Low-Dose Anti-Thymocyte Globulin (ATG) Preserves β-Cell Function and Improves HbA1c in New-Onset Type 1 Diabetes

OBJECTIVE

A pilot study suggested that combination therapy with low-dose anti-thymocyte globulin (ATG) and pegylated granulocyte colony-stimulating factor (GCSF) preserves C-peptide in established type 1 diabetes (T1D) (duration 4 months to 2 years). We hypothesized that 1) low-dose ATG/GCSF or 2) low-dose ATG alone would slow the decline of β-cell function in patients with new-onset T1D (duration <100 days).

RESEARCH DESIGN AND METHODS

A three-arm, randomized, double-masked, placebo-controlled trial was performed by the Type 1 Diabetes TrialNet Study Group in 89 subjects: 29 subjects randomized to ATG (2.5 mg/kg intravenously) followed by pegylated GCSF (6 mg subcutaneously every 2 weeks for 6 doses), 29 to ATG alone (2.5 mg/kg), and 31 to placebo. The primary end point was mean area under the curve (AUC) C-peptide during a 2-h mixed-meal tolerance test 1 year after initiation of therapy. Significance was defined as one-sided P value < 0.025.

RESULTS

The 1-year mean AUC C-peptide was significantly higher in subjects treated with ATG (0.646 nmol/L) versus placebo (0.406 nmol/L) (P = 0.0003) but not in those treated with ATG/GCSF (0.528 nmol/L) versus placebo (P = 0.031). HbA_1c was significantly reduced at 1 year in subjects treated with ATG and ATG/GCSF, P = 0.002 and 0.011, respectively.

CONCLUSIONS

Low-dose ATG slowed decline of C-peptide and reduced HbA_1c in new-onset T1D. Addition of GCSF did not enhance C-peptide preservation afforded by low-dose ATG. Future studies should be considered to determine whether low-dose ATG alone or in combination with other agents may prevent or delay the onset of the disease.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Insulin secretion measured by stimulated C-peptide in long-established Type 1 diabetes in the Diabetes Control and Complications Trial (DCCT)/ Epidemiology of Diabetes Interventions and Complications (EDIC) cohort: a pilot study

AIMS

To evaluate whether clinically relevant concentrations of stimulated C-peptide in response to a mixed-meal tolerance test can be detected after almost 30 years of diabetes in people included in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications cohort.

METHODS

Mixed-meal tolerance tests were performed in a sample of 58 people. C-peptide levels were measured using a chemiluminescent immunoassay. This sample size assured a high probability of detecting C-peptide response if the true prevalence was at least 5%, a level that would justify the subsequent assessment of C-peptide in the entire cohort.

RESULTS

Of the 58 participants, 17% showed a definite response, defined as one or more post-stimulus concentrations of C-peptide > 0.03 nmol/l, and measurable concentrations were found in all participants.

CONCLUSIONS

These results show that a stimulated C-peptide response can be measured in some people with long-term Type 1 diabetes. Further investigation of all participants in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study will help relate long-term residual C-peptide response to glycaemia over time and provide insight into the relevance of this response in terms of insulin dose, severe hypoglycaemia, retinopathy, nephropathy and macrovascular disease. Establishing the clinical relevance of long-term C-peptide responses is important in understanding the impact that therapy to preserve or improve β-cell function may have in patients with long-term Type 1 diabetes.

A Diabetes Outcome Progression Trial (ADOPT): baseline characteristics of Type 2 diabetic patients in North America and Europe

AIMS

To examine baseline characteristics of patients recruited into ADOPT, a multinational trial comparing three oral glucose-lowering monotherapies.

METHODS

Between April 2000 and June 2002, 4360 patients aged 30-75 years with Type 2 diabetes diagnosed for < 3 years and remaining on diet therapy alone with fasting plasma glucose levels (FPG) between 7.0 and 10.0 mmol/l were enrolled by 488 North American and European centres. Medical histories, anthropometric data and laboratory measurements were determined using common methodologies.

RESULTS

The mean (SD) age of the patients was 57 (10) years, body mass index 32.2 (6.4) kg/m(2), HbA(1c) 7.4 (0.9)%; 58% were male, 88% Caucasian and 15% smoked. North American Caucasians (NAC) were younger, more obese, and more insulin resistant than European Caucasians (EUC), but had better pancreatic B-cell function. NAC had lower total, low-density lipoprotein- and high-density liporpotein-cholesterol concentrations with higher triglyceride concentrations and were more often on lipid-lowering treatment. They had lower blood pressure levels but were equally likely to be on antihypertensive treatment. Metabolic syndrome was more frequent and microalbuminuria less frequent in NAC. Within North America, NAC had lower HbA(1c) concentrations than Blacks, Hispanics and Asians despite similar or higher FPG and 30-min postchallenge glucose concentrations.

CONCLUSIONS

Caucasian North American and European ADOPT patients differ with respect to adiposity, insulin resistance and metabolic syndrome prevalence. North American Blacks, Hispanics and Asians had lower HbA(1c) concentrations than NAC despite similar or higher glucose concentrations. These phenotypic differences may influence the progression of Type 2 diabetes and the response to initial oral glucose-lowering monotherapy.

