Remote ischemic perconditioning protects the liver from ischemia-reperfusion injury

BACKGROUND

Ischemia-reperfusion (IR)-induced injury is a frequent sequel of major liver resections. IR injury after prolonged surgical interventions could be the source of increased risk of postoperative morbidity and mortality. Hepatoprotective effects of this new feasible method called remote ischemic perconditioning (RIPER) were investigated in our rat model of IR injury.

MATERIALS AND METHODS

Male Wistar rats underwent ischemia for 60 min on two-thirds of their livers, followed by 1, 6, and 24 h of reperfusion (n = 72, 8 per group). During liver ischemia, but before reperfusion, rats in the treated groups received four cycles of brief infrarenal aortic clamping as perconditioning. Liver microcirculation was monitored by laser Doppler flowmeter parallel with mean arterial pressure measurements. Liver tissue injury and redox homeostasis were investigated. Furthermore, serum tumor necrosis factor alpha (TNF-α) levels were measured.

RESULTS

In the RIPER group, compared with the IR group, serum transaminase levels were significantly lower after each reperfusion period (alanine aminotransferase: 1 h, P < 0.001; 6 h, P < 0.05; 24 h, P < 0.01 and aspartate aminotransferase: 1 h, P < 0.001; 6 h, P < 0.05; 24 h, P < 0.05). Reperfusion microcirculatory parameters significantly improved in the perconditioned group compared with those in the IR group (reperfusion area: P = 0.005; maximal plateau: P = 0.0002). Regarding TNF-α levels, significant differences were detected between the two IR injured groups (RIPER versus IR: 1 h, 34.3 ± 12.8 pg/mL versus 205.7 ± 60.9 pg/mL, P < 0.001; 6 h, 60.6 ± 11.7 pg/mL versus 110.4 ± 21.6 pg/mL, P < 0.05). Results of the histologic assessment and redox state measurements also showed favorable changes.

CONCLUSIONS

Our team firstly reported the protective effects of RIPER on liver morphology, redox homeostasis, and microcirculation and proposed the changes of TNF-α expression.

Sublingual microcirculation is impaired in post-cardiac arrest patients

AIM

We hypothesized that microcirculatory dysfunction, similar to that seen in sepsis, occurs in post-cardiac arrest patients and that better microcirculatory flow will be associated with improved outcome. We also assessed the association between microcirculatory dysfunction and inflammatory markers in the post-cardiac arrest state.

METHODS

We prospectively evaluated the sublingual microcirculation in post-cardiac arrest patients, severe sepsis/septic shock patients, and healthy control patients using Sidestream Darkfield microscopy. Microcirculatory flow was assessed using the microcirculation flow index (MFI) at 6 and 24h in the cardiac arrest patients, and within 6h of emergency department admission in the sepsis and control patients.

RESULTS

We evaluated 30 post-cardiac arrest patients, 16 severe sepsis/septic shock patients, and 9 healthy control patients. Sublingual microcirculatory blood flow was significantly impaired in post-cardiac arrest patients at 6h (MFI 2.6 [IQR: 2-2.9]) and 24h (2.7 [IQR: 2.3-2.9]) compared to controls (3.0 [IQR: 2.9-3.0]; p<0.01 and 0.02, respectively). After adjustment for initial APACHE II score, post-cardiac arrest patients had significantly lower MFI at 6-h compared to sepsis patients (p<0.03). In the post-cardiac arrest group, patients with good neurologic outcome had better microcirculatory blood flow as compared to patients with poor neurologic outcome (2.9 [IQR: 2.4-3.0] vs. 2.6 [IQR: 1.9-2.8]; p<0.03). There was a trend toward higher median MFI at 24h in survivors vs. non-survivors (2.8 [IQR: 2.4-3.0] vs. 2.6 [IQR: 2.1-2.8] respectively; p<0.09). We found a negative correlation between MFI-6 and vascular endothelial growth factor (VEGF) (r=-0.49, p=0.038). However, after Bonferroni adjustment for multiple comparisons, this correlation was statistically non-significant.

CONCLUSION

Microcirculatory dysfunction occurs early in post-cardiac arrest patients. Better microcirculatory function at 24h may be associated with good neurologic outcome.

Comparison of parasite sequestration in uncomplicated and severe childhood Plasmodium falciparum malaria

Objectives

To determine whether sequestration of parasitized red blood cells differs between children with uncomplicated and severe Plasmodium falciparum malaria.

