Search

An analysis properties of the constitutive relations of the theory of deformation for physically nonlinear materials with properties depending on the type of stress state is carried out. These relations take into account two forms of nonlinearity, one of them is associated with the nonlinearity of the deformation diagrams and another one is associated with the change in these diagrams depending on the loading conditions. The distributions of stresses and strains in a rotating disk made of a material with properties sensitive to the type of stress state are investigated and a comparison with the results of calculations for a material with properties invariant to the form of external forces is performed.

Objective Investigate the dynamics of morphological and functional markers of vascular remodeling in patients with arterial hypertension (AH), including those with concomitant type 2 diabetes mellitus (DM2), during 12-month administration of perindopril A.Material and Methods The study included patients with grade I-II AH, with and without DM2 (30 and 32 patients, respectively), who underwent outpatient correction of initially ineffective antihypertensive therapy and administration of perindopril A, 10 mg/day. Morphological and functional parameters of vascular remodeling were evaluated in all patients at baseline and at 12 months using photoplethysmography. Stiffness index (SI) and phase shift (PS) were measured in large vessels. Reflection index (RI) and occlusion index (OI) were measured in microvessels. Computed nailfold videocapillaroscopy was used to determine capillary density (CD) at rest (CDr), CD during venous occlusion test (CDvo), and CD during reactive hyperemia test (CDrh). Data are medians [interquartile range].Results After 12-month administration of perindopril A, the morphological and functional parameters of vascular remodeling in AH patients without DM2 significantly improved at all vascular levels. SI decreased to 9.25 [7.8; 10.93 ] m/s and PS increased to 7.4 [5.6; 9.05] ms. In microvasculature, a statistically significant reduction was observed in RI, 31 [27; 36.5]%, and an increase was observed in OI, which characterizes endothelium function, 1.75 [1.68; 1.9]. Capillary CDr significantly increased to 40.5 [34.93; 46] cap/mm2, as did CDvo and CDrh. At the same time, in the group of patients with AH and DM2, a significant improvement was observed for the large vessels. SI decreased to 9.8 [9.08; 10.58] m/s, and PS increased to 6.95 [5.13; 10.08]. The RI index, reflecting the structural condition of arterioles, significantly decreased to 34 [25.9; 45.53]%, and the OI index, characterizing endothelial function, did not change significantly, 1.4 [1.3; 1.6]. Capillary CDr significantly increased to 31.55 [27.68; 34.7 ] cap/mm2; however, CDvo and CDrh did not change significantly. Renal function improved in both groups.Conclusion Both groups demonstrated improvement of morphological parameters at all levels of the arterial bed. However, patients with AH and concomitant DM2 showed no improvement of the endothelial function of arterioles and capillaries compared to improvement in AH patients without DM2. This reflected the more severe endothelial dysfunction present in AH patients with DM2.

Aim. To study some vascular remodeling markers in hypertensive patients depending on the presence of type 2 diabetes mellitus.Material and methods. The study included patients with essential hypertension 1-2 degrees of increase in blood pressure with/without type 2 diabetes (30 and 32 patients respectively). Using photoplethysmography in combination with reactive hyperemia test structural and functional markers of vascular remodeling were determined: in large vessels – stiffness index and phase shift; in microvessels – reflection index and the occlusion index. Using the computer video capillaroscopy of the nail bed the density of the capillary network at rest, after venous occlusion and after the test with reactive hyperemia was determined. ELISA was used for determining the level of humoral markers of endothelium dysfunction and vascular bed remodeling: metalloproteinase 9, metalloproteinase 9 inhibitor, E-selectin, endothelin, transforming growth factor (TGF-β1), endothelial growthfactor A.Results. In compare with hypertensive patients in hypertensive patients with type 2 diabetes significantly higher stiffness index values (11.15 [10.05; 12.35] vs 10.15 [8.83; 11.83] m/s; p=0.04) were found as well as significantly lower (p=0.00) capillary network density at rest (26.4 [24.2; 27.6] vs 35.1 [33.0; 45.0] cap/mm2; p=0.00) after the tests with reactive hyperemia (29 [24; 33.3] vs 40.0 [35.0;43.3] cap/mm2; p=0.00) and venous occlusion (32.5 [27.8; 34.5] vs 40.0 [33.0; 45.0] cap/mm2). In hypertensive patients with type 2 diabetes significantly higher levels of TFG-β1 (11648 [4117.8; 37933.8] vs 3938.5 [1808.8; 7694] pg/ml; p=0.00) and significantly lower levels of endothelin-1 (0,46 [0,29;1,3] vs 1.73 [0.63; 2.30] ng/ml; p=0.01) was detected in compare with hypertensive patients without type 2 diabetes.Conclusion. In both groups some signs of vascular remodeling were found at the level of both large arteries and microvessels (arterioles and capillaries). However, the group of hypertension + type 2 diabetes mellitus had statistically significantly more pronounced changes in arterial stiffness, capillary network density, as well as humoral markers levels of fibrosis and endothelial dysfunction.

Chronic heart failure (CHF) with preserved ejection fraction (CHFpEF) is an unsolved, socially relevant challenge since it is associated with a high level of morbidity and mortality. Early markers for this pathology are unavailable, and therapeutic approaches are undeveloped. This necessitates extensive studying the mechanisms of CHFpEF to identify therapeutic targets. According to current notions, systemic inflammation and endothelial dysfunction play an important role in the pathogenesis of CHFpEF. These processes induce the development of myocardial fibrosis and impairment of cardiomyocyte relaxation, thereby resulting in diastolic dysfunction and increased left ventricular (LV) filling pressure. Neuregulin-1 (NRG-1) is a paracrine growth factor and a natural agonist of ErbB receptor family synthesized in the endothelium of coronary microvessels. The NRG-1 / ErbB4 system of the heart is activated at early stages of CHFpEF to enhance the cardiomyocyte resistance to oxidative stress. Preclinical and clinical (phases II and III) studies have shown that the recombinant NRG-1 therapy results in improvement of myocardial contractility and in LV reverse remodeling. Results of recent studies suggest possible anti-inflammatory and antifibrotic effects of NRG-1, which warrants studying the activity of this system in patients with CHFpEF.