Impact of groin flap ischemia-reperfusion on red blood cell micro-rheological parameters in a follow-up study on rats.

BACKGROUND: Flap hypoperfusion or ischemia-reperfusion (I/R) may occur during preparation-transposition procedures and by postoperative thrombotic complications. Behind the microcirculatory disturbances micro-rheological alterations are also supposed. OBJECTIVE: We aimed to investigate the groin flap I/R with following-up micro-rheological parameters. METHODS: Anesthetized rats were subjected to Control or I/R groups. Groin flaps were prepared bilaterally, pedicled on the superficial epigastric vessels. In the Control group the flaps were re-sutured after one hour, while in I/R group microvascular clips were applied on the pedicles for 60 minutes, then the flaps were repositioned. Besides daily wound control, before the operation and on the 1st, 3rd, 5th, 7th and 14th postoperative days blood samples were collected for testing red blood cell (RBC) deformability (rotational ektacytometry) and aggregation (light-transmission aggregometry). RESULTS: RBC deformability significantly worsened by the 3rd-7th postoperative day in I/R group. RBC aggregation enhanced significantly by the 1st day, in I/R group it remained elevated on the 3rd day as well. In a complicated case with unilateral flap necrosis, RBC deformability and aggregation worsening was outlined from its group (base, 1st, 3rd day). CONCLUSION: Wound healing affected micro-rheological parameters in the early postoperative period. Flap I/R exacerbated the alterations. The parameters markedly worsened in case of flap necrosis.

N,N-dimethyltryptamine Prevents Renal Ischemia-Reperfusion Injury in a Rat Model.

BACKGROUND: Ischemia reperfusion (I/R) injury remains one of the most challenging fields of organ transplantation. It is highly associated with the use of expanded criteria donors that might conclude to delayed graft function or early or late graft failure. OBJECTIVE: To investigate the metabolic, microcirculatory parameters, and histologic changes under the effect of N,N-dimethyltryptamine (DMT) in a renal I/R model in rats. METHOD: In 26 anesthetized rats both kidneys were exposed. In the control group (n = 6) no other intervention happened. In 20 other animals, the right renal vessels were ligated, and after 60 minutes the right kidney was removed. The left renal vessels were clamped for 60 minutes then released, followed by 120 minutes of reperfusion. In the I/R group (n = 10), there was no additive treatment, while in I/R + DMT group (n = 10) DMT was administered 15 minutes before ischemia. Blood samples were taken, laser Doppler measurement was performed, and both kidneys were evaluated histologically. RESULTS: Microcirculation (blood flux units [BFU]) diminished in all groups, but remarkably so in the I/R + DMT group. This group compensated better after the 30th minute of reperfusion. The control and I/R + DMT groups had similar BFUs after 120 minutes of reperfusion, but in the I/R group BFU was higher. Tubular necrosis developed in the I/R and I/R + DMT groups too; it was moderated under DMT effect, and severe without. Histologic injuries were less in I/R + DMT Group compared to non-treated animals. CONCLUSION: Histologic changes characteristic to I/R injuries were reversible and microcirculation recovered at the end of 120 minutes reperfusion under the administration of DMT. DMT can be used for renoprotection in kidney transplantation.

Is the early or delayed remote ischemic preconditioning the more effective from a microcirculatory and histological point of view in a rat model of partial liver ischemia-reperfusion?1.

PURPOSE: To compare early- and late-effect remote ischemic preconditioning (RIPC) by analysing the microcirculatory, hemodynamic and histological changes in partial liver ischemia-reperfusion of rats. METHODS: 60-minute partial liver ischemia followed by 120-minute reperfusion was performed without (Control group, n=7) or with preconditioning. In RIPC groups a tourniquet was applied around the left thigh using 3 cycles of 10-minute ischemia/10-minute reperfusion, one (RIPC-1, n=7) or twenty-four hours (RIPC-24, n=7) before I/R. Hemodynamic and microcirculatory measurements were performed before and after ischemia and in 30th, 60th and 120th minute of reperfusion and histological examination at the end of reperfusion. RESULTS: Blood pressure decreased in all groups followed by biphasic changes in Control group. In RIPC groups R120 values returned almost to normal. Heart rate increased in Control and RIPC-1 groups at R120, while RIPC-24 did not show significant changes. Microcirculation of non-ischemic liver stayed constant in Control and showed significant changes in RIPC-24 group, while in ischemic liver elevated by R120 in all groups. RIPC didn't reduce histological alterations. CONCLUSION: Considering the survival and the results, both remote ischemic preconditioning protocols had beneficial effect in hepatic ischemia-reperfusion, however the histopathological findings were controversial.

