Differential pattern for regulating insulin secretion, insulin resistance, and lipid metabolism by osteocalcin in male and female T2DM patients

Relationship between bone turnover markers and renal disease in elderly patients with type 2 diabetes: a cross-sectional study

OBJECTIVE

The prevalence of type 2 diabetes mellitus (T2DM) and bone metabolism disorders increase with age. Diabetic kidney disease (DKD) is one of the most serious microvascular complications of T2DM, and bone metabolism disorders are closely linked to the occurrence of DKD. The relationship between bone turnover markers(BTMs) and the kidney disease in elderly patients with T2DM remains unclear. Therefore, this study aims to investigate the association between common BTMs and DKD in a large sample of elderly patients. The goal is to provide a basis for early identification of high-risk individuals for DKD among elderly T2DM patients from a bone metabolism perspective.

METHODS

In this cross-sectional study, BTMs were collected from a cohort of 2,051 hospitalized Chinese patients. The relationships between 25-hydroxyvitamin D (25-OH-D), β-CrossLaps (β-CTX), osteocalcin (OSTEOC), intact parathyroid hormone (iPTH), and total type I collagen N-terminal propeptide (TP1NP), and DKD, as well as urinary albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR) were analyzed using regression analysis and restrictive cubic spline (RCS) curves.

RESULTS

Higher 25-OH-D levels were independently linked to a lower incidence of DKD and decreased UACR. The RCS curves showed a linear association of 25-OH-D and DKD, approaching the L-shape. β-CTX was independently and positively correlated with UACR. There is an independent positive correlation between OSTEOC and UACR and a negative correlation with eGFR. iPTH is independently and positively correlated with DKD incidence and UACR, and negatively correlated with eGFR. Additionally, the RCS curves showed a non-linear association of OSTEOC and iPTH and DKD, approaching the J-shape, and the point of inflection is 10.875 ng/L and 34.15 pg/mL respectively. There is an independent positive correlation between TP1NP and UACR incidence, and a negative correlation with eGFR. Risk estimates significantly increase with higher TP1NP levels in the RCS model.

CONCLUSION

BTMs are closely associated with kidney disease in elderly patients with T2DM. These discoveries potentially assist clinicians in establishing more preventive measures and targeted treatment strategies for elderly patients with T2DM.

Associations of obesity-related indices with prediabetes regression to normoglycemia among Chinese middle-aged and older adults: a prospective study

Background

Prediabetes is associated with increased cardiovascular risk and all-cause mortality, while its regression will decrease the risks. This study investigated the associations of six obesity-related indices (waist-to-height ratio (WHtR), body roundness index (BRI), conicity index (CI), body shape index (ABSI), Chinese visceral adiposity index (CVAI), and triglyceride glucose (TyG) index) with prediabetes regression based on the China Health and Retirement Longitudinal Study (CHARLS), enrolling middle-aged and older adults.

Methods

We included 2,601 participants with prediabetes from CHARLS, who were followed up from 2011-2012 to 2015-2016, with blood samples collected for measuring fasting plasma glucose and hemoglobin A1c. All the obesity-related indices at baseline and their dynamic changes were calculated and categorized into tertiles. Logistic regression analysis was applied to obtain the odds ratio (OR) and 95% confidence intervals (CIs). Attributable fractions (AFs) and 95% CIs of these indices and the dynamic changes were calculated with the AF package in R software, and the cutoff values of initial obesity-related indices were obtained by the receiver operating characteristic (ROC) analysis.

