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At least 253 records · Page 14Linked to original sources

PubMed1997

[Influence of reperfusion following ischemia on microvessels and microcirculation of skeletal muscle].

In order to study the influence of reperfusion following ischemia on microvesseles and microcirculation of skeletal muscle, unilateral hindlimbs of 16 rabbits were subjected to normothermic ischemia for 2 and 5 hours by tourniquet. After release of the tourniquet, microcirculation of the peritenon on dorsum of the foot was observed for 1 hours by intravital microscope. At 1 hour and 72 hours following reperfusion, the anterior tibia muscle biopsiy were taken and the specimens were subjected to light and electron microscopic examinations. It was found that after release of the tourniquet, in the limbs undergone 2 hours ischemia, there was immediate and well distributed reflow in the microvesseles of peritenon though a few aggregates of red cells and increase in the number of adherent leukocytes occured in some venules, and the microvesseles of the skeletal muscle only showed signs of minimal injury, the muscle fibers could survive in the limbs undergone 5 hours of ischemia, however, there was serious disturbance of microcirculation in the peritenon, which was characterized by "no reflow" in most area and there was significant increase in the number of leukocytes adherent to venular endothelium, and the microvesseles of the skeletal muscle showed signs of severe injury, including remarkable swelling of the endothelial cell, disruption of the basement membrane and interstitial edema, and finally, most of the muscle fibers had necrosis occured. The results demonstrated that reperfusion following ischimia might result in microvascular injury and microcirculation disorder in the ischemic area. The degree of the injury and disorder depended on the duration of ischemic period, and was an important factor which determined the fate of the parenchymal cell.

Animals↗

PubMed1989

[Photoplethysmography as a means of early diagnosis of changes in the microcirculation of children and adolescents with type I diabetes. Preliminary study].

Recent progress in non invasive diagnostic techniques for the study of the microcirculation, evoked a great interest in the screening of the patients with a diabetic microangiopathy. The authors, in this paper, wanted to evaluate the usefulness of photoplethysmography in the study of the microcirculation in children affected by type I diabetes; this technique was proposed as very reliable, non invasive and easily repeatable. 42 diabetic patients, with an age from 6 to 18 years, and a group of 12 healthy subjects of the same age, as a control group, were considered. Two particular points of interest were found: the statistical correlation between familial pathology for a vascular disease and the photoplethysmographic findings and the significant correlation between the age of the pathology and the beginning of the microcirculation disease. The authors, from their experience, evaluate the photoplethysmography as a reliable technique in the screening of all the diabetic subjects, children and adults, to evidence, as soon as possible, eventual lesions of the microcirculation for the beginning of an adequate therapy.

Adolescent↗

PubMed1996

Interferon alfa induces leukocyte capillary trapping in rat retinal microcirculation.

BACKGROUND: Interferon alfa has been suggested as a possible treatment for choroidal neovascularization. However, retinal complications following interferon therapy have been reported. OBJECTIVE: To evaluate the effects of interferon alfa on leukocyte dynamics in the rat retinal microcirculation. METHODS: Interferon alfa of different doses was intravenously administered in rats. Leukocyte dynamics were observed with acridine orange digital fluorography, which uses a nuclear fluorescent dye of acridine orange and scanning laser ophthalmoscopy. This technique allows visualization of leukocyte movements in the retinal microcirculation in vivo. RESULTS: After interferon alfa was administered, leukocytes adhered to vascular walls and became trapped in the retinal microcirculation. Leukocyte trapping was dose-dependent. CONCLUSIONS: Interferon alfa increased leukocyte adherence to vascular endothelium and subsequent leukocyte trapping in the retinal capillaries. Interferon alfa may activate leukocytes, and activated leukocytes may be involved in the pathogenesis of microinfarction associated with interferon-induced retinopathy.

Acridine Orange↗

PubMedDate not supplied

Microcirculation in pancreatic function.

The pancreas is involved in two major bodily functions: production of hormones involved in the control of carbohydrate metabolism and the production of enzymes essential to digestion. Pancreatic function is mediated by both neurological and humoral control. The major pathway for humoral control is through the circulatory system, the level of action being in the microcirculation. This introductory paper explores the need for a deeper understanding of the dynamic morphology, i.e. the actual flow patterns in the microcirculation, as a function of the physiological state and demand to complement the careful ultrastructural mapping of the microvasculature. The current state of knowledge in this field is reviewed as a basis for identifying important areas of knowledge and ignorance, and some suggestions are made as to possible procedures for further experimental studies, particularly in the microscopic observation of the dynamics of the microcirculation with special emphasis on the need for transport studies in both directions across the microvascular wall.

