Glucose Excursions Between States of Glycemia With Progression to Type 1 Diabetes in the Diabetes Prevention Trial�CType 1 (DPT-1)

OBJECTIVE

We characterized fluctuations between states of glycemia in progressors to type 1 diabetes and studied whether those fluctuations are related to the early C-peptide response to oral glucose.

RESEARCH DESIGN AND METHODS

Oral glucose tolerance tests (OGTTs) from differing states of glycemia were compared within individuals for glucose and C-peptide. Dysglycemic OGTTs (DYSOGTTs) were compared with normal OGTTs (NLOGTT), while transient diabetic OGTTs (TDOGTTs) were compared with subsequent nondiabetic OGTTs and with OGTTs performed at diagnosis.

RESULTS

Of 135 progressors with four or more OGTTs, 30 (22%) went from NLOGTTs to DYSOGTTs at least twice. Area under the curve (AUC) glucose values from the second NLOGTT were higher (P < 0.001) than values from the first NLOGTT. Among 98 progressors whose DYSOGTTs and NLOGTTs were synchronized for the time before diagnosis, despite higher glucose levels (P < 0.01 at all time points) in the DYSOGTTs, 30- to 0-min C-peptide difference values changed little. Likewise, 30- to 0-min C-peptide difference values did not differ between TDOGTTs and subsequent (within 3 months) nondiabetic OGTTs in 55 progressors. In contrast, as glucose levels increased overall from the first to last OGTTs before diagnosis (P < 0.001 at every time point, n = 207), 30- to 0-min C-peptide difference values decreased (P < 0.001).

CONCLUSIONS

Glucose levels fluctuate widely as they gradually increase overall with progression to type 1 diabetes. As glucose levels increase, the early C-peptide response declines. In contrast, glucose fluctuations are not related to the early C-peptide response. This suggests that changes in insulin sensitivity underlie the glucose fluctuations.Glucose levels can fluctuate substantially during the progression to type 1 diabetes (1). In this report, we examine glucose variability and explore its basis by comparing the C-peptide response to oral glucose between states of glycemia. The findings provide additional insights into the metabolic progression to type 1 diabetes.     

Does Homeostasis Model Assessment of Insulin Resistance have a predictive value for post-coronary artery bypass grafting surgery outcomes?

Objective

This study aims to investigate whether pre-operative Homeostasis Model Assessment Insulin Resistance (HOMA-IR) value is a predictor in non-diabetic coronary artery bypass grafting patients in combination with hemoglobin A1c, fasting blood glucose and insulin levels.

Methods

Eighty one patients who were admitted to Cardiovascular Surgery Clinic at our hospital between August 2012 and January 2013 with a coronary artery bypass grafting indication were included. Patients were non-diabetic with <6.3% hemoglobin A1c and were divided into two groups including treatment and control groups according to normal insulin resistance (HOMA-IR<2.5, Group A; n=41) and high insulin resistance (HOMA-IR>2.5, Group B; n=40), respectively. Pre-operative fasting blood glucose and insulin were measured and serum chemistry tests were performed. The Homeostasis Model Assessment Insulin Resistance values were calculated. Statistical analysis was performed.

Results

There was a statistically significant difference in fasting blood glucose and HOMA-IR values between the groups. Cross-clamping time, and cardiopulmonary bypass time were longer in Group B, compared to Group A (P=0.043 and P=0.031, respectively). Logistic regression analysis revealed that hemoglobin A1c was not a reliable determinant factor alone for pre-operative glucometabolic evaluation of non-diabetic patients. The risk factors of fasting blood glucose and cardiopulmonary bypass time were more associated with high Homeostasis Model Assessment Insulin Resistance levels.

Conclusion

Our study results suggest that preoperative screening of non-diabetic patients with Homeostasis Model Assessment Insulin Resistance may improve both follow-up visit schedule and short-term outcomes, and may be useful in risk stratification of the high-risk population for impending health problems.     

Insulin and Metformin Regulate Circulating and Adipose Tissue Chemerin

OBJECTIVE

To assess chemerin levels and regulation in sera and adipose tissue from women with polycystic ovary syndrome (PCOS) and matched control subjects.

RESEARCH DESIGN AND METHODS

Real-time RT-PCR and Western blotting were used to assess mRNA and protein expression of chemerin. Serum chemerin was measured by enzyme-linked immunosorbent assay. We investigated the in vivo effects of insulin on serum chemerin levels via a prolonged insulin-glucose infusion. Ex vivo effects of insulin, metformin, and steroid hormones on adipose tissue chemerin protein production and secretion into conditioned media were assessed by Western blotting and enzyme-linked immunosorbent assay, respectively.

RESULTS

Serum chemerin, subcutaneous, and omental adipose tissue chemerin were significantly higher in women with PCOS (n = 14; P < 0.05, P < 0.01). Hyperinsulinemic induction in human subjects significantly increased serum chemerin levels (n = 6; P < 0.05, P < 0.01). In adipose tissue explants, insulin significantly increased (n = 6; P < 0.05, P < 0.01) whereas metformin significantly decreased (n = 6; P < 0.05, P < 0.01) chemerin protein production and secretion into conditioned media, respectively. After 6 months of metformin treatment, there was a significant decrease in serum chemerin (n = 21; P < 0.01). Importantly, changes in homeostasis model assessment–insulin resistance were predictive of changes in serum chemerin (P = 0.046).

