Carotid intima-media thickness as a surrogate marker of cardiovascular disease in diabetes.

BACKGROUND: Diabetes mellitus is associated with a high risk of cardiovascular disease. Carotid intima-media thickness (CIMT) is increasingly used as a surrogate marker for atherosclerosis. Its use relies on its ability to predict future clinical cardiovascular end points. METHODS: This review examines the evidence linking CIMT as a surrogate marker of vascular complications in people with type 1 and type 2 diabetes. We have also reviewed the various treatment strategies which have been shown to influence CIMT. CONCLUSIONS: CIMT measurement is an effective, noninvasive tool which can assist in identifying people with diabetes who are at higher risk of developing microvascular and macrovascular complications. It may also help to evaluate the effectiveness of various treatment strategies used to treat people with diabetes.

The Role of Asymmetric Dimethylarginine (ADMA) in Endothelial Dysfunction and Cardiovascular Disease.

Endothelium plays a crucial role in the maintenance of vascular tone and structure. Endothelial dysfunction is known to precede overt coronary artery disease. A number of cardiovascular risk factors, as well as metabolic diseases and systemic or local inflammation cause endothelial dysfunction. Nitric oxide (NO) is one of the major endothelium derived vaso-active substances whose role is of prime importance in maintaining endothelial homeostasis. Low levels of NO are associated with impaired endothelial function. Asymmetric dimethylarginine (ADMA), an analogue of L-arginine, is a naturally occurring product of metabolism found in human circulation. Elevated levels of ADMA inhibit NO synthesis and therefore impair endothelial function and thus promote atherosclerosis. ADMA levels are increased in people with hypercholesterolemia, atherosclerosis, hypertension, chronic heart failure, diabetes mellitus and chronic renal failure. A number of studies have reported ADMA as a novel risk marker of cardiovascular disease. Increased levels of ADMA have been shown to be the strongest risk predictor, beyond traditional risk factors, of cardiovascular events and all-cause and cardiovascular mortality in people with coronary artery disease. Interventions such as treatment with L-arginine have been shown to improve endothelium-mediated vasodilatation in people with high ADMA levels. However the clinical utility of modifying circulating ADMA levels remains uncertain.

Endothelial progenitor cells in subclinical hypothyroidism: the effect of thyroid hormone replacement therapy.

CONTEXT: Subclinical hypothyroidism (SCH) is associated with cardiovascular (CV) risk factors, and possibly CV disease. However, its management remains controversial. Endothelial progenitor cells (EPC), expressing both endothelial and stem cell markers, are known to offer a novel CV risk marker. OBJECTIVE: The aim of the study was to ascertain whether EPC count or function is reduced in SCH and whether it improves with T(4) therapy. DESIGN AND INTERVENTION: EPC were studied in peripheral blood by fluorescence-activated cell sorter and following in vitro cultures before and after T(4) together with CV risk factors in 20 SCH and healthy controls (HC). MAIN OUTCOME MEASURE: EPC count was measured at baseline and after T(4) replacement in SCH. RESULTS: EPC count was significantly reduced in SCH compared to HC: median (range)-CD133+/VEGFR-2+, 0.09 (0.02-0.44) vs. 0.47 (0.17-2.12), P < 0.001; CD34+/VEGFR-2+, 0.10 (0.04-0.46) vs. 0.39 (0.11-2.13), P < 0.001; whereas EPC function was similar. There was a significant positive correlation between CD133+/VEGFR-2+ with free T(4) levels (r = 0.38; P = 0.02); high-density lipoprotein cholesterol levels (r = 0.51; P = 0.001); and negative correlation with TSH concentrations (r = -0.64; P < 0.001). After adjustment for conventional CV risk factors, SCH predicted lower EPC count, beta coefficient/P value: CD133+/VEGFR-2+ (-0.77/<0.001), and CD34+/VEGFR-2+ (-0.71/<0.001). In SCH participants, EPC count increased and was similar to HC after T(4); CD133+/VEGFR-2+, 0.32 (0.03-0.94) vs. 0.09 (0.02-0.44), P < 0.001; and CD34+/VEGFR-2+, 0.26 (0.06-0.88) vs. 0.10 (0.04-0.46), P < 0.001. CONCLUSION: SCH predicted lower EPC count, which improved with T(4) treatment, independent of other CV risk factors, providing additional evidence that T(4) replacement may improve CV risk in SCH.

A study of endothelial function and circulating asymmetric dimethylarginine levels in people with Type 1 diabetes without macrovascular disease or microalbuminuria.

