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.

Beneficial postoperative micro-rheological effects of intraoperative administration of diclophenac or ischemic preconditioning in patients with lower extremity operations - Preliminary data.

BACKGROUND: Ischemia-reperfusion (I/R) may worsen blood rheology that has been demonstrated by clinical and experimental data. It is also known that anti-inflammatory agents and preconditioning methods may reduce I/R injury. OBJECTIVE: We aimed to analyze hemorheological alterations in elective knee operations and the effects of intraoperative nonsteroidal anti-inflammatory drug (NSAID) administration and application of ischemic preconditioning. METHODS: Hemorheological variables of 17 patients with total knee replacement or anterior crucial ligament replacement were analyzed. The ischemic (tourniquet) time was 92±15 minutes. Seven patients did not receive NSAID (Control group), 5 patients got i.v. sodium-diclophenac 10 minutes before and 6 hours after reperfusion. Five patients had ischemic preconditioning (3×15 minutes). Blood samples were collected before the ischemia, 10 minutes after reperfusion, on the 1st and 2nd p.o. day. RESULTS: Whole blood viscosity didn't show notable inter-group differences, except for a slight decrease in the preconditioning group. RBC deformability decreased, erythrocyte aggregation enhanced by the 1st and 2nd p.o. days in Control group. In NSAID and preconditioning groups the changes were moderate, aggregation values significantly lowered compared to the Control group. CONCLUSION: Intraoperatively administered diclophenac or ischemic preconditioning could moderate the deterioration in micro-rheological parameters caused by I/R in patients.

Changes of Hematological and Hemorheological Parameters in Rabbits with Hypercholesterolemia.

Hypercholesterolemia plays an important role in the development of atherosclerosis, leading to endothelial dysfunction, ischemic events, and increased mortality. Numerous studies suggest the pivotal role of rheological factors in the pathology of atherosclerosis. To get a more detailed hematological and hemorheological profile in hypercholesterolemia, we carried out an experiment on rabbits. Animals were divided into two groups: the control group (Control) was kept on normal rabbit chow, the high-cholesterol diet group (HC) was fed with special increased cholesterol-containing food. Hematological parameters (Sysmex K-4500 automate), whole blood and plasma viscosity (Hevimet-40 capillary viscometer), red blood cell (RBC) aggregation (Myrenne MA-1 aggregometer), deformability and mechanical stability (LoRRca MaxSis Osmoscan ektacytometer) were tested. The white blood cell and platelet count, mean corpuscular volume, and mean corpuscular hemoglobin were significantly higher in the HC group, while the RBC count, hemoglobin, and hematocrit values were lower than the Control data. Viscosity values corrected to 40% hematocrit were higher in the HC group. The RBC aggregation significantly increased in the HC vs. the Control. The HC group showed significantly worse results both in RBCs' deformability and membrane stability. In conclusion, the atherogenic diet worsens the hematological and macro- and micro-rheological parameters, affecting blood flow properties and microcirculation.

Examination of the relation between red blood cell aggregation and hematocrit in human and various experimental animals.

BACKGROUND: Red blood cell (RBC) aggregation plays an important role in the physiological processes of the microcirculation. The complete mechanism of aggregation is still unclear, and it is influenced by several cellular and plasmatic factors. One of these factors is the hematocrit (Hct). OBJECTIVE: We hypothesized that the relation of RBC aggregation and Hct differs between species. METHODS: From anticoagulated blood samples of healthy volunteers, rats, dogs, and pigs, 20, 40, and 60 %Hct RBC, autologous plasma suspensions were prepared. Hematological parameters and RBC aggregation was determined by light-transmission and light-reflection method. RESULTS: Suspensions at 20%and 60%Hct expressed lower RBC aggregation than of 40%Hct suspensions, showing inter-species differences. By curve fitting the Hct at the highest aggregation value differed in species (human: 45.25%- M 5 s, 40.86%- amp; rat: 44.44 %- M1 10 s, 39.37%- amp; dog: 42.48%- M 5 s, 44.29%- amp; pig: 47.63%- M 5 s, 52.8%- amp). CONCLUSION: RBC aggregation - hematocrit relation shows inter-species differences. Human blood was found to be the most sensitive for hematocrit changes. The more obvious differences could be detected by M 5 s by light-transmission method and amplitude parameter using light-reflection method.

Alterations of Selected Hemorheological and Metabolic Parameters Induced by Physical Activity in Untrained Men and Sportsmen.