CONCLUSIONS

Serum and adipose tissue chemerin levels are increased in women with PCOS and are upregulated by insulin. Metformin treatment decreases serum chemerin in these women.Polycystic ovary syndrome (PCOS), a common endocrinopathy affecting 5–10% of women in the reproductive age, is characterized by menstrual dysfunction and hyperandrogenism and is associated with insulin resistance and pancreatic β-cell dysfunction, impaired glucose tolerance (IGT), type 2 diabetes, dyslipidemia, and visceral obesity (1,2). The consequent hyperinsulinemia is more prevalent in lean and obese women with PCOS when compared with age- and weight-matched normal women (3).The metabolic syndrome is associated with excessive accumulation of central body fat. As well as its role in energy storage, adipose tissue produces several hormones and cytokines termed ‘adipokines’ that have widespread effects on carbohydrate and lipid metabolism. They appear to play an important role in the pathogenesis of insulin resistance, diabetes, and atherosclerosis (4). Furthermore, it is apparent that accumulation of visceral adipose tissue poses a greater cardiometabolic risk than subcutaneous adipose tissue (5) as removal of visceral rather than subcutaneous adipose tissue has been shown to improve insulin sensitivity (6). Moreover, differences in gene expression of adipocyte-secreted molecules (adipokines) suggest that there are inherent adipose tissue depot–specific differences in the endocrine function of adipose tissue. In relation to this, we have published data on the increased levels of vaspin in women with PCOS (7); vaspin is a recently described adipokine mainly formed in human visceral adipose tissue that has insulin-sensitizing effects (8).Recently, Bozaoglu et al. (9) reported chemerin as a novel adipokine, circulating levels of which significantly correlated with BMI, circulating triglycerides, and blood pressure, features of the metabolic syndrome. In addition, chemerin or chemerin receptor knockdown impaired differentiation of 3T3-L1 cells and attenuated the expression of adipocyte genes involved in glucose and lipid homeostasis (10).With the aforementioned in mind and the fact that there is no literature with regards to chemerin in human adipose tissue and its regulation, in study 1, we assessed circulating chemerin as well as mRNA expression and protein levels of chemerin in subcutaneous and omental adipose tissue depots in women with PCOS against age, BMI, and waist-to-hip ratio (WHR) in matched control subjects. Furthermore, we studied the in vivo (study 2) and ex vivo effects of insulin on circulating chemerin levels via a prolonged insulin-glucose infusion in humans and primary adipose tissue explant cultures, respectively. In study 3 we studied the effects of metformin therapy, widely used in the treatment of PCOS in women, on circulating chemerin levels in tandem with associated changes to clinical, hormonal, and metabolic parameters in the same cohort of PCOS in women. Additionally, we studied the ex vivo effects of metformin and steroid hormones in human primary adipose tissue explants.     

Progression to Diabetes in Relatives of Type 1 Diabetic Patients: Mechanisms and Mode of Onset

OBJECTIVE

Relatives of type 1 diabetic patients are at enhanced risk of developing diabetes. We investigated the mode of onset of hyperglycemia and how insulin sensitivity and β-cell function contribute to the progression to the disease.

RESEARCH DESIGN AND METHODS

In 328 islet cell autoantibody–positive, nondiabetic relatives from the observational arms of the Diabetes Prevention Trial-1 Study (median age 11 years [interquartile range 8], sequential OGTTs (2,143 in total) were performed at baseline, every 6 months, and 2.7 years [2.7] later, when 115 subjects became diabetic. β-Cell glucose sensitivity (slope of the insulin-secretion/plasma glucose dose-response function) and insulin sensitivity were obtained by mathematical modeling of the OGTT glucose/C-peptide responses.

RESULTS

In progressors, baseline insulin sensitivity, fasting insulin secretion, and total postglucose insulin output were similar to those of nonprogressors, whereas β-cell glucose sensitivity was impaired (median 48 pmol/min per m² per mmol/l [interquartile range 36] vs. 87 pmol/min per m² per mmol/l [67]; P < 0.0001) and predicted incident diabetes (P < 0.0001) independently of sex, age, BMI, and clinical risk. In progressors, 2-h glucose levels changed little until 0.78 years before diagnosis, when they started to rise rapidly (∼13 mmol · l⁻¹ · year⁻¹); glucose sensitivity began to decline significantly (P < 0.0001) earlier (1.45 years before diagnosis) than the plasma glucose surge. During this anticipation phase, both insulin secretion and insulin sensitivity were essentially stable.