Is the early or delayed remote ischemic preconditioning the more effective from a microcirculatory and histological point of view in a rat model of partial liver ischemia-reperfusion?

Abstract Purpose: To compare early- and late-effect remote ischemic preconditioning (RIPC) by analysing the microcirculatory, hemodynamic and histological changes in partial liver ischemia-reperfusion of rats. Methods: 60-minute partial liver ischemia followed by 120-minute reperfusion was performed without (Control group, n=7) or with preconditioning. In RIPC groups a tourniquet was applied around the left thigh using 3 cycles of 10-minute ischemia/10-minute reperfusion, one (RIPC-1, n=7) or twenty-four hours (RIPC-24, n=7) before I/R. Hemodynamic and microcirculatory measurements were performed before and after ischemia and in 30th, 60th and 120th minute of reperfusion and histological examination at the end of reperfusion. Results: Blood pressure decreased in all groups followed by biphasic changes in Control group. In RIPC groups R120 values returned almost to normal. Heart rate increased in Control and RIPC-1 groups at R120, while RIPC-24 did not show significant changes. Microcirculation of non-ischemic liver stayed constant in Control and showed significant changes in RIPC-24 group, while in ischemic liver elevated by R120 in all groups. RIPC didn't reduce histological alterations. Conclusion: Considering the survival and the results, both remote ischemic preconditioning protocols had beneficial effect in hepatic ischemia-reperfusion, however the histopathological findings were controversial.

Beneficial effects of remote organ ischemic preconditioning on micro-rheological parameters during liver ischemia-reperfusion in the rat.

BACKGROUND: Remote ischemic preconditioning (RIPC) can be protective against the damage. However, there is no consensus on the optimal amount of tissue, the number and duration of the ischemic cycles, and the timing of the preconditioning. The hemorheological background of the process is also unknown. OBJECTIVE: To investigate the effects of remote organ ischemic preconditioning on micro-rheological parameters during liver ischemia-reperfusion in rats. METHODS: In anesthetized rats 60-minute partial liver ischemia was induced with 120-minute reperfusion (Control, n = 7). In the preconditioned groups a tourniquet was applied on the left thigh for 3×10 minutes 1 hour (RIPC-1, n = 7) or 24 hours (RIPC-24, n = 7) prior to the liver ischemia. Blood samples were taken before the operation and during the reperfusion. Acid-base, hematological parameters, erythrocyte aggregation and deformability were tested. RESULTS: Lactate concentration significantly increased by the end of the reperfusion. Erythrocyte deformability was improved in the RIPC-1 group, erythrocyte aggregation increased during the reperfusion, particularly in the RIPC-24 group. CONCLUSIONS: RIPC alleviated several hemorheological changes caused by the liver I/R. However, the optimal timing of the RIPC cannot be defined based on these results.

Age- and gender-related hemorheological alterations in intestinal ischemia-reperfusion in the rat.

BACKGROUND: Intestinal ischemia-reperfusion (I/R) is a life-threatening clinical disorder. During I/R, the microrheological parameters of blood (red blood cell deformability and aggregation) worsen, which may contribute to microcirculatory deterioration. Age and gender also have a great influence on hemorheological parameters. We aimed to investigate the gender and age-related microrheological alterations during intestinal I/R. MATERIALS AND METHODS: After the cannulation of the left femoral artery, median laparotomy was performed in Crl:WI rats under general anesthesia. In the young control animals there were no other interventions (female n = 7; male n = 7). In the young (female n = 7; male n = 7) and older I/R groups (female n = 6; male n = 6), the superior mesenteric artery was clipped for 30 min, and a 120-min reperfusion period was observed afterward. Blood samples were taken before and at the 30-min ischemia, in the 30th, 60th, and 120th min of the reperfusion. Hematological parameters, erythrocyte deformability, and aggregation were determined. RESULTS: Hematocrit increased significantly in the younger female I/R group. Red blood cell count was higher in male and older animals. In case of white blood cell count, male animals had higher values compared with females. Platelet count elevated in the younger male and older female I/R animals. Red blood cell deformability worsened, mainly in the male and older I/R groups. Enhanced erythrocyte aggregation was seen in all groups, being more expressed in the female I/R groups. CONCLUSIONS: Microrheological parameters show gender and age-related differences during intestinal I/R. These observations have importance in the planning and evaluation of experimental data.