Methods

We quantified circulating-, total- and sequestered-parasite biomass, using a mathematical model based on plasma concentration of P. falciparum histidine rich protein 2, in Gambian children with severe (n = 127) and uncomplicated (n = 169) malaria.

Results

Circulating- and total-, but not sequestered-, parasite biomass estimates were significantly greater in children with severe malaria than in those with uncomplicated malaria. Sequestered biomass estimates in children with hyperlactataemia or prostration were similar to those in uncomplicated malaria, whereas sequestered biomass was higher in patients with severe anaemia, and showed a trend to higher values in cerebral malaria and fatal cases. Blood lactate concentration correlated with circulating- and total-, but not sequestered parasite biomass. These findings were robust after controlling for age, prior antimalarial treatment and clonality of infection, and over a realistic range of variation in model parameters.

Conclusion

Extensive sequestration is not a uniform requirement for severe paediatric malaria. The pathophysiology of hyperlactataemia and prostration appears to be unrelated to sequestered parasite biomass. Different mechanisms may underlie different severe malaria syndromes, and different therapeutic strategies may be required to improve survival.

Effects of different resuscitation fluid on severe acute pancreatitis

AIM: To compare effects of different resuscitation fluid on microcirculation, inflammation, intestinal barrier and clinical results in severe acute pancreatitis (SAP).

METHODS: One hundred and twenty patients with SAP were enrolled at the Pancreatic Disease Institute between January 2007 and March 2010. The patients were randomly treated with normal saline (NS group), combination of normal saline and hydroxyethyl starch (HES) (SH group), combination of normal saline, hydroxyethyl starch and glutamine (SHG group) in resuscitation. The ratio of normal saline to HES in the SH and SHG groups was 3:1. The glutamine (20% glutamine dipeptide, 100 mL/d) was supplemented into the resuscitation liquid in the SHG group. Complications and outcomes including respiratory and abdominal infection, sepsis, abdominal hemorrhage, intra-abdominal hypertension, abdominal compartment syndrome (ACS), renal failure, acute respiratory distress syndrome (ARDS), multiple organ dysfunction syndrome (MODS), operation intervention, length of intensive care unit stay, length of hospital stay, and mortality at 60 d were compared. Moreover, blood oxygen saturation (SpO₂), gastric intramucosal pH value (pHi), intra-abdominal pressure (IAP), inflammation cytokines, urine lactulose/mannitol (L/M) ratio, and serum endotoxin were investigated to evaluate the inflammatory reaction and gut barrier.

RESULTS: Compared to the NS group, patients in the SH and SHG groups accessed the endpoint more quickly (3.9 ± 0.23 d and 4.1 ± 0.21 d vs 5.8 ± 0.25 d, P < 0.05) with less fluid volume (67.26 ± 28.53 mL/kg/d, 61.79 ± 27.61 mL/kg per day vs 85.23 ± 21.27 mL/kg per day, P < 0.05). Compared to the NS group, incidence of renal dysfunction, ARDS, MODS and ACS in the SH and SHG groups was obviously lower. Furthermore, incidence of respiratory and abdominal infection was significantly decreased in the SH and SHG groups, while no significant difference in sepsis was seen. Moreover, less operation time was needed in the SH and SHG group than the NS group, but the difference was not significant. The mortality did not differ significantly among these groups. Blood SpO₂ and gastric mucosal pHi in the SH and SHG groups increased more quickly than in the NS group, while IAP was significantly decreased in the SH and SHG group. Moreover, the serum tumor necrosis factor-α, interleukin-8 and C-reactive protein levels in the SH and SHG groups were obviously lower than in the NS group at each time point. Furthermore, urine L/M ratio and serum endotoxin were significantly lower in the SH group and further decreased in the SHG group.

CONCLUSION: Results indicated that combination of normal saline, HES and glutamine are more efficient in resuscitation of SAP by relieving inflammation and sustaining the intestinal barrier.

Cellular signalling pathways mediating dilation of porcine pial arterioles to adenosine A₂A receptor activation

AIMS

Adenosine is a potent vasodilator contributing to cerebral blood flow regulation during metabolic stress. However, the distribution of adenosine receptor subtypes and underlying signalling mechanisms for dilation of pial arterioles remain unclear. The present study aimed at addressing these issues.