Results

During the 4-year follow-up period, 562 (21.61%) participants regressed from prediabetes to normoglycemia. They had lower initial BRI, WHtR, CI, ABSI, CVAI, and TyG than those who did not (P < 0.05). After multivariable adjustment, participants in the first tertile of initial BRI (OR, 1.45, 95%CIs, 1.09-1.93), WHtR (OR, 1.46, 95%CIs, 1.10-1.95), and CVAI (OR, 1.47, 95%CIs, 1.11-1.93) had increased odds of prediabetes regression compared with those in the highest tertile. Participants with decreased TyG (OR, 2.08; 95%CIs, 1.61-2.70) also had increased odds of prediabetes regression compared with those with increased TyG. The cutoff values of initial obesity-related indices were 4.374 for BRI, 0.568 for WHtR, 8.621 for TyG, 1.320 for CI, 0.083 for ABSI, and 106.152 for CVAI, respectively. The AFs were 21.10% for BRI < 4.374, 20.85% for WHtR < 0.568, 17.48% for CVAI < 107.794, and 17.55% for ΔTyG < 0, respectively.

Conclusion

Low initial BRI, WHtR, and CVAI, as well as TyG reduction, were significantly related to prediabetes regression to normoglycemia, and the AFs were around 20%. Less abdominal fat and insulin resistance reduction would benefit future health outcomes among people with prediabetes.

Association between osteocalcin, a pivotal marker of bone metabolism, and secretory function of islet beta cells and alpha cells in Chinese patients with type 2 diabetes mellitus: an observational study

BACKGROUND

Several recent studies have found that Osteocalcin (OCN), a multifunctional protein secreted exclusively by osteoblasts, is beneficial to glucose metabolism and type 2 diabetes mellitus (T2DM). However, the effects of OCN on islets function especially islet ɑ cells function in patients with type 2 diabetes mellitus characterized by a bi-hormonal disease are still unclear. The purpose of this cross-sectional study was to investigate the relationship between serum OCN and the secretion of islet β cells and ɑ cells in Chinese patients with type 2 diabetes mellitus.

METHODS

204 patients with T2DM were enrolled. Blood glucose (FBG, PBG0.5h, PBG1h, PBG2h, PBG3h), insulin (FINS, INS0.5h, INS1h, INS2h, INS3h), C-peptide (FCP, CP0.5h, CP1h, CP2h, CP3h), and glucagon (GLA0, GLA0.5 h, GLA1h, GLA2h, GLA3h) levels were measured on 0 h, 0.5 h, 1 h, 2 h, and 3 h after a 100 g standard bread meal load. Early postprandial secretion function of islet β cells was calculated as Δcp0.5h = CP0.5-FCP. The patients were divided into low, medium and high groups (T1, T2 and T3) according to tertiles of OCN. Comparison of parameters among three groups was studied. Correlation analysis confirmed the relationship between OCN and pancreatic secretion. Multiple regression analysis showed independent contributors to pancreatic secretion.

MAIN RESULTS

FBG, and PBG2h were the lowest while Δcp0.5h was the highest in the highest tertile group (respectively, p < 0.05). INS3h, area under the curve of insulin (AUC_ins3h) in T3 Group were significantly lower than T1 Group (respectively, p < 0.05). GLA1h in T3 group was lower than T1 group (p < 0.05), and GLA0.5 h in T3 group was lower than T2 and T1 groups (p < 0.05). Correlation analysis showed OCN was inversely correlated with Homeostatic model of insulin resistance (HOMA-IR), INS3h, AUC_ins3h (p < 0.05), and was still inversely correlated with FCP, GLA0.5 h, GLA1h, area under the curve of glucagon (AUC_gla3h) (respectively, p < 0.05) after adjustment for body mass index (BMI) and alanine aminotransferase (ALT). The multiple regression analysis showed that OCN was independent contributor to Δcp0.5h, GLA0.5h and GLA1h (respectively, p < 0.05).

CONCLUSIONS

Higher serum OCN level is closely related to better blood glucose control, higher insulin sensitivity, increased early-phase insulin secretion of islet β cells and appropriate inhibition of postprandial glucagon secretion of islet ɑ cells in adult patients with type 2 diabetes mellitus.