BACKGROUND: Asymmetric dimethylarginine (ADMA) is a competitive inhibitor of endothelial nitric oxide synthase (eNOS) that is associated with endothelial dysfunction, and is a risk marker for cardiovascular disease, a significant problem in Type 1 diabetes. The aim of the present study was to measure circulating ADMA, and define its association with endothelial dysfunction and endothelial markers in people with Type 1 diabetes with low likelihood of macrovascular disease. METHODS: Sixty-one young people with Type 1 diabetes without macrovascular disease or nephropathy and 62 healthy volunteers underwent brachial artery flow-mediated dilatation (FMD) and assay of plasma ADMA and adhesion molecules. RESULTS: Age, gender, BMI, lipid profile and renal function were similar in the two groups. People with Type 1 diabetes had impaired FMD compared to healthy controls (5.0 +/- 0.4 vs 8.9 +/- 0.4%; p < 0.001). Plasma ADMA levels were significantly lower in the people with diabetes compared to healthy controls (0.52 +/- 0.12 vs 0.66 +/- 0.20 micromol/l, p < 0.001). Plasma ICAM-1, E-selectin and PAI-1 levels were significantly higher in people with diabetes compared to healthy controls (median 201 (IQR 172-226) vs 180 (156-216) microg/l, p = 0.027; 44.2 (32.6-60.9) vs. 33.1 (22.4-51.0) microg/l; p = 0.003 and 70.8 (33.3-85.5) vs 46.3 (23.9-76.8) microg/l, p = 0.035). Plasma ADMA and VCAM-1 levels were positively correlated (r = 0.37, p = 0.003) in people with diabetes. There was no correlation between the plasma ADMA and FMD. CONCLUSION: ADMA levels are not associated with endothelial dysfunction in young adults with Type 1 diabetes without microalbuminuria or known macrovascular disease. This suggests that the impaired endothelial function in these individuals is not a result of eNOS inhibition by ADMA.

Predicting the development of macrovascular disease in people with type 1 diabetes: A 9-year follow-up study.

The aim of the article was to use prospectively collected data on people with type 1 diabetes to assess which routinely collected clinical measures predict the development of macrovascular disease in people with type 1 diabetes. Data have been collected in a structured format at an annual review since 1985. For this study, all people with type 1 diabetes in the database in both 1992 and 2001 were ascertained. Data were extracted for a diagnosis of coronary artery disease, stroke, and peripheral vascular disease (macrovascular complications). Presence of other microvascular complications was also ascertained. Forty-one of 404 (10.1%) people had macrovascular disease at the index visit in 1992 and 61 others developed macrovascular complications during follow-up. People who developed macrovascular complications were older (48 +/- 12 versus 36 +/- 11 [SD] years; P = 0.000), had longer duration of diabetes (28 +/- 12 versus 18 +/- 11 years; P = 0.000), higher BMI (26.7 +/- 4.6 versus 25.4 +/- 3.6 kg/m2; P = 0.041), higher base line serum cholesterol (5.9 +/- 1.7 versus 5.2 +/- 1.1 mmol/L, P = 0.007), higher median base line triglyceride levels (1.5 [IQ range 0.9-2.6] versus 1.1 [0.8-1.7] mmol/L; P = 0.002), higher systolic BP (145 +/- 21 versus 129 +/- 20 mmHg; P = 0.000), and higher serum creatinine (102 +/- 57 versus 86 +/- 17 micromol/L; P = 0.038) than those who did not. We found no significant difference in the base line glycated hemoglobin in the two groups. The multivariate model showed that age, duration of diabetes, systolic BP, and serum cholesterol and creatinine levels predicted the development of macrovascular complications, which were also associated with the later development of microalbuminuria. Macrovascular complications developed in 16.8% of people with type 1 diabetes over a 9-year follow-up, and were predicted by potentially modifiable factors including higher BP, BMI, and serum triglyceride and cholesterol levels.

Cardiovascular risk factors predicting the development of distal symmetrical polyneuropathy in people with type 1 diabetes: A 9-year follow-up study.

The aim of the article was to use prospectively collected data on people with type 1 diabetes to examine which routinely collected clinical measures predict the development of peripheral neuropathy in people with type 1 diabetes. Within the Newcastle Diabetes Services, structured data collection at an annual review has been collected since 1985. This includes metabolic measures, cardiovascular risk factors, and markers of complications. From 1990 data collection was standardized and computerized. For this study, all people with type 1 diabetes in the database in both 1992 and 2001 were ascertained. Data were extracted for a diagnosis of peripheral neuropathy (based on neuropathic symptoms, absence of pinprick sensation, and abnormal biothesiometer measurements and/or monofilament sensation) and for the other metabolic and cardiovascular risk measures, as well as markers of other microvascular complications. Associations with the development of neuropathy were sought. Eighteen of 404 people already had peripheral neuropathy in 1992, and 38 others developed neuropathy during follow-up. People who developed neuropathy were older (47 +/- 14 [SD] versus 36 +/- 11 years; P = 0.000), had longer-duration of diabetes (27 +/- 13 versus 18 +/- 10 years; P = 0.001), higher baseline serum cholesterol (5.8 +/- 1.3 versus 5.2 +/- 1.2 mmol/L, P = 0.017), and higher systolic (139 +/- 18 versus 129 +/- 20 mmHg; P = 0.003) and diastolic BP (82 +/- 12 versus 76 +/- 11 mmHg; P = 0.009) than those who remained free of neuropathy. We found no significant difference for BMI and glycated hemoglobin. The multivariate model showed that diastolic BP, duration of diabetes, serum cholesterol, and history of callus/ulcers on the feet predicted the development of peripheral neuropathy. Neuropathy developed in 11.4% of people with type 1 diabetes over a 9-year follow-up, and was predicted by factors normally associated with cardiovascular rather than microvascular disease.