Optimal tissue oxygen supply is essential for proper athletic performance and endurance. It also depends on perfusion, so on hemorheological properties and microcirculation. Regular exercise is beneficial to the rheological status, depending on its type, intensity, and duration. We aimed to investigate macro and microrheological changes due to short, high-intensity exercise in professional athletes (soccer and ice hockey players) and untrained individuals. The exercise was performed on a treadmill ergometer during a spiroergometry examination. Blood samples were taken before and after exercise to analyze lactate concentration, hematological parameters, blood and plasma viscosity, and red blood cell (RBC) deformability and aggregation. Leukocyte, RBC and platelet counts, and blood viscosity increased with exercise, by the largest magnitude in the untrained group. RBC deformability slightly impaired after exercise, but showed better values in ice hockey versus soccer players. RBC aggregation increased with exercise, dominantly in ice hockey players. Lactate increased mostly in soccer players, and the respiratory exchange rate was the lowest in ice hockey players. Overall, short, high-intensity exercise altered macro and microrheological parameters, mostly in the untrained group. Significant differences were found between the two sports. The data can be useful in training status monitoring, selection, and in revealing the causes of physical loading symptoms.

The first local experiences with rheopheresis treatment / A rheopheresiskezeléssel szerzett elso hazai tapasztalatok.

Összefoglaló. Háttér: A rheopheresis egy szelektív, extracorporalis, kettos kaszkádfiltrációs eljárás, mely elozetes plazmaszeparációt követoen egy speciális filter segítségével kivonja a vérplazmából a hiperviszkozitásért felelos komponenseket, úgymint alacsony suruségu lipoprotein, lipoprotein(a), triglicerid, koleszterin, fibrinogén, α2-makroglobulin, Von Willebrand-faktor, immunglobulin-M. Módszer és Betegek: Klinikánkon az elmúlt 5 évben MONET filter alkalmazásával összesen 80 kezelést végeztünk hiperviszkozitással összefüggo, idoskori száraz maculadegeneratióban, diabeteses alsó végtagi fekélyben, illetve neuropathiában. Eredmények: A dolgozatban beszámolunk kedvezo klinikai tapasztalatainkról, a viszkozitás, a klinikai tünetek és az elektroneurográfiai paraméterek tükrében. Orv Hetil. 2021; 162(10): 375-382. BACKGROUND: Rheopheresis is a selective, extracorporeal, double cascade filtration method. After a previous plasma separation, with the help of a special filter it extracts compounds from blood plasma which are responsible for hyperviscosity such as low-density lipoprotein, lipoprotein(a), triglyceride, cholesterine, fibrinogen, α2-macroglobulin, Von Willebrand factor, immunoglobulin M. METHOD AND PATIENTS: In the past 5 years, with the application of MONET filter we performed 80 therapies to treat age-related macula degeneration, diabetic foot ulcers and neuropathy which are complicated with hyperviscosity. RESULTS: The review describes our benefical clinical experiences in consideration of viscosity, clinical symptoms and electroneurography parameters. Orv Hetil. 2021; 162(10): 375-382.

Which remote ischemic preconditioning protocol is favorable in renal ischemia-reperfusion injury in the rat?

BACKGROUND: The optimal timing of remote ischemic preconditioning (RIPC) in renal ischemia-reperfusion (I/R) injury is still unclear. We aimed to compare early- and delayed-effect RIPC with hematological, microcirculatory and histomorphological parameters. METHODS: In anesthetized male CrI:WI Control rats (n = 7) laparotomy and femoral artery cannulation were performed. In I/R group (n = 7) additionally a 45-minute unilateral renal ischemia with 120-minute reperfusion was induced. The right hind-limb was strangulated for 3×10 minutes (10-minute intermittent reperfusion) 1 hour (RIPC-1 group, n = 7) or 24 hour (RIPC-24 group, n = 6) prior to the I/R. Hemodynamic, hematological parameters and organs' surface microcirculation were measured. RESULTS: Control and I/R group had the highest heart rate (p < 0.05 vs base), while the lowest mean arterial pressure (p < 0.05 vs RIPC-1) were found in the RIPC-24 group. The highest microcirculation values were measured in the I/R group (liver: p < 0.05 vs Control). The leukocyte count increased in I/R group (base: p < 0.05 vs Control), also this group's histological score was the highest (p < 0.05 vs Control). The RIPC-24 group had a significantly lower score than the RIPC-1 (p = 0.0025 vs RIPC-1). CONCLUSION: Renal I/R caused significant functional and morphological, also in the RIPC groups. According to the histological examination the delayed-effect RIPC method was more effective.