Hemorheological and metabolic consequences of renal ischemia-reperfusion and their modulation by N,N-dimethyl-tryptamine on a rat model.

BACKGROUND: Micro-rheological relations of renal ischemia-reperfusion (I/R) have not been completely elucidated yet. Concerning anti-inflammatory agents, it is supposed that sigma-1 receptor agonist N,N-dimethyl-tryptamin (DMT) can be useful to reduce I/R injury. OBJECTIVE: To investigate the micro-rheological and metabolic parameters, and the effects of DMT in renal I/R in rats. METHODS: In anesthetized rats from median laparotomy both kidneys were exposed. In Control group (n = 6) no other intervention happened. In I/R group (n = 10) the right renal vessels were ligated and after 60 minutes the organ was removed. The left renal vessels were clamped for 60 minutes followed by 120-minute reperfusion. In I/R+DMT group (n = 10) DMT was administered 15 minutes before the ischemia. Blood samples were taken before/after ischemia and during the reperfusion for testing hematological, metabolic parameters, erythrocyte deformability and aggregation. RESULTS: Lactate concentration significantly increased and accompanied with decreased blood pH. Enhanced erythrocyte aggregation and impaired deformability were observed from the 30th minute of reperfusion. In I/R+DMT group we found diminished changes compared to the I/R group (lactate, pH, electrolytes, red blood cell deformability and aggregation). CONCLUSIONS: Metabolic and micro-rheological parameters impair during renal I/R. DMT could reduce but not completely prevent the changes in this rat model.

Intestinal ischemia-reperfusion leads to early systemic micro-rheological and multiorgan microcirculatory alterations in the rat.

BACKGROUND: Intestinal ischemia-reperfusion (I/R) is a potentially life-threatening situation and its pathomechanism is not fully understood yet. OBJECTIVE: To investigate the early micro-rheological, microcirculatory and morphological consequences of intestinal I/R in a rat model. METHODS: CD rats were anesthetized and subjected to Control (n = 7) or I/R (n = 7) groups. Left femoral artery cannulation and median laparotomy were performed. In the I/R group the superior mesenteric artery was clamped for 30 minutes. Blood samples were taken before (Base) and after the ischemia, at the 30th, 60th and 120th minutes of the reperfusion (R-30, R-60, R-120). Hematological parameters, erythrocyte deformability and aggregation were determined. On the jejunum, the liver and the right kidney laser Doppler flowmetry tests were completed. At the end of experiment histological samples were taken. RESULTS: Hematocrit, leukocyte and platelet counts increased during the reperfusion. Erythrocyte deformability worsened versus Control. All erythrocyte aggregation index values of I/R group increased gradually. Intestinal microcirculatory blood flux units (BFU) did not recover completely after ischemia, at R-30 liver BFU values were lower, and kidney values decreased by R-120. Histology showed signs of I/R injury. CONCLUSIONS: Micro-rheological parameters may show early and significant deterioration during the reperfusion that might contribute further to microcirculatory alterations.

Morphological and microcirculatory evaluation of the rat testis after detorsion with or without a capsular release with a tunica vaginalis flap.

Testicular torsion may lead to serious ischemia, and the viability depends on the duration of torsion and the effect of ischemia-reperfusion. Testicular decompression and tunica vaginalis flap application technique were introduced in 2008 by Kutikov et al. We aimed to examine the impact of this method on the testicular microcirculation and hemorheological parameters in a rat model. Six adult rats underwent bilateral scrotal exploration. Intravaginal torsion of the testis was created by 720° rotation on both sides for 2 h. After detorsion, the right testes underwent tunica albuginea incision and tunica vaginalis flap application. Testicular microcirculation was monitored and hematological parameters, erythrocyte deformability, and aggregation were determined. Measurements were performed before and after torsion, directly after detorsion, on the 1 st -2 nd and 8 th postoperative day. After the last sampling, testicles were removed to determine their volume for histological examinations. The microcirculatory parameters demonstrated slight differences between testicles. Apical zone of the left (nondecompressed) testicles had elevated compared to the middle zone (P < 0.05). On the 2 nd and 8 th day, the microcirculation of the testes normalized but not equally. The erythrocyte aggregation and deformability decreased by the 8 th day. Both testicles underwent atrophy and epithelial necrosis, but the volume of the decompressed ones was lower (1.07 ± 0.08 vs 1.25 ± 0.31). Histologically, there was no significant difference in epithelial damage score between decompressed and nondecompressed testes. In conclusion, 2-h ischemia led to alteration in testicular microcirculation, reduction in volume, changes in hemorheological parameters and serious epithelial necrosis both in decompressed and nondecompressed testicles without remarkable differences.

