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PubMed1992

[Microcirculation in unphysiological flaps at early stage after operation: an experimental study].

Microcirculation and blood perfusion in unphysiological flaps were observed with rabbit ear microcirculation chamber. The microcirculation of the venous flap in two days after operation was reestablished mainly by diversion of blood flow through the "to and fro" movement of venous blood. Arteriovenous anastomoses were gradually opened, resulting in the microcirculation to restore normal perfusion, venous blood through the anastomoses into arteriole then to capillaries. The microcirculation of arterialized venous flaps was almost the same as that of the venous flaps. In two days after operation, the diversion of blood flow perfused the capillaries under high pressure, so that the flow velocity and rate were much faster and larger than those of the venous flaps. The microcirculation of venouslized arterial flap, nourished by venous blood through the arterial system, was the same as that of the physiological flap. But the capillaries were perfused venous blood flow, and the blood flow velocity and rate were much slower and smaller than those of the physiological flap.

Animals↗
PubMed2006

[In vivo fluorescent microscopy of the liver microcirculation after embolization with a newly developed trans-proper hepatic arterial infusion animal model].

OBJECTIVE: To evaluate the value of the in vivo fluorescent microscopy in studying the changes of liver microcirculation after embolization with a newly developed animal model for tans-proper hepatic arterial infusion, and to summarize the method of making this animal model. METHODS: Ten Sprague-Dawley rats were used in this study. After a midline abdominal incision, microcatheter was placed into the gastroduodenal artery (GDA). The tip of the catheter was placed facing the orifice of proper hepatic artery. After infusions of 0.02%, 0.1%, 0.5%, 1% fluorescent sodium, fluorescent microscopy was used to evaluate the liver microcirculation. The image quality was then accessed. Embolization was obtained by injections of Lipiodol and Degradable Starch Microspheres (DSM) from the microcatheter. Corresponding changes of the liver microcirculation was evaluated by fluorescent microscopy. RESULTS: From the 10 rats, 8 animal models were successfully established. The microcirculation of the liver could be clearly visualized by the fluorescent microscopy. The optimal concentration of fluorescent sodium was 0.1%. The direct and indirect phenomena caused by embolic material could be evaluated by fluorescent microscopy. CONCLUSION: Fluorescent microscopy with the corresponding Trans-hepatic arterial infusion animal model is a valuable method to evaluate the microcirculation of the liver and can be used for the evaluation of changes of liver microcirculation caused by embolization material.

Animals↗
PubMed1999

MR microcirculation assessment in cervical cancer: correlations with histomorphological tumor markers and clinical outcome.

This article reviews the experience available to date on microcirculation assessment in cancer of the cervix including correlation studies of magnetic resonance (MR) microcirculatory parameters with histo-morphometric predictors and direct correlation with patient outcome. The data suggest that MR microcirculation parameters do not always correlate with histo-morphometric parameters, while there is evidence that MR parameters predict patients' treatment outcome. These observations raise the issue that perhaps the histo-morphometric parameters, accepted gold standards for tumor angiogenesis and prognostic factors, reflect anatomical information at a "static" single time point and may not always provide sufficient information on the "dynamic" microcirculation function of the tumor. MR microcirculation assessment reflects both anatomical and functional information and may provide this additional information on the "dynamic" angiogenic and metabolic status of a tumor. Therefore, assessment of tumor microcirculation may augment the individual risk profile in cervical cancer patients and has the potential to impact on therapy selection and treatment outcome.

Contrast Media↗
PubMed1996

Prostaglandins modulate the responsiveness of the gastric microcirculation of sodium nitroprusside in cirrhotic rats.

Cirrhotic rats have an increased susceptibility to ethanol-induced gastric injury, related to an inability to mount a defensive gastric hyperemic response to luminal irritants, and associated with an impaired reactivity of the gastric microcirculation to nitric oxide (NO)/cyclic guanosine monophosphate (cGMP)-dependent vasodilators. Whether this hyporesponsiveness is in some way related to depressed prostaglandin synthesis by the stomach of cirrhotic rats is not clear. The aims of this study were to evaluate the role of NO and prostaglandins in the regulation of the gastric microcirculation under resting conditions and in response to administration of sodium nitroprusside, as well as to investigate the mechanisms of the hyporesponsiveness of the gastric microcirculation to nitrovasodilators. Cirrhosis was induced in rats by bile duct ligation, and controls had sham-operation. NG-nitro-L-arginine-methyl-ester (L-NAME) and indomethacin administration produced a greater reduction in gastric blood flow in cirrhotic rats than controls. Indomethacin pretreatment almost completely abolished the responsiveness to sodium nitroprusside (NaNP) in cirrhotic rats, while not affecting controls. Long-term administration of misoprostol to cirrhotic rats restored to normal the responsiveness to NaNP, whereas long-term administration of aspirin to healthy rats resulted in a hyporesponsiveness of the gastric microcirculation to NaNP similar to that seen in cirrhotic rats. We conclude that there are interactions between NO and prostaglandins in regulating gastric blood flow in both healthy and cirrhotic rats. The hyporesponsiveness of the gastric microcirculation of cirrhotic rats to a nitrovasodilator may occur as a consequence of prolonged depression of gastric prostaglandin synthesis.

