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

Local and Systemic Micro-Rheological Changes during Intestinal Anastomosis Operation: A Metabolic Dependence in an Experimental Model

Hemorheological factors may show arterio-venous differences. Alterations in acid-base and metabolic parameters may also influence these factors. However, little is known about changes in micro-rheological parameters during abdominal surgery, influencing splanchnic circulation. In anesthetized pigs, the external jugular vein, femoral artery and vein were cannulated unilaterally, and paramedian laparotomy was performed. In the anastomosis group, after resecting a bowel segment, end-to-end jejuno-jejunostomy was completed. Blood samples (from cannulas and by puncturing the portal vein) were taken before and after the intervention. Hematological, acid-base and blood gas parameters, metabolites, red blood cell (RBC) deformability and aggregation were determined. The highest hematocrit was found in portal blood, increasing further by the end of operation. A significant pH decrease was seen, and portal blood showed the highest lactate and creatinine concentration. The highest RBC aggregation values were found in arterial, the lowest in renal venous blood. The RBC aggregation increased with higher lactate concentration and lower pH. Osmotic gradient deformability declined, with the lowest values in portal and renal venous samples. In conclusion, micro-rheological parameters showed arterio-venous and porto-renal venous differences, influenced by oxygenation level, pH and lactate concentration. The intestinal anastomosis operation caused an immediate micro-rheological deterioration with portal venous dominancy in this experiment.

Effects of butyrate on intestinal ischemia-reperfusion injury via the HMGB1-TLR4-MyD88 signaling pathway

BACKGROUND

This study combined bioinformatics and experimental verification in a mouse model of intestinal ischemia-reperfusion injury (IRI) to explore the protection mechanism exerted by butyrate against IRI.

METHODS

GeneCards, Bioinformatics Analysis Tool for Molecular Mechanisms of Traditional Chinese Medicine and GSE190581 were used to explore the relationship between butyrate and IRI and aging. Protein-protein interaction networks involving butyrate and IRI were constructed via the STRING database, with hub gene analysis performed through Cytoscape. Functional enrichment analysis was conducted on intersection genes. A mouse model of IRI was established, followed by direct arterial injection of butyrate. The experiment comprised five groups: normal, sham, model, vehicle, low-dose butyrate, and high-dose butyrate. Intestinal tissue observation was done via transmission electron microscopy (TEM), histological examination via hematoxylin and eosin (H&E) staining, tight junction proteins detection via immunohistochemistry, and Western blot analysis of hub genes. Drug-target interactions were evaluated through molecular docking.

RESULTS

Butyrate protected against IRI by targeting 458 genes, including HMGB1 and TLR4. Toll-like receptor pathway was implicated. Butyrate improved intestinal IRI by reducing mucosal damage, increasing tight junction proteins, and lowering levels of HMGB1, TLR4, and MyD88. Molecular docking showed strong binding energies between butyrate and HMGB1 (-3.7 kcal/mol) and TLR4 (-3.8 kcal/mol).

CONCLUSIONS

According to bioinformatics predictions, butyrate mitigates IRI via multiple-target and multiple-channel mechanisms. The extent of IRI can be reduced by butyrate through the inhibition of the HMGB1-TLR4-MyD88 signaling pathway, which is related to senescence.

Bioinformatic Analysis of lncRNA Mediated CeRNA Network in Intestinal Ischemia/Reperfusion Injury

INTRODUCTION

Recently, accumulating studies have reported the roles of competitive endogenous RNA (ceRNA) networks in ischemia/reperfusion (I/R) injury in several organs, including the liver, kidney, heart, brain, and intestine. However, the functions and mechanisms of long noncoding RNAs (lncRNAs)-which serve as ceRNA networks in intestinal I/R injury-remain elusive.

METHODS

RNA expression data were retrieved from the National Center for Biotechnology Information-Gene Expression Omnibus database. Differentially expressed microRNAs (miRNAs) (miDEGs) were explored between the sham and intestinal I/R injury samples. Next, targeted lncRNAs and messenger RNAs in the database were matched based on miDEGs. Hub ceRNA networks were constructed and visualized via Cytoscape. Intersection analysis was performed to screen mDEGs between two datasets. Finally, the vital nodes of the ceRNA networks were validated by quantitative PCR.

