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.

Pancreatic cystic islet-cell tumors. Clinical and pathologic features in two cases with cyst fluid analysis

Cystic islet-cell tumors are rare neoplasms that may be confused with more familiar cystic pancreatic lesions, such as pseudocysts, serous cystadenoma, and mucinous tumors. Analysis of aspirated cyst fluid for tumor markers (carcinoembryonic antigen [CEA], CA-125, and CA-15.3), enzymes (amylase and lipase), viscosity, and cytology has been proposed as an aid to preoperative differential diagnosis. These tests will distinguish mucinous from nonmucinous cysts and usually help in determining malignancy. However, cyst fluid parameters from rarer types of pancreatic cystic tumors have not been described. We report the clinical and pathologic features of two cystic islet-cell tumors including cyst fluid parameters in one of the cases. Two cases of cystic islet-cell tumors were identified by clinical history, histopathologic, and immunohistochemical techniques. Cyst fluid was aspirated intraoperatively from one case and analyzed for CEA, CA-125, CA 15.3, insulin, amylase, viscosity, and cytology. Cyst fluid analysis showed low values for CEA, CA-125, and CA-15.3, low viscosity, and variable amylase content. This spectrum of findings is similar to that of serous cystadenomas. Cyst fluid cytologic examination was positive for neuroendocrine-type epithelial cells and insulin levels were elevated, observations indicative of an islet-cell tumor. Analysis of fluid from cystic islet-cell tumors may aid in the preoperative differentiation of these tumors from more common pancreatic cystic lesions. These findings represent the first report of the characteristics of the fluid in these uncommon tumors.