Analysis of Variance↗
PubMed1997

Use of dynamic capillaroscopy for studying cutaneous microcirculation in patients with diabetes mellitus.

To investigate the relationship between cutaneous microcirculation and retinopathy in diabetes mellitus, we studied by dynamic capillaroscopy 35 diabetes mellitus patients, including 10 patients without retinopathy, 10 patients with background retinopathy, and 15 patients with proliferative retinopathy. We found that (1) cutaneous and retinal microcirculation in diabetes mellitus in long-term diabetes mellitus, regressional rather than proliferational changes occurred in skin vasculature as compared to that in retina; (2) functional impairments of cutaneous microcirculation, that is, decreased resting capillary blood cell velocity, peak blood cell velocity, and prolonged time to peak capillary blood cell velocity by dynamic capillaroscopy, could be detected in diabetes mellitus patients without retinopathy; (3) the degree of tortouosity of capillaries, impairment in peak capillary blood cell velocity, and time to peak capillary blood cell velocity of cutaneous microcirculation were significantly correlated with the gravity of retinopathy in diabetes mellitus patients; (4) abnormal leakage of fluorescence in cutaneous microcirculation appeared in diabetes mellitus patients with or without abnormal fluorescein angiography in retina. In conclusion, dynamic capillaroscopy used in concert with ophthalmoscopy and fluorescein angiography can facilitate a comprehensive examination of vasculopathy in diabetes mellitus.

Adult↗
PubMed1982

[Manipulated selective inhibition of microcirculation in cancer tissues].

This paper confirms previous results that hyperglycemia (5 g/l) lasting 250 min, when combined with local hyperthermia (43 degrees C) for the last 100 min, strongly inhibits microcirculation in Yoshida sarcomas and DS-carcinosarcomas. This inhibition occurs independently of heparinization of the animals (700 IU/200 G body weight) so blood coagulation cannot be an important factor in the mechanism of microcirculation inhibition. After inhibition of microcirculation (detected by measuring tissue death after application of Evans' blue) the dye concentration in the tumor tissue increased unspecifically with a certain time delay and was then only slightly lower than in the untreated tumors. The causes of this observation area discussed. The blood volume of the tumors investigated amounted to about 4 vol.-%. The microcirculation of untreated tumors amounted to between 33 and 50% of the microcirculation of normal tissue (muscle). High doses of Evans' blue inhibited blood coagulation.

Animals↗
PubMed2002

Spatial variation of plasma flow in the oxazolone-stimulated microcirculation.

INTRODUCTION: In cutaneous lymphocytic inflammation, enhanced regional blood flow is suggested by persistent erythema and warmth. Direct assessment of the microcirculation, however, has been limited by tissue edema and skin thickness. METHODS: To assess the microcirculatory adaptations to the epicutaneous antigen oxazolone, we studied the first pass kinetics and microvascular topography of the inflammatory skin microcirculation using a specially adapted epi-illumination intravital microscopy system. The fluorescence intravital videomicroscopy and streaming image acquisition of fluorescein-labeled dextran (approximately 500,000 MW) injections were used to assess changes in plasma flow. RESULTS: Direct plasma tracer injections of both the oxazolone-stimulated and control microcirculation demonstrated comparable transit times (leading edge and intensity-weighted peak times) from the carotid artery to the superficial vascular plexus (p > 0.05). In contrast to transit times, continuous infusion of the plasma tracer demonstrated a significant increase in the delivery of the fluorescein-labeled dextran to the oxazolone-stimulated microcirculation. Quantitative morphometry of intravital microscopic images demonstrated a 2.2-fold increase in the mean diameter of vessels in the superficial vascular plexus (p < 0.01). Further, fluorescence intensity mapping indicated that the increase was associated with increased perfusion of focal regions of the superficial vascular plexus (p < 0.001). CONCLUSIONS: These results indicate that the oxazolone-stimulated adaptations of the inflammatory microcirculation include both microvascular dilatation and the redistribution of plasma flow.