Animals↗

PubMed1999

MR imaging of tumor microcirculation: promise for the new millennium.

Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) is a method of imaging the physiology of the microcirculation. A series of recent clinical studies have shown that DCE MRI can measure and predict tumor response to therapy. Recent advances in MR technology provide the enhanced spatial and temporal resolution that allow the application of this methodology in the management of cancer patients. The September issue of this journal provided a microcirculation section to update readers on this exciting and challenging topic. Evidence is mounting that DCE MRI-based measures correlate well with tumor angiogenesis. DCE MRI has already been shown in several types of tumors to correlate well with traditional outcome measures, such as histopathologic studies, and with survival. These new measures are sensitive to tumor physiology and to the pharmacokinetics of the contrast agent in individual tumors. Moreover, they can present anatomical images of tumor microcirculation at excellent spatial resolution. Several issues have emerged from recent international workshops that must be addressed to move this methodology into routine clinical practice. First, is complex modeling of DCE MRI really necessary to answer clinical questions reliably? Clinical research has shown that, for tumors such as bone sarcomas, reliable outcome measures of tumor response to chemotherapy can be extracted from DCE MRI by methods ranging from simple measures of enhancement to pharmacokinetic models. However, the use of similar methods to answer a different question-the differentiation of malignant from benign breast tumors-has yielded contradictory results. Thus, no simple, one-size-fits-all-tumors solution has yet been identified. Second, what is the most rational and reliable data collection procedure for the DCE MRI evaluation? Several groups have addressed population variations in some key variables, such as tumor T(1)0 (T(1) prior to contrast administration) and the arterial input function C(a)(t) for contrast agent, and how they influence the precision and accuracy of DCE MRI outcomes. However, despite these potential complications, clinical studies in this section show that some tumor types can be assessed by relatively simple dynamic measures and analyses. The clinical scenario and tumor type may well determine the required complexity of the DCE MRI exam procedure and its analysis. Finally, we suggest that a consensus on naming conventions (nomenclature) is needed to facilitate comparison and analysis of the results of studies conducted at different centers. J. Magn. Reson. Imaging 10:903-907, 1999.

Arteries↗

PubMed1995

Morphology of pancreatic microcirculation in the monkey: light and scanning electron microscopic study.

The morphology of the microcirculation of the pancreas in 20 monkeys (Macaca mulatta) was studied by scanning electron microscopy (SEM) of vascular corrosion casts and light microscopy (LM) of China ink-injected/cleared tissues. The principal results were that 1) insulo-acinar portal vessels were found between the endocrine and exocrine parts in the pancreas. The blood flows from the endocrine to the exocrine part. 2) Depending on the different microvascular arrangement, there were two patterns of microcirculation in the islet: in 66% of islets the direction of microcirculation was from cortex to core, and in 44% from core to cortex. 3) Islets could be categorized in three classes on the basis of size: the small islets (40-100 microns in diameter), the intermediate islets (101-240 microns in diameter), and the large islets (241-340 microns in diameter). 4) Insulo-insular portal routes were observed in the pancreas of the monkey. Some intermediate or large islets were connected to an adjacent small islet by one or two, occasionally more, efferent vessels. These small islets received no arterial branch and were entirely supplied by the portal vessels--the efferent vessels of intermediate or large islets. The authors suggest this new pattern to be termed the insulo-insular portal system. 5) A single centrally located intralobular artery as the exclusive vessel supplied each pancreatic lobule of the monkey, there being no anastomosis between the intralobular arteries and any of their branches. This anatomic feature might be the morphological basis of the pancreatic microcirculatory disturbance and microvascular impairment occurring during acute pancreatitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1995

Histopathology of muscle flap microcirculation following prolonged ischemia.

The purpose of this study was to evaluate histological changes occurring in the microcirculation of a muscle flap following prolonged ischemia and to correlate them with the flow hemodynamics. The cremaster muscle flap model was used for direct in vivo studies of the microcirculation. In 45 rats, vascular clamps were applied to the iliac and femoral vessels following flap isolation. Flaps were subjected to various periods of ischemia, ranging from 4 to 6 hours, and 2 hr of reperfusion. In vivo observations of the microcirculation and vessel diameter measurements were taken at 1 hour intervals for an 8 hr period. With prolonged ischemia, return of circulation to the flap was delayed and no flow was observed following 6 hr of ischemia. Morphologic changes at 6 hr revealed red cell and platelet thrombi formation within the capillaries, marked dilatation of postcapillary venules, endothelial swelling in the capillaries, and microhemorrhage formation around the venules.