Sarcocystis-infection of cattle in Hungary.

BACKGROUND: Reports on Sarcocystis-infection of cattle are outdated or lacking in many European countries, including those in the Central-Eastern part of the continent. Therefore, to assess the prevalence of Sarcocystis spp. among bovids in Hungary, a countrywide survey was initiated. In addition, fulminant deaths of four cattle, that showed clinical signs and post mortem lesions resembling acute sarcocystiosis ("Dalmeny disease"), were investigated. METHODS: During the countrywide survey individual heart and oesophagus samples were collected at slaughterhouses from 151 beef cattle and from 15 buffalo, kept in 31 places of Hungary. Analysis for Sarcocystis spp. was carried out with conventional PCRs for the 18S rDNA gene and gel electrophoresis, followed by sequencing of 36 strongly positive samples. Mortality cases were evaluated by histological, molecular, bacteriological and virological analyses of samples from various organs. RESULTS: Among slaughtered cattle the rate of Sarcocystis-infection was 66%. S. cruzi was identified as the most prevalent species in aurochs-like breed, and the zoonotic S. hominis in Hungarian grey cattle. Concerning the sudden deaths of cattle, Sarcocystis-infection could not be demonstrated in organs showing haemorrhages, but S. cruzi cysts were present in the muscles. In one case "S. sinensis" was molecularly identified in the blood (indicating sarcocystaemia). Results of analyses for bacterial/viral pathogens were negative. CONCLUSIONS: S. cruzi appears to be the most prevalent Sarcocystis sp. in cattle in Hungary, followed by the zoonotic S. hominis. However, the rate of infection with both species was shown to differ between cattle breeds. The suspected role of Sarcocystis spp. as causative agents of the fatal cases could not be confirmed.

Re-emergence of bovine piroplasmosis in Hungary: has the etiological role of Babesia divergens been taken over by B. major and Theileria buffeli?

BACKGROUND: The prevalence of bovine babesiosis caused by Babesia divergens has been declining during the past decades in northeastern Hungary, and no cases have been observed since 2008. Infections of cattle with B. major and Theileria buffeli were hitherto reported in southern and western Europe. In other parts of the globe, there is evidence of emergence and a growing clinical importance of T. buffeli and closely related genotypes of the T. orientalis complex. FINDINGS: In a herd of 88 beef cattle kept in northeastern Hungary, bovine piroplasmosis was diagnosed in nine animals through the examination of blood smears or by molecular methods. B. major was identified in five animals, two of which died. In addition, four cattle harboured T. buffeli, and one of these animals was anaemic. Despite their presence, a contributory role of Anaplasma marginale and A. phagocytophilum could not be established in the disease cases. CONCLUSIONS: In this study B. major and bovine theileriosis is reported for the first time in central-eastern Europe, where clinical cases were associated with a mild winter.

Simultaneous investigation of hemodynamic, microcirculatory and arterio-venous micro-rheological parameters in infrarenal or suprarenal aortic cross-clamping model in the rat.

We aimed to investigate hemodynamic, microcirculatory and hemorheological consequence of infrarenal or suprarenal aortic cross-clamping (IRAXC, SRAXC) in the rat. We hypothesized that the magnitude of the changes are different. Twenty-one male rats were randomized into Control, IRAXC or SRAXC groups. Under anesthesia the right carotid artery was cannulated for monitoring heart rate and mean arterial pressure, then median laparotomy was performed. In AXC groups the abdominal aorta and the caudal caval vein were atraumatically clamped for 60 minutes below or above the renal vessels. Before and just after the ischemia, in the 30th and 60th minutes of the reperfusion besides hemodynamic test, laser Doppler flowmetry was used on the liver's, small-intestine's and the kidney's surface, then arterial (cannulated carotid artery) and venous (lateral tail vein) blood samples were taken for determining hematological, acid-base, erythrocytes' deformability, osmoscan and aggregation parameters. We found that when hemodynamic changes were prominent, microcirculatory or hemorheological parameters did not show such large differences. However, every parameter changed in various manners, showing more or less differences between IRAXC and SRAXC groups. Although the largest deviations were observable in SRAXC group, the acid-base and hemodynamic alterations were much more expressed than the micro-rheological ones. Further investigations of in vivo relations-correlations of changes in hemodynamic, microcirculatory, metabolic and hemorheological factors need further studies providing simultaneous monitoring possibilities.