Association of serum osteocalcin levels with glucose metabolism in trauma patients

Osteocalcin (OC) is an endocrine hormone that regulates glucose metabolism.The aim of this study was to investigate the relationship between serum OC levels and glucose metabolism after trauma.This was a retrospective study of trauma patients admitted to the Department of Emergency Medicine between October 2017 and April 2019. Age, height, weight, injury severity score, and previous medical history were recorded. Serum N-terminal mid-fragment of OC (N-MID OC), hemoglobin Alc (HbA1c), fasting plasma glucose (FPG), fasting insulin (FINS), C-peptide, and other biochemical indicators were measured. Differences between the HbA1c-L (HbA1c <6.5%) and HbA1c-H (HbA1c ≥6.5%) groups were compared. The association of N-MID OC with indicators of glucose metabolism was analyzed.Out of 394 trauma patients, leukocyte and FPG levels in the HbA1c-H group (n = 93) were higher (P < .05), while N-MID OC levels were lower (P = .011) than the HbA1c-L group (n = 301). N-MID OC was negatively correlated with HbA1c in the total population (r = -0.273, P < .001) as well as in the HbA1c-L (r = -0.289, P < .001) and HbA1c-H (r = -0.390, P < 0.001) groups, and was positively correlated with C-peptide in the HbA1c-H group (r = 0.395, P < .001). The different quartiles in the HbA1c-L showed that N-MID OC declined with increasing HbA1c, which was higher than N-MID OC levels in the HbA1c-H group. Multiple linear regression analysis revealed that serum HbA1c was independently associated with serum OC levels after trauma (β=-1.608, P < .001).This study strongly suggests the importance of serum OC on glucose metabolism in trauma patients. HbA1c is independently associated with serum OC levels.

FGF23-klotho axis as predictive factors of fractures in type 2 diabetics with early chronic kidney disease

BACKGROUND

The aim of our study was to evaluate the relevance of FGF23-klotho axis in the predisposition for bone fractures in type 2 diabetic patients with early chronic kidney disease.

METHODS

In a prospective study we included 126 type 2 diabetic patients with CKD stages 2-3 (from 2010 to 2017). We used descriptive statistics, ANOVA and chi-square test. Our population was divided into two groups according to the occurrence of a bone fracture event or not, and the groups were compared considering several biological and laboratorial parameters. We employed a multiple regression model to identify risk factors for bone fracture events and hazard ratios (HR) were calculated using a backward stepwise likelihood ratio (LR) Cox regression.

RESULTS

Patients with a fracture event displayed higher levels of FGF-23, Phosphorus, PTH, TNF-α, OxLDL, HOMA-IR, calcium × phosphorus product and ACR and lower levels of Osteocalcin, α-Klotho, 25(OH)D3 and eGFR compared with patients without a fracture event (p < 0.001). The number of patients with a fracture event was higher than expected within inclining CKD stages (χ2, p = 0.06). The occurrence of fracture and the levels of TNF- α, klotho, 25(OH)D3 and OxLDL were found to predict patient entry into RRT (p < 0.05). Age, osteocalcin, α-Klotho and FGF-23 independently influenced the occurrence of bone fracture (p < 0.05).

CONCLUSIONS

α-Klotho and FGF-23 levels may have a good clinical use as biomarkers to predict the occurrence of fracture events.

The Potential Role of Undercarboxylated Osteocalcin Upregulation in Microvascular Insufficiency in a Rat Model of Diabetic Cardiomyopathy

BACKGROUND

Diabetic cardiomyopathy (DCM) is accompanied by microvascular complications that lead to myocardial dysfunction and heart failure. Most conventional therapies cannot ameliorate the microvascular insufficiency in DCM. In this study, we tested the hypothesis that undercarboxylated osteocalcin (ucOC) may be a new adjuvant therapy against the progression of DCM and its underlying microvascular pathology.

