Antiapoptotic and protective effects of roscovitine on ischemia-reperfusion injury of the rat liver

Astaxanthin treatment reduces kidney damage and facilitates antioxidant recovery in lithium-intoxicated rats

OBJECTIVE

This study aimed to evaluate the protective effects of astaxanthin against lithium-induced nephrotoxicity, focusing on histopathological changes, oxidative stress modulation, and alteration in the expression of key proteins related to apoptosis and inflammation.

METHODS

In this study, 56 male rats were utilized and divided into experimental groups subjected to lithium-induced nephrotoxicity, with and without astaxanthin treatment, over 14 and 28 days. The parameters assessed included oxidative stress markers (MDA, GSH, SOD), protein expression levels of BCL-2, BAX, TNF- α, PI3K, NF-κ B-p65, IL-1β, and comprehensive histopathological examinations to evaluate the integrity of renal tissue.

RESULTS

Lithium exposure led to significant renal damage, as evidenced by histological distortions in renal architecture, increased oxidative stress indicated by elevated MDA levels, and dysregulated expressions of apoptotic and inflammatory proteins. Notably, histopathological analysis revealed glomerular and tubular degeneration in lithium-treated groups. Astaxanthin treatment effectively mitigated these effects, demonstrating its efficacy in reducing lipid peroxidation, rebalancing apoptotic proteins, suppressing pro-inflammatory cytokines, and preserving renal histological structure. The concurrent use of lithium and astaxanthin showed a considerable amelioration of lithium-induced damage, suggesting astaxanthin's role in attenuating the nephrotoxic effects of lithium, both at a molecular and structural level.

CONCLUSION

Astaxanthin demonstrates significant renoprotective effects against lithium-induced nephrotoxicity, suggesting its utility as an effective adjunctive therapy. Through its potent antioxidative, anti-inflammatory, and anti-apoptotic actions, astaxanthin effectively reduces renal damage associated with lithium treatment, underscoring its potential for enhancing renal health in patients receiving lithium therapy.

Beneficial effects of quercetin on vincristine-induced liver injury in rats: Modulating the levels of Nrf2/HO-1, NF-kB/STAT3, and SIRT1/PGC-1α

Our experimental objective was to investigate the hepatotoxic effect of vincristine (VCR) administration in rats and determined whether combined therapy with Quercetin (Quer) ensured protection. Five groups with seven rats each were used for this purpose, and experimental groups were formulated as follows: Control group; Quer group; VCR group; VCR plus Quer 25 group; VCR plus Quer 50 group. The results showed that VCR significantly increased the activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) enzymes. Besides, VCR caused considerable increases in the malondialdehyde (MDA) contents, along with significant decreases in reduced glutathione levels, superoxide dismutase, catalase, and glutathione peroxidase enzyme activities in the rat livers. Quer treatment in VCR toxicity markedly decreased the activity of ALT, AST, ALP enzymes, and MDA contents and enhanced the activities of antioxidant enzymes. The results also showed that VCR significantly increased the levels of NF-kB, STAT3, and the expression of caspase 3, Bax, and MAP LC3 and decreased the expression of Bcl2 and levels of Nrf2, HO-1, SIRT1, and PGC-1α. Compared to the VCR group, Quer treatment exhibited significantly lower levels of NF-kB, STAT3, and the expression of caspase 3, Bax, and MAP LC3, and higher levels of Nrf2, HO-1, SIRT1, and PGC-1α. In conclusion, our study demonstrated that Quer could alleviate the harmful effects of VCR via activation of NRf2/HO-1 and SIRT1/PGC-1α pathways, and via attenuation of oxidative stress, apoptosis, autophagy, and NF-kB/STAT3 pathways.

Quercetin dose affects the fate of hepatic ischemia and reperfusion injury in rats: An experimental research

BACKGROUND

Quercetin found in fruits and vegetables has an antioxidative effect. We aimed to investigate the protective effects of quercetin according to different doses on hepatic and ischemia-reperfusion (I/R) injury.

METHODS

Fifty mature male Sprague-Dawley rats were randomly divided into five groups (n = 10 for each). All the animal groups underwent laparotomy. Group 1 rats served as a sham-operated group. Groups 2-5 underwent 1 h hepatic ischemia and were followed by 2 h reperfusion. Group 3-5 animals received an additional intraperitoneal dose of 25, 50 or 100 mg/kg quercetin respectively before I/R operation. Blood samples were collected for determining serum aspartate transaminase (AST), alanine transaminase (ALT) and malondialdehyde (MDA) levels. Also, liver tissue samples were taken for measuring of liver MDA concentration and for histopathology assessment.

