Serum Levels of Acyl-Carnitines along the Continuum from Normal to Alzheimer's Dementia

This study aimed to determine the serum levels of free L-carnitine, acetyl-L-carnitine and 34 acyl-L-carnitine in healthy subjects and in patients with or at risk of Alzheimer's disease. Twenty-nine patients with probable Alzheimer's disease, 18 with mild cognitive impairment of the amnestic type, 24 with subjective memory complaint and 46 healthy subjects were enrolled in the study, and the levels of carnitine and acyl-carnitines were measured by tandem mass spectrometry. The concentrations of acetyl-L-carnitine progressively decreased passing from healthy subjects group (mean±SD, 5.6±1.3 μmol/L) to subjective memory complaint (4.3±0.9 μmol/L), mild cognitive impairment (4.0±0.53 μmol/L), up to Alzheimer's disease (3.5±0.6 μmol/L) group (p<0.001). The differences were significant for the comparisons: healthy subjects vs. subjective memory complaint, mild cognitive impairment or Alzheimer's disease group; and subjective memory complaint vs. Alzheimer's disease group. Other acyl-carnitines, such as malonyl-, 3-hydroxyisovaleryl-, hexenoyl-, decanoyl-, dodecanoyl-, dodecenoyl-, myristoyl-, tetradecenoyl-, hexadecenoyl-, stearoyl-, oleyl- and linoleyl-L-carnitine, showed a similar decreasing trend, passing from healthy subjects to patients at risk of or with Alzheimer's disease. These results suggest that serum acetyl-L-carnitine and other acyl-L-carnitine levels decrease along the continuum from healthy subjects to subjective memory complaint and mild cognitive impairment subjects, up to patients with Alzheimer's disease, and that the metabolism of some acyl-carnitines is finely connected among them. These findings also suggest that the serum levels of acetyl-L-carnitine and other acyl-L-carnitines could help to identify the patients before the phenotype conversion to Alzheimer's disease and the patients who would benefit from the treatment with acetyl-L-carnitine. However, further validation on a larger number of samples in a longitudinal study is needed before application to clinical practice.

Surgical cure for type 2 diabetes by foregut or hindgut operations: a myth or reality? A systematic review

BACKGROUND

Bariatric surgery results in remission of type 2 diabetes mellitus in a significant proportion of patients. Animal research has proposed the foregut and hindgut hypotheses as possible mechanisms of remission of T2DM independent of weight loss. These hypotheses have formed the basis of investigational procedures designed to treat T2DM in non-obese (in addition to obese) patients. The aim of this study was to review the procedures that utilise the foregut and hindgut hypotheses to treat T2DM in humans.

METHODS

A systematic review was conducted to identify the investigational procedures performed in humans that are based on the foregut and hindgut hypotheses and then to assess their outcomes.

RESULTS

Twenty-four studies reported novel procedures to treat T2DM in humans; only ten utilised glycated haemoglobin A1c (HbA1c) in their definition of remission. Reported remission rates were 20-40 % for duodenal-jejunal bypass (DJB), 73-93 % for duodenal-jejunal bypass with sleeve gastrectomy (DJB-SG), 62.5-100 % for duodenal-jejunal bypass sleeve (DJBS) and 47-95.7 % for ileal interposition with sleeve gastrectomy (II-SG). When using a predetermined level of HbA1c to define remission, the remission rates were lower (27, 63, 0 and 65 %) for DJB, DJB-SG, DJBS and II-SG.

CONCLUSIONS

The outcomes of the foregut- and hindgut-based procedures are not better than the outcomes of just one of their components, namely sleeve gastrectomy. The complexity of these procedures in addition to their comparable outcomes to a simpler operation questions their utility.

Addition of Simvastatin to Standard Therapy for the Prevention of Variceal Rebleeding Does Not Reduce Rebleeding but Increases Survival in Patients With Cirrhosis

BACKGROUND & AIMS

The combination of β-blockers and band ligation is the standard approach to prevent variceal rebleeding, but bleeding recurs and mortality is high. The lipid-lowering drug simvastatin decreases portal pressure, improves hepatocellular function, and might reduce liver fibrosis. We assessed whether adding simvastatin to standard therapy could reduce rebleeding and death after variceal bleeding in patients with cirrhosis.

METHODS

We performed a multicenter, double-blind, parallel trial of 158 patients with cirrhosis receiving standard prophylaxis to prevent rebleeding (a β-blocker and band ligation) in Spain from October 2010 through October 2013. Within 10 days of bleeding, subjects were randomly assigned, but stratified by Child-Pugh class of A or B vs C, to groups given simvastatin (20 mg/d the first 15 days, 40 mg/d thereafter; n = 69) or placebo (n = 78). Patients were followed for as long as 24 months. The primary end point was a composite of rebleeding and death, and main secondary end points were the individual components of the composite (death and rebleeding).

RESULTS

The primary end point was met by 30 of 78 patients in the placebo group and 22 of 69 in the simvastatin group (P = .423). Seventeen patients in the placebo group died (22%) vs 6 patients in the simvastatin group (9%) (hazard ratio for adding simvastatin to therapy = 0.39; 95% confidence interval: 0.15-0.99; P = .030). Simvastatin did not increase survival of patients with Child-Pugh class C cirrhosis. Rebleeding occurred in 28% of patients in the placebo group and 25% in the simvastatin group (P = .583). Serious adverse events occurred in 53% of patients in the placebo group and 49% in the simvastatin group (P = .752); the percentages of serious adverse events related to therapy were 11% in the placebo group vs 8% in the in the simvastatin group (P = .599). Two patients in the simvastatin group, each with advanced liver disease, developed rhabdomyolysis.

CONCLUSIONS

In a randomized controlled trial, addition of simvastatin to standard therapy did not reduce rebleeding, but was associated with a survival benefit for patients with Child-Pugh class A or B cirrhosis. Survival was not the primary end point of the study, so these results require validation. The incidence of rhabdomyolysis in patients receiving 40 mg/d simvastatin was higher than expected. European Clinical Trial Database ID: EUDRACT 2009-016500-24; ClinicalTrials.gov ID: NCT01095185.

Efficacy of Bariatric Surgery in Type 2 Diabetes Mellitus Remission: the Role of Mini Gastric Bypass/One Anastomosis Gastric Bypass and Sleeve Gastrectomy at 1 Year of Follow-up. A European survey

BACKGROUND

A retrospective study was undertaken to define the efficacy of both mini gastric bypass or one anastomosis gastric bypass (MGB/OAGB) and sleeve gastrectomy (SG) in type 2 diabetes mellitus (T2DM) remission in morbidly obese patients (pts).

METHODS

Eight European centers were involved in this survey. T2DM was preoperatively diagnosed in 313/3252 pts (9.62%). In 175/313 patients, 55.9% underwent MGB/OAGB, while in 138/313 patients, 44.1% received SG between January 2006 and December 2014.