CONCLUSIONS

In high-risk relatives, β-cell glucose sensitivity is impaired and is a strong predictor of diabetes progression. The time trajectories of plasma glucose are frequently biphasic, with a slow linear increase followed by a rapid surge, and are anticipated by a further deterioration of β-cell glucose sensitivity.The onset of type 1 diabetes typically is acute. The immune-mediated destruction of pancreatic β-cells, however, is known to occur over years (1,2). During this prodromic phase, several classes of autoantibodies can be detected in the serum of many, though not all, subjects progressing to diabetes (3–5). Number and titer of such autoantibodies mark the risk of disease, particularly in genetically predisposed individuals (6), but do not tell when hyperglycemia will emerge (7). What precipitates β-cell failure remains unknown. A reduced acute insulin response to an intravenous glucose challenge is thought to reflect reduction of β-cells below a critical mass or function and is used as a metabolic marker of future diabetes (8,9), but the natural history of β-cell incompetence has not clearly been defined. Furthermore, the contribution of insulin resistance to metabolic decompensation is controversial. Thus, in the Seattle Family Study, insulin sensitivity (as the S_I from an intravenous glucose challenge) did not distinguish between progressors and nonprogressors (10); likewise, insulin resistance (as the homeostasis model assessment of insulin resistance index) did not affect progression when insulin secretion was relatively well preserved in the ENDIT study (11). In contrast, in the Melbourne Pre-diabetes Family study, Fourlanos et al. (12) found that insulin resistance (as the homeostasis model assessment of insulin resistance factored by acute insulin response) was a significant predictor of incident type 1 diabetes over a 4-year follow up. In any event, the interactions between insulin release, β-cell dysfunction, and insulin resistance have not been dissected out.The Diabetes Prevention Trial–Type 1 (DPT-1) recruited a large number of autoantibody-positive relatives of probands with type 1 diabetes who were at risk of disease because of multiple autoantibody positivity or reduced acute insulin response to intravenous glucose (13). Oral glucose tolerance was tested at frequent intervals over the course of several years until appearance of diabetes or study end (14). Measurement of the C-peptide response to oral glucose makes it possible to quantify β-cell function and estimate insulin sensitivity (15). The DPT-1 cohort was therefore uniquely suited to investigate mechanisms and mode of onset of type 1 diabetes.     

Role of vascular endothelial growth factor as a tumour marker in osteosarcoma: a prospective study

Purpose

A prospective study was undertaken to evaluate the diagnostic and prognostic significance of serum levels of vascular endothelial growth factor (VEGF) in patients with primary localised osteosarcoma.

Methods

Serum VEGF levels were measured by an enzyme-linked immunosorbent assay (ELISA) in blood samples collected prechemotherapy, postchemotherapy, and postsurgery in 40 patients with histologically proven primary osteosarcoma. Comparison was made between serum VEGF level of healthy controls (n = 10) and prechemotherapy patient sera to evaluate its diagnostic potential. Serum VEGF levels of patients with and without metastasis were compared. Immunohistochemical staining was done to establish the correlation between serum and tissue VEGF expression. The Kaplan–Meier curve was used for survival analysis

Results

No significant relationship was observed between serum VEGF levels and age, gender, tumour size, local recurrence or histopathological subtypes of osteosarcoma. We observed significantly raised mean serum VEGF in patient sera compared with healthy controls (p = 0.001). Significant fall in mean serum VEGF level was observed following chemotherapy (p = 0.001). Patients who developed metastases had significantly higher serum VEGF levels compared with the nonmetastatic group (P = 0.001). Serum VEGF levels correlated well with VEGF expression in tissues.

Conclusion

Serum VEGF levels might prove to be of diagnostic, predictive and prognostic value in patients with primary osteosarcoma, although further studies with larger sample size and longer follow-up is needed to support the hypothesis.     

Intranasal Insulin Enhances Postprandial Thermogenesis and Lowers Postprandial Serum Insulin Levels in Healthy Men

OBJECTIVE

Animal studies indicate a prominent role of brain insulin signaling in the regulation of peripheral energy metabolism. We determined the effect of intranasal insulin, which directly targets the brain, on glucose metabolism and energy expenditure in humans.

RESEARCH DESIGN AND METHODS

In a double-blind, placebo-controlled, balanced within-subject comparison, 19 healthy normal-weight men (18–26 years old) were intranasally administered 160 IU human insulin after an overnight fast. Energy expenditure assessed via indirect calorimetry and blood concentrations of glucose, insulin, C-peptide, and free fatty acids (FFAs) were measured before and after insulin administration and the subsequent consumption of a high-calorie liquid meal of 900 kcal.

RESULTS

Intranasal insulin, compared with placebo, increased postprandial energy expenditure, i.e., diet-induced thermogenesis, and decreased postprandial concentrations of circulating insulin and C-peptide, whereas postprandial plasma glucose concentrations did not differ from placebo values. Intranasal insulin also induced a transient decrease in prandial serum FFA levels.

CONCLUSIONS

Enhancing brain insulin signaling by means of intranasal insulin administration enhances the acute thermoregulatory and glucoregulatory response to food intake, suggesting that central nervous insulin contributes to the control of whole-body energy homeostasis in humans.Animal studies have yielded evidence that the regulation of whole-body energy flux critically depends on intact brain insulin signaling (1,2). Most recent findings have shown that the hypothalamic administration of insulin increases brown adipose tissue thermogenesis by direct inhibitory effects on warm-sensitive neurons (3). Moreover, studies in rodents have demonstrated that in addition to its direct inhibitory effect on hepatic gluconeogenesis, insulin acts in the hypothalamus to decrease glucose production in the liver (4,5), thus establishing an insulin-driven brain-liver axis that controls systemic glucose homeostasis. We examined whether insulin acting in the human brain exerts comparable effects on energy homeostasis by administering intranasal insulin that bypasses the blood-brain barrier and reaches the brain compartment along the olfactory nerve (6,7), modulating central nervous functions in the absence of relevant peripheral effects (8). Notably, intranasal insulin reduces food intake (9) and body fat content (10) in healthy men, indicating that following intranasal administration, the hormone accesses neuronal networks relevant for energy homeostasis. Against this background, in the present study we assessed the effects of intranasal insulin on the glucoregulatory and thermoregulatory response to food intake in humans.     