MATERIALS AND METHODS

Diabetes was induced in Wistar rats with a high-fat diet combined with streptozotocin injections, and ucOC was upregulated after warfarin administration in the treated group. After 8 weeks, cardiac functions were assessed using a Langendorff apparatus. Cardiac tissue samples were also extracted to assess the ucOC receptor and vascular endothelial growth factor (VEGF) for histopathological studies.

RESULTS

Both the systolic and the diastolic dysfunction observed in the DCM group were significantly improved after the increase in ucOC blood levels. Significant improvement in VEGF and CD31 expression after warfarin injection was associated with increased capillary density, neovascularization, and decreased myocardial fibrosis together with the reestablishment of myocardial structural and ultrastructural patterns.

CONCLUSION

Undercarboxylated osteocalcin may have a promising effect in improving microvascular insufficiency and myocardial dysfunction in DCM.

Correlation Between Serum miR-154-5p and Osteocalcin in Males and Postmenopausal Females of Type 2 Diabetes With Different Urinary Albumin Creatinine Ratios

Purpose: To investigate the serum levels of miR-154-5p, osteocalcin (OC), and other clinical parameters in male and post-menopausal female type 2 diabetes mellitus (T2DM) patients with different urinary albumin creatinine ratio (UACR) levels and to discuss the relationship between miR-154-5p and glycolipid metabolism, bone metabolism, and different urinary albumin excretion rate in T2DM. Methods: Seven hundred thirty-eight T2DM patients were categorized into six groups, including 374 men and 364 post-menopausal women who were sub-divided into three groups based on albumin excretion that involved normal albuminuria, microalbuminuria, and large amount of albuminuria (138, 127, 109, 135, 125, and 104 cases, UACR<30, 30-300, and >300 mg/g, M1, M2, M3, F1, F2, and F3). Measurement of circulating miR-154-5p, OC, and other biochemical indicators were performed by real-time PCR, ELISA, and chemiluminescence assays in T2DM patients and in 141 M0 and 139 F0 control subjects. Results: There are few differences appeared between groups. Comparing with men, women had higher age, waist-to-hip ratio (WHR), adiponectin (ADPN), connective tissue growth factor (CTGF), UACR, procollagen type 1 N-terminal propeptide (P1NP), β-C-terminal telopeptide of type I collagen (β-CTx), OC, and miR-154-5p, but lower FPG, HOMA-IR, and HbA1c. T2DM patients with albuminuria (micro or macro) had lower bone turnover markers (P1NP, β-CTx, and OC) and adiponectin, but higher HbA1c, CTGF, and miR-154-5p. In addition, after regression analysis, UACR was positively correlated with CTGF, HbA1c, and miR-154-5p, and negatively correlated with ADPN and bone turnover markers (P1NP, β-CTx, and OC). However, OC showed a positive correlation with ADPN and other bone turnover markers (P1NP and β-CTx), but negative correlation with CTGF, UACR, and miR-154-5p in all three groups. Conclusion: These findings suggested that increased serum levels of miR-154-5p and decreased OC levels may influence osteogenesis and proteinuria in T2DM and may identify novel targets for diagnosis and treatment of diabetic kidney disease and osteoporosis.

Fluoride Exposure Induces Inhibition of Sodium/Iodide Symporter (NIS) Contributing to Impaired Iodine Absorption and Iodine Deficiency: Molecular Mechanisms of Inhibition and Implications for Public Health