RESULTS

Two hundred six out of 313 (63.7 %) pts reached 1 year of follow-up. The mean body mass index (BMI) for MGB/OAGB pts was 33.1 ± 6.6, and the mean BMI for SG pts was 35.9 ± 5.9 (p < 0.001). Eighty-two out of 96 (85.4%) MGB/OAGB pts vs. 67/110 (60.9%) SG pts are in remission (p < 0.001). No correlation was found in the % change vs. baseline values for hemoglobin A1c (HbA1c) and fasting plasma glucose (FPG) in relation to BMI reduction, for both MGB/OAGB or SG (ΔFPG 0.7 and ΔHbA1c 0.4 for MGB/OAGB; ΔFPG 0.7 and ΔHbA1c 0.1 for SG). At multivariate analysis, high baseline HbA1c [odds ratio (OR) = 0.623, 95% confidence interval (CI) 0.419-0.925, p = 0.01], preoperative consumption of insulin or oral antidiabetic agents (OR = 0.256, 95% CI 0.137-0.478, p = <0.001), and T2DM duration >10 years (OR = 0.752, 95% CI 0.512-0.976, p = 0.01) were negative predictors whereas MGB/OAGB resulted as a positive predictor (OR = 3.888, 95% CI 1.654-9.143, p = 0.002) of diabetes remission.

CONCLUSIONS

A significant BMI decrease and T2DM remission unrelated from weight loss were recorded for both procedures if compared to baseline values. At univariate and multivariate analyses, MGB/OAGB seems to outperform significantly SG. Four independent variables able to influence T2DM remission at 12 months have been identified.

Circulating Betatrophin Is Increased in Patients with Overt and Subclinical Hypothyroidism

Thyroid hormone (TH) affects many metabolic processes such as promoting oxidation of sugar, fat, and protein in many tissues. Thyroid dysfunction is associated with metabolic disorders. The newly discovered adipocyte- and hepatocyte-derived cytokine, betatrophin, has been reported to be involved in metabolic diseases, but its influence on thyroid dysfunction is uncertain. Therefore, the present study aims to evaluate circulating betatrophin levels in subjects with different thyroid function status and to predict the factors associated with betatrophin levels, especially whether thyroid stimulating hormone (TSH), TH, or thyroid autoantibodies are associated with betatrophin levels. In the study, serum betatrophin was measured in the subjects grouped as overt hypothyroidism (OH), subclinical hypothyroidism (SCH), euthyroid with isolated thyroid peroxidase antibody positivity (isolated Ab), and healthy control (HC), according to their thyroid functions. From our results, we found that betatrophin may be associated with thyroid insufficiency but not thyroid autoimmunity. Thus, when interpreting the results of betatrophin, thyroid functions should also be taken into consideration.

Association between metformin and vitamin B12 deficiency in patients with type 2 diabetes: A systematic review and meta-analysis

AIM

Metformin is the most widely used oral hypoglycaemic drug, but it may lower B₁₂ status, which could have important clinical implications. We undertook a systematic review and meta-analysis of the relationship between metformin use and vitamin B₁₂ deficiency in persons with type 2 diabetes.

METHODS

Electronic database searches were undertaken (1st January 1957-1st July 2013) using the Cochrane library, Scopus, CINAHL, Grey literature databases, Pub Med Central, NICE Clinical Guidelines UK, and ongoing clinical trials. Included studies were of any study design, with data from patients with type 2 diabetes of any age or gender, taking any dose or duration of metformin. Planned primary outcomes were serum vitamin B₁₂ levels, % prevalence or incidence of vitamin B₁₂ deficiency and risk of vitamin B₁₂ deficiency.

RESULTS

Twenty-six papers were included in the review. Ten out of 17 observational studies showed statistically significantly lower levels of vitamin B₁₂ in patients on metformin than not on metformin. Meta-analysis performed on four trials demonstrated a statistically significant overall mean B₁₂ reducing effect of metformin of 57pmol/L [WMD (fixed)=-0.57 (95% CI: -35 to -79pmol/L)] after 6weeks to 3months of use.

CONCLUSION

The evidence from this review demonstrates an association between metformin usage and lower levels of vitamin B₁₂ by 57pmol/L, which leads to frank deficiency or borderline status in some patients with type 2 diabetes. This suggests that it is prudent to monitor B₁₂ levels in these patients who are at increased risk of deficiency.

The Effects of Dietary Iron and Capsaicin on Hemoglobin, Blood Glucose, Insulin Tolerance, Cholesterol, and Triglycerides, in Healthy and Diabetic Wistar Rats

Objective

Our aim was to assess the effects of dietary iron, and the compound capsaicin, on hemoglobin as well as metabolic indicators including blood glucose, cholesterol, triglycerides, insulin, and glucose tolerance.

Materials and Methods

Our animal model was the Wistar rat, fed a chow diet, with or without experimentally induced diabetes. Diabetic males were fed control, low, or high-iron diets, the latter, with or without capsaicin. Healthy rats were fed identical diets, but without the capsaicin supplement. We then measured the parameters listed above, using the Student t-test and ANOVA, to compare groups.

Results

Healthy rats fed a low-iron diet exhibited significantly reduced total cholesterol and triglyceride levels, compared with rats fed a control diet. Significantly reduced blood lipid was also provoked by low dietary iron in diabetic rats, compared with those fed a control diet. Insulin, and glucose tolerance was only improved in healthy rats fed the low-iron diet. Significant increases in total cholesterol were found in diabetic rats fed a high-iron diet, compared with healthy rats fed the same diet, although no statistical differences were found for triglycerides. Hemoglobin levels, which were not statistically different in diabetic versus healthy rats fed the high-iron diet, fell when capsaicin was added. Capsaicin also provoked a fall in the level of cholesterol and triglycerides in diabetic animals, versus diabetics fed with the high iron diet alone. In conclusion, low levels of dietary iron reduced levels of serum triglycerides, hemoglobin, and cholesterol, and significantly improved insulin, and glucose tolerance in healthy rats. In contrast, a high-iron diet increased cholesterol significantly, with no significant changes to triglyceride concentrations. The addition of capsaicin to the high-iron diet (for diabetic rats) further reduced levels of hemoglobin, cholesterol, and triglycerides. These results suggest that capsaicin, may be suitable for the treatment of elevated hemoglobin, in patients.