Magnesium in cardioplegia: Is it necessary?

Objective

To study the effectiveness of magnesium in cardioplegic solution in preventing postoperative arrhythmias and perioperative ischemia.

Design

Randomized, control study.

Setting

The cardiovascular surgery division of a major referral centre for the maritime provinces of Canada.

Patients

Fifty patients scheduled to undergo coronary artery bypass who had a normal ejection fraction, normal preoperative serum magnesium level and no history of atrial or ventricular arrhythmia were randomized into two groups of 25 patients. One group received magnesium sulfate (15 mmol/L) in the cardioplegic solution (group 1), the other (control) group did not receive magnesium sulfate in the cardioplegic solution (group 2).

Intervention

Coronary artery bypass grafting during which myocardial protection was provided by intermittent cold blood cardioplegia.

Outcome Measures

Postoperative serum magnesium levels, cardiac-related death, infarction and arrhythmias.

Results

All group 2 patients had a lower postoperative serum magnesium level than group 1 patients. There were no cardiac-related deaths in either group. More group 2 patients had ischemic electrocardiographic changes than group 1 patients (p < 0.03). Non-Q-wave myocardial infarction occurred in two patients (one in each group). Eight patients in group 2 had atrial fibrillation compared with five patients in group 1. Ventricular ectopia occurred significantly (p < 0.01) more frequently in group 2 than in group 1.

Conclusion

The addition of magnesium to the cardioplegic solution is beneficial in reducing the incidence of perioperative ischemia and ventricular arrhythmia in patients who undergo coronary bypass grafting.     

The development of indications for the preoperative use of recombinant erythropoietin

Objective

To develop indications for the preoperative use of recombinant erythropoietin (rHuEPO) alone and in conjunction with preoperative autologous donation (PAD).

Design

A 2-round modified Delphi-consensus process.

Participants

Nine physicians representing multiple clinical specialties, practice environments and geographic locations.

Method

From evidence tables and a literature summary (MEDLINE database from January 1985 to August 1996) provided and using the RAND-UCLA appropriateness method, the physicians developed 264 indications for the preoperative use of rHuEPO by permuting 7 clinical factors (age, history of transfusion or antibody incompatibility, hemoglobin level, anemia of chronic disease, expected blood loss, presence of cardiovascular or cardiopulmonary disease and patient anxiety). These indications were rated on a 9-point appropriateness scale. Median scores and measures of agreement were determined.

Outcome measures

The significance of cost constraints or cost and blood supply constraints and the impact of each clinical factor on the ratings as judged by statistical analysis.

Results

Of the 264 indications, 54% were rated appropriate, 18% uncertain and 28% inappropriate. Expected blood loss had the greatest impact on the ratings (high expected blood loss had a 5.9 point more appropriate rating on the 9-point scale than low expected blood loss [p < 0.0001]). Preoperative hemoglobin level also significantly influenced the ratings (p < 0.0001). Compared with the clinical context, the ratings under the cost constraint were 1.0 less appropriate (p < 0.0001) for rHuEPO alone and 1.2 less appropriate for rHuEPO and PAD (p < 0.0001). The ratings for patients with moderate expected blood loss were significantly influenced by the cost constraint (less appropriate).

Conclusions

Expected blood loss and preoperative hemoglobin level were the best indicators of rHuEPO appropriateness. Different contexts modify the appropriateness ratings of an expensive drug like rHuEPO.     

Elevated leptin expression in rat model of traumatic spinal cord injury and femoral fracture

Background

Few studies have reported a relationship between leptin induced by spinal cord injury (SCI) and healing bone tissue.

Objective

To observe serum and callus leptin expression within the setting of fracture and traumatic SCI.

Methods

Seventy-two male Sprague Dawley rats were randomized equally into four groups: control, SCI group, fracture group, and fracture/SCI group. Rats were sacrificed at 7, 14, 21, and 28 days post-fracture/SCI. Serum leptin was detected using radioimmunoassay at 1, 7, 14, 21, and 28 days, and callus formation was measured radiologically at 14, 21, and 28 days. Callus leptin was analyzed by means of immunohistochemistry.

Results

Serum leptin in the fracture group, SCI group, and combined fracture/SCI group were all significantly increased compared to control group at the 1, 7, 14, and 2-day time points (P < 0.05). Serum leptin in the combined fracture/SCI group was significantly higher than in the fracture group at 7, 14, and 21 days (P < 0.05), and higher than in SCI groups at 14 and 21days after operation (P < 0.05). The percentage of leptin-positive cells in the fracture/SCI callus, and callus volume was significantly higher than in the fracture-only group (P < 0.001).