Modulation of micro-rheological and hematological parameters in the presence of artificial carotid-jugular fistula in rats.

BACKGROUND: Arteriovenous fistula (AVF) may affect erythrocytes through many pathways (e.g., mechanical, inflammatory). However, these effects haven't been elucidated completely yet. OBJECTIVE: To follow-up the hemorheological and the hematological changes in the presence of artificial carotid-jugular fistula in rats. METHODS: Female Wistar rats were subjected to sham-operated group (SG, n = 6) and to fistula group (FG, n = 10). Under general anesthesia, the right carotid artery and jugular vein were isolated via a neck incision, and in the FG carotid-jugular fistula was performed by microsurgical techniques. Hematological variables, red blood cell (RBC) deformability and membrane (mechanical) stability parameters were determined before operation and on the 1st and 6th postoperative weeks. Density separated samples ('young' and 'old' RBCs) were also tested. RESULTS: In FG group hematocrit, RBC and platelet counts increased gradually to reach highly significant level of increment on the 6th postoperative week. RBC deformability significantly was impaired. The membrane stability test showed lower deformability values after applying mechanical shearing. No significant differences were observed between density separated RBC subpopulations. CONCLUSIONS: The presence of arteriovenous fistula may lead to an increment of RBC mass and impairment of RBC deformability. These changes could be one of the pathways through which the fistula influences the microcirculation.

Renal ischemia-reperfusion-induced metabolic and micro-rheological alterations and their modulation by remote organ ischemic preconditioning protocols in the rat.

BACKGROUND: Pathomechanism and optimal renoprotective protocol for remote ischemic preconditioning (RIPC) have not been completely revealed yet. OBJECTIVE: To investigate micro-rheological effects of early and delayed RIPC in renal ischemia-reperfusion (I/R) in the rat. METHODS: In Control group the left femoral artery was cannulated and the left kidney was gently exposed. In the I/R group 45-minute renal ischemia with 120-minute reperfusion period was monitored. In the RIPC groups a 3×10-minute protocol was applied using tourniquet around the right hind-limb 1 hour (RIPC-1) or 24 hours (RIPC-24) prior to the I/R. Blood samples were taken for testing blood gas, acid-base, metabolic and hemorheological parameters. RESULTS: Lactate and potassium concentration significantly increased in I/R that could be reduced by RIPC, especially in RIPC-24. Creatinine concentration increased further in RIPC groups. I/R and RIPC-1 decreased the pH, RIPC-24 increased. RIPC-24 reduced the drop in base excess. Erythrocyte deformability worsened by renal I/R. In RIPC groups deformability decreased additively. However, RIPC-1 could improve the condition. RIPC-24 showed the highest erythrocyte aggregation values during reperfusion. CONCLUSIONS: Renal I/R worsened metabolic and micro-rheological parameters that could be modulated by RIPC protocols. However, it could not be decided whether the early or the delayed protocol is better.

Effects of aging and gender on micro-rheology of blood in 3 to 18 months old male and female Wistar (Crl:WI) rats.

BACKGROUND: Age- and gender-related alterations of hemorheological parameters have not been completely elucidated to date. Experiments on older animals may give valuable information on this issue. However, the majority of rheological studies have been performed in young rodents. OBJECTIVE: We aimed to investigate the influence of aging and gender on hemorheological parameters in rats. METHODS: Coeval male (n=10) and female (n=10) Wistar (Crl:WI) rats were followed-up over 15 months. Blood samples were obtained from the lateral tail vein at 3, 4, 5, 9, 12, 15 and 18 months of age. Hematological parameters, red blood cell deformability (elongation under shear), osmotic gradient deformability and erythrocyte aggregation were tested. Body weight and the estrus cycle (in females) were also examined. RESULTS: Erythrocyte aggregation showed age- and gender-related variations. Red blood cell deformability was greater in females and gradually decreased over the 15-month period in both genders. Erythrocyte aggregation was greater in male rats at most ages, but did not show consistent changes with age. CONCLUSIONS: The micro-rheological parameters showed age-related alterations with gender differences. The effect of the estrous cycle cannot be excluded in female rats. The results provide reference data for studies of aging in rats and of the mechanism related to age and gender differences in hemorheology.

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.

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.

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.

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.