Clinically and pharmacologically relevant interactions of antidiabetic drugs

Patients with type 2 diabetes mellitus often require multifactorial pharmacological treatment due to different comorbidities. An increasing number of concomitantly taken medications elevate the risk of the patient experiencing adverse drug effects or drug interactions. Drug interactions can be divided into pharmacokinetic and pharmacodynamic interactions affecting cytochrome (CYP) enzymes, absorption properties, transporter activities and receptor affinities. Furthermore, nutrition, herbal supplements, patient's age and gender are of clinical importance. Relevant drug interactions are predominantly related to sulfonylureas, thiazolidinediones and glinides. Although metformin has a very low interaction potential, caution is advised when drugs that impair renal function are used concomitantly. With the exception of saxagliptin, dipeptidyl peptidase-4 (DPP-4) inhibitors also show a low interaction potential, but all drugs affecting the drug transporter P-glycoprotein should be used with caution. Incretin mimetics and sodium-glucose cotransporter-2 (SGLT-2) inhibitors comprise a very low interaction potential and are therefore recommended as an ideal combination partner from the clinical-pharmacologic point of view.

Long-term Metformin Use and Vitamin B12 Deficiency in the Diabetes Prevention Program Outcomes Study

CONTEXT

Vitamin B12 deficiency may occur with metformin treatment, but few studies have assessed risk with long-term use.

OBJECTIVE

To assess the risk of B12 deficiency with metformin use in the Diabetes Prevention Program (DPP)/DPP Outcomes Study (DPPOS).

DESIGN

Secondary analysis from the DPP/DPPOS. Participants were assigned to the placebo group (PLA) (n = 1082) or the metformin group (MET) (n = 1073) for 3.2 years; subjects in the metformin group received open-label metformin for an additional 9 years.

SETTING

Twenty-seven study centers in the United States.

PATIENTS

DPP eligibility criteria were: elevated fasting glucose, impaired glucose tolerance, and overweight/obesity. The analytic population comprised participants with available stored samples. B12 levels were assessed at 5 years (n = 857, n = 858) and 13 years (n = 756, n = 764) in PLA and MET, respectively.

INTERVENTION

Metformin 850 mg twice daily vs placebo (DPP), and open-label metformin in the metformin group (DPPOS).

MAIN OUTCOME MEASURES

B12 deficiency, anemia, and peripheral neuropathy.

RESULTS

Low B12 (≤ 203 pg/mL) occurred more often in MET than PLA at 5 years (4.3 vs 2.3%; P = .02) but not at 13 years (7.4 vs 5.4%; P = .12). Combined low and borderline-low B12 (≤ 298 pg/mL) was more common in MET at 5 years (19.1 vs 9.5%; P < .01) and 13 years (20.3 vs 15.6%; P = .02). Years of metformin use were associated with increased risk of B12 deficiency (odds ratio, B12 deficiency/year metformin use, 1.13; 95% confidence interval, 1.06–1.20). Anemia prevalence was higher in MET, but did not differ by B12 status. Neuropathy prevalence was higher in MET with low B12 levels.

CONCLUSIONS

Long-term use of metformin in DPPOS was associated with biochemical B12 deficiency and anemia. Routine testing of vitamin B12 levels in metformin-treated patients should be considered.

The role of nerve inflammation and exogenous iron load in experimental peripheral diabetic neuropathy (PDN)

BACKGROUND

Iron is an essential but potentially toxic metal in mammals. Here we investigated a pathogenic role of exogenous iron in peripheral diabetic neuropathy (PDN) in an animal model for type 1 diabetes.

METHODS

Diabetes was induced by a single injection of streptozotocin (STZ) in 4-month-old Sprague-Dawley rats. STZ-diabetic rats and non-diabetic rats were fed with high, standard, or low iron diet. After three months of feeding, animals were tested.

RESULTS

STZ-rats on standard iron diet showed overt diabetes, slowed motor nerve conduction, marked degeneration of distal intraepidermal nerve fibers, mild intraneural infiltration with macrophages and T-cells in the sciatic nerve, and increased iron levels in serum and dorsal root ganglion (DRG) neurons. While motor fibers were afflicted in all STZ-groups, only a low iron-diet led also to reduced sensory conduction velocities in the sciatic nerve. In addition, only STZ-rats on a low iron diet showed damaged mitochondria in numerous DRG neurons, a more profound intraepidermal nerve fiber degeneration indicating small fiber neuropathy, and even more inflammatory cells in sciatic nerves than seen in any other experimental group.

CONCLUSIONS

These results indicate that dietary iron-deficiency rather than iron overload, and mild inflammation may both promote neuropathy in STZ-induced experimental PDN.

Diabetic neuropathy is not associated with homocysteine, folate, vitamin B12 levels, and MTHFR C677T mutation in type 2 diabetic outpatients taking metformin

BACKGROUND

Hyperhomocysteinemia and vitamin B12 deficiency may be involved in the development of diabetic peripheral neuropathy (DPN). Metformin therapy may reduce vitamin B12 plasma levels, thus contributing to DPN.

AIM AND METHODS

The purposes of this cross-sectional study were to assess (1) the potential associations of DPN with serum levels of homocysteine (tHcy), B-vitamins, and/or the common methylenetetrahydrofolate reductase (MTHFR) C677T mutation; (2) the influence of chronic treatment with metformin on tHcy and B-vitamins concentrations and, finally, (3) to evaluate whether, by this influence, metformin is a risk factor for DPN in a group of type 2 diabetic outpatients.

RESULTS

Our data showed that fasting tHcy, folate, and vitamin B12 levels and the MTHFR C677T genotype distribution were comparable between subjects with (n = 79, 30 %) and without DPN (n = 184, 70 %). Metformin-treated subjects (n = 124, 47 %) showed significantly lower levels of vitamin B12 (P < 0.001), but the prevalence of DPN was not different when compared to those not treated with this drug (33 vs. 27 %, P = NS). At univariate regression analysis, DPN was associated with age, duration of diabetes, HbA1c, creatinine levels, and the presence of coronary heart disease (CHD), and negatively with HDL-C concentrations (P < 0.05 all), but at multivariate regression analysis, high creatinine levels (P = 0.06), low HDL-C levels (P = 0.013), and a higher prevalence of CHD (P = 0.001) were the only variables independently associated with DPN in this population.

CONCLUSIONS

In conclusion, in these type 2 diabetic outpatients circulating levels of tHcy, folate, and the MTHFR C677T mutation are not associated with DPN, which was predicted by creatinine levels, CHD, and dyslipidemia. Metformin therapy is associated with a mild vitamin B12 level reduction, but not with DPN.

Reconfiguration of the small intestine and diabetes remitting effects of Roux-en-Y gastric bypass surgery

PURPOSE OF REVIEW

Alterations in small intestinal physiology are proposed to play a causative role in the beneficial impact of Roux-en-Y gastric bypass on type 2 diabetes mellitus. The present article describes the key proposed mechanisms implicated with an emphasis on some of the newer findings in the field.