METHODS AND RESULTS

Isolated porcine pial arterioles were subjected to study of vasomotor function, localization of adenosine receptors, and production of nitric oxide (NO). Concentration-dependent vasodilation to adenosine was inhibited by A₂A receptor antagonist ZM241385 but not by A₁ receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine. A₂A receptors were detected in endothelium and smooth muscle of pial arterioles via immunohistochemistry. Adenosine significantly increased arteriolar production of NO, and the induced dilation was insensitive to KATP channel blocker glibenclamide but was attenuated by endothelial denudation, NO synthase inhibitor L-NAME, or guanylyl cyclase inhibitor ODQ in a similar manner. Both inward rectifier potassium (Kir) channel inhibitor barium and cAMP signalling inhibitor Rp-8-Br-cAMPS attenuated adenosine-induced dilation. In the presence of L-NAME or the absence of endothelium, addition of Rp-8-Br-cAMPS but not barium further reduced adenosine-induced responses. Barium diminished endothelium-independent vasodilation to NO donor sodium nitroprusside. Comparable to the adenosine-induced response, vasodilation to A₂A receptor agonist CGS21680 was attenuated by endothelial removal, ZM241385, L-NAME, barium, or Rp-8-Br-cAMPS, but not by glibenclamide.

CONCLUSION

Adenosine evokes dilation of porcine pial arterioles via parallel activation of endothelial and smooth muscle A₂A receptors. Stimulation of endothelial NO production activates smooth muscle guanylyl cyclase for vasodilation by opening Kir channels. Adenosine also activates smooth muscle cAMP signalling leading to vasodilation.

Prolonged vasoconstriction of resistance arteries involves vascular smooth muscle actin polymerization leading to inward remodelling

AIMS

Inward remodelling of the resistance vasculature is predictive of hypertension and life-threatening cardiovascular events. We hypothesize that the contractile mechanisms responsible for maintaining a reduced diameter over time in response to prolonged stimulation with vasoconstrictor agonists are in part responsible for the initial stages of the remodelling process. Here we investigated the role of vascular smooth muscle (VSM) actin polymerization on agonist-induced vasoconstriction and development of inward remodelling.

METHODS AND RESULTS

Experiments were conducted in Sprague-Dawley rat resistance vessels isolated from the cremaster and mesentery. Within blood vessels, actin dynamics of VSM were monitored by confocal microscopy after introduction of fluorescent actin monomers through electroporation and by differential centrifugation to probe globular (G) and filamentous (F) actin content. Results indicated that 4 h of agonist-dependent vasoconstriction induced inward remodelling and caused significant actin polymerization, elevating the F-/total-actin ratio. Inhibition of actin polymerization prevented vessels from maintaining prolonged vasoconstriction and developing inward remodelling. Activation of the small GTPases Rho/Rac/Cdc42 also increased the F-/total-actin ratio and induced inward remodelling, while inhibition of Rho kinase or Rac-1 prevented inward remodelling. Disruption of the actin cytoskeleton reversed the inward remodelling caused by prolonged vasoconstriction, but did not affect the passive diameter of freshly isolated vessels.

CONCLUSION

These results indicate that vasoconstriction-induced inward remodelling is in part caused by the polymerization of actin within VSM cells through activation of small GTPases.

The effects of non-leukoreduced red blood cell transfusions on microcirculation in mixed surgical patients

BACKGROUND

The impact of the storage process on oxygen-carrying properties of red blood cells and the efficacy of red blood cell (RBC) transfusions concerning tissue oxygenation remain an issue of debate in transfusion medicine. Storage time and leukocyte content probably interact since longer storage duration is thought to cause greater accumulation of leukocyte-derived cytokines and red blood cell injury.

OBJECTIVES

The aim of this study was to investigate the effects of storage and the efficacy of fresh (stored for less than 1 week) versus aged (stored for more than 3 weeks) non-leukoreduced RBC transfusions on sublingual microvascular density and flow in mixed surgical patients.

METHODS

Eighteen surgical patients were included in this study. Patients were randomly assigned into two groups receiving fresh (Group A) and aged (Group B) RBC transfusions. Sublingual microcirculatory functional capillary density (FCD) and microvascular flow index (MFI) were assessed using orthogonal polarization spectral (OPS) imaging. Measurements and collection of blood samples were performed after induction of general anesthesia, before RBC transfusion and 30 min after the RBC transfusion ended.