Skin collagen glycation, glycoxidation, and crosslinking are lower in subjects with long-term intensive versus conventional therapy of type 1 diabetes: relevance of glycated collagen products versus HbA1c as markers of diabetic complications. DCCT Skin Collagen Ancillary Study Group. Diabetes Control and Complications Trial

The relationships between long-term intensive control of glycemia and indicators of skin collagen glycation (furosine), glycoxidation (pentosidine and N(epsilon)-[carboxymethyl]-lysine [CML]), and crosslinking (acid and pepsin solubility) were examined in 216 patients with type 1 diabetes from the primary prevention and secondary intervention cohorts of the Diabetes Control and Complications Trial. By comparison with conventional treatment, 5 years of intensive treatment was associated with 30-32% lower furosine, 9% lower pentosidine, 9-13% lower CML, 24% higher acid-soluble collagen, and 50% higher pepsin-soluble collagen. All of these differences were statistically significant in the subjects of the primary prevention cohort (P < 0.006-0.001) and also of the secondary intervention cohort (P < 0.015-0.001) with the exception of CML and acid-soluble collagen. Age- and duration-adjusted collagen variables were significantly associated with the HbA1c value nearest the biopsy and with cumulative prior HbA1c values. Multiple logistic regression analyses with six nonredundant collagen parameters as independent variables and various expressions of retinopathy, nephropathy, and neuropathy outcomes as dependent variables showed that the complications were significantly associated with the full set of collagen variables. Surprisingly, the percentage of total variance (R2) in complications explained by the collagen variables ranged from 19 to 36% with the intensive treatment and from 14 to 51% with conventional treatment. These associations generally remained significant even after adjustment for HbA1c, and, most unexpectedly, in conventionally treated subjects, glycated collagen was the parameter most consistently associated with diabetic complications. Continued monitoring of these subjects may determine whether glycation products in the skin, and especially the early Amadori product (furosine), have the potential to be predictors of the future risk of developing complications, and perhaps be even better predictors than glycated hemoglobin (HbA1c).

The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus

BACKGROUND

Long-term microvascular and neurologic complications cause major morbidity and mortality in patients with insulin-dependent diabetes mellitus (IDDM). We examined whether intensive treatment with the goal of maintaining blood glucose concentrations close to the normal range could decrease the frequency and severity of these complications.

METHODS

A total of 1441 patients with IDDM--726 with no retinopathy at base line (the primary-prevention cohort) and 715 with mild retinopathy (the secondary-intervention cohort) were randomly assigned to intensive therapy administered either with an external insulin pump or by three or more daily insulin injections and guided by frequent blood glucose monitoring or to conventional therapy with one or two daily insulin injections. The patients were followed for a mean of 6.5 years, and the appearance and progression of retinopathy and other complications were assessed regularly.

RESULTS

In the primary-prevention cohort, intensive therapy reduced the adjusted mean risk for the development of retinopathy by 76 percent (95 percent confidence interval, 62 to 85 percent), as compared with conventional therapy. In the secondary-intervention cohort, intensive therapy slowed the progression of retinopathy by 54 percent (95 percent confidence interval, 39 to 66 percent) and reduced the development of proliferative or severe nonproliferative retinopathy by 47 percent (95 percent confidence interval, 14 to 67 percent). In the two cohorts combined, intensive therapy reduced the occurrence of microalbuminuria (urinary albumin excretion of > or = 40 mg per 24 hours) by 39 percent (95 percent confidence interval, 21 to 52 percent), that of albuminuria (urinary albumin excretion of > or = 300 mg per 24 hours) by 54 percent (95 percent confidence interval 19 to 74 percent), and that of clinical neuropathy by 60 percent (95 percent confidence interval, 38 to 74 percent). The chief adverse event associated with intensive therapy was a two-to-threefold increase in severe hypoglycemia.

CONCLUSIONS

Intensive therapy effectively delays the onset and slows the progression of diabetic retinopathy, nephropathy, and neuropathy in patients with IDDM.

Progression and remission of renal disease in the Lupus Nephritis Collaborative Study. Results of treatment with prednisone and short-term oral cyclophosphamide

OBJECTIVE

To describe the clinical course of severe lupus nephritis and to identify the risk factors for progression to renal failure among patients treated with prednisone and short-term courses of low-dose oral cyclophosphamide.

DESIGN

Ancillary analyses of data from the Lupus Nephritis Collaborative Study (LNCS).

SETTING

University hospital medical centers (14).

PATIENTS

The 86 patients who participated in the LNCS (mean follow-up, 136 weeks [2.6 years]) and a subgroup of 63 patients with follow-up of more than 48 weeks (mean follow-up, 160 weeks [3.1 years]).

MEASUREMENTS

Initial clinical and pathologic features, response to therapy within 48 weeks, and subsequent clinical events, including development of renal failure.