Conclusions

Overall, elevated leptin expression was demonstrated within healing bone especially in the 21 days of a rat model combining fracture and SCI. A close association exists between leptin levels and the degree of callus formation in fractures.     

Laparoscopic versus open appendectomy: a prospective randomized trial of 81 patients

Objective

To compare the efficacy of laparoscopic appendectomy (LA) and open appendectomy (OA) in the treatment of acute appendicitis.

Design

A prospective randomized trial.

Setting

A university teaching hospital.

Patients

Eighty-one patients with a diagnosis of acute appendicitis were prospectively randomized to undergo either LA or OA. The two groups were matched for age and sex.

Interventions

LA or OA.

Main Outcome Measures

Number of days in hospital and time to full recovery.

Results

The mean hospital stay for LA was 3.23 days compared with 3.03 days for OA (p < 0.001). The mean number of narcotic injections required for patients in the LA group was 4.05 compared with 5.58 for patients in the OA group (p < 0.001). The mean time to complete recovery for patients in the LA group was 9.0 days compared with 16.2 days for patients in the OA group (p < 0.001). The mean operative time for LA was 73.8 minutes compared with 45.0 minutes for OA (p < 0.001). Three patients in the LA group had intra-abdominal abscesses (p > 0.25). No significant difference in wound infection rates was demonstrated (p > 0.05). Similarly, pain scores at 7 and 28 days showed no significant difference (p > 0.05).

Conclusions

With LA significantly fewer narcotic injections are required and there is a more rapid return to normal activities. LA takes longer to perform and was associated with three intra-abdominal abscesses. In cases of simple acute appendicitis the hospital stay for LA is significantly shorter.     

Homogeneous Insulin and C-Peptide Sensors for Rapid Assessment of Insulin and C-Peptide Secretion by the Islets

OBJECTIVE

Glucose-stimulated islet insulin or C-peptide secretion experiments are a fundamental tool for studying and assessing islet function. The goal of this work was to develop Ab-based fluorescent homogenous sensors that would allow rapid, inexpensive, near-instantaneous determinations of insulin and C-peptide levels in biological samples.

RESEARCH DESIGN AND METHODS

Our approach was to use molecular pincer design (Heyduk et al., Anal Chem 2008;80:5152–5159) in which a pair of antibodies recognizing nonoverlapping epitopes of the target are modified with short fluorochrome-labeled complementary oligonucleotides and are used to generate a fluorescence energy transfer (FRET) signal in the presence of insulin or C-peptide.

RESULTS

The sensors were capable of detecting insulin and C-peptide with high specificity and with picomolar concentration detection limits in times as short as 20 min. Insulin and C-peptide levels determined with the FRET sensors showed outstanding correlation with determinations performed under the same conditions with enzyme-linked immunosorbent assay. Most importantly, the sensors were capable of rapid and accurate determinations of insulin and C-peptide secreted from human or rodent islets, verifying their applicability for rapid assessment of islet function.

CONCLUSIONS

The homogeneous, rapid, and uncomplicated nature of insulin and C-peptide FRET sensors allows rapid assessment of β-cell function and could enable point-of-care determinations of insulin and C-peptide.Diabetes comprises a heterogeneous group of hyperglycemic disorders. There are two major forms of diabetes: 1) type 1 diabetes, which is associated with an autoimmune-mediated attack and destruction of pancreatic β-cells resulting in insulin deficiency, and 2) type 2 diabetes, which is characterized by insufficient insulin production or impaired insulin action. For type 1 diabetic subjects, insulin injections are used to regulate plasma glucose levels, while type 2 diabetic subjects are usually treated by diet, oral agents, and insulin therapy. If uncontrolled, elevated plasma levels of glucose increase the risk for the development of diabetic complications such as cardiovascular disease, kidney disease, neurological disorders, and blindness. Intensive insulin therapy reduces the risk of such complications, although there is an increased risk of hypoglycemic episodes with this therapy, which, if severe, can result in coma or seizures. Insulin is synthesized as a precursor protein, proinsulin, that is processed by specific proteases found in insulin granules to the active hormone (containing an A and B chain connected by two disulfide linkages). During the processing of insulin, the connecting sequence (C-peptide) is also produced, and C-peptide is released into the bloodstream with insulin at times of insulin demand.Glucose-stimulated insulin or C-peptide secretion by the islets is a fundamental tool for studying and assessing islet function. Current methodologies to determine β-cell function rely on the use of radioimmunoassay or enzyme-linked immunosorbent assay (ELISA)-based assays to detect either insulin or C-peptide produced by β-cells. These methods are time-consuming and, in many cases, require the use of radioactivity. Development of a specific methodology for detecting insulin and/or C-peptide that reduces the time required to determine β-cell function would provide a tremendous advantage over methods currently being used. Such a methodology could also have clinical applications, for example, as a rapid method to characterize β-cell function in the transplantation of human islets, a potential therapy for type 1 diabetic patients. Transplantation of human islets, isolated from cadaver donors, has been used for a number of years in an effort to gain insulin independence in type 1 diabetic subjects; however, this procedure has been only marginally successful (1,2). Recently, the Edmonton group has described a new protocol for the transplantation of human islets that was successful in attaining short-term insulin independence in seven of seven patients (3), and similar results have been reproduced by others (4–6). One key feature of the Edmonton protocol is the immediate transplantation of islets after isolation. Previous protocols cultured islets for extended periods of time in part to determine islet viability and function prior to transplantation (7). A methodology that would allow rapid assessment of glucose-stimulated insulin secretion potentially could be used to enhance characterization of islets before transplantation.In a previous study, we described a new Ab-based sensor technology that allowed simple fluorescence-based homogenous detection of target proteins (7). The goal of this work was to determine whether this sensor design could be adapted for rapid detection of insulin and C-peptide and used for very rapid determination of islet functional activity (insulin secretion). We show that our sensors allow near-instantaneous determination of the insulin or C-peptide produced by isolated human or rodent islets, validating their applicability for rapid assessment of islet quality. We believe that the uncomplicated and rapid characteristics of our assay will allow for the deployment of methods for insulin and C-peptide determinations in a point-of-care setting.     