RESULTS

In both groups RBC transfusions caused an increase in hemoglobin concentration (p<0.001). RBC transfusions increased FCD in Group A (p<0.001), while FCD remained unaffected in Group B. Changes in MFI following RBC transfusion in both groups remained unaltered.

CONCLUSIONS

Fresh non-leukoreduced RBC transfusions but not RBCs stored for more than 3weeks, were effective in improving microciruculatory perfusion by elevating the number of perfused microvessels in mixed surgical patients.

Aging exacerbates microvascular endothelial damage induced by circulating factors present in the serum of septic patients

The elderly patients show a significantly elevated mortality rate during sepsis than younger patients, due to their higher propensity to microvascular dysfunction and consequential multiorgan failure. We tested whether aging renders vascular endothelial cells more susceptible to damage induced by inflammatory factors present in the circulation during sepsis. Primary microvascular endothelial cells derived from young (3 months) and aged (24 months) Fischer 344 × Brown Norway rats were treated with sera obtained from sepsis patients and healthy controls. Oxidative stress (MitoSox fluorescence), death receptor activation (caspase 8 activity), and apoptotic cell death (caspase 3 activity) induced by treatment with septic sera were exacerbated in aged endothelial cells as compared with responses obtained in young cells. Induction of heme oxygenase-1 and thrombomodulin in response to treatment with septic sera was impaired in aged endothelial cells. Treatment with septic sera elicited greater increases in tumor necrosis factor-α expression in aged endothelial cells, as compared with young cells, whereas induction of inducible nitric oxide synthase, intercellular adhesion molecule-1, and vascular cell adhesion molecule did not differ between the two groups. Collectively, aging increases sensitivity of microvascular endothelial cells (MVECs) to oxidative stress and cellular damage induced by inflammatory factors present in the circulation during septicemia. We hypothesize that these responses may contribute to the increased vulnerability of elderly patients to multiorgan failure associated with sepsis.

Premature aging of the microcirculation in patients with advanced chronic kidney disease

Background

Increasing age and advanced chronic kidney disease (CKD) are both associated with an attenuated vasodilator response of the skin microcirculation. In the present study, we investigated the effect of aging on microvascular reactivity in patients with advanced CKD.

Methods

Acetylcholine (ACh)-mediated endothelium-dependent vasodilation and sodium nitroprusside (SNP)-mediated endothelium-independent vasodilation were assessed by iontophoresis combined with laser Doppler flowmetry. Microvascular function was compared between 52 patients with advanced CKD (stage 4–5: n = 16; end-stage renal disease: n = 36) and 33 healthy control subjects. As aging has an important effect on microvascular function, both control subjects and CKD patients were divided in subgroups younger and older than 45 years. Linear regression analysis was applied to assess potential associations between microvascular function and various demographic and clinical parameters.

Results

There were three main findings. (1) In young patients with advanced CKD, both ACh- and SNP-mediated vasodilations were impaired if compared to young healthy controls (p = 0.04 and p = 0.056, respectively). (2) In young patients with advanced CKD, microvascular function was similar to old healthy controls and elderly patients with advanced CKD. (3) Whereas age was inversely associated with microvascular function in healthy controls (log ACh-mediated vasodilation R = −0.41; p = 0.02 and log SNP-mediated vasodilation R = −0.38; p = 0.03), no such relation was found in patients with advanced CKD.

Conclusions

Our results are consistent with premature aging of the microvascular vasodilatory capacity in patients with advanced CKD.

Lower limb pain caused by insufficient muscular microcirculation

Lumbar spinal surgery is a common procedure to treat low back pain. To remark that lower limb perfusion insufficiency may induce the similar syndrome as neuropathic pain, 1,076 cases of postspinal surgery was surveyed within 5 years, in which 51 cases had no obvious improvement 3 months after surgery; 27 cases received second operation because of instability, inadequate decompression, and wrong level; and the other 27 cases including 3 cases after twice spinal surgeries were enrolled. Physical examinations were presented with atypical neuropathic pain and muscle wasting at single lower limbs which deteriorated with long-distance walking. Computed tomography or magnetic resonance imaging scan was studied including the neural structure and lower limb angiography. The report showed degenerative change without definite neural structural compression or vascular occlusion. There was also no significant finding of electrodiagnostic study. The rest radionuclide study of lower limb muscle and myocardium was performed in these 27 cases using Thallium-201. All patients presented 9-24 % (~14%) muscle perfusion difference compared with two legs. Most of peripheral arterial occlusion disease cases presented the symptoms with ischemic pain and vascular claudication. In the study, the patients presented not only ischemic limb but also the bizarre symptoms, such as low back pain with or without radiating root pain and sensory disturbance. Physicians should be aware of the possibility of lower limb pain caused by lower perfusion syndrome.