RESULTS

A total of 189 miDEGs were identified. Forty miRNAs were found to be associated with 240 predicted target genes from miRWalk 3.0. The ceRNA network was constructed with 10 miRNAs, including the 1700020114Rik/mmu-miR-7a-5p/Klf4 axis. Furthermore, the expression of lncRNA 1700020114Rik (P < 0.05) and messenger RNA Klf4 (P < 0.01) was markedly decreased in mouse models of intestinal I/R injury, whereas the expression level of mmu-miR-7a-5p was significantly increased (P < 0.05).

CONCLUSIONS

The results provide novel insights into the molecular mechanism of ceRNA networks in intestinal I/R injury and highlight the potential of the 170002700020114Rik/mmu-miR-7a-5p/Klf4 axis in the prevention and treatment of intestinal I/R injury.

Estradiol Valerate Affects Hematological and Hemorheological Parameters in Rats

Polycystic ovary syndrome (PCOS) is one of the most common endocrinological diseases in women. Although the risk of cardiovascular diseases is high in PCOS, the number of scientific publications describing hemorheological changes is not significant. We aimed to perform a comprehensive hematological and micro-rheological study on experimentally induced PCOS in rats.Wistar rats were divided into control (n = 9) and PCOS groups (n = 9), in which animals received single-dose estradiol valerate. Measurements were carried out before treatment and monthly for four months. Bodyweight, blood glucose concentration, hematological parameters, red blood cell (RBC) deformability, and aggregation were measured. A histological examination of the ovary was performed at the end of the experiment. The blood glucose level and the bodyweight were significantly elevated vs. base in the PCOS group. A significant decrease was seen in RBC count, hemoglobin, and hematocrit. The maximal elongation index showed a significant increase. PCOS also resulted in a significant increase in RBC aggregation index parameters. The histological and hormone examinations confirmed developed PCOS. The administration of estradiol valerate caused significant changes during the examined period in hematological and hemorheological parameters. Our results draw attention to the possible usefulness of micro-rheological investigations in further studies on PCOS.

HMGB1 signaling-regulated endoplasmic reticulum stress mediates intestinal ischemia/reperfusion-induced acute renal damage

BACKGROUND

Ischemia/reperfusion of the intestine often leads to distant organ injury, but the mechanism of intestinal ischemia/reperfusion-induced renal dysfunction is still not clear. The present study aimed to investigate the mechanisms of acute renal damage after intestinal ischemia/reperfusion challenge and explore the role of released high-mobility group box-1 in this process.

METHODS

Intestinal ischemia/reperfusion was induced in male Sprague-Dawley rats by clamping the superior mesenteric artery for 1.5 hours. At different reperfusion time points, anti-high-mobility group box-1 neutralizing antibodies or ethyl pyruvate were administered to neutralize or inhibit circulating high-mobility group box-1, respectively.

RESULTS

Significant kidney injury was observed after 6 hours of intestinal reperfusion, as indicated by increased serum levels of urea nitrogen and creatinine, increased expression of neutrophil gelatinase-associated lipocalin, interleukin-6, and MIP-2, and enhanced cell apoptosis, as indicated by cleaved caspase 3 levels in renal tissues. The levels of phosphorylated eIF2ɑ, activating transcription factor 4, and C/EBP-homologous protein (CHOP) were markedly elevated, indicating the activation of endoplasmic reticulum stress in the impaired kidney. High-mobility group box-1 translocated to cytoplasm in the intestine and serum concentrations of high-mobility group box-1 increased notably during the reperfusion phase. Both anti-high-mobility group box-1 antibodies and ethyl pyruvate treatment significantly reduced serum high-mobility group box-1 concentrations, attenuated endoplasmic reticulum stress in renal tissue and inhibited the development of renal damage. Moreover, the elevated expression of receptor for advanced glycation end products in the kidneys after intestinal ischemia/reperfusion was abrogated after high-mobility group box-1 inhibition.

CONCLUSION

These results suggested that high-mobility group box-1 signaling regulated endoplasmic reticulum stress and promoted intestinal ischemia/reperfusion-induced acute kidney injury. High-mobility group box-1 neutralization/inhibition might serve as a pharmacological intervention strategy for these pathophysiological processes.