MAIN RESULTS

Renal failure developed in 18 patients (21%). An observed elevation in serum creatinine concentration was the only initial feature predictive of subsequent renal failure. Mean (+/- SD) initial serum creatinine levels were higher in patients who subsequently developed renal failure (244 +/- 134 mumol/L [2.76 +/- 1.52 mg/dL] compared with 163 +/- 103 mumol/L [1.85 +/- 1.17 mg/dL]; P = 0.007). The risk for renal failure was higher among patients with initial serum creatinine levels greater than 106 mumol/L (1.2 mg/dL) (29% compared with 6.5%; P = 0.014). Response to therapy (defined as resolution of initial serum creatinine elevations within 48 weeks) refined the prognosis based on initial serum creatinine determinations. The risk for subsequent renal failure was higher among patients who failed to respond to therapy within 48 weeks (30% compared with 0%; P = 0.015). By comparison, 9% of patients with normal initial serum creatinine levels progressed to renal failure after 48 weeks.

CONCLUSIONS

Initial serum creatinine levels and responses to initial therapy with prednisone and short-term cyclophosphamide, as used in the LNCS, can guide further therapy. Patients with normal initial serum creatinine levels or resolution of initial serum creatinine elevations within 48 weeks have a low risk for renal failure and may not require long-term treatment with cyclophosphamide.

The effects of chenodiol on biliary lipids and their association with gallstone dissolution in the National Cooperative Gallstone Study (NCGS)

The National Cooperative Gallstone Study was a double-masked trial conducted to determine the efficacy and safety of chenodeoxycholic acid (chenodiol) for dissolution of cholesterol gallstones. Patients with radiolucent gallstones were randomly allocated to either a high dose (750 mg/d, n = 305) or low dose (375 mg/d, n = 306) of chenodiol or placebo (n = 305) administered for 2 yr. Specimens of gallbladder bile were obtained for biliary lipid analysis on 50% of all white obtained for biliary lipid analysis on 50% of all white patients at base line and after 3-mo therapy, on 45% at 12 mo, and on 36% at 24 mo. Among these specimens, 20% were inadequate for analysis. For analysis of data, available values during therapy were averaged up to time of dissolution, study exit, or study termination. In the high-dose group, percent chenodiol (molar percent of all bile acids) increased markedly and remained high during the 2 yr of follow-up. Also, molar percent cholesterol decreased significantly and remained low during the 2 yr of follow-up. In the low-dose group, percent chenodiol increased and remained significantly increased. Percent cholesterol saturation decreased at 3 mo, but at 24 mo it was not different from that in the placebo group, suggesting a physiological adaptation to the low dose by 2 yr. 79% of patients on high dose had greater than 70% chenodiol. Among these, half showed unsaturated bile (less than 100% cholesterol saturation) while the remainder were supersaturated; in the former group with unsaturated bile, 23% had complete dissolution and 51% had partial (greater than 50% reduction in stone size) or complete dissolution. In contrast, those with over 70% chenodiol and supersaturated bile had only 5% complete dissolution. Thus, development of unsaturated bile was a major factor associated with gallstone dissolution. The data also indicate that values for percent cholesterol saturation were a better predictor of gallstone dissolution than molar percent chenodiol, although a high percent chenodiol usually was required to obtain unsaturation.

Central laboratory quality control in the National Cooperative Gallstone Study

This article presents the rationale, selection, operation, and quality control of the Central Serum and Central Bile Laboratories utilized by the National Cooperative Gallstone Study. The external quality control protocols were designed to monitor long-term stability of the analytical procedures and to measure the precision of the measurements as affected by the collection, labelling, storage, shipping, and laboratory methods. For both laboratories, the assessment of long-term stability by pool standards failed to produce the data necessary to come to relevant conclusions. Several of the problems involved, however, did lead to protocol changes that increased the reliability of the laboratory data. The use of duplicate measurements to monitor precision was more successful and demonstrated acceptable performance of these systems. This article describes the external quality control surveillance procedures employed in the NCGS, their strengths and weaknesses, statistical methods for the analysis of such quality control programs, and the implications for the final statistical analyses of the clinical trial patient data.

Validation of a computer-assisted method for estimating the number and volume of gallstones visualized by cholecystography

It is likely that in the near future there will be widespread use of medicinal therapy to dissolve gallstones. The efficacy of medicinal therapy can best be determined by attempting to relate the total surface area of a collection of gallstones to the composition of bile in patients undergoing therapy. Surface area, in turn, can be directly related to gallstone size and number. In this study, involving 48 cholecystectomized patients, we have shown that standard cholecystography, together with a computer-assisted method of metrology, can effectively monitor the above parameters. Determinations of the standard deviation of 1) replicate readings (35.8%) and 2) averaged metrology estimates compared with actual stone volumes (42.9%), as well as correlation of actual stone volumes with averaged metrology estimates (r = 0.961), indicated the magnitude of assessed change in stone volume that would be necessary to accept a roentgenographic decrease or increase in stone size with 95% confidence. Even with the increased precision found in the computer-assisted method as described, to attain a 98% certainty of some volume change it was necessary to have metrology volume change of 50% or more. Actual stone counts were without significant error in 87.5% of the determinations.