin (mTOR) and phospho-mTOR (p-mTOR) were determined by Western blot. RESULTS: The stable overexpression BTBD10 of INS-1 cell was successfully constructed. Overproduction of BTBD10 promoted beta cell proliferation. The phosphorylation of Akt and mTOR was increased and the ratio of p-Akt/Akt and p-mTOR/mTOR was enhanced in the INS-1 overexpressed by BTBD10. But the expression of total Akt and mTOR presented no obvious changes. CONCLUSION: The overexpression BTBD10 of INS-1 cell could activate of Akt/mTOR signalling pathway via stimulating phospho-mTOR and Akt, and enhance overall cell protein translation, so as to promote proliferation of INS-1 cell.

[The correlation between hyperinsulinemia and pulse wave velocity].

OBJECTIVE: To study the correlation between hyperinsulinemia (HIns) and arteriosclerosis in one community in Beijing. METHODS: Subjects who received arteriosclerosis screening in physical examination annually were studied. All subjects were received 75g oral glucose tolerance test (OGTT) to evaluate glucose metabolic level, and brachial-ankle pulse wave velocity (baPWV) examination to evaluate arteriosclerosis. The correlation between hyperinsulinemia and pulse wave velocity was analyzed. RESULTS: Among all the 1046 subjects under investigation, baPWV of subjects with HIns was higher than subjects with normoinsulinemic (NIns) in different glucose metabolism status [normal glucose tolerance, (1381.2 ± 280.8) cm/s vs (1280.3 ± 218.7) cm/s; imparied glucose regulation, (1557.5 ± 319.3) cm/s vs (1474.7 ± 305.1) cm/s; diabetes, (1764.3 ± 476.6) cm/s vs (1664.2 ± 374.6) cm/s], especially in subjects with normal glucose tolerance (P < 0.01). The prevalence of cardiovascular risk factors in subjects with HIns was much higher than subjects with NIns (P < 0.01). Multiple logistic regression analysis showed that hyperinsulinemia was the risk factor of arteriosclerosis, and the OR (95%CI) of subjects with HIns was 1.91 (1.169 - 3.105, P < 0.01) as compared to the subjects with NIns. CONCLUSION: The subjects with HIns suffered from much more metabolic risk factors than NIns. Hyperinsulinemia that closely correlated with baPWV was a risk factor of arteriosclerosis.

[Comparison of postprandial insulin and fasting insulin on the evaluation of cardiovascular risk factors].

OBJECTIVE: To study the feasibility of using postprandial insulin (2hINS) and fasting insulin (FINS) on evaluation of insulin resistance, comparison was conducted between 2hINS and FINS on evaluation of cardiovascular risk factors. METHODS: A survey were conducted among individuals in the community in May 2008 and data of routine clinical examination were collected. All subjects were investigated and received 75 g oral glucose tolerance test (OGTT), and fasting and OGTT2 h blood glucose as well as insulin concentrations were determined. Hyperinsulinemia was defined as a FINS or 2hINS concentration at or above the 95th percentile of the distribution among normal glucose tolerance individuals. RESULTS: 1148 individuals were investigated and insulin concentration in male was similar to female. Prevalence of 2hHINS (40.8%) in individuals with abnormal glucose metabolism was higher than FHINS (18.4%, P < 0.01). The number of metabolic risk factors in subjects with 2hHINS was similar to subjects with FHINS. After adjustment by sex, age, BMI and waist circumference, partial correlation analysis showed that the correlation between 2hINS and 2hPG (r = 0.370) was higher than that of FINS and FPG (r = 0.104); FINS was higher correlated with TG and HDL- cholesterol than 2hINS, however, 2hINS was higher correlated with diastolic blood pressure, total cholesterol and LDL-cholesterol than FINS. Logistic regression analysis showed that FHINS and 2hHINS were both the independent risk factor of metabolic syndrome, the OR (95%CI) were 5.11 (2.953 - 8.842) and 3.46 (2.109 - 5.687). CONCLUSION: 2hINS and FINS were both closely associated with cardiovascular risk factors. The correlation was inconsistent when 2hINS and FINS were related to different risk factors. The combination of 2hINS and FINS might be more helpful on evaluation of insulin resistance.