RECENT FINDINGS

Augmented incretin and diminished anti-incretin effects postsurgery are explored and a model proposed that reconciles the hindgut and foregut hypotheses of improved glycaemic control as being complementary rather than mutually exclusive. Synthesis of recent findings on postbypass changes in intestinal glucose handling then follows. Finally an updated view of the role of distal bile diversion and changes in the microbiota on enteroendocrine signalling is presented.

SUMMARY

A series of nonmutually exclusive changes in small intestinal physiology likely make a significant contribution to improved glycaemic control postgastric bypass. Longitudinal data indicate that these effects do not translate into a long-term cure. A number of surgery-induced changes, however, are amenable to device-based and pharmacology-based mimicry, and this is an area for prioritization of future research focus.

Energy balance and metabolic changes with sodium-glucose co-transporter 2 inhibition

Sodium-glucose co-transporter 2 (SGLT2) inhibitors are the latest addition to the class of oral glucose-lowering drugs. They have been rapidly adopted into clinical practice because of therapeutic advantages, including weight loss and reduction in blood pressure, in addition to glycaemic benefits and a low intrinsic risk of hypoglycaemia. Although there are extensive data on the clinical effects of SGLT2 inhibition, the metabolic effects of inhibiting renal glucose reabsorption have not been fully described. Recent studies have identified compensatory metabolic effects, such as an increase in endogenous glucose production, and have also shown an increase in glucagon secretion during SGLT2 inhibition. In addition, there is a discrepancy between the expected and observed weight loss found in clinical studies on SGLT2 inhibitors, probably as a result of changes in energy balance with this treatment approach. SGLT2 inhibition is likely to have intriguing effects on whole body metabolism which have not been fully elucidated, and which, if explained, might help optimize the use of this new class of medicines.

Dietary and Policy Priorities for Cardiovascular Disease, Diabetes, and Obesity: A Comprehensive Review

Suboptimal nutrition is a leading cause of poor health. Nutrition and policy science have advanced rapidly, creating confusion yet also providing powerful opportunities to reduce the adverse health and economic impacts of poor diets. This review considers the history, new evidence, controversies, and corresponding lessons for modern dietary and policy priorities for cardiovascular diseases, obesity, and diabetes mellitus. Major identified themes include the importance of evaluating the full diversity of diet-related risk pathways, not only blood lipids or obesity; focusing on foods and overall diet patterns, rather than single isolated nutrients; recognizing the complex influences of different foods on long-term weight regulation, rather than simply counting calories; and characterizing and implementing evidence-based strategies, including policy approaches, for lifestyle change. Evidence-informed dietary priorities include increased fruits, nonstarchy vegetables, nuts, legumes, fish, vegetable oils, yogurt, and minimally processed whole grains; and fewer red meats, processed (eg, sodium-preserved) meats, and foods rich in refined grains, starch, added sugars, salt, and trans fat. More investigation is needed on the cardiometabolic effects of phenolics, dairy fat, probiotics, fermentation, coffee, tea, cocoa, eggs, specific vegetable and tropical oils, vitamin D, individual fatty acids, and diet-microbiome interactions. Little evidence to date supports the cardiometabolic relevance of other popular priorities: eg, local, organic, grass-fed, farmed/wild, or non-genetically modified. Evidence-based personalized nutrition appears to depend more on nongenetic characteristics (eg, physical activity, abdominal adiposity, gender, socioeconomic status, culture) than genetic factors. Food choices must be strongly supported by clinical behavior change efforts, health systems reforms, novel technologies, and robust policy strategies targeting economic incentives, schools and workplaces, neighborhood environments, and the food system. Scientific advances provide crucial new insights on optimal targets and best practices to reduce the burdens of diet-related cardiometabolic diseases.

Tipping the balance: Haemoglobinopathies and the risk of diabetes

AIM: To establish a link between the risk of diabetes with haemoglobinopathies by examining available evidence of the effects of iron and blood glucose homeostasis from molecular to epidemiological perspectives.

METHODS: A systematic literature search was performed using electronic literature databases using various search terms. The International Diabetes Federation World Atlas was used to generate a list of populations with high rates of diabetes. PubMed, Scopus and Google Scholar were used to identify which of these populations also had a reported prevalence of haemoglobin abnormalities.

RESULTS: Abnormalities in iron homeostasis leads to increases in reactive oxygen species in the blood. This promotes oxidative stress which contributes to peripheral resistance to insulin in two ways: (1) reduced insulin/insulin receptor interaction; and (2) β-cell dysfunction. Hepcidin is crucial in terms of maintaining appropriate amounts of iron in the body and is in turn affected by haemoglobinopathies. Hepcidin also has other metabolic effects in places such as the liver but so far the extent of these is not well understood. It does however directly control the levels of serum ferritin. High serum ferritin is found in obese patients and those with diabetes and a meta-analysis of the various studies shows that high serum ferritin does indeed increase diabetes risk.

CONCLUSION: From an epidemiological standpoint, it is plausible that the well-documented protective effects of haemoglobinopathies with regard to malaria may have also offered other evolutionary advantages. By contributing to peripheral insulin resistance, haemoglobinopathies may have helped to sculpt the so-called “thrifty genotype”, which hypothetically is advantageous in times of famine. The prevalence data however is not extensive enough to provide concrete associations between diabetes and haemoglobinopathies - more precise studies are required.

Association of Serum Ferritin Level with Risk of Incident Abnormal Glucose Metabolism in Southwestern China: a Prospective Cohort Study

This prospective cohort study aimed to analyze the association between serum ferritin levels and the risk of abnormal glucose metabolism (AGM) in Southwestern Chinese population. The 383 subjects who are aged ≥20 years and free of AGM at baseline between in 2007 and in 2008 were included in Southwestern China, and their baseline serum ferritin levels were measured. Among these subjects, 140 subjects were developed into AGM during the follow-up (2008-2012). In logistic regression models, the relative risk in the top versus that in the lowest quartile of serum ferritin levels was 2.86 (p = 0.013) in females and 3.50 (p = 0.029) in males after adjusting the age, gender, family history of diabetes, current smoking, and alcohol; however, serum ferritin levels were not significantly associated with incident of AGM after controlling for metabolic factors (waist circumference, systolic pressure (SBP), triglyceride (TG), and homeostasis model assessment formula insulin resistance (HOMA-IR)). Elevated serum ferritin levels are associated with AGM but not an independent risk factor.

Circulating hepcidin in type 2 diabetes: A multivariate analysis and double blind evaluation of metformin effects

SCOPE

Very few studies have evaluated serum hepcidin in patients with type 2 diabetes and they have reported conflicting results. In addition, the effect of antidiabetic drugs on circulating hepcidin has not been explored so far. The aims of the study were to evaluate hepcidin concentrations and hepcidin/ferritin ratio in type 2 diabetes subjects and healthy non-diabetic controls and to evaluate the effect of metformin on hepcidin concentrations.