The sodium iodide symporter (NIS) is the plasma membrane glycoprotein that mediates active iodide transport in the thyroid and other tissues, such as the salivary, gastric mucosa, rectal mucosa, bronchial mucosa, placenta and mammary glands. In the thyroid, NIS mediates the uptake and accumulation of iodine and its activity is crucial for the development of the central nervous system and disease prevention. Since the discovery of NIS in 1996, research has further shown that NIS functionality and iodine transport is dependent on the activity of the sodium potassium activated adenosine 5'-triphosphatase pump (Na+, K+-ATPase). In this article, I review the molecular mechanisms by which F inhibits NIS expression and functionality which in turn contributes to impaired iodide absorption, diminished iodide-concentrating ability and iodine deficiency disorders. I discuss how NIS expression and activity is inhibited by thyroglobulin (Tg), tumour necrosis factor alpha (TNF-α), transforming growth factor beta 1 (TGF-β1), interleukin 6 (IL-6) and Interleukin 1 beta (IL-1β), interferon-γ (IFN-γ), insulin like growth factor 1 (IGF-1) and phosphoinositide 3-kinase (PI3K) and how fluoride upregulates expression and activity of these biomarkers. I further describe the crucial role of prolactin and megalin in regulation of NIS expression and iodine homeostasis and the effect of fluoride in down regulating prolactin and megalin expression. Among many other issues, I discuss the potential conflict between public health policies such as water fluoridation and its contribution to iodine deficiency, neurodevelopmental and pathological disorders. Further studies are warranted to examine these associations.

A Calcium-Deficient Diet in Dams during Gestation Increases Insulin Resistance in Male Offspring

Calcium (Ca) plays an important role in the pathogenesis of insulin resistance syndrome. Osteocalcin (OC), a bone formation biomarker, acts directly on β-cells and increases insulin secretion. We determined the effects of Ca deficiency during pregnancy and/or lactation on insulin resistance in offspring. Female Wistar rats consumed either a Ca-deficient or control diet ad libitum from three weeks preconception to 21 days postparturition. Pups were allowed to nurse their original mothers until weaning. The offspring were fed a control diet beginning at weaning and were killed on day 180. Serum carboxylated OC (Gla-OC) and undercarboxylated OC (Glu-OC), insulin and adipokines in offspring were measured. In males, mean levels of insulin, glucose, and HOMA-IR were higher in the Ca-deficient group than in the control group. In addition, ionized Ca (iCa) was inversely associated with serum Glu-OC and adiponectin in males. In females, mean levels of Glu-OC and Gla-OC in the Ca-deficient group were higher than in the control group. In all offspring, serum leptin levels were correlated with serum insulin levels, and inversely correlated with iCa. In conclusion, maternal Ca restriction during pregnancy and/or lactation influences postnatal offspring Ca metabolism and insulin resistance in a sex-specific manner.

The Effect of Sitagliptin on Lipid Metabolism of Fatty Liver Mice and Related Mechanisms

Background

In clinics, patients with type 2 diabetes complicated with non-alcoholic fatty liver disease (NAFLD) have been shown to receive significant improvements in blood glucose levels, lipid levels, and liver function after sitagliptin treatment, although the mechanism of drug action remains poorly understood. This study investigated the possible mechanism of sitagliptin on lipid metabolism of NAFLD mice.

Material/Methods

Male C57/BL6 mice were induced for NAFLD via 16 weeks of a high-fat diet, and were treated with 15 mg/kg/day sitagliptin for 16 consecutive weeks. Blood lipid levels were measured and samples were stained with hematoxylin and eosin (H&E) and oil red staining for liver pathology and lipid deposition. Serum levels of fibroblast growth factor (FGF)-9 and FGF-21 were quantified by enzyme-linked immunosorbent assay (ELISA). Peroxisome proliferator-activated receptor (PPAR)-α, and cAMP reactive element binding homolog (CREBH) were measured by Western blotting, while fatty acid synthase and carnitine palmitoyltransferase 1 (CPT1) mRNA levels were assayed by RT-PCR.

Results

Compared to the control group, the NAFLD model mice had liver fatty disease, lower serum FGF-21 and FGF-19 levels, elevated serum lipid levels, depressed PPAR-α, CREBH, and CPT1 expression, and enhanced FAS expression (p<0.05). Sitagliptin treatment depressed blood lipid levels, increased serum FGF-21 and FGF-19 levels, PPAR-α, CREBH, and CPT1 expression, and suppressed FAS expression (p<0.05).