Chronic Peripheral Hyperinsulinemia in Type 1 Diabetic Patients After Successful Combined Pancreas-Kidney Transplantation Does Not Affect Ectopic Lipid Accumulation in Skeletal Muscle and Liver

OBJECTIVE

So far it is unclear whether chronic peripheral hyperinsulinemia per se might contribute to ectopic lipid accumulation and consequently insulin resistance. We investigated the effects of systemic instead of portal insulin release in type 1 diabetic patients after successful pancreas-kidney transplantation (PKT) with systemic venous drainage on the intracellular lipid content in liver and soleus muscle, endogenous glucose production (EGP), and insulin sensitivity.

RESEARCH DESIGN AND METHODS

In nine PKT patients and nine matching nondiabetic control subjects, intrahepatocellular lipids (IHCLs) and intramyocellular lipids (IMCLs) were measured using ¹H nuclear magnetic resonance spectroscopy. Fasting EGP was measured using d-[6,6-²H²]glucose tracer dilution. A 3-h 75-g oral glucose tolerance test (OGTT) allowed us to assess kinetics of glucose, free fatty acids, insulin, and C-peptide concentrations in plasma and to calculate the clamp-like index (CLIX) for insulin sensitivity and the hepatic insulin resistance (HIR) index.

RESULTS

The PKT patients displayed approximately twofold increased fasting insulin (20 ± 6 vs. 9 ± 3 μU/ml; P < 0.0002) compared with that in nondiabetic control subjects and ∼10% increased fasting glucose (P < 0.02) concentrations, but during the OGTT areas under the concentration curves of C-peptide and insulin were similar. IHCL (PKT, 2.9 ± 2.5%; nondiabetic control subjects, 4.4 ± 6.6%), IMCL (PKT, 1.0 ± 0.4%; nondiabetic control subjects, 1.0 ± 0.5%), CLIX (PKT, 8 ± 2; nondiabetic control subjects, 7 ± 3), HIR (PKT, 25.6 ± 13.2; nondiabetic control subjects, 35.6 ± 20 [mg · min⁻¹ · kg⁻¹] × [μU/ml]), and EGP (PKT, 1.6 ± 0.2; nondiabetic control subjects, 1.7 ± 0.2 mg · min⁻¹ · kg⁻¹) were comparable between PKT patients and nondiabetic control subjects. IHCL was negatively correlated with CLIX in all participants (r = −0.55; P < 0.04).

CONCLUSIONS

Despite fasting peripheral hyperinsulinemia because of systemic venous drainage, type 1 diabetic patients after PKT show similar IHCL, IMCL, insulin sensitivity, and fasting EGP in comparison with nondiabetic control subjects. These results suggest that systemic hyperinsulinemia per se does not cause ectopic lipid accumulation in liver and skeletal muscle.Insulin resistance has been linked to lipid accumulation in insulin-responsive tissues such as liver and skeletal muscle (1–3), but it is not yet clear if ectopic fat accumulation induces insulin resistance and consequently hyperinsulinemia or whether increased intracellular lipid content is rather the result of long-term hyperinsulinemia.Poorly controlled type 1 diabetic patients (4) as well as insulin-resistant type 2 diabetic subjects and the offspring of type 2 diabetic subjects displayed increased intracellular lipid content in skeletal muscle when compared with healthy individuals (1), whereas well-controlled type 1 diabetic patients exhibited an unchanged intramyocellular lipid content (5).Pancreatic transplantation in diabetic subjects with end-stage renal disease restores insulin secretion and glucose tolerance (6). Combined pancreas-kidney transplantation (PKT) with systemic venous drainage provides a human model that allows to study the long-term effects of systemic instead of portal insulin delivery on glucose metabolism and intracellular lipid content. It is worth noting that insulin replacement in diabetic patients is commonly administered subcutaneously into the systemic circulation and not through the portal vein (4,7). It is unclear whether this peripheral route of insulin delivery has clinically relevant consequences.We studied whether the systemic route of insulin appearance could affect intracellular lipid content in liver and skeletal muscle, as well as endogenous glucose production (EGP) in type 1 diabetes after successful pancreas transplantation.     

