Differential impact of subclinical carotid artery disease on cerebral structure and functioning in type 1 diabetes patients with versus those without proliferative retinopathy.

BACKGROUND: Type 1 diabetes mellitus (T1DM) is associated with cerebral compromise, typically found in patients with microangiopathy. Associations between subclinical macroangiopathy and the brain, whether or not in the presence of microangiopathy, have not been fully explored in T1DM. We hypothesized that subclinical macroangiopathy in adult T1DM may affect the brain and interacts with microangiopathy. METHODS: In 51 asymptomatic T1DM patients with, 53 without proliferative retinopathy and 51 controls, right common carotid artery ultrasound was used to assess intima media thickness (cIMT) and distensibility (cD). Neuropsychological tests for cognitive functions, and magnetic resonance imagining for white matter integrity and functional connectivity, i.e. neuronal communication, were used. RESULTS: After correction for confounders, cIMT was borderline significantly increased in all T1DM patients (P = 0.071), whereas cD was not statistically significantly altered (P = 0.45). Patients with proliferative retinopathy showed the largest increase in cIMT and decrease in cD. In all participants, after adjustment for confounders, increased cIMT was related to decreased white matter integrity (ß = -0.198 P = 0.041) and decreased functional connectivity in visual areas (ß = -0.195 P = 0.046). For cognition, there was a significant interaction between cIMT and the presence of proliferative retinopathy after adjustment for confounding factors (all P < 0.05). Increased cIMT was associated with lower general cognitive ability (ß = -0.334; P = 0.018), information processing speed (ß = -0.361; P = 0.010) and attention (ß = -0.394; P = 0.005) scores in patients without, but not in patients with proliferative retinopathy. CONCLUSIONS: These findings suggest that subclinical macroangiopathy may be a factor in the development of diabetes-related cognitive changes in uncomplicated T1DM, whereas in patients with advanced T1DM, proliferative retinopathy may rather be the driving force of cerebral compromise.

Urinary matrix metalloproteinase-8 and -9 activities in type 2 diabetic subjects: A marker of incipient diabetic nephropathy?

Matrix metalloproteinases (MMPs) may play a pathophysiological role in the development of diabetic nephropathy (DN). We hypothesized that urinary MMP activity in patients with type 2 diabetes mellitus (T2DM) is related to a decline in renal function. We determined MMP-2, -8 and -9 activity in 24-h urine collections in relation to risk factors for DN in T2DM patients with (UA, n=27) and without albuminuria (NA, n=48) and controls (CO, n=28). MMP-8 and -9 levels were highest in UA patients (P<0.01). Of UA patients, 93% had at least one MMP increased, compared to 78% of NA patients and 46% of CO (P=0.001). Age, diabetes duration, BMI, systolic blood pressure, fasting plasma glucose, HbA1c and renal function were determinants of MMP-8 and -9 (P<0.05). In summary, MMP-8 and -9 are highest in T2DM UA patients. MMP-9, showed the strongest associations with clinical parameters related to DN.