Conclusions

Sitagliptin can protect liver tissue and modulate lipid metabolism in NAFLD mice via elevating FGF-21 and FGF-19, upregulating liver PPAR-α and CREBH levels, and mediating expression levels of key enzymes for lipid metabolism.

Infections: A Possible Risk Factor for Type 2 Diabetes

Diabetes mellitus is one of the biggest challenges to human health globally, with an estimated 95% of the global diabetic population having type 2 diabetes. Classical causes for type 2 diabetes, such as genetics and obesity, do not account for the high incidence of the disease. Recent data suggest that infections may precipitate insulin resistance via multiple mechanisms, such as the proinflammatory cytokine response, the acute-phase response, and the alteration of the nutrient status. Even pathogen products, such as lipopolysaccharide and peptidoglycans, can be diabetogenic. Therefore, we argue that infections that are known to contribute to insulin resistance should be considered as risk factors for type 2 diabetes.

Osteocalcin, Vascular Calcification, and Atherosclerosis: A Systematic Review and Meta-analysis

BACKGROUND

Osteocalcin (OC) is an intriguing hormone, concomitantly being the most abundant non-collagenous peptide found in the mineralized matrix of bone, and expanding the endocrine function of the skeleton with far-reaching extra-osseous effects. A new line of enquiry between OC and vascular calcification has emerged in response to observations that the mechanism of vascular calcification resembles that of bone mineralisation. To date, studies have reported mixed results. This systematic review and meta-analysis aimed to identify any association between OC and vascular calcification and atherosclerosis.

METHODS AND RESULTS

Databases were searched for original, peer reviewed human studies. A total of 1,453 articles were retrieved, of which 46 met the eligibility criteria. Overall 26 positive, 17 negative, and 29 neutral relationships were reported for assessments between OC (either concentration in blood, presence of OC-positive cells, or histological staining for OC) and extent of calcification or atherosclerosis. Studies that measured OC-positive cells or histological staining for OC reported positive relationships (11 studies). A higher percentage of Asian studies found a negative relationship (36%) in contrast to European studies (6%). Studies examining carboxylated and undercarboxylated forms of OC in the blood failed to report consistent results. The meta-analysis found no significant difference between OC concentration in the blood between patients with "atherosclerosis" and control (p = 0.13, n = 1,197).

CONCLUSION

No definitive association was determined between OC and vascular calcification or atherosclerosis; however, the presence of OC-positive cells and histological staining had a consistent positive correlation with calcification or atherosclerosis. The review highlighted several themes, which may influence OC within differing populations leading to inconclusive results. Large, longitudinal studies are required to further current understanding of the clinical relevance of OC in vascular calcification and atherosclerosis.

Conversations between insulin and bone: Potential mechanism of high bone density in patients with Berardinelli-Seip Congenital Lipodystrophy

Berardinelli-Seip Congenital Lipodystrophy (BSCL) is a rare autosomal recessive syndrome characterized by a difficulty storing lipid in adipocytes, low body fat, hypertriglyceridemia, and fat liver. The serum leptin is usually very low, and serum insulin, as well as HOMA_IR (homeostasis model assessment), is very high and correlated positively with bone mineral density (BMD). Despite deficiency/insufficiency of vitamin D, low body mass index, low daily calcium intake, physical inactivity, and menarche at a later age, BSCL patients usually have normal or even high BMD. We hypothesize that low leptin and high insulin may play a role in this outcome. Understanding the potential pathophysiological mechanism of these bone abnormalities will help to clarify the effects of extreme insulin resistance in the bone.