Animals↗

PubMed1994

A novel method to assess reactivities of retinal microcirculation.

This study introduces a novel method of bovine retinal microcirculation preparation to assess reactivities of retinal microvessels in ex vivo. This preparation is perfused intraluminally through the retinal artery. Effects of vasoactive hormones on these microvessels can be studied by perfusion or topical application to muscle bath. Effects of these compounds on the retinal microvessels of 1A (180- to 200-microns diameters), 2A (50- to 60-microns diameter), and 3A (20- to 30-microns diameter) can be assessed simultaneously using video microscopy. In this study, the water-soluble compound endothelin-1, when applied topically, caused dose-dependent vasoconstriction of all microvessels but had no effect when perfused intraluminally. On the other hand, lipid-soluble prostaglandin F2 alpha (PGF alpha) caused dose-dependent vasoconstriction when administered either intra- or extraluminally. Furthermore, preconstricted retinal arterioles (by PGF alpha) were dilated in a dose-dependent manner when acetylcholine was perfused through the retinal artery. This vasodilation was attenuated by atropine or N3-monomethyl arginine, a nitric oxide synthase inhibitor. Topical potassium chloride also caused dose-dependent vasoconstriction of all retinal microvessels. Fluorescein angiography showed no breakdown of the blood-retinal barrier. Thus, in this ex vivo perfused bovine retinal microcirculation preparation, the water-soluble compounds may not cross the blood-retinal barrier to affect microcirculation while lipid soluble can affect this circulation. Additionally this study shows that endothelial-derived compounds, endothelin and nitric oxide, caused vasoconstriction and dilation, respectively.

Acetylcholine↗

PubMed1997

Skin microcirculation during tapwater iontophoresis in humans: cathode stimulates more than anode.

The aim of this controlled study was to evaluate the influence of anode and cathode on skin blood flow by using direct current. Skin microcirculation and skin temperature of 26 healthy subjects (17 men and 9 women, 20-64 years of age) without any vascular diseases were registered when a tapwater iontophoresis was applied. Thermoindifferent water temperature was used to prevent thermic effects on microcirculation. The blood flow measurement was conducted by laser-Doppler flowmetry on the proximal forearm and on the back of the wrist. The skin temperature was measured before and after treatment by an infrared thermometer. In 19 persons there was an intense erythema on the side of the cathode and an only modest one on the side of the anode, while 7 persons showed meager reactions on both sides. The erythema rose strongly from the distal (back of the hand) to the proximal forearm. The comparison of the microcirculation of the arms showed an increase of 120% at the anode and of 700% at the cathode. The differences between the two sides were significant (P < 0.001). After the end of tapwater iontophoresis the skin temperature increased more on the side of the cathode than on the anode side (P < 0.001). The frequency of vasomotion did not change. The vasomotion amplitude increased 67% at the anode (P < 0.05) and 175% at the cathode (P < 0.001). The increased blood flow effect was not age or sex dependent. Although the increased blood flow effect was six times larger on the cathode side, the subjects did not perceive any subjective difference.

Adult↗

PubMed1999

Thermodiffusion for continuous quantification of hepatic microcirculation--validation and potential in liver transplantation.

Hepatic microcirculation is a main determinant of reperfusion injury and graft quality in liver transplantation. Methods available for the quantification of hepatic microcirculation are indirect, are invasive, or preclude postoperative application. The aim of this study was the validation of thermodiffusion in a new modification allowing long-term use in the clinical setting. In six pigs Doppler flowmeters were positioned around the hepatic artery and portal vein for the measurement of total liver blood flow. Liver perfusion was quantified by thermodiffusion and compared to H(2) clearance as an established technique under baseline conditions, during different degrees of portal venous obstruction and during occlusion of the hepatic artery. Thermodiffusion measurements were recorded for five days postoperatively followed by histological evaluation of the hepatic puncture site. Perfusion data obtained by thermodiffusion were significantly correlated to H(2) clearance (r = 0.94, P < 0. 001) and to liver blood flow (r = 0.9, P < 0.05). The agreement between thermodiffusion and H(2) clearance was excellent (mean difference -2.1 ml/100 g/min; limits of agreement -12.5 and 8.3 ml/100 g/min). Occlusion of the portal vein or hepatic artery was immediately detected by thermodiffusion, indicating a decrease of perfusion by 64 +/- 7% or 27 +/- 5% of baseline, respectively. Perfusion values at baseline and during vascular occlusion were reproducible during the entire observation period. Histological changes of the liver tissue adjacent to the thermodiffusion probes were minute and did not influence long-term measurements. In vivo validation proved that enhanced thermodiffusion is a minimally invasive technique for the continuous, real-time quantification of hepatic microcirculation. Changes in liver perfusion can be safely detected over several days postoperatively. The implication for liver transplantation has led to the clinical application of thermodiffusion.