Animals↗
PubMed1998

A novel model for the study of synovial microcirculation in the mouse knee joint in vivo.

A novel model for the investigation of the microcirculation in synovial tissue of the mouse knee joint is presented. The mouse knee joint was exposed on a specially designed plexiglass stage with a slight flexion. After partial resection of the skin, the patella tendon was cut transversally, which allowed for visualization of the "Hoffa's fatty body", an intraarticular fatty tissue containing synovial cells on the interior surface of the joint. An intravital fluorescence microscope was adjusted to observe the microcirculation of this intraarticular synovial tissue without opening of the joint capsula. For staining of the plasma, fluorescein isothiocyanate (FITC)-dextran was used, and for the staining of leukocytes rhodamine 6G was used. The tissue investigated presents with a high-density honeycomb-like capillary network, containing some postcapillary venules and a few arterioles. The following parameters were assessed off-line using a computer-assisted microcirculation analysis system: flow and diameter of arterioles and postcapillary venules, as well as functional capillary density. Moreover, leukocyte-endothelial cell interaction was quantified by counting the number of rolling cells and cells adhering to the endothelium in postcapillary venules. As an indication of endothelial leakage, macromolecular extravasation was also assessed. To validate the model, we investigated these parameters at three time points during an observation period of 60 min. There was no change in functional capillary density, nor in vessel diameter after 60 min of observation. Moreover, there was neither a change in the number of rolling cells, nor in the number of cells adhering to the endothelium nor in extravasation of FITC-dextran, thus indicating the stability of the preparation. The new model allows the quantitative analysis of the intraarticular microcirculation of the synovial fatty tissue in vivo. It provides insight into the dynamics of synovial microcirculation and leukocyte-endothelial cell interaction in acute or chronic joint inflammation.

Adipose Tissue↗
PubMed2006

Reduced tolerance of exercise in fibromyalgia may be a consequence of impaired microcirculation initiated by deficient action of nitric oxide.

Although the underlying mechanism responsible for muscular fatigue and exercise intolerance remains to be elucidated, it is reported two major mechanisms, central and peripheral hypothesis. As a peripheral mechanism, there are few reports on abnormalities of the microcirculation in patients with fibromyalgia. The key point to note is that ischemia associated with a modest decline in tissue oxygen causes muscle fatigue. It has been shown that have been found low muscle levels of phosphates and abnormalities in microcirculation in fibromyalgia. Based on several novel data, production abnormalities of nitric oxide level might lead to symptoms of fatigue as a long term effect. There a vicious cycle concerning impairment of microcirculation in FM. The cycle is firstly initiated decrease of production of nitric oxide in the endothelial level by some trigger factors. Changed level of nitric oxide may cause microcirculation abnormalities in the tissue levels, muscular region. At the end of these phases, muscular fatigue and exercise intolerance may progressively develop in the FM. It is possible that this theory appears to provide a physiopathological explanation for decreased exercise capacity in patients with fibromyalgia. This paper describes a plausible mechanism for the development of exercise intolerance on microcirculation abnormalities.

Exercise Tolerance↗
PubMed2006

Evaluation of antiangiogenic treatment effects on tumors' microcirculation by Bayesian physiological pharmacokinetic modeling and magnetic resonance imaging.

A physiological pharmacokinetic (PBPK) model was used to estimate tumor microcirculation in nude mice with a grafted tumor. The kinetics of a rapid clearance blood pool agent, Vistarem, were investigated by dynamic MRI after bolus administration. Signal enhancements were recorded in arterial blood and in tumor tissue. To analyze these data, we developed a whole-body mathematical model of the agent's biodistribution using physiological parameters. The model included six compartments: arterial and venous plasma, tumor (split into capillaries and interstitium), and the rest of the body (also split into capillaries and interstitium). As an application, changes in tumor microcirculation parameters were evaluated in mice receiving either an antiangiogenic treatment (ZD4190) or a placebo. The analysis was performed in a Bayesian framework, and the model was fitted to experimental data using Markov Chain Monte Carlo techniques. Results showed a significant difference in tumor microcirculation between the two groups of mice when the microcirculation parameters are considered together. This whole-body physiological model enables to analyze jointly data in tumor tissue and in arterial blood. This leads to accurate estimates of microcirculation parameters and the evaluation of their uncertainty.