RESULTS

The highest levels of biochemical parameters were observed in group 2. In quercetin-treated groups, serum AST, ALT, MDA levels, and tissue MDA concentration were decreased as inversely with increasing quercetin dose. Microscopic evaluation revealed that most conspicuous histological improvement was observed in 50 mg/kg quercetin co-treated rats. 25 and 100 mg/kg quercetin co-treatment could not protect completely against hepatic I/R injury.

CONCLUSION

Quercetin can be effective in preventing of hepatic I/R injury when the correct dose was used.

Discovery and development of Seliciclib. How systems biology approaches can lead to better drug performance

Seliciclib (R-Roscovitine) was identified as an inhibitor of CDKs and has undergone drug development and clinical testing as an anticancer agent. In this review, the authors describe the discovery of Seliciclib and give a brief summary of the biology of the CDKs Seliciclib inhibits. An overview of the published in vitro and in vivo work supporting the development as an anti-cancer agent, from in vitro experiments to animal model studies ending with a summary of the clinical trial results and trials underway is presented. In addition some potential non-oncology applications are explored and the potential mode of action of Seliciclib in these areas is described. Finally the authors argue that optimisation of the therapeutic effects of kinase inhibitors such as Seliciclib could be enhanced using a systems biology approach involving mathematical modelling of the molecular pathways regulating cell growth and division.

Role of CDK5/cyclin complexes in ischemia-induced death and survival of renal tubular cells

Ischemia reperfusion processes induce damage in renal tubules and compromise the viability of kidney transplants. Understanding the molecular events responsible for tubule damage and recovery would help to develop new strategies for organ preservation. CDK5 has been traditionally considered a neuronal kinase with dual roles in cell death and survival. Here, we demonstrate that CDK5 and their regulators p35/p25 and cyclin I are also expressed in renal tubular cells. We show that treatment with CDK inhibitors promotes the formation of pro-survival CDK5/cyclin I complexes and enhances cell survival upon an ischemia reperfusion pro-apoptotic insult. These findings support the benefit of treating with CDK inhibitors for renal preservation, assisting renal tubule protection.

Efficacy and safety of hepatectomy performed with intermittent portal triad clamping with low central venous pressure

Background. This retrospective study was designed to investigate the efficacy and safety of intermittent portal triad clamping (PTC) with low central venous pressure (CVP) in liver resections. Methods. Between January 2007 and August 2013, 115 patients underwent liver resection with intermittent PTC. The patients' data were retrospectively analyzed. Results. There were 58 males and 57 females with a mean age of 55 years (±13.7). Cirrhosis was found in 23 patients. Resections were performed for malignant disease in 62.6% (n = 72) and for benign disease in 37.4% (n = 43). Major hepatectomy was performed in 26 patients (22.4%). Mean liver ischemia period was 27.1 min (±13.9). The mortality rate was 1.7% and the morbidity rate was 22.6%. Cumulative clamping time (t = 3.61, P < 0.001) and operation time (t = 2.38, P < 0.019) were significantly correlated with AST alterations (D-AST). Cumulative clamping time (t = 5.16, P < 0.001) was significantly correlated with D-ALT. Operation time (t = 5.81, P < 0.001) was significantly correlated with D-LDH. Conclusions. Intermittent PTC under low CVP was performed with low morbidity and mortality. Intermittent PTC can be safely applied up to 60 minutes in both normal and impaired livers.

Hepatic microcirculation in inflow and inflow-outflow occlusion of the liver

BACKGROUND

Total vascular exclusion (TVE) causes warm liver ischemia. The aim of this study was to investigate the patterns of injury caused by inflow-outflow obstruction in the rat liver.

MATERIALS AND METHODS

Twenty-four Wistar-Albino rats were divided into three groups: liver inflow occlusion (Group A), inflow-outflow occlusion (Group B) and intermittent inflow-outflow occlusion applied for 15 minutes. Microcirculation was measured with laser Doppler flowmetry during the procedure. Samples for biochemical and histopathological analyses were collected at the end of the ischemia period.