An overview of osteocalcin progress

An increasing amount of data indicate that osteocalcin is an endocrine hormone which regulates energy metabolism, male fertility and brain development. However, the detailed functions and mechanism of osteocalcin are not well understood and conflicting results have been obtained from researchers worldwide. In the present review, we summarize the progress of osteocalcin studies over the past 40 years, focusing on the structure of carboxylated and undercarboxylated osteocalcin, new functions and putative receptors, the role of osteocalcin in bone remodeling, specific expression and regulation in osteoblasts, and new indices for clinical studies. The complexity of osteocalcin in completely, uncompletely and non-carboxylated forms may account for the discrepancies in its tertiary structure and clinical results. Moreover, the extensive expression of osteocalcin and its putative receptor GPRC6A imply that there are new physiological functions and mechanisms of action of osteocalcin to be explored. New discoveries related to osteocalcin function will assist its potential clinical application and physiological theory, but comprehensive investigations are required.

Long-term oral administration of osteocalcin induces insulin resistance in male mice fed a high-fat, high-sucrose diet

Uncarboxylated osteocalcin (GluOC), a bone-derived hormone, regulates energy metabolism by stimulating insulin secretion, pancreatic β-cell proliferation, and adiponectin expression in adipocytes. Previously, we showed that long-term intermittent or daily oral administration of GluOC reduced the fasting blood glucose level, improved glucose tolerance, and increased the fasting serum insulin concentration as well as pancreatic β-cell area in female mice fed a normal or high-fat, high-sucrose diet. We have now performed similar experiments with male mice and found that such GluOC administration induced glucose intolerance, insulin resistance, and adipocyte hypertrophy in those fed a high-fat, high-sucrose diet. In addition, GluOC increased the circulating concentration of testosterone and reduced that of adiponectin in such mice. These phenotypes were not observed in male mice fed a high-fat, high-sucrose diet after orchidectomy, but they were apparent in orchidectomized male mice or intact female mice that were fed such a diet and subjected to continuous testosterone supplementation. Our results thus reveal a sex difference in the effects of GluOC on glucose homeostasis. Given that oral administration of GluOC has been considered a potentially safe and convenient option for the treatment or prevention of metabolic disorders, this sex difference will need to be taken into account in further investigations.

Association between osteocalcin and glucose metabolism: a meta-analysis

This meta-analysis aimed to investigate the associations between osteocalcin (Ocn) and fasting plasma glucose (FPG) and glycated hemoglobin A1c (HbA1c). It was revealed that both total Ocn and undercarboxylated Ocn (unOcn) were negatively related with FPG and HbA1c, and the association of unOcn with FPG was more pronounced in men.

INTRODUCTION

The aim of this study was to investigate the strength of associations between Ocn and FPG and HbA1c using a meta-analysis approach.

METHODS

A search was carried out using the databases of PubMed, ISI Web of Science, and the Cochrane library from 2007 to 2014 to identify related studies. A pooled effect size with 95 % confidence intervals (CI) was derived.

RESULTS

The meta-analysis included 39 studies involving 23,381 participants. The overall correlation was -0.16 (95 % CI, -0.19 to -0.14) between total Ocn (tOcn) and FPG and -0.15 (95 % CI, -0.20 to -0.11) between undercarboxylated Ocn (unOcn) and FPG. In the analysis of the association between Ocn and HbA1c, the pooled correlation was -0.16 (95 % CI, -0.18 to -0.14) for tOcn and -0.16 (95 % CI, -0.23 to -0.08) for unOcn. The magnitude of the correlation between unOcn and FPG is significantly higher in men than in women (r = -0.18, 95 % CI, -0.21 to -0.14; r = -0.09, 95 % CI, -0. 13 to -0.05, respectively; P for interaction < 0.05). Similar trend was also found between unOcn and HbA1c but without significance (for men, r = -0.19, 95 % CI, -0.24 to -0.14; for women, r = -0.09, 95 % CI, -0.22 to 0.04, respectively; P for interaction > 0.05). No indication of significant publication bias was found in any method.