Animals↗
PubMed2005

Femur window--a new approach to microcirculation of living bone in situ.

BACKGROUND: The processes of osteogenesis, bone remodelling, fracture repair and metastasis to bone are determined by complex sequential interactions involving cellular and microcirculatory parameters. Consequently studies targeting the analysis of microcirculatory parameters on such processes should mostly respect these complex conditions. However these conditions could not yet be achieved in vitro and therefore techniques that allow a long-term observation of functional and structural parameters of microcirculation in bone in vivo at a high spatial resolution are needed to monitor dynamic events, such as fracture healing, bone remodelling and tumor metastasis. METHODS: We developed a bone chamber implant (femur window) for long-term intravital microscopy of pre-existing bone and its microcirculation at an orthotopic site in mice preserving the mechanical properties of bone. After bone chamber implantation vascular density, vessel diameter, vessel perfusion, vascular permeability and leukocyte-endothelial interactions (LEIs) in femoral bone tissue of c57-black mice (n=11) were measured quantitatively over 12 days using intravital fluorescence microscopy. Furthermore a model for bone defect healing and bone metastasis in the femur window was tested. RESULTS: Microvascular permeability and LEIs showed initially high values after chamber implantation followed by a significant decrease to a steady state at day 6 and 12, whereas structural parameters remained unaltered. Bone defect healing and tumor growth was observed over 12 and 90 days respectively. CONCLUSION: The new femur window design allows a long-term analysis of structural and functional properties of bone and its microcirculation quantitatively at a high spatial resolution. Altered functional parameters of microcirculation after surgical procedures and their time dependent return to a steady state underline the necessity of long-term observations to achieve unaltered microcirculatory parameters. Dissection of the complex interactions between bone and microcirculation enables us to evaluate physiological and pathological processes of bone and may give new insights especially in dynamic events e.g. fracture healing, bone remodeling and tumor metastasis.

Animals↗
PubMed2001

Fluvastatin therapy improves microcirculation in patients with hyperlipidaemia.

The purpose of this study was to investigate the effect of fluvastatin on the microcirculation of patients with hyperlipidaemia (low-density lipoprotein cholesterol > 160 mg/dL, triglycerides < 350 mg/dl) inadequately controlled by diet. After a dietary run-in of 4 weeks, patients were randomised in a double-blind study to receive fluvastatin 40 mg twice daily (n = 24) or placebo (n = 24) for 12 weeks. The effect on microcirculation was assessed using capillary microscopy and laser Doppler fluxmetry at the nailfold at baseline and at 6 and 12 weeks after initiation of therapy. Capillaroscopy showed that fluvastatin improved microcirculation, i.e. time to peak flow during postocclusive reactive hyperaemia dropped from 19.7 +/- 7.2 s at baseline to 12.3 +/- 9.5 s at week 6 (P < 0.01) and 10.6 +/- 6.5 s at week 12 (P < 0.0001). These results were confirmed using laser Doppler fluxmetry to study microcirculation in thermoregulatory capillaries at the same site. A significant decrease in total and LDL-cholesterol was achieved during fluvastatin therapy. In conclusion, fluvastatin therapy improves microcirculation in nutritive as well as thermoregulatory capillaries in hypercholesterolaemic patients within 6 weeks.

Anticholesteremic Agents↗
PubMedDate not supplied

Sinusoidal embolization: impact of iodized oil on hepatic microcirculation.

PURPOSE: To determine the effects of iodized oil, which is used in chemoembolization of liver cancer, on hepatic microcirculation and to measure the time required for recovery of microcirculation. MATERIALS AND METHODS: Iodized oil was injected in 0.1-, 0.2-, and 0.4-mL/kg doses into the hepatic artery in three groups of rats (n = 63). In vivo microscopy was performed during and immediately after the procedure and on days 1, 3, 7, 15, 30, and 60. A control group of rats underwent identical microscopy procedures. RESULTS: Changes in microcirculation occurred after injections with iodized oil. Oil injected into the hepatic artery entered the portal vein and flowed into the sinusoids to create an incomplete sinusoidal embolization. Recovery of the sinusoidal circulation occurred 3, 7, and 30 days after injections of 0.1, 0.2, and 0.4 mL/kg of oil, respectively. CONCLUSIONS: The liver tolerated oil embolization well. Despite the changes in microcirculation and a nonlinear recovery time, the microcirculation completely recovered, even with a 0.4-mL/kg dose.