RESULTS

Significant alterations in microcirculation were determined by application of vascular control maneuvers. Microcirculation in the central and dome segments were affected adversely compared with the dome segments in all experimental groups. TVE induced severe disturbances in hepatic microcirculation with more prominent hepatocellular damage. Damage to central segments of the rat liver was more prominent with inflow occlusion; whereas inflow-outflow occlusion produced more prominent damage to dome segments. Intermittent application of TVE clamping was associated with more hepatocellular damage compared with continuous TVE.

CONCLUSION

Our mapping methodology within the liver parenchyma suggested that hepatovenous back-perfusion is a principle source of continuity of microcirculation in the rat liver during inflow occlusion. Inflow-outflow occlusion caused more tissue damage compared with inflow occlusion. Ischemic preconditioning during TVE did not increase the tolerance of the liver against ischemia.

Repercussões pulmonares após isquemia hepática parcial e reperfusão: modelo experimental

OBJETIVO: Descrever um modelo experimental de lesão de isquemia/reperfusão hepática com manifestações sistêmicas, representadas pelo envolvimento pulmonar, que possa ser utilizado por aqueles que pretendem compreender esse fenômeno. MÉTODOS: Ratos Wistar machos (200-250g) foram usados. Quatorze foram alocados em dois grupos, sendo G1 com oito submetidos somente à laparotomia e G2, seis à isquemia e reperfusão hepática. As funções hepática (aminotransferases séricas, respiração mitocondrial, histologia) e pulmonar (teste do azul de Evans) foram analisadas. RESULTADOS: houve diferença estatística significativa entre G1 e G2 ao se comparar valores de AST (24,3 ± 108 e 5406 ± 2263), ALT (88,5 ± 28,5 e 5169 ± 2690), razão de controle respiratório (3,41 ± 0,17 e 1,91 ± 0,55) e relação ADP/O (1,93 ± 0,03 e 1,45 ± 0,27), lesões histológicas (necrose, células inflamatórias, hemorragia, microesteatose) e teste do azul de Evans (194,31 ± 53 e 491,8 ± 141). CONCLUSÃO: O modelo mostrou-se útil para o estudo de lesão de isquemia/reperfusão hepática.

Decreased apoptosis in fatty livers submitted to subnormothermic machine-perfusion respect to cold storage

Machine perfusion at subnormothermic temperature (20°C), MP20, was developed by Vairetti et al. and showed to afford a better preservation of fatty livers respect to traditional cold storage (CS) in terms of enzyme release into the perfusate and bile, glycogen stores, energy charge and oxidative stress. Here we investigated whether it also caused decreased cell death by apoptosis. Fatty and lean Zucker rats were submitted to MP20 or CS for 6 h and reperfused normothermically for 2 h. Apoptotic cells were revealed by immunohistochemistry of activated caspase-3 and M30 (new epitope on CK18 degraded by caspase-3) and by the TUNEL assay. Portal pressure was also determined. A statistically significant reduction of hepatocyte apoptosis, but especially of sinusoidal cells was determined for fatty livers submitted to MP20 respect to CS. Portal pressure was significantly lower after MP20 respect to CS. The reduction of sinusoidal cell death by apoptosis without need for anti-apoptotic therapies appears particularly positive since apoptotic sinusoidal cells hinder microcirculation in the sinusoids and are thrombogenic. These results further confirm the potential of MP20 for preserving fatty livers that would be otherwise discarded as grafts, and thus for increasing the donor pool for liver transplantation.

Twice switched at birth: cell cycle-independent roles of the "neuron-specific" cyclin-dependent kinase 5 (Cdk5) in non-neuronal cells

Cdk5 (cyclin-dependent kinase 5 or initially NCLK for neuronal CDC2-like kinase) was switched twice at its birth nearly twenty years ago: first it was thought to be cyclin-dependent, second it was assumed to be primarily of importance in neuronal cells-both turned out not to be the case. In this review we want to discuss issues of pharmacological inhibition, to highlight the versatile roles, and to summarize the growing evidence for the functional importance of Cdk5 in non-neuronal tissues, such as blood cells, tumor cells, epithelial cells, the vascular endothelium, testis, adipose and endocrine tissues. The organizing principles we follow are apoptosis/cell death, migration/motility, aspects of inflammation, and, finally, secretion/metabolism.

