Structural and functional state of various parts of skin microcirculation at an early stage of hypertension in working-age men.

STUDY PURPOSE: To conduct a cross-sectional study on the structural and functional characteristics of various parts of skin microcirculation in working-age men with newly diagnosed hypertension (HTN). MATERIALS AND METHODS: The study included 118 male participants (ages 30 to 60) who were not regularly taking any medicine, had no medical complaints, and subjectively considered themselves healthy at the time of study. All participants underwent a cross-sectional comprehensive medical examination. The following tests were performed: complete blood count, biochemical blood tests, video capillaroscopy (VCS), laser Doppler flowmetry (LDF) and photoplethysmography (PPG) on the left hand fingers, determination of flow-mediated vasodilation of the brachial artery, echocardiography, ultrasound of extracranial and femoral arteries, 24-h ambulatory blood pressure monitoring (ABPM). According to ABPM data, the participants were divided into two equal groups called a control group(CG) and a hypertension group(HG). There were 59 participants with normal BP in CG, and 59 participants with newly diagnosed HTN in HG. RESULTS: Nailfold VCS of the ring finger revealed no significant differences between the groups at the level of exchange microvessels. According to LDF data, there was no decrease in tissue perfusion and signs of an increase in the activity of endothelial, neurogenic, and myogenic regulation of the tone of precapillary arterioles in the HTN group. According to PPG of the index finger, in contrast to CG, HTN participants had significantly higher values of the following parameters: normalized augmentation index (Alp75) - 3.8 % and - 5.25 % (p < 0.005), stiffness index (SI) - 7.6 m/s and 7.35 m/s (p < 0.05), reflection index (RI) - 36.5 % and 28.4 % (p < 0.005), respectively. DISCUSSION: Working-age men in the early stage of HTN have neither capillary rarefaction nor an increase in the tone of skin precapillary arterioles. The largest contribution to peripheral vascular resistance in the onset of HTN is most likely made by large muscular arterioles, in which the neurogenic regulation of vascular tone predominates.

Parameters of cutaneous microvasculature in men of working age with newly diagnosed arterial hypertension.

OBJECTIVE: To investigate structural and functional features of cutaneous microvasculature in men of working age with newly diagnosed arterial hypertension (AH). MATERIALS AND METHODS: The study included 161 apparently healthy men from 30 to 60 years, who underwent a comprehensive examination of cardiovascular system "from the heart to the capillaries". Control group (CG) included 60 normotensive men. AH group included 101 men with elevated BP. RESULTS: There is no rarefaction of the capillary bed and latent fluid retention in the interstitial space in the skin in men with AH. No data were obtained for increased endothelial, neurogenic and myogenic tone of resistive cutaneous precapillary arterioles in AH group, but a decrease in the perfusion efficiency of the endothelial and myogenic mechanisms of tissue perfusion modulation was noted. CONCLUSION: Obtained results allow making the assumption that metabolic disorders at the level of capillaries that are of a systemic nature prevail in men with the onset of AH.

[Present-day possibilities of non-invasive control over microcirculation and metabolism in man]. / Sovremennye vozmozhnosti neinvazivnogo kontrolia mikrotsirkuliatsii i obmena veshchestv u cheloveka.

The main function of the microcirculatory bed consists in maintaining tissue homeostasis at an optimal level irrespective of the effect of various external and internal factors. Of all types of metabolism (diffusive, filtration-reabsorption and vesicular), directly dependent on the haemodynamic parameters is filtration-reabsorption metabolism which provides exchange of water, low-molecular-weight and water-soluble substances at the opposite to the heart «pole¼ of the cardiovascular system. The present study was aimed at testing a hypothesis that activation of metabolic processes in man would be accompanied by alterations in haemodynamic parameters which may be registered by means of modern non-invasive methods of examination, i. e., laser Doppler flowmetry (LDF) and computer-assisted capillaroscopy (CCS). We used actovegin as an activator of metabolic processes. The study included acute pharmacological testing in apparently healthy volunteers (n=28), a course of taking actovegin in patients with cognitive dysfunctions on the background of arterial hypertension (n=60) and in patients with chronic ischaemia of the lower limbs (n=80). The obtained findings of LDF and CCS demonstrated that the known metabolic effects of actovegin (improved utilization of oxygen and glucose by tissues) were accompanied by an increase in the number of functioning capillaries, increased velocity of capillary blood flow with a decrease in the degree of hydration of the interstitial space, thus reducing the «blood-cell¼ distance for nutrients and products of tissue metabolism. Improvement of capillary blood flow was determined by a decrease in the tonicity of the capillary sphincters, thus leading to reduced arteriolar-venular shunting of blood with predominant supply to the capillary bed, improved NO-mediated regulation of the value of the lumen of the precapillary arterioles by the microvascular endothelium, improved reaction of resistant microvessels to various dilatation stimuli. The obtained results make it possible to draw a conclusion that modern non-invasive methods of study of human microcirculation (LDF and CCS) are informative not only for assessment of the functional state of the microcirculatory bed of the skin but make it possible to evaluate efficacy of the filtration-reabsorption mechanism of metabolism.

