Drag-Reducing Polymers Improve Vascular Hemodynamics and Tissue Oxygen Supply in Mouse Model of Diabetes Mellitus.

Diabetes mellitus (DM) is a chronic metabolic disease characterised by hyperglycaemia and glucose intolerance caused by impaired insulin action and/or defective insulin secretion. Long-term hyperglycaemia leads to various structural and functional microvascular changes within multiple tissues, including the brain, which involves blood-brain barrier alteration, inflammation and neuronal dysfunction. We have shown previously that drag-reducing polymers (DRP) improve microcirculation and tissue oxygen supply, thereby reducing neurologic impairment in different rat models of brain injury. We hypothesised that DRP could improve cerebral and skin microcirculation in the situation of progressive microangiopathies associated with diabetes using a mouse model of diabetes mellitus. Diabetes was induced in C57BL/6 J mice with five daily consecutive intraperitoneal injections of streptozotocin (50 mg/kg/day). Animals with plasma glucose concentrations greater than 250 mg/dL were considered diabetic and were used in the study following four months of diabetes. DRP (2 ppm) was injected biweekly during the last two weeks of the experiment. Cortical and skin (ear) microvascular cerebral blood flow (mCBF) and tissue oxygen supply (NADH) were measured by two-photon laser scanning microscopy (2PLSM). Cerebrovascular reactivity (CVR) was evaluated by measuring changes in arteriolar diameters and NADH (tissue oxygen supply) during the hypercapnia test. Transient hypercapnia was induced by a 60-second increase of CO2 concentration in the inhalation mixture from 0% to 10%. Compared to non-diabetic animals, diabetic mice had a significant reduction in the density of functioning capillaries per mm3 (787 ± 52 vs. 449 ± 25), the linear velocity of blood flow (1.2 ± 0.31 vs. 0.54 ± 0.21 mm/sec), and the tissue oxygen supply (p < 0.05) in both brain and skin. DRP treatment was associated with a 50% increase in all three parameters (p < 0.05). According to the hypercapnia test, CVR was impaired in both diabetic groups but more preserved in DRP mice (p < 0.05). Our study in a diabetic mouse model has demonstrated the efficacy of hemorheological modulation of blood flow by DRP to achieve increased microcirculatory flows and tissue oxygen supply.

[Cerebrovascular resistance in patients with severe combined traumatic brain injury].

UNLABELLED: Cerebrovascular resistance is an important parameter of the microcirculation. The main objective of cerebrovascular resistance is to maintain the constancy of cerebral blood flow and protect downstream vessels when changing perfusion pressure. The purpose of the study was to assess cerebrovascular resistance (CVR) in patients with severe combined traumatic brain injury (CTBI) with and without intracranial hematomas (IHs). MATERIAL AND METHODS: We analyzed treatment outcomes in 70 patients with severe CTBI (42 males and 28 females). The mean age was 35.5 ± 14.8 years (min 15 years; max 73 years). All patients were divided into 2 groups, depending on the presence of intracranial hemorrhage. The first group included 34 patients without IH, and the second group included 36 patients with epidural (6), subdural (26), and multiple (4) hematomas. The GCS score was 10.4 ± 2.6 in the first group and 10.6 ± 2.8 in the second group. The ISS severity injury score was 32 ± 8 in the first group and 31 ± 11 in the second group. All patients were operated on within the first 3 days, with 30 (83.3%) patients being operated on during the first day. Perfusion computed tomography (PCT) of the brain was performed within 1-14 days after TBI in the first group and within 2-8 days after surgical evacuation of hematoma in the second group. After PCT, the mean arterial pressure was measured, and the blood flow rate in the middle cerebral artery was determined using transcranial dopplerography. Cerebrovascular resistance was calculated using the formula modificated by P. Scheinberg. Comparisons between the groups were performed using the Student t-test and χ² criterion. RESULTS: The mean CVR values in each group (both with and without hematomas) were statistically significantly higher than the mean normal value of this parameter. Intergroup comparison of CVR values demonstrated a statistically significant increase in the CVR level in group 2 on the side of removed hematoma compared to group 1 (p=0.037). CVR in the perifocal zone of removed hematoma remained significantly higher compared to the symmetrical zone of the contralateral hemisphere (p=0.0009). CONCLUSION: Cerebrovascular resistance in patients with combined traumatic brain injury is significantly increased compared to the normal value. Cerebrovascular resistance in the perifocal zone after evacuation of hematoma in patients with multiple injury remains significantly increased compared to the symmetrical zone in the contralateral hemisphere.

[Delayed surgical operations in benign supratentorial gliomas].

Benign gliomas are slowly growing primary brain tumors with prolonged natural course and tendency to malignization. Selection of methods of treatment of patients with good quality of life is being discussed. 'Conservative' as well as active surgical tactics are supported. The paper describes results of treatment of 19 patients with benign supratentorial gliomas. Follow-up period varied from 4 months to 17 years. Aspects of volume evolution and surgical excision of tumor are highlighted.