Animals↗

PubMed1999

A single high dose of vitamin C counteracts the acute negative effect on microcirculation induced by smoking a cigarette.

Cigarette smoking is associated with marked acute changes in microcirculation including reduced blood flow. We tested the hypothesis that the reduced blood flow velocity is due to the imbalance between prooxidants and antioxidants that occurs as a consequence of smoking and that it can be reduced by an antioxidant. The effect of smoking a single cigarette on nail-fold microcirculation was analyzed in 24 healthy subjects with varying smoking habits. Vital capillary microscopy was used and the blood cell flow velocity in the capillaries was evaluated before and 1-30 min after smoking. Smoking induced a marked decrease in microcirculatory blood flow in 23 of the 24 subjects (40-50% decrease 1-5 min after smoking). This change was reduced by more than 50% in the same subjects after intake of 2 g of vitamin C 2 h before smoking (P < 0.0001 by ANOVA test) with smokers responding similarly to nonsmokers in these experiments. Intake of 1 g of vitamin C had no significant effect on the smoking-induced changes in most of the subjects tested (n = 11). Pretreatment with aspirin had little or no effect on the response to smoking (n = 9). Our results show that treatment with a single high dose of vitamin C can reduce and in some individuals even completely abolish the negative acute effect on microcirculation induced by smoking a single cigarette. This effect of vitamin C is not likely to be mediated by the cyclooxygenase system.

Adult↗

PubMed2001

Differences in cortical microcirculation in the kidneys of unilaterally congenital hydronephrotic rats.

The surgically induced split hydronephrotic kidney has been generally accepted as a valid model for the assessment of renal microcirculation by means of intravital microscopy. Whereas nearly all previous work on this issue has been done with a transillumination technique, we used an epiillumination model that is suitable for investigation of microvascular perfusion in both normal and hydronephrotic kidneys without surgical manipulation of the ureter. By means of the congenital unilaterally hydronephrotic Tauchi rat, microcirculation of the hydronephrotic and that of the nonhydronephrotic kidney were compared. For that purpose both the hydronephrotic and the nonhydronephrotic kidneys of Tauchi rats were exteriorized on a specially designed microscopy stage. After injection of FITC-dextran and rhodamine 6G, microvascular perfusion was assessed in both kidneys. The new model allowed visualization of arterioles, capillaries, and postcapillary venules in both the hydronephrotic and the nonhydronephrotic kidneys. Glomeruli could only be regularly seen in the hydronephrotic kidney, but also in some normal kidneys. Capillary blood cell velocity was significantly higher in the hydronephrotic kidneys (0.67 +/- 0.03 mm/s) compared to the normal kidney (0.32 +/- 0.05 mm/s; P < 0.05), whereas capillary diameters were smaller (4.2 +/- 0.02 microm vs. 5.7 +/- 0.2 microm; P < 0.05). In addition, the hydronephrotic kidney showed a significantly lower density of perfused microvessels compared to the normal controls. Epiillumination intravital microscopy allows assessment of the cortical microcirculation in both the hydronephrotic and the nonhydronephrotic kidneys without surgical induction of hydronephrosis. The hydronephrotic kidney shows significant microcirculatory differences compared to normal kidneys that should be taken into account when using a hydronephrotic model for pharmacological testing.

Animals↗

PubMed1993

Endocardial coronary microcirculation of the beating heart.

Direct and continuous observation of subendocardial (deep myocardial) microcirculation provides essential information on coronary circulation, since cardiac contraction affects subendocardial vessels most vigorously. To achieve this aim, we developed a portable needle-probe video-microscope with a charge-coupled-device (CCD) camera to visualize the subendocardial microcirculation. Images of the subendocardial microcirculation of a porcine beating heart were successfully observed in all cases. The vascular compression by cardiac contraction decreased the diameter of subendocardial arterioles and venules by about 20%.