Treatment with low-molecular-weight heparin reduces blood levels of PAF and ET-1/NO in rats with severe acute pancreatitis and hyperlipemia

AIM: To investigate the effect of treatment with low-molecular-weight heparin (LMWH) on microcirculation dysfunction in rats with severe acute pancreatitis (SAP) and hyperlipemia.

METHODS: SD rats were fed a high-fat diet for four weeks to induce hyperlipemia and randomly divided into sham operation group, control group, and experimental group. The control group and experimental group were then used to induce SAP, while the sham operation group underwent a sham operation. At 0, 6, 12 and 18 h after SAP induction, the experimental group was subcutaneouly injected with LMWH, and the control group was injected with normal saline. The concentrations of PAF and ET-1/NO in the portal vein blood were measured, and pancreatic microcirculatory structure was observed by electron microscopy.

RESULTS: The concentrations of PAF and ET-1/NO in the experimental group (5.9250 mmol/L ± 0.6113 mmol/L, 3.5368 ± 0.26) were significantly lower than those in the control group (7.4059 mmol/L ± 0.4281 mmol/L, 4.1697 ± 0.08), but were significantly higher than those in the sham operation group (4.4950 mmol/L ± 0.2628 mmol/L, 2.5133 ± 0.20). In addition, treatment with LWMH improved pancreatic microcirculation.

CONCLUSION: Treatment with LMWH improves pancreatic microcirculation in rats with SAP and hyperlipemia.

Recurrence of Takotsubo cardiomyopathy with coronary slow flow phenomenon

This report presents the case of a 54-year-old female with Takotsubo cardiomyopathy that recurred 12 years after the first episode. The coronary angiography at the first admission revealed ergonovine-induced coronary vasoconstriction in the left coronary artery, and recurrence recurred after the interruption of vasodilator therapy to prevent vasospasm. In addition, the coronary angiography both in the first and second event demonstrated coronary slow flow phenomenon, which improved after the intracoronary administration of nicorandil. These findings indicate that coronary microvascular constriction plays an important role in the pathophysiology of Takotsubo cardiomyopathy.

Regulation of Coronary Vasomotor Function by Reactive Oxygen Species

Overproduction of reactive oxygen species is closely associated with cardiovascular diseases in part by impairing endothelial function and consequently compromising blood flow regulation. Superoxide and hydrogen peroxide are elevated under various disease states with reduced endothelium-derived nitric oxide bioavailability. The oxidative stress elicited by angiotensin II, C-reactive protein and tumor necrosis factor-α is mediated by the activation of different redox signaling pathways in the microvasculature. The upregulation of L-arginine consuming enzyme arginase also contributes to the reduced nitric oxide bioavailability during oxidative stress. Hydrogen peroxide exhibits vasodilator function in the coronary microcirculation and plays an important role in the physiological regulation of coronary blood flow. However, excessive production of hydrogen peroxide impairs endothelial function by reducing L-arginine availability through hydroxyl radical-mediated upregulation of arginase. This review summarizes the current knowledge on the effects superoxide and hydrogen peroxide on vasomotor function regulated by the endothelium-derived nitric oxide and prostacyclin in the coronary microcirculation.

Slow Coronary Flow is Related to Increased Carotid Intima-Media Thickness but Not Pulse Wave Velocity

Background and Objectives

Slow coronary flow (SCF) is characterized by delayed contrast dye opacification without significant stenosis of epicardial coronary arteries. However, the pathophysiology and clinical implications of SCF are not fully understood. Some reports have suggested that SCF might be caused by atherosclerosis in the coronary artery microvasculature. Measuring carotid intima-media thickness (IMT) and pulse wave velocity (PWV), which are non-invasive and simple diagnostic tools, was developed to detect subclinical atherosclerosis. Thus, we determined IMT and PWV, and their possible relationship in a SCF group and a normal coronary flow (NCF) group of patients.