Animals↗
PubMedDate not supplied

[Evaluation of late radiation-induced changes in superficial microcirculation after acute beta-irradiation. II. Prognostic importance of cutaneous Doppler laser].

OBJECTIVE: The changes that occur in the tissular microcirculation after accidental acute irradiation account for some of the early effects of such irradiation, especially at the cutaneous level. The prognostic importance of the cutaneous laser doppler was tested in an experimental model of acute beta-irradiation. METHODS: Ten pigs were given beta-irradiation with a high single localized dose of 90Sr/90Y (32 or 64 Gy, 7 mg/cm2) delivered to the flank, and were evaluated 2, 7, 14, 21 and 28 days thereafter. Each individual was its own control. The local microcirculation was measured in the resting state and during thermal stimulation at 42 degrees C, using a Periflux cutaneous Doppler laser with p413 probes. Three periods of six minutes each were continuously recorded: period 1 (P1) represented basal resting cutaneous perfusion, with the slope p corresponding to the increase in perfusion when two minutes of thermal stimulation at 42 degrees C began; P2 to plateau perfusion during this stimulation; and P3 to perfusion on the return to equilibrium. RESULTS: After acute beta-irradiation in the pig, all the cutaneous microcirculation parameters measured (P1, p, P2 and P3) had risen at day 2 in the irradiated area by a factor of 2 to 4, depending on the dose (p < 0.001), compared to the adjacent control area. On the other hand, as from day 7, the resting and the stimulated microcirculation varied little, except for a reduction of the slope p by a factor of 2 (p < 0.05) after the strongest radiation dose. CONCLUSION: After acute irradiation, the increase in the resting cutaneous microcirculation may correspond to immediate but transitory capillary vasodilatation that accompanies the initial erythema in accidental irradiation. The absence of vascular response to thermal stimulation seems to be a good means of reaching an early diagnosis of delayed cutaneous radiation necrosis.

Animals↗
PubMedDate not supplied

[Evaluation of late radiation-induced changes in superficial microcirculation. I. Clinical benefit of the cutaneous Doppler laser].

OBJECTIVE: The changes that occur in the tissular microcirculation after therapeutic irradiation (RT) account for some of the late effects of irradiation, especially on the cutaneous level. As a rule, the methods of exploring the superficial microcirculation only measure blood flow indirectly. Only the Doppler laser can provide direct measurements of blood parameters in vivo in man. METHODS: Thirty women who had been irradiated with 45 + 20 Gy of locoregional fractionated adjuvant RT for breast cancer developed local radiation-induced fibrosis six years later (+/- 5). The local microcirculation was measured in the resting state and during thermal stimulation at 42 degrees C, using a Periflux cutaneous Doppler laser with p413 probes. Three periods of six minutes each were continuously recorded: period 1 (P1) represented basal resting cutaneous perfusion, with the slope p corresponding to the increase in perfusion when two minutes of thermal stimulation at 42 degrees C began; P2 to plateau perfusion during this stimulation; and P3 to perfusion on the return to equilibrium. Each individual was its own control. RESULTS: In the women treated by RT, the resting microcirculation in the skin underlying an area of late fibrosis rose by a factor of 2 during P1 (p < 0.001), and the P2/P1 ratio decreased by a factor of 2 (p < 0.001), compared to the control area. After thermal stimulation, there was no change in p, P2 or P3. CONCLUSION: Although a hypovascularization is frequently found in late sequelae of RT, we observed an increase of the cutaneous microcirculation associated with a maladjustment of the endothelial response to a thermal stimulation. These observations seem to reflect the presence of dilated new capillaries of the telangiectatic type, which are macroscopically undetectable.

Adult↗
PubMed1997

Trafficking of activated lymphocytes into the RENCA tumour microcirculation in vivo in mice.