Molecular Biology of Apoptosis in Ischemia and Reperfusion

This study reviews the current understanding of the mechanisms that mediate the complex processes involved in apoptosis secondary to ischemia and reperfusion (I/R) and is not intended as a complete literature review of apoptosis. Several biochemical reactions trigger a cascade of events, which activate caspases. These caspases exert their effect through downstream proteolysis until the final effector caspases mediate the nuclear features characteristic of apoptosis, DNA fragmentation and condensation. Within the context of ischemia, the hypoxic environment initiates the expression of several genes involved in inflammation, the immune response, and apoptosis. Many of these same genes are activated during reperfusion injury in response to radical oxygen species generation. It is plausible that inhibition of specific apoptotic pathways via inactivation or downregulation of those genes responsible for the initiation of inflammation, immune response, and apoptosis may provide promising molecular targets for ameliorating reperfusion injury in I/R-related processes. Such inhibitory mechanisms are discussed in this review. Important targets in I/R-related pathologies include the brain during stroke, the heart during myocardial infarction, and the organs during harvesting and/or storage for transplantation. In addition, we present data from our ongoing research of specific signal transduction-related elements and their role in ischemia/reperfusion injury. These data address the potential therapeutic application of anti-inflammatory and anti-ischemic compounds in the prevention of I/R damage.

Heterogeneity of Damage Between Segments of Rat Liver After Inflow-Outflow Obstruction

BACKGROUND

Total vascular exclusion (TVE) causes warm liver ischemia. The complete explanation of the events during inflow and outflow obstruction of the liver during selective TVE has not yet been studied. The aim of this study was to investigate the liver injury caused by inflow-outflow obstruction in the rat liver.

MATERIALS AND METHODS

Forty Wistar-Albino rats were divided into four groups. Liver inflow occlusion (groups A and C) or inflow-outflow occlusion (groups B and D) was applied for 30 minutes. Samples were collected at the end of the ischemia period. We examined oxidative injury in the liver tissue and liver histopathology.

RESULTS

Oxidative stress and histopathologic alterations were more prominent with TVE application. Significant alterations were shown in hepatic superoxide dismutase, glutathione, and glutathione S-transferase levels. Central segments of the rat liver were affected significantly from inflow occlusion, whereas dome segments were significantly damaged from inflow-outflow occlusion.

CONCLUSIONS

Inflow-outflow occlusion of the liver caused more tissue damage compared with inflow occlusion. The pattern of distribution of the damage due to TVE seemed different from other well-known ischemia-reperfusion injuries.

Evaluation of Liver Damage After Application of TVE in the Rat Model

INTRODUCTION

The aim of this study was to investigate the effects of total vascular exclusion (TVE) on the liver during the early period of reperfusion.

MATERIALS AND METHODS

Forty Wistar-Albino rats were divided into four groups. Portal pedicle clamping (groups 1 and 2) or TVE (groups 3 and 4) were applied for 10 minutes. Samples were collected at the time of clamp release (groups 1 and 3) and at 30 minutes of reperfusion (groups 2 and 4). We examined oxidative injury to and histopathology of the liver.

RESULTS

Oxidative stress was more prominent with TVE application. Significant alterations were shown in hepatic superoxide dismutase, catalase, glutathione, and glutathione S-transferase levels. The levels of malondialdehyde and myeloperoxidase were not altered significantly.

CONCLUSION

Inflow-outflow occlusion of the liver causes more oxidative stress compared with inflow occlusion.

Multiple gene differential expression patterns in human ischemic liver: Safe limit of warm ischemic time

AIM: To investigate the multiple gene differential expression patterns in human ischemic liver and to produce the evidence about the hepatic ischemic safety time.

METHODS: The responses of cells to hepatic ischemia and hypoxia at hepatic ischemia were analyzed by cDNA microarrary representing 4000 different human genes containing 200 apoptotic correlative genes.

RESULTS: There were lower or normal expression levels of apoptotic correlative genes during the periods of hepatic ischemia for 0-15 min, the maintenance homostatic genes were expressed significantly higher at the same time. But at the hepatic ischemia for 30 min, the expression levels of maintenance homeostatic genes were down-regulated, the expressions of many apoptotic correlative genes and nuclear transcription factors were activated and up-regulated.

CONCLUSION: HIF-1, APAF-1, PCDC10, FBX5, DFF40, DFFA XIAP, survivin may be regarded as the signal genes to judge the degree of hepatic ischemic-hypoxic injure, and the apoptotic liver cell injury due to ischemia in different time limits. The safe limit of human hepatic warm ischemic time appears to be generally less then 30 min.