METHODS AND RESULTS

Study 1: Cross-sectional multivariate study of 239 non-diabetic individuals and 65 people with type 2 diabetes. The multivariate analysis included covariates of chronic inflammation, BMI, pharmacological treatment, menopausal status and insulin resistance. Study 2: Randomized, double-blinded, placebo-controlled 4-month trial metformin compared to placebo among 36 type 2 diabetic patients. In both groups diet was controlled by maintaining a hypocaloric intake across the trial. Hepcidin levels were significantly lower in patients with type 2 diabetes than in non-diabetic individuals either in crude or adjusted regression models (P<0.05). Hepcidin decreased in both arms of the trial (Placebo, p = 0.004; metformin, p = 0.022).

CONCLUSION

Circulating hepcidin was significantly and independently lower in type 2 diabetes. Metformin treatment is not associated with reductions in hepcidin but hypocaloric diet could be involved.

Is Bariatric Surgery an Effective Treatment for Type II Diabetic Kidney Disease?

Type II diabetic kidney disease is devastating to patients and society alike. This review will evaluate bariatric surgery as a treatment for diabetic kidney disease primarily through its ability to induce and maintain regression of type II diabetes. The review begins by outlining the global challenge of diabetic kidney disease, its link to obesity, and the comparative benefits of bariatric surgery on weight and type II diabetes. It then surveys comprehensively the relevant literature, which reports that although bariatric surgery is associated with reductions in albuminuria, its effect on harder clinical end points like progression of diabetic kidney disease is not known. The review also includes a critical assessment of the risks and costs of bariatric surgery and concludes by acknowledging the major knowledge gaps in the field and providing research strategies to overcome them. Until these knowledge gaps are filled, clinicians will be forced to rely on their own subjective judgment in determining the benefit-risk ratio of bariatric surgery for patients with diabetic kidney disease.

Factors Influencing Self-Management in Chinese Adults with Type 2 Diabetes: A Systematic Review and Meta-Analysis

Diabetes is a major public health problem in China. Diabetes self-management is critical for patients to achieved better health outcomes, however, previous studies have shown suboptimal diabetes self-management performance. We conducted a systematic review and meta-analysis to identify factors associated with diabetes self-management in Chinese adults. The results showed that confrontation, resignation, overall health beliefs, perceived susceptibility, perceived barriers, and self-efficacy were factors associated with overall diabetes self-management performance and six aspects of diabetes self-management behaviors. There is some limited evidence to suggest that provider-patient communication, married individuals, higher educational level, and higher household income level may also be linked to better diabetes self-management practice. Having healthcare insurance and utilizing chronic illness resources generally appeared to have a favorable effect on diabetes self-management performance. In addition, there were a number of factors for which the evidence is too limited to be able to ascertain its strength of association with diabetes self-management practice. The findings of this review suggest that diabetes self-management behaviors are affected by a wide range of personal and environmental factors, which allow health care providers to develop theory-based strategies to improve diabetes-self-management behaviors in this population.

Long-Term Outcomes of Obesity Surgery and Implications for Health System Planning

Weight loss surgery is currently the only treatment that offers significant and sustained weight loss for those with severe and complex obesity. Obesity levels have reached a sustained high, whereby several percent of a country's population would qualify for surgery based upon current national guidelines. Worldwide, the provision of surgery is highly variable and to treat all the affected population, it would require at least a 100-fold increase in the provision of services. This has important cost and commissioning implications for health-care planners. Reliable level 1 evidence of the long-term effects of obesity surgery is still lacking, and the long-term complication profiles and re-operation rates unclear, which could have significant impact on health-care systems in the future. The chronic disease management of obesity in a population must be integrated with education and prevention and the brief intervention of weight loss surgery and the management of its sequelae, to prevent significant future morbidity and mortality.

Up-regulation of MSH2, XRCC1 and ATM genes in patients with type 2 diabetes and coronary artery disease

AIMS

Coronary artery disease (CAD) is a major problem in some patients with type 2 diabetes mellitus (T2DM). CAD has been suggested to be the main result of reduced efficacy of DNA repair systems. Analysis of the DNA repair system in patients with diabetes can potentially uncover the molecular basis of their susceptibility to the CAD. The aim of the present study was to compare the expression levels of some important DNA repair genes, including ATM, XRCC1 and MSH2, in CAD+ versus CAD- patients with T2DM. Furthermore, the relevance of putative single nucleotide polymorphisms (SNPs) in the promoter regions of these genes with mRNA expression was evaluated.

METHODS

Expression analysis was performed by RT-qPCR on 76 patients with T2DM (41 CAD+ and 35 CAD- individuals confirmed by angiography). The genotypes of the patients were examined by polymerase chain reaction-restriction fragment length polymorphism analysis.

RESULTS

Significant up-regulation of the MSH2 (2.49-fold, P=0.001), XRCC1 (2.11-fold, P=0.001) and ATM (2.15-fold, P=0.003) genes was observed in patients with T2DM and CAD. We could not detect any function for SNPs by comparing gene expression. In a receiver operating characteristic (ROC) curve analysis, the area under the ROC curve for sum of relative expressions of all genes reached 0.81 (95% CI: 0.690-0.936, P=0.003), which indicates a potential biomarker for identifying patients with T2DM and CAD.

CONCLUSION

These results suggest that expression levels of DNA repair genes may serve as informative biomarkers for identifying patients with T2DM and CAD.

Bariatric Surgery for Type 2 Diabetes Mellitus in Patients with BMI <30 kg/m2: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE

The role of bariatric surgery in non-obese patients with type 2 diabetes (T2DM) remains unclear, and its use in clinical practice is controversial. We conducted a systemic review and meta-analysis to investigate the metabolic changes after surgical treatment in diabetic patients with body mass index (BMI) <30 kg/m2.

METHODS

We conducted a comprehensive search in MEDLINE (PubMed), EMBASE and the Cochrane Library of published articles from January 2000 to April 2013 reporting the clinical outcome changes in various metabolic outcomes in diabetic patients with BMI <30 kg/m2.

RESULTS

Ten prospective studies including 290 patients were included in the meta-analysis. Bariatric surgery led to an overall 2.79 kg/m2 [95%CI 2.05~3.53, P<0.00001] reduction in BMI, a 1.88%[95%CI 1.32~2.43, P<0.00001] reduction in glycosylated hemoglobin, a 3.70 mmol/L [95%CI, 1.93~5.47, P<0.00001] reduction in fasting blood glucose, a 6.69 mmol/L [95%CI, 2.29~11.08, P=0.003] reduction in postprandial glucose, anda 3.37 [95%CI 0.55~6.18, P=0.02] reduction in homeostasis model assessment of insulin resistance (HOMA-IR). After surgical treatment, 76.2% of the patients were insulin free, and 61.8% patients were off medication. In total, 90(42.4%), 10(37%) and 34(37.2%) patients had post-surgical HbA1c levels of <6%,<6.5% and<7%, respectively. No deaths were observed in the included studies, and the major complication rate was 6.2%.