Animals↗

PubMed1990

Superposition of arteriolar vasomotion waves and regulation of blood flow in skeletal muscle microcirculation.

In skin muscle microcirculation of Syrian hamsters, rhythmic diameter changes were studied along the arteriolar network, under normoxic conditions, at rest. A teflon coated-aluminum chamber was implanted in the dorsum skin of animals. The microcirculation was investigated using intravital microscopy technique. Vessel diameters were determined by a computer-assisted method. Power spectrum analysis of vasomotion recordings was carried out with Fast Fourier Transform and Autoregressive modelling. To determine vasomotion waveform spreading, cross-spectral data (amplitude and phase) were computed, using the modified periodogram method (FFT). The arterioles were classified according to Strahler's method. Order 1 vessels (diameter: 7.50 +/- 1.16 microns) showed the highest frequency, 4-15 cycles per min, and percentage amplitude in the range 60-100%. Order 2 and 3 arterioles had intermediate frequencies, and amplitude in the range 50-100%, and 15-50%, respectively. The largest order 4 vessels (diameter: 28.97 +/- 9.55 microns) had the lowest frequency, 0.3-3 cpm, and amplitude in the range 5-20%. In most networks, cross-correlation analysis revealed two groups of frequency components. Low frequency group was propagated from order 4 and 3 vessels downstream. High frequency components were transmitted upstream from order 1 and 2 arterioles. Therefore, a complex superposition of waveforms resulted from the activity of discrete points along the microvasculature. In conclusion, rhythmic diameter changes of arterioles in skeletal muscle microcirculation regulate blood flow distribution in capillary units and control tissue oxygenation.

Animals↗

PubMed1990

Adrenergic vasomotion in the coronary microcirculation.

The goal of this study was to determine the alpha-adrenergic receptor subtype(s) responsible for constriction at different microvascular levels in the coronary circulation. To accomplish these goals, the epicardial coronary microcirculation of intact beating hearts was viewed through an intravital microscope using stroboscopic epi-illumination. An initial study was designed to establish sites of alpha-adrenergic constriction to norepinephrine in preparations with intact vasomotor tone. For the primary experimental goal, coronary microvascular responses to selective alpha 1-adrenergic (phenylephrine) or alpha 2-adrenergic (BHT-933) agonists were evaluated, when coronary autoregulatory escape mechanisms were blunted during hypoperfusion. Infusion of norepinephrine decreased diameter of arterial vessels greater than 100 microns in diameter, but downstream coronary arterioles dilated significantly, representing autoregulatory escape from adrenergic vasoconstriction. In studies designed to examine the adrenergic receptor subtype (during hypoperfusion), phenylephrine produced modest constriction of vessels throughout the microcirculation (6-9% decrease in diameter), whereas BHT-933 produced marked constriction of small coronary microvessels, those less than 100 microns in diameter (24% decrease in diameter). From these results we conclude: 1) norepinephrine infusion causes disparate responses in the coronary microvasculature: constriction occurs in vessels greater than 100 microns in diameter, but dilation, via autoregulatory escape, predominates in vessels less than 100 microns in diameter; 2) alpha 1-adrenergic receptors are located in coronary arterioles and arteries; and 3) alpha 2-adrenergic receptors are preferentially located in small coronary arterioles. Thus, alpha 1- and alpha 2-adrenergic activation can produce dissimilar constrictor effects in the coronary microcirculation during hypoperfusion.

Adrenergic alpha-Agonists↗

PubMed1995

[Significance of therapy timing for the effects of systemic and local therapy with the ACE inhibitor captopril on intestinal microcirculation in manifest mesenteric ischemia. An animal experiment study in the swine].