[Effect of drug therapy for chronic obliterating diseases of lower-limb arteries on the state of the microcirculatory bed].

UNLABELLED: Search for an optimal method of conservative treatment of patients presenting with chronic obliterating disease of lower limb arteries (CODLLA) still remains an important and hitherto unsolved problem. Comparative studies of different drugs and objective assessment of their efficacy may be carried out using the method of laser Doppler flowmetry (LDF) with wavelet analysis of fluctuations in blood flow. OBJECTIVE: The study was aimed at assessing efficacy of using Actovegin in conservative treatment of patients presenting with chronic obliterating disease of the lower extremities induced by occlusive and stenotic lesions of the arterial bed. MATERIAL AND METHODS: The study included a total of 80 patients with stage 2B chronic ischaemia of the lower limbs. The patients were subdivided into two groups. Group One comprised 40 patients undergoing a course of intravenous infusions of Actovegin (at a dose of 250 ml, 4 mg/ml) as monotherapy for 10 days. Group Two comprised 40 patients receiving intravenous infusion of dextranes, as well as pentoxyphyllin at a dose of 100 mg/day. The state of microcirculation before and after the course of the infusion therapy was assessed by means of LDF with wavelet analysis of blood follow fluctuations. The basal blood flow was registered at a temperature of + 32° C for 10 minutes followed by a thermal test, i. e., heating to + 42oC for 30-40 minutes. RESULTS: The course of infusion therapy in Group One patients was followed by an increase of the amplitude of myogenic fluctuation by 56% (p=0.006) and a decrease in the index of blood flow shunting (p=0.1) with basal perfusion, as well as an increase in the maximum level of perfusion (p=0.006). Group Two patients showed were found to have only statistically significant shortening of the time of reaching the maximum level of thermal hyperaemia. The increase of the pain-free walking distance averagely amounted to 58.8% in Group One patients and 60.7% in Group Two (p=0.068). Patients of the both groups showed satisfactory tolerance of the carried out therapy. No undesirable adverse events were observed. CONCLUSION: LDF with wavelet analysis of fluctuations of blood flow makes it possible to thoroughly study the mechanisms of action of therapeutic agents on microcirculation in patients with CODLLA . The use of Actovegin as monotherapy in CODLLA patients leads to a decrease in the myogenic tonus of precapillary arterioles and capillary sphincters, to a decrease in the arteriolar-venular shunting of blood flow with predominant supply of blood to the capillary bed, to an increase in the oxide-synthase function of the endothelium of microvessels (endothelioprotective effect), as well as to an increase in the maximum level of thermal vasodilatation. Hence, Actovegin may be considered as a promising therapeutic agent for pharmacotherapy of CODLLA.

[Vascular endothelium as a target for therapeutic action].

Proceeding from semi-centennial successful experience of clinical application of Actovegin in various-aetiology diseases of the vascular bed of the lower limbs, the present study was aimed at assessing interconnection between metabolic and microhaemodynamic processes in the human skin. Activation of metabolic processes was achieved by means of intravenous infusions of Actovegin and the microcirculatory processes were investigated using non-invasive methods in a total of 28 apparently healthy volunteers. The functional state of the arteriolar and venular portions of the microcirculatory bed of the skin was evaluated by means of laser Doppler flowmetry with wavelet analysis of oscillations of blood flow in the skin of the right forearm, while the parameters of the capillary blood flow were assessed by means of computer-assisted capillaroscopy in the nail bed of the 4th finger of the right hand. The known metabolic effects of Actovegin were accompanied and followed by a reliable increase in the amplitude of vasomotions within the range of the endothelial, neurogenic, and myogenic rhythms, suggesting a decrease in tonicity of the precapillary arterioles and, consequently, increased velocity of the capillary blood flow and decreased dimensions of the pericapillary zone, thus indicating improved metabolic processes in the skin. The obtained findings demonstrate close relationship between the processes of metabolism and microhaemodynamics, making it possible to suppose that amplitude activity within the range of the endothelial rhythm (0,0095-0,021 Hz) on laser Doppler flowmetry reflects not only the vasomotor but also metabolic function of the microvascular endothelium.

[Role of nitric oxide and lipid peroxidation in pathogenesis of acute experimental pancreatitis].

In experiment, conducted on 130 Wistar line rats, there was studied up the influence of nitric oxide on the peroxidal oxidation of lipids intensity, activity of enzymes of the antioxidant defense system and morphological changes in acute pancreatitis. Modern suggestions about the influence of the nitric oxide system on pathogenetic mechanisms of an acute pancreatitis and possibilities of correcting therapy were scrutinized. It was established, that the nitrates and the nitrites content in the blood serum of experimental animals correlates positively with the pancreatic oedema index and severity of its morphological changes as well. Intraperitoneal injection of 20% water solution of L-arginine in dosage 200 mg per 100 g of an animal body mass have had aggravated an acute pancreatitis course; intravenous injection of 1% water solution of methylene blue in dosage 1 mg per 100 g of an animal body mass caused pancreatoprotective effect.