CONCLUSIONS

Based on the currently available data, bariatric surgery might improve glycemic control and weight loss in a very limited range with a doubled surgical complication rate in drug-refractory T2DM patients with BMI <30 kg/m2. It remains too premature to suggest bariatric surgery for non-obese T2DM patients.

A review of potential metabolic etiologies of the observed association between red meat consumption and development of type 2 diabetes mellitus

Epidemiological studies suggest that red and processed meat consumption is related to an increased risk of type 2 diabetes. However, it is not clearly understood which components of red and processed meat contribute to this increased risk. This review examines potential mechanisms addressing the role of saturated fatty acid, sodium, advanced glycation end products (AGEs), nitrates/nitrites, heme iron, trimethylamine N-oxide (TMAO), branched amino acids (BCAAs) and endocrine disruptor chemicals (EDCs) in the development of type 2 diabetes based on data from published clinical trials and animal models. TMAO which is derived from dietary carnitine and choline by the action of bacterial enzymes followed by oxidation in the liver may be a strong candidate molecule mediating the risk of type 2 diabetes. BCAAs may induce insulin resistance via the mammalian target of rapamycin complex 1 (mTORC1) and ribosomal protein S6 kinase β 1 (S6k1)-associated pathways. The increased risk associated with processed meat compared with red meat suggests that there are interactions between the saturated fat, salt, and nitrates in processed meat and iron, AGEs and TMAO. Intervention studies are required to clarify potential mechanisms and explore interactions among components, in order to make firm recommendations on red and processed meat consumption.

The impact of laparoscopic sleeve gastrectomy on weight loss and obesity-associated comorbidities: the results of 3 years of follow-up

BACKGROUND

Laparoscopic sleeve gastrectomy is one of the most recent advances in the surgical treatment of morbid obesity. Extended follow-up studies of large cohorts are needed to establish the usefulness of the operation. The objectives of this study are to delineate the role of sleeve gastrectomy in weight loss and in comorbidities among obese patients.

METHODS

Patients who underwent laparoscopic sleeve gastrectomy in a single bariatric center were followed up for a 3-year period. Weight loss and status of several comorbidities were assessed at the 1st, 3rd, 6th, 12th, 18th, 24(th), and 36th postoperative month.

RESULTS

Overall, after 3 years of follow-up of 88 patients, the mean body mass index (BMI) of the patients was 29.8 kg/m(2) (SD ±6.1), the % total weight loss was 38.1% (SD ±12.9), the % excess weight loss was 69.5% (SD ±17.5), and the % estimated BMI loss was 81.4% (SD ±22.3). These parameters changed significantly over the first year of follow-up (p < 0.001) and subsequently stabilized. The percentages of patients with hypertension (33.3%), hyperlipidemia (26.4%), diabetes mellitus (20.7%), obstructive sleep apnea (20.2%), and gastroesophageal reflux disease (GERD-27%) were significantly reduced (10.5, 9.2, 1.1, 1.1, and 9.2% respectively at 36 months postoperation), while 10 new cases of GERD appeared postoperatively. However, only three of the new GERD cases required medication, and only one of them experienced symptoms that persisted after the 3-year period.

CONCLUSION

Three years of close follow-up of patients who had undergone laparoscopic sleeve gastrectomy demonstrated satisfactory weight loss results. Promising results were also obtained regarding various comorbidities of obese patients. Longer follow-up studies for more patients are needed to delineate the exact role of sleeve gastrectomy on postoperative outcomes.

Substrate-anchored and degradation-sensitive anti-inflammatory coatings for implant materials

Implant materials need to be highly biocompatible to avoid inflammation in clinical practice. Although biodegradable polymeric implants can eliminate the need for a second surgical intervention to remove the implant materials, they may produce acidic degradation products in vivo and cause non-bacterial inflammation. Here we show the strategy of “substrate-anchored and degradation-sensitive coatings” for biodegradable implants. Using poly(lactic acid)/hydroxyapatite as an implant material model, we constructed a layer-by-layer coating using pH-sensitive star polymers and dendrimers loaded with an anti-inflammatory drug, which was immobilised through a hydroxyapatite-anchored layer. The multifunctional coating can effectively suppress the local inflammation caused by the degradation of implant materials for at least 8 weeks in vivo. Moreover, the substrate-anchored coating is able to modulate the degradation of the substrate in a more homogeneous manner. The “substrate-anchored and degradation-sensitive coating” strategy therefore exhibits potential for the design of various self-anti-inflammatory biodegradable implant materials.

Functionalized self-assembling peptide improves INS-1 β-cell function and proliferation via the integrin/FAK/ERK/cyclin pathway

Islet transplantation is considered to be a curative treatment for type 1 diabetes mellitus. However, disruption of the extracellular matrix (ECM) leads to β-cell destruction and graft dysfunction. In this study, we developed a functionalized self-assembling peptide, KLD-F, with ECM mimic motifs derived from fibronectin and collagen IV, and evaluated its effect on β-cell function and proliferation. Atomic force microscopy and rheological results showed that KLD-F could self-assemble into a nanofibrous scaffold and change into a hydrogel in physiological saline condition. In a three-dimensional cell culture model, KLD-F improved ECM remodeling and cell-cell adhesion of INS-1 β-cells by upregulation of E-cadherin, fibronectin, and collagen IV. KLD-F also enhanced glucose-stimulated insulin secretion and expression of β-cell function genes, including Glut2, Ins1, MafA, and Pdx-1 in INS-1 cells. Moreover, KLD-F promoted proliferation of INS-1 β-cells and upregulated Ki67 expression by mediating cell cycle progression. In addition, KLD-F improved β-cell function and proliferation via an integrin/focal adhesion kinase/extracellular signal-regulated kinase/cyclin D pathway. This study highlights the fact that the β-cell-ECM interaction reestablished with this functionalized self-assembling peptide is a promising method to improve the therapeutic efficacy of islet transplantation.

Does patient empowerment predict self-care behavior and glycosylated hemoglobin in chinese patients with type 2 diabetes?

BACKGROUND

Patient empowerment is playing an increasingly important role in diabetes and related disorders. This study evaluated the correlations among patient empowerment, self-care behavior, and glycemic control among patients with type 2 diabetes in mainland China.