The aim of the study was to establish a model of tumour microcirculation in vivo using the murine renal cell carcinoma cell line (RENCA) implanted into the mouse cremaster muscle, and subsequently to investigate the trafficking of syngeneic lymphocyte subpopulations into both the RENCA tumour and the surrounding normal cremaster muscle microcirculation. We have demonstrated that RENCA tumour cells, at a dose of 1.5 x 10(5) per 30 microl injected into the cremaster muscle, reproducibly produced a vascularized tumour suitable for in vivo microscopy at 10-14 days. Injection of fluorescently labelled effector cells (1 x 10(6)) including naive splenocytes, T-cell enriched populations and ex vivo interleukin 2 (IL-2)-activated splenocytes all migrated to and flowed through both the tumour and the normal microcirculation, with negligible adhesion. However, we observed the selective recruitment, localization and arrest of IL-2-activated splenocytes (P < 0.05) into the tumour microcirculation, and the subsequent extravasation of cells into the tumour intestitium in some instances. This did not occur with the other effector cells. We also observed the absence of leucocyte rolling in the tumour microcirculation, suggesting an impairment in adhesion molecule expression on the tumour endothelium. We have therefore established the potential of this model for defining further effector cell-tumour-endothelium interactions.

Animals↗
PubMed2000

Cerebral nitric oxide concentration and microcirculation during hypercapnia, hypoxia, and high intracranial pressure in pigs.

Intracerebral nitric oxide (NO) concentration was measured to establish the technique and to investigate the response of the NO concentration to CO(2)variations, hypoxia, and reduced cerebral perfusion pressure. An intracerebral nitric oxide sensor was used in 10 pigs. Cerebral microcirculation was measured by laser Doppler flowmetry. Five pigs received 40 mg/kg nitro-1-arginine methyl ester (L-NAME). Baseline NO concentration was 246 +/- 42 nM. Hypercapnia increased cerebral microcirculation (P< 0.05) and NO concentration (P< 0.05). Hypoxia decreased NO concentration (P< 0.05). During high intracranial pressure, cerebral microcirculation decreased (P< 0.05) before the NO concentration decreased (P< 0.05), and after normalisation of the intracranial pressure the NO concentration increased, but more slowly than the cerebral microcirculation. L-NAME caused a decrease in cerebral microcirculation (P< 0.05) and NO concentration (P< 0.05) to a new steady state, and L-NAME attenuated the changes in NO concentration after hypoxia (P< 0.05) and high intracranial pressure (P< 0.05). In conclusion, the electrochemical sensor appears to reliably detect changes in localised intracerebral NO concentration and seems to be a promising tool for direct measurement of this chemically unstable substance.

Animals↗
PubMed2000

Effects of alpha-lipoic acid on microcirculation in patients with peripheral diabetic neuropathy.

Diabetic polyneuropathy is a serious complication in patients with diabetes mellitus. In addition to the maintenance of a sufficient metabolic control, alpha-lipoic acid (ALA) (Thioctacid, Asta Medica) is known to have beneficial effects on diabetic polyneuropathy although the exact mechanism by which ALA exerts its effect is unknown. In order to study the effect of ALA on microcirculation in patients with diabetes mellitus and peripheral neuropathy one group of patients (4 female, 4 male, age 60+/-3 years, diabetes duration 19+/-4 years, BMI 24.8+/-1.3 kg/m2) received 1200 mg ALA orally per day over 6 weeks (trial 1). A second group of patients (5 female, 4 male, age 65+/-3 years, diabetes duration 14+/-4 years, BMI 23.6+/-0.7 kg/m2) was studied before and after they had received 600 mg ALA or placebo intravenously over 15 minutes in order to investigate whether ALA has an acute effect on microcirculation (trial 2). Patients were investigated by nailfold video-capillaroscopy. Capillary blood cell velocity was examined at rest and during postreactive hyperemia (occlusion of the wrist for 2 minutes, 200 mmHg) which is a parameter of the perfusion reserve on demand. The oral therapy with ALA resulted in a significant decrease in the time to peak capillary blood cell velocity (tpCBV) during postocclusive hyperemia (trial 1: 12.6+/-3.1 vs 35.4+/-10.9 s, p<0.05). The infusion of ALA also decreased the tpCBV in patients with diabetic neuropathy (trial 2: before: 20.8+/-4,5, ALA: 11.74+/-4.4, placebo: 21.9-5.0 s, p<0.05 ALA vs both placebo and before infusions) indicating that ALA has an acute effect on microcirculation. Capillary blood cell velocity at rest (rCBV), hemodynamic parameters, hemoglobinA1c and local skin temperature remained unchanged in both studies. These results demonstrate that in patients with diabetic polyneuropathy ALA improves microcirculation as indicated by an increased perfusion reserve on demand. The observed effects are apparently acute effects. With the restriction of the pilot character of this investigation the findings support the assumption that ALA might exert its beneficial effects at least partially by improving microcirculation which is likely to occur also at the level of the vasa nervorum.

Antioxidants↗