Hemorheological and Microcirculatory Factors in Liver Ischemia-Reperfusion Injury-An Update on Pathophysiology, Molecular Mechanisms and Protective Strategies

Hepatic ischemia-reperfusion injury (IRI) is a multifactorial phenomenon which has been associated with adverse clinical outcomes. IRI related tissue damage is characterized by various chronological events depending on the experimental model or clinical setting. Despite the fact that IRI research has been in the spotlight of scientific interest for over three decades with a significant and continuous increase in publication activity over the years and the large number of pharmacological and surgical therapeutic attempts introduced, not many of these strategies have made their way into everyday clinical practice. Furthermore, the pathomechanism of hepatic IRI has not been fully elucidated yet. In the complex process of the IRI, flow properties of blood are not neglectable. Hemorheological factors play an important role in determining tissue perfusion and orchestrating mechanical shear stress-dependent endothelial functions. Antioxidant and anti-inflammatory agents, ischemic conditioning protocols, dynamic organ preservation techniques may improve rheological properties of the post-reperfusion hepatic blood flow and target endothelial cells, exerting a potent protection against hepatic IRI. In this review paper we give a comprehensive overview of microcirculatory, rheological and molecular–pathophysiological aspects of hepatic circulation in the context of IRI and hepatoprotective approaches.

Incidence, Characteristics, Laboratory Findings and Outcomes in Acro-Ischemia in COVID-19 Patients

Aim

In addition to its respiratory impact of SARS-CoV2, skin lesions of probable vascular origin have been described. This study intends to quantify the incidence of acro-ischemic lesions in COVID-19 infected adult subjects in our population, describing clinical patterns and associated findings.

Methods

All adult confirmed cases of COVID-19 infection who presented with acro-ischemic lesions and received care in our institution were prospectively enrolled up to May 15th, 2020. The variables included demographics, comorbidities, analytical parameters, clinical presentations and COVID-19 treatment.

Results

We enrolled 24 patients. The overall rate of acro-ischemic findings in COVID-19 patients was 1.2% [0.6% for outpatients and 2.9% for hospitalized (ICU and non-ICU patients)], but the observed incidence for acro-ischemia in ICU patients was remarkably higher (23.0%, p<0.001). We have described four different clinical patterns of acroischemia: atypical Raynaud´s phenomenon (ARP), (4); pseudo-pernio (PP), (5); severe microcirculatory ischemia with preserved pulse (SMI), (6); and dry gangrene with arteriosclerosis obliterans (AO), (9). Kendall´s τ correlation with lung disease severity was 0.877 (95% CI, 0.756 to 0.968); p<0.01). ARP individuals were predominantly female, while SMI appeared lately in elderly hospitalized subjects with better prognosis. AO occurred in patients with more comorbidity and younger than those with SMI. We observed other associated lesions of suggestive ischemic nature in other organs in all groups (15 patients of total sample). Plasma procalcitonin was significantly higher in patients who developed SMI (median and interquartile range: 9.99 (4.2, 12.3) mg/mL vs 0.26 (0.11, 0.89) mg/mL; p<0.001), and D-dimer level at hospital admission was significantly higher in AO patients (median and interquartile range: 1166 (1050, 2111) mg/L vs 502 (448, 777) mg/L; p<0.001).

Conclusion

The observed risk for acroischemia in COVID-19 is high in ICU patients (23%). We have described four different clinical patterns of acroischemia (ARP, PP, SMI and AO) associated with lung disease severity. Authors have communicated various lesions of suggestive ischemic nature in other organs. Raynaud-like pattern is reported as a "novelty".

Eicosanoid production varies by sex in mesenteric ischemia reperfusion injury

Intestinal ischemia/reperfusion (I/R)-induced injury is an inflammatory response with significant morbidity and mortality. The early inflammatory response includes neutrophil infiltration. However, the majority of rodent studies utilize male mice despite a sexual dimorphism in intestinal I/R-related diseases. We hypothesized that sex may alter inflammation by changing neutrophil infiltration and eicosanoid production. To test this hypothesis, male and female C57Bl/6 mice were subjected to sham treatment or 30 min intestinal ischemia followed by a time course of reperfusion. We demonstrate that compared to male mice, females sustain significantly less intestinal I/R-induced tissue damage and produced significant LTB₄ concentrations. Male mice release PGE₂. Finally, treatment with a COX-2 specific inhibitor, NS-398, attenuated I/R-induced injury, total peroxidase level, and PGE₂ production in males, but not in similarly treated female mice. Thus, I/R-induced eicosanoid production and neutrophil infiltration varies between sexes suggesting that distinct therapeutic intervention may be needed in clinical ischemic diseases.