We present the results of a study based on an animal model concurring whether captopril can improve microcirculation in the small intestine in nonocclusive mesenteric ischemia dependent on when therapy is begun. Cardiogenic shock was produced by pericardial tamponade with starch solution. The flow in the carotid artery could be reduced to 43% of the preshock value. In four therapy groups and a control group the intestinal microcirculation was examined by laser Doppler flowmetry in the serosa and mucosa. The measurements were taken at regular intervals during the 4 h of the experiments. Captopril was either given systemically or locoregionally through the upper mesenteric artery. Therapy was given at the beginning of the shock or 1 h after induction of shock at a dosage of 0.25 mg/kg body weight as a bolus and continuous application of 10 micrograms/kg body wt. Concerning the hemodynamic changes during shock the group receiving captopril systemically at the beginning of shock showed a significant (P = 0.05) improvement in microcirculation compared to the controls and other therapy groups. Flow reduction was seen in the controls (156-32 relative flow units = RFU) in group Ia (systemic therapy 1 h after shock), as well as the controls (129 to 12 RFU) and, in group Ib (systemic therapy beginning with shock) a flow rise could be seen (307 to 481 RFU). In group IIa (local therapy 1 h after shock) (a steady flow was seen (168-170 RFU) and in group IIb (local therapy beginning with shock) and group Ib an increase in flow was also measured (226-303 RFU). This positive effect of captopril on the intestinal perfusion was observed when applied 1 h after the induction of shock.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1996

Impact of adhesion molecules of the selectin family on liver microcirculation at reperfusion following cold ischemia.

We investigated the role of adhesion molecules in the early phase of reperfusion following cold ischemia. Livers of male Lewis rats were preserved for 0 h (group A) or 24 h in University of Wisconsin (UW) solution without additives (group B) or in UW solution with anti-ICAM-1 antibody (group C) or anti-E-selectin-1, SLe(x) and SLe(a) antibodies (group D). The livers were then reperfused with diluted rat whole blood (DWB; groups A and B). DWB containing anti-ICAM-1 and LFA-1 antibodies (group C) or DWB containing anti-L-selectin, SLe(x) and SLe(a) antibodies (group D). The reperfusion was performed at 37 degrees C for 1 h at 5 cm H2O of perfusion pressure. During reperfusion, hepatic microcirculation was assessed by monitoring portal and peripheral tissue blood flow. Bile production was significantly reduced in group B livers compared with those in group A. Anti-ICAM-1 and LFA-1 antibodies failed to improve hepatic microcirculation, whereas anti-LECAM-1, SLe(x) and SLe(a) antibodies significantly improved the microcirculation. Bile production in group C and D livers was comparable to that in group B livers. Preservation for 24 h significantly increased the release of TNF-alpha from 0.207 to 43.7 pg/g per hour during reperfusion. Monoclonal antibodies to the adhesion molecules did not suppress the release of TNF-alpha in groups C and D. Histological examination demonstrated a lack of leukocyte infiltration or thrombus in hetapic microvessels. The extent of hepatocyte necrosis did not differ among groups B, C, and D. We conclude that the microcirculatory disturbance in the early phase of reperfusion occurs as a result of the tethering of leukocytes through the interaction of the selectin family and their ligands, and that the ICAM-1-LFA-1 pathway is not involved in this step. The lack of improvement in bile production with antibodies to the selectin family and their ligands strongly suggests that other mechanisms participate in the deterioration of hepatic function.

Adenosine↗

PubMed1997

Endothelin-1 levels in portal venous blood in relation to hepatic tissue microcirculation disturbance and hepatic cell injury after ischemia/reperfusion.

This study was conducted to clarify the role of endothelin-1 in the portal vein after hepatic ischemia/ reperfusion and to ascertain whether it is related to hepatic microcirculation disturbance. Using a canine ischemic liver model, the portal and systemic endothelin-1 levels were measured before ischemia, then after 1 h and 2 h of reperfusion, and comparatively evaluated with the serum levels of GOT and lactic dehydrogenase (LDH). As an indicator of liver tissue microcirculation, tissue blood flow volume (TBF) was also measured in the site subjected to ischemia. The animals were divided into: group 1, which received ischemia for 30 min; group 2, which received ischemia for 60 min; and group 3, which received a sequence repeated four times of 15 min ischemia and 10 min reperfusion. The portal endothelin-1 level became significantly elevated after reperfusion compared to that before ischemia in all groups, being significantly higher in group 2 than in the other groups. The systemic endothelin-1 level also increased after reperfusion; significantly in group 2. The portal endothelin-1 level was generally higher than the systemic level, which again was statistically significant in group 2. After 2 h of reperfusion, a significant positive correlation was found between the portal endothelin-I level and serum LDH, whereas a significant negative correlation was found between the portal endothelin-1 level and TBF. The finding that the portal endothelin-1 level became elevated after hepatic ischemia/reperfusion suggests that it probably plays an essential role in hepatic ischemia/ reperfusion injury by adversely influencing tissue microcirculation.

Animals↗