SUBJECTS AND METHODS

We conducted a multicenter cross-sectional study. Eight hundred eighty-five patients who sought care at hospitals in Nanjing, Changsha, Yunnan, and Chongqing, China, were enrolled. Structured questionnaires and medical records provided the data. The instruments included a demographic and clinical questionnaire, the Diabetes Empowerment Scale-Short Form, and the Chinese version of the Summary of Diabetes Self-Care Activities Scale. Glycosylated hemoglobin (HbA1c) was used as a measure of glycemic control. The data analyses are presented as proportions, means (±SD), β, and 95% confidence intervals (CIs). Multilinear regressions were used to examine the correlations among the scores of patient empowerment, self-care behavior, and HbA1c values.

RESULTS

Linear regression revealed that patient empowerment was a statistically significant predictor of patients' self-care behavior even after controlling for age, gender, marital status, educational level, and diabetes duration. Diet (β=0.449; 95% CI, 0.370, 0.528), exercise (β=0.222; 95% CI, 0.164, 0.279), blood glucose testing (β=0.152; 95% CI, 0.106, 0.199), medication taking (β=0.062; 95% CI, 0.030, 0.095), and foot care (β=0.279; 95% CI, 0.217, 0.342). Additionally, patient empowerment was a statistically significant predictor of HbA1c (β=-0.094; 95% CI, -0.123, -0.065).

CONCLUSIONS

Our study indicated that perceived diabetes empowerment is a predictor of self-care behavior and HbA1c in Chinese patients with type 2 diabetes. Therefore, interventions to enhance and promote patient empowerment should be essential components of diabetes education programs to improve self-care behavior and glycemic control.

Is type 2 diabetes really resolved after laparoscopic sleeve gastrectomy? Glucose variability studied by continuous glucose monitoring

The study was carried out on type 2 diabetic obese patients who underwent laparoscopic sleeve gastrectomy (LSG). Patients underwent regular glycemic controls throughout 3 years and all patients were defined cured from diabetes according to conventional criteria defined as normalization of fasting glucose levels and glycated hemoglobin in absence of antidiabetic therapy. After 3 years of follow-up, Continuous Glucose Monitoring (CGM) was performed in each patient to better clarify the remission of diabetes. In this study, we found that the diabetes resolution after LSG occurred in 40% of patients; in the other 60%, even if they showed a normal fasting glycemia and A1c, patients spent a lot of time in hyperglycemia. During the oral glucose tolerance test (OGTT), we found that 2 h postload glucose determinations revealed overt diabetes only in a small group of patients and might be insufficient to exclude the diagnosis of diabetes in the other patients who spent a lot of time in hyperglycemia, even if they showed a normal glycemia (<140 mg/dL) at 120 minutes OGTT. These interesting data could help clinicians to better individualize patients in which diabetes is not resolved and who could need more attention in order to prevent chronic complications of diabetes.

Vitamin B12 deficiency - A 21st century perspective

Vitamin B12 deficiency is a common condition which can present with non-specific clinical features, and in severe cases with neurological or haematological abnormalities. Although classically caused by pernicious anaemia, this condition now accounts for a minority of cases and vitamin B12 deficiency occurs most often due to food-bound cobalamin malabsorption. Since missing the diagnosis can result in potentially severe complications, including degeneration of the spinal cord and pancytopaenia, vitamin B12 deficiency must be diagnosed early and managed appropriately. Intramuscular injections have been the mainstay of treatment, but oral replacement therapy can be effective in many cases. There is accumulating evidence that high vitamin B12 levels (values varied from 350-1,200 pmol/l) are associated with haematological and hepatic disorders, in particular with malignancy. This review focuses on the developments in the clinical features and management of vitamin B12 deficiency over the last decade.

Metabolic changes induced by the biliopancreatic diversion in diet-induced obesity in male rats: the contributions of sleeve gastrectomy and duodenal switch

The mechanisms underlying the body weight and fat loss after the biliopancreatic diversion with duodenal switch (BPD/DS) remain to be fully delineated. The aim of this study was to examine the contributions of the two main components of BPD/DS, namely sleeve gastrectomy (SG) and duodenal switch (DS), on energy balance changes in rats rendered obese with a high-fat (HF) diet. Three different bariatric procedures (BPD/DS, SG, and DS) and three sham surgeries were performed in male Wistar rats. Sham-operated animals fed HF were either fed ad libitum (Sham HF) or pair weighed (Sham HF PW) by food restriction to the BPD/DS rats. A group of sham-operated rats was kept on standard chow and served as normal diet control (Sham Chow). All three bariatric surgeries resulted in a transient reduction in food intake. SG per se induced a delay in body weight gain. BPD/DS and DS led to a noticeable gut malabsorption and a reduction in body weight and fat gains along with significant elevations in plasma levels of glucagon-like peptide-1(7-36) and peptide YY. BPD/DS and DS elevated energy expenditure above that of Sham HF PW during the dark phase. However, they reduced the volume, oxidative metabolism, and expression of thermogenic genes in interscapular brown adipose tissue. Altogether the results of this study suggest that the DS component of the BPD/DS, which led to a reduction in digestible energy intake while sustaining energy expenditure, plays a key role in the improvement in the metabolic profile led by BPD/DS in rats fed a HF diet.

Poorly controlled type 2 diabetes is accompanied by significant morphological and ultrastructural changes in both erythrocytes and in thrombin-generated fibrin: implications for diagnostics

We have noted in previous work, in a variety of inflammatory diseases, where iron dysregulation occurs, a strong tendency for erythrocytes to lose their normal discoid shape and to adopt a skewed morphology (as judged by their axial ratios in the light microscope and by their ultrastructure in the SEM). Similarly, the polymerization of fibrinogen, as induced in vitro by added thrombin, leads not to the common ‘spaghetti-like’ structures but to dense matted deposits. Type 2 diabetes is a known inflammatory disease. In the present work, we found that the axial ratio of the erythrocytes of poorly controlled (as suggested by increased HbA1c levels) type 2 diabetics was significantly increased, and that their fibrin morphologies were again highly aberrant. As judged by scanning electron microscopy and in the atomic force microscope, these could be reversed, to some degree, by the addition of the iron chelators deferoxamine (DFO) or deferasirox (DFX). As well as their demonstrated diagnostic significance, these morphological indicators may have prognostic value.

Methods for biomimetic remineralization of human dentine: a systematic review

This study aimed to review the laboratory methods on biomimetic remineralization of demineralized human dentine. A systematic search of the publications in the PubMed, TRIP, and Web of Science databases was performed. Titles and abstracts of initially identified publications were screened. Clinical trials, reviews, non-English articles, resin-dentine interface studies, hybrid layer studies, hybrid scaffolds studies, and irrelevant studies were excluded. The remaining papers were retrieved with full texts. Manual screening was conducted on the bibliographies of remaining papers to identify relevant articles. A total of 716 studies were found, and 690 were excluded after initial screening. Two articles were identified from the bibliographies of the remaining papers. After retrieving the full text, 23 were included in this systematic review. Sixteen studies used analogues to mimic the functions of non-collagenous proteins in biomineralization of dentine, and four studies used bioactive materials to induce apatite formation on demineralized dentine surface. One study used zinc as a bioactive element, one study used polydopamine, and another study constructed an agarose hydrogel system for biomimetic mineralization of dentine. Many studies reported success in biomimetic mineralization of dentine, including the use of non-collagenous protein analogues, bioactive materials, or elements and agarose hydrogel system.