Subjects and Methods

We included 101 patients who complained of chest pain but had a normal coronary angiogram. Thrombolysis in Myocardial Infarction frame count (TIMI frame count, TFC) was evaluated in the left and right coronary arteries. We defined SCF as a TFC of more than 25. Carotid IMT was measured by ultrasonography in both common carotid arteries. PWV was calculated from pulse transit time between the brachial and ankle arteries.

Results

Fifteen patients were included in the SCF group and 86 patients in the NCF group. Male patients (n=11, 73.3%) were significantly more common in the SCF group than in the NCF group (n=37, 43.0%, p<0.05). The TFC of the SCF and NCF groups were 28.8±3.5 and 15.7±4.5, respectively. The carotid IMT in the SCF group increased significantly compared to that in the NCF group (1.2±0.3 mm vs. 0.8±0.1 mm, p<0.01). However, no significant difference in PWV was observed between the two groups.

Conclusion

SCF may reflect early atherosclerotic changes in the coronary artery microvasculature.

Changes in color and blood flow of the tongue of HBV transgenic mice

AIM: To examine the changes in color and microvascular blood flow of the tongue of HBV transgenic mice.

METHODS: Ten C57BL/6J-HBV transgenic mice and 10 normal mice were used in the study. The tongue color of the mice was observed daily. The microvascular blood flow of tongue and liver were detected with a laser Doppler blood flowmeter. Blood samples were taken to measure serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Pathological changes in the tongue and liver were evaluated by HE staining.

RESULTS: The tongue was purple in color in six HBV transgenic mice and dark red in the remaining four transgenic mice. In contrast, the tongue of normal mice was light red in color. The hue of the tongue become darker and brightness become weaker in HBV transgenic mice (0.206 ± 0.13 vs 0.794 ± 0.13; 0.479 ± 0.07 vs 0.331 ± 0.04, P < 0.01, P < 0.001) compared to normal mice. The microvascular blood flow perfusion and velocity in the tongue and liver in HBV transgenic mice decreased significantly compared to normal mice. Obvious inflammatory changes were observed in the liver and tongue of HBV transgenic mice.

CONCLUSION: The tongue of most HBV transgenic mice became purple, whose mechanism is related with microcirculation disorder. Inflammatory changes in the liver and tongue in HBV transgenic mice are perhaps the main cause of microcirculation disorder.

Cardiovascular physiology at the bench for application in the clinic

Our research focuses on microphysiological aspects of the cardiovascular system, with an emphasis on what is occurring in heart tissues, to learn more about how various diseases arise and how they can be avoided or cured. These diseases include atherosclerosis, diabetes, myocardial infarction, obesity and ischemia/reperfusion (I/R). We use animal models, particularly mice, to aid us in these studies. A key feature of our work centers on dissection of coronary arterioles and examining their functionality using drugs, electrophysiology, fluoroscopy, genomics, proteomics, and standard chemical analyses to determine their physiological status, and compare it with other treated animals. My laboratory is focusing on anti-inflammatory and antioxidative stress therapeutic effects, the roles of sodium salicylate, exercise and resveratrol in type 2 diabetes, I/R injury, obesity, and atherosclerosis. Recently, we began investigations of the effects of stem cells and gastric bypass surgery on vascular dysfunction in obesity and diabetes. Our work identifies how diet, exercise, surgical interventions and drugs can be considered to combat these diseases in a clinical setting.

Hemolysis results in impaired intestinal microcirculation and intestinal epithelial cell injury

AIM: To study the effect of circulating cell-free oxyhemoglobin (FHb) on intestinal microcirculation and intestinal epithelial injury in a rat model.

METHODS: To induce elevated intravascular circulating FHb, male Sprague-Dawley rats received water or FHb infusion. Microcirculatory changes in jejunum, ileum and colon were evaluated using fluorescent microspheres. Intestinal injury was quantified as plasmatic release of ileal lipid binding protein (iLBP) and verified by histological analysis of the ileum.

RESULTS: Water and FHb infusions resulted, when compared with saline infusion, in reduced intestinal microcirculation (after 30 min P < 0.05, or better; after 60 min FHb infusion P < 0.05 for jejunum and colon). Circulating FHb levels correlated significantly with release of iLBP (Spearman r = 0.72, P = 0.0011). Epithelial cell injury of the villi was histologically observed after water and FHb infusions.