Expression of Vascular endothelial growth factor in Ewing's sarcoma

Purpose

Vascular endothelial growth factor (VEGF) is the most potent stimulator of angiogenesis. The aim of this study was to evaluate the role of serum VEGF as a diagnostic, predictive and prognostic marker in Ewing’s sarcoma.

Methods

Patients with histopathologically proven diagnosis of Ewing’s sarcoma without prior chemotherapy or radiotherapy were invited to take part in the study. Pre-chemotherapy, post-chemotherapy and post-surgery blood samples were collected for analysis of serum VEGF levels. Blood samples from ten sex- and age-matched healthy volunteers were collected for estimation of VEGF levels to act as control. Human VEGF Elisa kit (Bender Medsystem, Austria) was used to assess the serum VEGF levels.

Results

A total of nine cases of Ewing’s sarcoma were included in the study. Mean age in the group was 12.44 years (range, seven to 18 years). Mean and median serums VEGF level in the study population were 4,547.78 pg/ml and 3,780.00 pg/ml, respectively. Ten age- and sex-matched healthy volunteers were selected as controls. No significant correlation was obtained between serum VEGF, age, sex and tumour size. Mean serum VEGF was significantly raised in the study group as compared to controls (p = 0.001). We observed a significant decline in serum VEGF level following neoadjuvant chemotherapy (p = 0.008). No correlation could be established between serum VEGF level pulmonary metastasis and overall survival.

Conclusion

Serum VEGF might have a role as a diagnostic and predictive marker in patients with Ewing’s sarcoma.     

One hand is better than two: conversion from pure laparoscopic to the hand-assisted approach during difficult nephrectomy

INTRODUCTION

The incidence of conversion from a laparoscopic to an open approach during nephrectomy is reported at 6-8%.¹ Conversion to an open procedure may be necessary to control haemorrhage or allow progress in dissection but the well established benefits of minimally invasive surgery (MIS) are obviously lost. Hand-assisted laparoscopy (HAL) also offers the benefits to the patient of MIS. We have used HAL to convert from the pure laparoscopic approach during difficult nephrectomies, rather than converting to traditional open surgery.

MATERIALS AND METHODS

A review of our prospective database was carried out to identify any conversions from the pure laparoscopic approach during nephrectomy or nephroureterectomy for benign or malignant disease.

RESULTS

A total of 87 laparoscopic nephrectomies (LNs) were identified over a 3-year period. There were five conversions to the HAL approach (5.7%) and no conversions to open surgery. The reason for conversion was failure to progress in all five cases. Operative times averaged 190 minutes with blood loss of 180ml. Histology revealed xanthogranulomatous pyelonephritis in four cases and renal cell carcinoma in one case. The median postoperative stay was 4 days.

CONCLUSIONS

Conversion to HAL during LN maintains the benefits of MIS in difficult nephrectomy and should be considered prior to converting to open surgery.     

Functional Variants in MBL2 Are Associated With Type 2 Diabetes and Pre-Diabetes Traits in Pima Indians and the Old Order Amish

OBJECTIVE

MBL2 encodes the mannose-binding lectin, which is a key player in the innate immune system and has recently been found to play a role in insulin resistance and development of type 1 diabetes and gestational diabetes mellitus. To assess the role of MBL2 in diabetes susceptibility, this gene was analyzed in the Pima Indian population, which has a high prevalence of type 2 diabetes.

RESEARCH DESIGN AND METHODS

Nineteen tag single nucleotide polymorphisms (SNPs) were genotyped in a population-based sample of 3,501 full-heritage Pima Indians, and selected SNPs were further genotyped in independent samples of Native American (n = 3,723) and Old Order Amish (n = 486) subjects.

RESULTS

Two variants, a promoter SNP (rs11003125) at −550 bp with a risk allele frequency of 0.77 and a Gly54Asp (rs1800450) with a risk allele frequency of 0.83, were associated with type 2 diabetes in the full-heritage Pima Indians (odds ratio 1.30 per copy of the G allele for rs1103125, P = 0.0007, and 1.30 per copy of the glycine allele for rs1800450, P = 0.002, adjusted for age, sex, birth year, and family membership). These associations replicated in an independent Native American sample (1.19, P = 0.04, for rs11003125) and a Caucasian sample, the Old Order Amish (1.51, P = 0.004, for rs1103125 and 2.38, P = 0.003, for rs1800450). Among Pima Indians with normal glucose tolerance, the diabetes risk allele glycine of Gly54Asp was associated with a decreased acute insulin response to an intravenous glucose bolus infusion (P = 0.004, adjusted for age, sex, percent body fat, glucose disposal under physiological insulin stimulation, and family membership).

