STREPTOZOTOCIN-INDUCED DIABETES MELLITUS - A PARADOX OF HIGH INTRINSIC PLATELET REACTIVITY AND LOW IN VITRO PLATELET AGGREGATION.

CONTEXT: Studies of platelet function in diabetics are inconsistent, some studies reporting higher platelet reactivity, while others showed no change. OBJECTIVE: We aimed to evaluate platelet indices and in vitro platelet aggregation in rats with long-lasting (28 weeks) diabetes mellitus. DESIGN: Twelve controls and 14 diabetic rats were investigated. Diabetes was induced in 11-week-old rats using streptozotocin (60 mg/kg,i.p.). Platelet indices and in vitro adenosine diphosphate (ADP)-, protease-activated receptor 4 (PAR4) agonist-, and arachidonic acid (AA)-induced platelet aggregation were assessed at the age of 38 weeks. RESULTS: Compared to controls, diabetic rats presented lower platelet count and plateletcrit (both p≤0.001), and higher mean platelet volume (p<0.01). ADP- (p=0.04) and AA-induced (p<0.01) platelet aggregation were lower in diabetic compared with control rats, whereas PAR4 agonist-induced platelet aggregation was similar between the two groups (p=1.00). CONCLUSIONS: This study demonstrates a paradox of high intrinsic platelet reactivity and low in vitro ADP- and AA-induced platelet aggregation in diabetic rats compared with non-diabetic controls. The relevance of in vitro platelet aggregation to the contribution of platelets to in vivo thromboembolic events in diabetic rats remains questionable.

Long-term type 1 diabetes mellitus creates a pro-atherogenic environment conducive to early atherosclerosis in rats.

INTRODUCTION: Experimental models are essential for clarifying the pathogenesis of atherosclerosis in the context of diabetes mellitus (DM). We aimed to evaluate the presence and the magnitude of several factors known to promote atherogenesis, and to assess the potential of a pro-atherogenic environment to stimulate the development of atherosclerotic lesions in a rat model of long-term type 1 DM. MATERIALS AND METHODS: Six control and five DM Wistar rats were evaluated. DM was induced at 11 weeks of age using streptozotocin (STZ; 60 mg/kg, intraperitoneal). Animals were monitored up to 38 weeks of age, when plasma glucose, lipid profile, and markers specific for systemic inflammation, endothelial dysfunction, and oxidative stress were measured. The amount of fat within the aortic wall was assessed semiquantitatively using Oil Red O staining. RESULTS: Diabetic rats presented significantly higher plasma glucose (p < 0.001), total cholesterol and triglycerides (both p = 0.02), high-sensitivity C-reactive protein (p = 0.01), and vascular endothelial growth factor (p = 0.04) levels, and significantly lower interleukin-10 (p = 0.04), superoxide dismutase (p < 0.01), and glutathione peroxidase (p = 0.01) levels than the control rats. Mild (grade 1) atherosclerotic lesions were observed in the aortic wall of 80% of the diabetic rats and in none of the control rats. CONCLUSIONS: This study presents a STZ-induced type 1 DM rat model with one of the longest follow-ups in the literature. In this model, long-term DM created a highly pro-atherogenic environment characterised by hyperglycemia, dyslipidemia, systemic inflammation, endothelial dysfunction, and oxidative stress that resulted in the development of early aortic atherosclerotic lesions.

[Type B aortic dissection--endovascular stent-graft repair. Case report]. / Disectie aortica tip B--rezolvare endovasculara prin stent-graft. Prezentare de caz.

The treatment of aortic dissections type B Stanford using endovascular stents represents one of the newest advances in the treatment of this diseases, less invasive alternative to classic surgical repair. Aortic stent-grafts initially were used in treatment of abdominal aortic aneurysms, and then to treat aneurysms, dissections and traumatic ruptures of the descending aorta, with good early and mid-term outcomes. Thoracic aortic aneurysms are frequently diagnosed in mid-age or elderly patients who have arterial hypertension, coronary artery disease, chronic obstructive pulmonary disease. Scientific data reveal a two-year mortality rate of > 70% in untreated patients, most deaths occurring due severe haemorrhages secondary aneurysm rupture. Development of endovascular techniques is naturally, due to the inherent complications of surgery in the distal thoracic aorta (paraplegia, renal failure, stroke). Endovascular deployment of stent-grafts in the treatment of Stanford B aortic dissections represents a possible and quite safe procedure. There is a continuous debate in medical literature about the best therapeutic decision in the treatment of extensive aortic dissections. We present a case of an extensive dissection of thoraco-abdominal aorta in a 55 years old hypertensive patient treated with an aortic stent-graft. Angiograms performed at the end of the procedure revealed complete occlusion of thoracic dissection, abdominal dissection remains untouched. One and three months post procedural evaluation showed a good follow up, with partial thrombosis of abdominal dissection without renal failure or ischaemic events.