CONCLUSION: This study shows that circulating FHb leads to a reduction in intestinal microcirculatory blood flow with marked injury to intestinal epithelial cells. These data support the hypothesis that circulating FHb contributes to the development of intestinal injury.

Coronary microvascular dysfunction in diabetes mellitus: A review

The exploration of coronary microcirculatory dysfunction in diabetes has accelerated in recent years. Cardiac function is compromised in diabetes. Diabetic patients manifest accelerated atherosclerosis in coronary arteries. These data are confirmed in diabetic animal models, where lesions of small coronary arteries have been described. These concepts are epitomized in the classic microvascular complications of diabetes, i.e. blindness, kidney failure and distal dry gangrene. Most importantly, accumulating data indicate that insights gained from the link between inflammation and diabetes can yield predictive and prognostic information of considerable clinical utility. This review summarizes the evidence for the predisposing factors and the mechanisms involved in diabetes, and assesses the current state of knowledge regarding the triggers for inflammation in this disease. We evaluate the roles of hyperglycemia, oxidative stress, polyol pathway, protein kinase C, advanced glycation end products, insulin resistance, peroxisome proliferator-activated receptor-γ, inflammation, and diabetic cardiomyopathy as a "stem cell disease". Furthermore, we discuss the mechanisms responsible for impaired coronary arteriole function. Finally, we consider how new insights in diabetes may provide innovative therapeutic strategies.

Blue or purple tongue in patients with chronic hepatitis B: mechanisms and clinical significance

AIM: To examine the distribution of blue or purple tongue in patients with chronic hepatitis B by analyzing the relationship of blue or purple tongue with age, gender, state of the illness, syndrome elements, and microcirculation.

METHODS: A total of 113 patients with chronic hepatitis B were investigated for tongue color, syndrome elements of Chinese medicine, state of the illness, and nail microcirculation.

RESULTS: Blue or purple is the main tongue color in patients with chronic hepatitis B. The development of blue or purple tongue is highly correlated with state of the illness (r = 0.293, P = 0.013), damp-heat syndrome element (r = -0.251, P = 0.023), blood stasis (r = -0.226, P = 0.043) and patients' age. Microcirculatory disturbance may be responsible for the formation of blue or purple tongue in patients with chronic hepatitis B.

CONCLUSION: The development of blue or purple tongue may provide a guide to syndrome differentiation in patients with chronic hepatitis B.

Perfusion CT findings in liver of patients with tumor during chemotherapy

AIM: To investigate the microcirculation changes in liver of patients with tumor during chemotherapy by perfusion computed tomography (CT).

METHODS: Sixty patients with tumor and 20 controls were enrolled in this study. Perfusion CT parameters of patients and controls were compared, including hepatic perfusion index (HPI), mean transit time (MTT), and permeability-surface area product (PS). Correlation between perfusion CT parameters, treatment cycle and alanine aminotransferase (ALT) level was studied.

RESULTS: No difference was found in HPI (25.68% ± 7.38% vs 26.82% ± 5.13%), MTT (19.67 ± 5.68 s vs 21.70 ± 5.43 s) and PS (17.00 ± 4.56 mL/100 mL per min vs 19.92 ± 6.35 mL/100 mL per min) between patients and controls. The HPI and MTT were significantly higher in patients undergoing 2 cycles of chemotherapy than in controls and those undergoing 1 cycle of chemotherapy (29.76% ± 5.87% vs 25.68% ± 7.38% and 25.35% ± 4.05%, and 25.61 ± 5.01 s vs 19.67 ± 5.68 s and 19.74 ± 4.54 s, respectively, P < 0.05). The HPI was higher in patients with hepatic steatosis than in controls and those without hepatic steatosis (30.85% ± 6.17% vs 25.68% ± 7.38% and 25.70% ± 4.24%, P < 0.05). Treatment cycle was well correlated with HPI and MTT (r = 0.40, r = 0.50, P < 0.01). ALT level was not correlated with perfusion CT parameters.

CONCLUSION: HPI and MTT are significantly increased in patients with tumor during chemotherapy and well correlated with treatment cycle. Chemotherapy affects hepatic microcirculation in patients with tumor. Changes in hepatic microcirculation can be quantitatively assessed by perfusion CT.

Curcumin reduces hepatic nitric oxide production in early-stage ischemia/reperfusion in rats

AIM: To investigate the effects of curcumin on the microcirculation in early-stage ischemia/reperfusion injury in rats.