CONCLUSIONS

This meta-analysis demonstrated that both unOcn and tOcn were similarly and negatively correlated with FPG and HbA1c in humans. The negative correlations between unOcn and glucose metabolism appear to be more pronounced in men than in women.

Searching for additional endocrine functions of the skeleton: genetic approaches and implications for therapeutics

Our knowledge of whole organism physiology has greatly advanced in the past decades through mouse genetics. In particular, genetic studies have revealed that most organs interact with one another through hormones in order to maintain normal physiological functions and the homeostasis of the entire organism. Remarkably, through these studies many unexpected novel endocrine means to regulate physiological functions have been uncovered. The skeletal system is one example. In this article, we review a series of studies that over the years have identified bone as an endocrine organ. The mechanism of action, pathological relevance, and therapeutic implications of the functions of the bone-derived hormone osteocalcin are discussed. In the last part of this review we discuss the possibility that additional endocrine functions of the skeleton may exist.

Early enteral nutrition within 24 hours or between 24 and 72 hours for acute pancreatitis: evidence based on 12 RCTs

Background

Although (EEN) is a relatively safer route by which to feed patients with severe acute pancreatitis (SAP) or predicted SAP (pSAP) compared to total parental nutrition (TPN), the appropriate starting time for EEN administration after admission is still controversial. This study pooled all relevant studies to assess the complications associated with EEN by stratifying relevant RCTs into subgroups according to the starting time (<24 h or between 24 and 72 h after admission).

Material/Methods

Relevant studies were searched for among 5 databases. The association between intervention and complications, including pancreatic infection, mortality, hyperglycemia, organ failure, and catheter-related septic complications, were assessed by using pooled risk ratio (RR) and the corresponding 95% confidential interval (CI).

Results

Twelve RCTs were identified through our literature search. Pooled analysis showed that EEN, but not TPN or delayed enteral nutrition (DEN), is associated with reduced risk of pancreatic infection, mortality, organ failure, hyperglycemia, and catheter-related septic complications. EEN within 24 h of admission presented significantly better outcome in morality than EEN between 24 and 72 h. However, no significant heterogeneity was observed in the risk of pancreatic infection, organ failure, hyperglycemia, and catheter-related septic complications between the 2 subgroups.

Conclusions

If the patients are reasonably expected to have high compliance to EN therapy, it could be considered as early as possible.

Alteration of lipid profile in subclinical hypothyroidism: a meta-analysis

BACKGROUND

Previous studies yielded controversial results about the alteration of lipid profiles in patients with subclinical hypothyroidism. We performed a meta-analysis to investigate the association between subclinical hypothyroidism and lipid profiles.

MATERIAL AND METHODS

We searched PubMed, Cochrane Library, and China National Knowledge Infrastructure articles published January 1990 through January 2014. Dissertation databases (PQDT and CDMD) were searched for additional unpublished articles. We included articles reporting the relationship between subclinical hypothyroidism and at least 1 parameter of lipid profiles, and calculated the overall weighted mean difference (WMD) with a random effects model. Meta-regression was used to explore the source of heterogeneity among studies, and the Egger test, Begg test, and the trim and fill method were used to assess potential publication bias.

RESULTS

Sixteen observational studies were included in our analysis. Meta-analysis suggested that the serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and total triglyceride levels were significantly increased in patients with subclinical hypothyroidism compared with euthyroidism individuals; the WMD were 12.17 mg/dl, 7.01 mg/dl, and 13.19 mg/dl, respectively (P<0.001 for all). No significant difference was observed for serum high-density lipoprotein cholesterol (HDL-C). Match strategy was the main source of heterogeneity among studies in TC and LDL-C analysis. Potential publication bias was found in TC and LDL-C analysis by the Egger test or Begg test and was not confirmed by the trim and fill method.

CONCLUSIONS

Subclinical hypothyroidism may correlate with altered lipid profile. Previous studies had limitations in the control of potential confounding factors and further studies should consider those factors.