CONCLUSIONS

Our data suggest that the functional variants in MBL2 contribute to type 2 diabetes susceptibility in both Native Americans and the Old Order Amish.Mannose-binding lectin (MBL) is a liver-derived serum lectin involved in the innate immune defense. Upon binding to specific carbohydrate structures on various microorganisms, MBL may utilize MBL serine protease (MASP)-2 to activate the third pathway of complement (lectin pathway) and thereby opsonophagocytosis (1).Serum MBL levels have been shown to be strongly correlated with the presence of variants within the MBL2 gene. Missense polymorphisms at codon 54 (resulting in a glycine to aspartic acid), codon 57 (resulting in a glycine to glutamic acid), and codon 52 (resulting in an arginine to cysteine) impair oligomer formation, leading to reduced serum levels of functional MBL. In addition, three promoter polymorphisms at position −550 bp G > C (H/l), −221 bp G > C (Y/X) and +4 bp C > T (P/Q) influence the expression of MBL2 (1–3).Deficiency of MBL has been associated with immunodeficiency, autoimmune disorders such as systemic lupus erythematosus, and rheumatoid arthritis (4,5). Recent studies have further implicated MBL deficiency in the development of type 1 diabetes (6), gestational diabetes mellitus (7), diabetic nephropathy (8), and insulin resistance and obesity (9). Based on the biological role of MBL2, this gene was investigated as a potential susceptibility gene for type 2 diabetes in Pima Indians.     

Insulin resistance in children with primary nephrotic syndrome and normal renal function

Background

Insulin resistance (IR) is an independent risk factor for atherosclerosis or cardiovascular events and renal function impairment. The aim of this study was to investigate IR in children with primary nephrotic syndrome (NS).

Methods

One-hundred and nineteen primary NS patients with normal renal function and 125 normal controls were studied. Fasting blood glucose, fasting serum insulin, and fasting serum C-peptide were measured. The Homa index of insulin resistance (HOMA-IR), Islet B cell function, and insulin sensitivity index were calculated. Correlations were assessed between HOMA-IR, fasting serum C-peptide, blood pressure, blood lipids, renal function, coagulation, clinical disease type, pathology and the early therapeutic effectiveness of high-dose glucocorticoids.

Results

There was no evidence of IR in the primary NS group. Although levels of fasting blood glucose, fasting serum insulin and fasting serum C-peptide were all within the normal ranges, fasting serum C-peptide was significantly higher compared to the controls. There was no disorder of carbohydrate metabolism in different hormone therapy efficacy and pathological diagnosis. Although IR was not detected, a significant increase in blood pressure, uric acid, blood lipids and coagulability was observed in the primary NS group.

Conclusion

A correlation observed between HOMA-IR, age, blood pressure, serum creatinine (Cr) and triglyceride may suggest that insulin sensitivity will emerge as renal disease progresses. Fasting serum C-peptide levels were increased in the primary NS group, suggesting that fasting serum C-peptide may be a protective factor.     

The influence of age on the severity of peritonitis

Objective

To evaluate the influence of age on the evolution and severity of peritonitis.

Design

A chart review.

Setting

An adult university hospital.

Patients

One hundred and twenty-two patients with acute appendicitis and 100 patients with acute colonic diverticulitis requiring operation or percutaneous drainage.

Main Outcome Measures

Patient age and sex, presence of perforation or gangrene (appendicitis), extent of peritonitis (diverticulitis); duration of symptoms prior to admission; admission leukocyte count; duration of hospitalization before surgery; length of hospital stay; and death rate.

Results

Patients with acute appendicitis who were aged 65 years or older were three times more likely than younger patients to have a gangrenous or perforated appendix (odds ratio 3.1, 95% confidence interval 1.1 to 8.4, p < 0.05); older patients with perforated diverticulitis were three times more likely than younger patients to have generalized peritonitis than localized (pericolic or pelvic) peritonitis (odds ratio 2.9, 95% confidence interval 1.2 to 7.5, p < 0.05).

Conclusion

These findings are consistent with the hypothesis that the biologic features of peritonitis differ in the elderly, who are more likely to present with an advanced or severe process than young patients.     

Effects of periodontal therapy on C-reactive protein and HDL in serum of subjects with periodontitis

Objective

To investigate the effects of nonsurgical periodontal therapy on levels of high-sensitivity C-reactive protein in the sera and its association with body mass index and high density lipoprotein in subjects with severe periodontitis.

Methods

Sera from 28 subjects (mean age: 34.36±6.24; 32% men) with severe periodontitis and 27 healthy controls (mean age: 33.18±6.42; 33% men) were collected prior to periodontal therapy. Blood samples were obtained from 23 subjects who completed therapy (9-12 months). Oral and systemic parameters such as the number of blood cells, glucose examination, lipid profile, and high-sensitivity C-reactive protein levels accessed by high-sensitivity immunonephelometry assay, were included.

Results

Before therapy, in the periodontitis group, the ratio of subjects with high-sensitivity C-reactive protein <0.3 mg/dL was statistically lower than in the control group (P<0.0216). After therapy, the ratio of subjects with high-sensitivity C-reactive protein <0.3 mg/dL was significantly higher (65.22%) (P<0.0339). The mean value for body mass index was statistically lower in subjects with high-sensitivity C-reactive protein <0.3 mg/dL (24.63±4.19), compared with those with high-sensitivity C-reactive protein >0.3 mg/dL (28.91±6.03) (P<0.0411). High density lipoprotein presented a mean value statistically higher after therapy (P<0.0027).

Conclusion

In systemically healthy subjects with periodontitis, periodontal therapy was associated with decreased levels of circulating high-sensitivity C-reactive protein and increase of high density lipoprotein in serum. The clinical trial was registered at http://www.clinicaltrials.gov.br/, No. RBR-24T799.