Pituitary apoplexy: a review of clinical presentation, management and outcome in 45 cases.

OBJECTIVE: To review clinical presentation, management and outcomes following different therapies in patients with pituitary apoplexy. METHODS: Retrospective analysis of case-records of patients with classical pituitary apoplexy treated in our hospitals between 1983-2004. RESULTS: Forty-five patients (28 men; mean age 49 years, range 16-72 years) were identified. Only 8 (18%) were known to have pituitary adenomas at presentation. Thirty-four (81%) patients had hypopituitarism at presentation. CT and MRI identified pituitary apoplexy in 28% and 91% cases, respectively. Twenty-seven (60%) patients underwent surgical decompression, whilst 18 (40%) were managed conservatively. Median time from presentation to surgery was 6 days (range 1-121 days). Patients with visual field defects were more likely than those without these signs to be managed surgically (p = 0.01). Complete or near-complete resolution occurred in 93% (13/14), 94% (15/16) and 93% (13/14) of the surgically treated patients with reduced visual acuity, visual field deficit and ocular palsy, respectively. All patients with reduced visual acuity (4/4), visual field deficit (4/4) and ocular palsy (8/8) in the conservative group had complete or near-complete recovery. Only 5 (19%) patients in the surgical group and 2 (11%) in the conservative group had normal pituitary function at follow up. One (4%) patient in the surgical group and 4 (22%) in the conservative group had a recurrence of pituitary adenoma. CONCLUSIONS: This large series suggests that the patients with classical pituitary apoplexy, who are without neuro-ophthalmic signs or exhibit mild and non-progressive signs, can be managed conservatively in the acute stage.

Medical therapy of macroprolactinomas in males: I. Prevalence of hypopituitarism at diagnosis. II. Proportion of cases exhibiting recovery of pituitary function.

Hyperprolactinaemia frequently causes secondary hypogonadism through central suppression of gonadotropin secretion. Macroprolactinomas (> 1 cm diameter) are more common in males and may additionally cause more generalised hypopituitarism. Recovery of the thyrotropic and/or corticotropic axes is well described following selective adenomectomy, but remains poorly defined in relation to medical (dopamine-agonist) therapy of macroprolactinomas. We therefore performed a retrospective examination of case records of male patients who had received medical therapy alone for macroprolactinoma between 1980-2001 (n = 35) and in whom tumor shrinkage was documented by interval pituitary imaging (reported throughout by a single neuroradiologist). Mean prolactin level at baseline was 59,932 mU/L (median 31,400; range 3,215-332,000); mean period of follow up was 4.2 years (median 2.6; range: 1.0-15). Defects of the following axes were evident at diagnosis: LH/FSH-testosterone (n = 27; 77%), TSH-T4 (n = 14; 41%-not including one case with pre-existing 1 degress hypothyroidism), ACTH-cortisol (n = 8; 23%). Overall, 14 men (40%) were deficient in 1 axis, seven (20%) in 2 axes and seven (20%) in 3 axes. Growth hormone secretory status was not systematically evaluated. In all but 6 patients, prolactin levels fell to normal or near-normal levels (mean 764 mU/L; median 260; range: < 10-4,833). Of the patients in whom adequate reassessment had been performed, thyrotroph function recovered in 4/9, corticotroph function in 4/6 and gonadotroph function in 16/26 cases. In four cases (11%) previously described, development of visual impairment as a result of the chiasmal traction syndrome necessitated a dose reduction in medical therapy to allow a degree of controlled tumor re-expansion. The prevalence at diagnosis of TSH and ACTH deficiency in men with macroprolactinomas was 41% and 23%, respectively. Among eight patients with insufficiency of TSH and/or ACTH secretion who underwent complete interval reassessment over several years of treatment, recovery of at least one axis occurred in six cases (75%). This study highlights the importance of screening ACTH- and/or TSH-deficient men during dopamine agonist therapy in order to identify cases where hypopituitarism has resolved.