Pleiotropic actions of iron balance in diabetes mellitus

As an essential element, iron plays a central role in many physiological processes, including redox balance, inflammation, energy metabolism, and environment sensing. Perturbations in iron homeostasis are associated with several conditions, including hyperglycemia and diabetes, both of which have been studied in patients and animal models. To clarify the pleiotropic role of iron homeostasis in diabetes development, the early studies on diseases with iron-overload, studies on clinical iron depletion therapies, associations between iron-related genetic polymorphisms and diabetes, and etiological mechanisms underlying iron perturbations-impaired insulin secretion and insulin sensitivity were carefully reviewed and discussed. Hereditary hemochromatosis, transfusion-dependent thalassemia, and excess heme iron intake can increase the risk of developing diabetes. Genetically modified mice and mice fed a high-iron diet present with discrepant phenotypes due to differences in tissue iron distribution. Moreover, several genetic polymorphisms related to iron homeostasis have been associated with the risk of developing diabetes. Tightly controlled iron metabolism is essential for insulin secretion and insulin sensitivity, and iron overload in pancreatic islets alters reactive oxygen species (ROS) generation, as well as hypoxia-inducible factor-1α (HIF-1α) stability and adenosine triphosphate (ATP) synthesis, thereby impairing the function and viability of β-cells. Decreased levels of adiponectin, macrophage-mediated inflammation, and ROS-mediated liver kinase B1 (LKB1)/adenosine monophosphate-activated protein kinase (AMPK) activation can contribute to iron overload-induced insulin resistance, whereas iron deficiency could also participate in obesity-related inflammation, hypoxia, and insulin resistance. Because iron homeostasis is closely correlated with many metabolic processes, future studies are needed in order to elucidate the finely tuned network among iron homeostasis, carbohydrate and lipid metabolism, inflammation, and hypoxia.

Serum ferritin is an important inflammatory disease marker, as it is mainly a leakage product from damaged cells

"Serum ferritin" presents a paradox, as the iron storage protein ferritin is not synthesised in serum yet is to be found there. Serum ferritin is also a well known inflammatory marker, but it is unclear whether serum ferritin reflects or causes inflammation, or whether it is involved in an inflammatory cycle. We argue here that serum ferritin arises from damaged cells, and is thus a marker of cellular damage. The protein in serum ferritin is considered benign, but it has lost (i.e. dumped) most of its normal complement of iron which when unliganded is highly toxic. The facts that serum ferritin levels can correlate with both disease and with body iron stores are thus expected on simple chemical kinetic grounds. Serum ferritin levels also correlate with other phenotypic readouts such as erythrocyte morphology. Overall, this systems approach serves to explain a number of apparent paradoxes of serum ferritin, including (i) why it correlates with biomarkers of cell damage, (ii) why it correlates with biomarkers of hydroxyl radical formation (and oxidative stress) and (iii) therefore why it correlates with the presence and/or severity of numerous diseases. This leads to suggestions for how one might exploit the corollaries of the recognition that serum ferritin levels mainly represent a consequence of cell stress and damage.

Identification of a non-growth factor role for GM-CSF in advanced atherosclerosis: promotion of macrophage apoptosis and plaque necrosis through IL-23 signaling

RATIONALE

Granulocyte macrophage colony-stimulating factor (GM-CSF, Csf2) is a growth factor for myeloid-lineage cells that has been implicated in the pathogenesis of atherosclerosis and other chronic inflammatory diseases. However, the role of GM-CSF in advanced atherosclerotic plaque progression, the process that gives rise to clinically dangerous plaques, is unknown.

OBJECTIVE

To understand the role of GM-CSF in advanced atherosclerotic plaque progression.

METHODS AND RESULTS

Ldlr(-/-) mice and Csf2(-/-)Ldlr(-/-) mice were fed a Western-type diet for 12 weeks, and then parameters of advanced plaque progression in the aortic root were quantified. Lesions from the GM-CSF-deficient mice showed a substantial decrease in 2 key hallmarks of advanced atherosclerosis, lesional macrophage apoptosis and plaque necrosis, which indicates that GM-CSF promotes plaque progression. Based on a combination of in vitro and in vivo studies, we show that the mechanism involves GM-CSF-mediated production of interleukin-23, which increases apoptosis susceptibility in macrophages by promoting proteasomal degradation of the cell survival protein Bcl-2 (B-cell lymphoma 2) and by increasing oxidative stress.

CONCLUSIONS

In low-density lipoprotein-driven atherosclerosis in mice, GM-CSF promotes advanced plaque progression by increasing macrophage apoptosis susceptibility. This action of GM-CSF is mediated by its interleukin-23-inducing activity rather than its role as a growth factor.

Modulated regeneration of acid-etched human tooth enamel by a functionalized dendrimer that is an analog of amelogenin

In the bioinspired repair process of tooth enamel, it is important to simultaneously mimic the organic-matrix-induced biomineralization and increase the binding strength at the remineralization interface. In this work, a fourth-generation polyamidoamine dendrimer (PAMAM) is modified by dimethyl phosphate to obtain phosphate-terminated dendrimer (PAMAM-PO3H2) since it has a similar dimensional scale and peripheral functionalities to that of amelogenin, which plays important role in the natural development process of enamel. Its phosphate group has stronger affinity for calcium ion than carboxyl group and can simultaneously provide strong hydroxyapatite (HA)-binding capability. The MTT assay demonstrates the low cytotoxicity of PAMAM-PO3H2. Adsorption tests indicate that PAMAM-PO3H2 can be tightly adsorbed on the human tooth enamel. Scanning electron microscopy and X-ray diffraction are used to analyze the remineralization process. After being incubated in artificial saliva for 3weeks, there is a newly generated HA layer of 11.23μm thickness on the acid-etched tooth enamel treated by PAMAM-PO3H2, while the thickness for the carboxyl-terminated one (PAMAM-COOH) is only 6.02μm. PAMAM-PO3H2 can regulate the remineralization process to form ordered new crystals oriented along the Z-axis and produce an enamel prism-like structure that is similar to that of natural tooth enamel. The animal experiment also demonstrates that PAMAM-PO3H2 can induce significant HA regeneration in the oral cavity of rats. Thus PAMAM-PO3H2 shows great potential as a biomimetic restorative material for human tooth enamel.