METHODS: Wistar rats were randomized into three groups: sham-operation group, dimethyl sulfoxide (DMSO) group (treated with 1 mL of DMSO twice) and curcumin group (treated with 40 mg/kg of curcumin twice). The level of serum transaminase, the content of hepatic nitric oxide (NO), and the expression of nitric oxide synthase (NOS), inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) mRNAs in liver tissue were determined to evaluate the effects of curcumin on the microcirculation in early-stage ischemia/reperfusion (reperfusion for 1 h and 3 h).

RESULTS: Compared with the DMSO group, curcumin decreased the levels of serum alanine transaminase (603.8 U/L ± 64.5 U/L vs 758.1 U/L ± 114.7 U/L and 837.1 U/L ± 33.3 U/L vs 1012.7 U/L ± 119.8 U/L, respectively; both P < 0.01) and aspartate aminotransferase (605.7 U/L ± 65.7 U/L vs 779.5 U/L ± 124.3 U/L and 849.6 U/L ± 36.0 U/L vs 1027.8 U/L ± 139.8 U/L, respectively; both P < 0.01), relieved hepatic pathological damage, reduced the content of NO (0.455 ± 0.056 vs 0.594 ± 0.087 and 0.492 ± 0.040 vs 0.671 ± 0.079, respectively; both P < 0.01) derived from iNOS, and down-regulated the expression of iNOS mRNA (0.426 ± 0.075 vs 0.569 ± 0.073 and 0.527 ± 0.066 vs 0.702 ± 0.089, respectively; both P < 0.01) in the liver tissue in early-stage ischemia/reperfusion (reperfusion for 1 h and 3 h).

CONCLUSION: Curcumin can relieve hepatic cell injury by decreasing the content of NO derived from iNOS and reducing hepatic microcirculation disturbance in early-stage ischemia/reperfusion injury in rats.

Effect of surgical traumas on microcirculation

Background:

Adequate microcirculation in different tissues maintains the physiological function and heals surgical wounds. In any surgical procedure, the commonly used instruments are cautery, tissue forceps, and clamps. The fact that their inappropriate use produces an adverse effect on microcirculation is often not realized. By this study, we could demonstrate live, the effect of these surgical traumas.

Methods:

The study was conducted on the inferiorly based fasciocutaneous flap with a fascial extension in patients with a distal leg defect. The extended fascial flap was mounted on a glass slide and observed for live microcirculation under ×160 magnification. Three methods were used: (a) cautery in low power, (b) microcrushing forceps to crush the vessels, and (c) noncrushing clamps at the base of the fascial flap.

Results:

It was observed that the vessels are well protected within the deep fascia. Once the fascia was pierced the current damaged the vessel wall. As the wattage was increased, it caused charring of the tissue and multiple vessels ultimately leading to cessation of blood flow. Once the vessel wall was crushed by forceps, blood extravasated in a variable intensity depending upon the size of the vessel. Clamping led to gradual slowing of blood flow with microclot formation. In certain vessels, there was discontinuity in the blood column and ultimately the blood flow stopped.

Conclusion:

This study showed live demonstration of the effect of surgical traumas on microcirculation. It should guide the surgeons to select the use of appropriate instruments which will cause minimal damage to vascularity and thereby lead to a better surgical outcome.

Vasculogenic mimicry and microcirculation in tumors

Vasculogenic mimicry (VM), a term that describes a novel form of angiogenesis-independent microcirculation pattern recently found in few highly aggressive tumors, is formed by tumor cells, rather than endothelial cells. VM is closely correlated with the invasiveness, metastasis and prognosis of related tumors. The presence of VM is associated with an embryonic like phenotype acquired by tumor cells and the biological effects of many proteins. Furthermore, tumor microenvironment also plays an important role in the development of VM. Here, we will review the advances in research on the characteristic, formative mechanisms and clinical significance of VM.

The microcirculation in sepsis

SUMMARY

Sepsis is a leading cause of mortality in critically ill patients. The pathophysiology of sepsis involves a highly complex and integrated response, including the activation of various cell types, inflammatory mediators, and the haemostatic system. Recent evidence suggests an emerging role of the microcirculation in sepsis, necessitating a shift in our locus away Irom the macrohaemodynamics to ill icrohaemodynanmics in a septic patient. This review article provides a brief overview of the microcirculation, its assessment techniques, and specific therapies to resuscitate the microhaemodynamics.