OBJECTIVEType 2 diabetes (T2DM) is associated with brain atrophy and cerebrovascular disease. We aimed to define the regional distribution of brain atrophy in T2DM and to examine whether atrophy or cerebrovascular lesions are feasible links between T2DM and cognitive function.RESEARCH DESIGN AND METHODSThis cross-sectional study used magnetic resonance imaging (MRI) scans and cognitive tests in 350 participants with T2DM and 363 participants without T2DM. With voxel-based morphometry, we studied the regional distribution of atrophy in T2DM. We measured cerebrovascular lesions (infarcts, microbleeds, and white matter hyperintensity [WMH] volume) and atrophy (gray matter, white matter, and hippocampal volumes) while blinded to T2DM status. With use of multivariable regression, we examined for mediation or effect modification of the association between T2DM and cognitive measures by MRI measures.RESULTST2DM was associated with more cerebral infarcts and lower total gray, white, and hippocampal volumes (all P < 0.05) but not with microbleeds or WMH. T2DM-related gray matter loss was distributed mainly in medial temporal, anterior cingulate, and medial frontal lobes, and white matter loss was distributed in frontal and temporal regions. T2DM was associated with poorer visuospatial construction, planning, visual memory, and speed (P ≤ 0.05) independent of age, sex, education, and vascular risk factors. The strength of these associations was attenuated by almost one-half when adjusted for hippocampal and total gray volumes but was unchanged by adjustment for cerebrovascular lesions or white matter volume.CONCLUSIONSCortical atrophy in T2DM resembles patterns seen in preclinical Alzheimer disease. Neurodegeneration rather than cerebrovascular lesions may play a key role in T2DM-related cognitive impairment.

In 1983 a large family with MEN-1 (designated Tasman 1) was identified in Tasmania. Kindred screening and case follow-up over the subsequent 15 years has yielded data on over 160 MEN-1-affected patients. Hyperparathyroidism is present in over 60% of gene carriers by age 20 years and 95% by age 30 years. Hyperplasia is the characteristic pathological finding. Kaplan-Meier analysis indicates hyperparathyroidism recurs in the majority of patients despite near-total parathyroidectomy. Gastrinoma, 'nonfunctioning' pancreatic adenoma and insulinoma occur in up to 60, 50 and 10% of patients, respectively. Metastatic gastroenteropancreatic (GEP) tumours develop in up to 35% of family members, being frequent in some branches of Tasman 1, whilst rare in others. Pituitary disease developed in 19% of patients. Prolactinoma and 'nonfunctioning' adenoma account for 76 and 24%, respectively, of pituitary abnormalities. Prolactinomas exhibit clustering within branches of the Tasman 1 kindred. Adrenal adenomas occur in 36% of patients. The majority of adrenal lesions are benign and nonsecretory and develop in association with pancreatic neoplasia. Carcinoid tumours are uncommon but important malignancies. Malignant thymic carcinoid occurs in male patients, whereas bronchial carcinoid occurs predominantly in women. Prior to recognition of MEN-1 in Tasman 1, complications of hyperparathyroidism and malignancy accounted for the majority of patient mortality. Since commencement of prospective screening, malignant GEP tumours and cardiovascular disease have become the most prevalent causes of death amongst MEN-1-affected patients.

Skeletal muscle microvascular (capillary) blood flow increases in the postprandial state or during insulin infusion due to dilation of precapillary arterioles to augment glucose disposal. This effect occurs independently of changes in large artery function. However, acute hyperglycemia impairs vascular function, causes insulin to vasoconstrict precapillary arterioles, and causes muscle insulin resistance in vivo. We hypothesized that acute hyperglycemia impairs postprandial muscle microvascular perfusion, without disrupting normal large artery hemodynamics, in healthy humans. Fifteen healthy people (5 F/10 M) underwent an oral glucose challenge (OGC, 50 g glucose) and a mixed-meal challenge (MMC) on two separate occasions (randomized, crossover design). At 1 h, both challenges produced a comparable increase (6-fold) in plasma insulin levels. However, the OGC produced a 1.5-fold higher increase in blood glucose compared with the MMC 1 h postingestion. Forearm muscle microvascular blood volume and flow (contrast-enhanced ultrasound) were increased during the MMC (1.3- and 1.9-fold from baseline, respectively, P < 0.05 for both) but decreased during the OGC (0.7- and 0.6-fold from baseline, respectively, P < 0.05 for both) despite a similar hyperinsulinemia. Both challenges stimulated brachial artery flow (ultrasound) and heart rate to a similar extent, as well as yielding comparable decreases in diastolic blood pressure and total vascular resistance. Systolic blood pressure and aortic stiffness remained unaltered by either challenge. Independently of large artery hemodynamics, hyperglycemia impairs muscle microvascular blood flow, potentially limiting glucose disposal into skeletal muscle. The OGC reduced microvascular blood flow in muscle peripherally and therefore may underestimate the importance of skeletal muscle in postprandial glucose disposal.

Adrenal lesions are common in MEN-1 and occur in association with pancreatic disease. Abdominal CT scan is more sensitive than ultrasonographic examination in detecting adrenal disease. Primary hypersecretory syndromes of the adrenal glands appear to be rare, and the majority of lesions follow an indolent clinical course.