Pyrrolidine dithiocarbamate reduces renal dysfunction and injury caused by ischemia/reperfusion of the rat kidney

Unveiling biomarkers and therapeutic targets in IgA nephropathy through large-scale blood transcriptome analysis

INTRODUCTION

IgA nephropathy (IgAN) is the most prevalent form of glomerulonephritis. Unfortunately, molecular biomarkers for IgAN derived from omics studies are still lacking. This research aims to identify critical genes associated with IgAN through large-scale blood transcriptome analysis.

METHODS

We constructed novel blood transcriptome profiles from peripheral blood mononuclear cells (PBMCs) of 53 Chinese IgAN patients and 28 healthy individuals. Our analysis included GO, KEGG, and GSEA for biological pathways. We analyzed immune cell profiles with CIBERSORT and constructed PPI networks with STRING, visualized in Cytoscape. Key differentially expressed genes (DEGs) were identified using CytoHubba and MCODE. We assessed the correlation between gene expressions and clinical data to evaluate clinical significance and identified hub genes through machine learning, validated with an open-access dataset. Potential drugs were explored using the CMap database.

RESULTS

We identified 333 DEGs between IgAN patients and healthy controls, mainly related to immune response and inflammation. Key pathways included NK cell mediated cytotoxicity, complement and coagulation cascades, antigen processing, and B cell receptor signaling. Cytoscape revealed 16 clinically significant genes (including KIR2DL1, KIR2DL3, VISIG4, C1QB, and C1QC, associated with sub-phenotype and prognosis). Machine learning identified two hub genes (KLRC1 and C1QB) for a diagnostic model of IgAN with 0.92 accuracy, validated at 1.00 against the GSE125818 dataset. Sirolimus, calcifediol, and efaproxiral were suggested as potential therapeutic agents.

CONCLUSION

Key DEGs, particularly VISIG4, KLRC1, and C1QB, emerge as potential specific markers for IgAN, paving the way for future targeted personalized treatment options.

Searching for Novel Sources of Hydrogen Sulfide Donors: Chemical Profiling of Polycarpa aurata Extract and Evaluation of the Anti-Inflammatory Effects

Hydrogen sulfide (H2S) is a signaling molecule endogenously produced within mammals' cells that plays an important role in inflammation, exerting anti-inflammatory effects. In this view, the research has shown a growing interest in identifying natural H2S donors. Herein, for the first time, the potential of marine extract as a source of H2S-releasing agents has been explored. Different fractions obtained by the Indonesian ascidian Polycarpa aurata were evaluated for their ability to release H2S in solution. The main components of the most active fraction were then characterized by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) and NMR spectroscopy. The ability of this fraction to release H2S was evaluated in a cell-free assay and J774 macrophages by a fluorimetric method, and its anti-inflammatory activity was evaluated in vitro and in vivo by using carrageenan-induced mouse paw edema. The anti-inflammatory effects were assessed by inhibiting the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), and interleukin-6 (IL-6), coupled with a reduction in nitric oxide (NO) and IL-6 levels. Thus, this study defines the first example of a marine source able to inhibit inflammatory responses in vivo through the release of H2S.

Protective effects of the nuclear factor kappa B inhibitor pyrrolidine dithiocarbamate on experimental testicular torsion and detorsion injury

Testicular torsion results with the damage of the testis and it is a surgical emergency. Pyrrolidine dithiocarbamate (PDTC) is a low-molecular-weight antioxidant and potent inhibitor of nuclear factor kappa B (NF-κB) activation. In this study, we aimed to investigate the effects of PDTC to testicular torsion-detorsion (T/D) injury. Forty adult male Sprague-Dawley rats were separated into four groups. A sham operation was performed in group I. In group II, torsion is performed 2 hours by 720 degree extravaginally testis. In group III, 4 h reperfusion of the testis was performed after 2 h of testicular torsion. In group IV, after performing the same surgical procedures as in group III, PDTC (100 mg/kg, intravenous's) was administered before 30 min of detorsion. The testes tissue malondialdehyde (MDA), superoxide dismutase (SOD) catalase (CAT) level was evaluated. Histological evaluations were performed after hematoxylin and eosin staining. Testicular tissue MDA levels were the highest in the T/D groups compared with treatment group. Administration of PDTC prevented a further increase in MDA levels. Significant decrease occurred in CAT and SOD levels in treatment group compared with the control group. The rats in the treatment group had normal testicular architecture. The results suggest that PDTC can be a potential protective agent for preventing the biochemical and histological changes related to oxidative stress in testicular injury caused by testis torsion.

Celastrol protects kidney against ischemia-reperfusion-induced injury in rats

BACKGROUND

Ischemia-reperfusion (IR) causes various damages in renal tissues, which is exacerbated by hypoxia-induced excessive inflammation and deteriorates the prognosis of patients after kidney surgery. Celastrol is a potent inflammation inhibitor that has little toxicity. In this report, we investigated whether celastrol protects against IR-induced renal injury in rats.

MATERIALS AND METHODS

Renal IR injury was induced by occlusion of the bilateral renal pedicles for 45 min followed by reperfusion for 6 h. Celastrol or vehicle solution was intraperitoneally injected 30 min before renal ischemia, respectively. Renal histology, function, and pro-inflammatory cytokines and mediators were assessed. The effect of celastrol on nuclear translocation of nuclear factor kappa B (NF-κB) was also measured.

RESULTS

Celastrol significantly suppressed elevation of the renal function markers and the lipid peroxidation level, alleviated renal tubular damage, and decreased the levels of tumor necrosis factor-α, interleukin-1β, and monocyte chemotactic protein-1 (MCP-1) messenger RNA in kidney caused by IR. Moreover, celastrol prevented IR-induced expression of pro-inflammatory mediators, which was associated with suppression of nuclear translocation of NF-κB subunit p65.

CONCLUSIONS

Celastrol ameliorated the acute kidney injury caused by IR, which was associated with inhibiting local NF-κB activation and inflammation. Our findings suggest that celastrol could be useful for preventing IR-induced renal injury.

Emerging role of PPAR-β/δ in inflammatory process associated to experimental periodontitis

The aim of the present study was to evaluate the contribution of peroxisome proliferator-activated receptor (PPAR-β/δ) in animal model of periodontitis. Male Sprague-Dawley rats were lightly anaesthetized with pentobarbitone (35 mg/kg). Sterile, 2-0 black braided silk thread was placed around the cervix of the lower left first molar and knotted medially. Animals received GW0742 (0.3 mg/kg, 10% DMSO, i.p. after the ligature placement and daily for eight days). At day 8, the gingivomucosal tissue encircling the mandibular first molar was removed. One the eighth day after placement of the ligature, we evaluated (1) NF-κB expression, (2) cytokines expression, (3) iNOS expression, (5) the nitration of tyrosine, (6) apoptosis, and (8) the degree of gingivomucosal tissues injury. Administration of GW0742 significantly decreased all of the parameters of inflammation as described above. Taken together, these results demonstrate that GW0742 exerts an anti-inflammatory role during experimental periodontitis and is able to ameliorate the tissue damage.

Erythropoietin preserves the integrity and quality of organs for transplantation after cardiac death

Previous studies have shown that treatment with erythropoietin (EPO) exerts important cytoprotective and antiapoptotic effects. Donor organs recovered after cardiac death (DCD) can alleviate the shortage of organs required for transplantation. However, organs obtained subsequent to cardiac death demonstrate an increased incidence of delayed graft function and primary nonfunction. The aim of this study was to determine the effects of EPO administration to the donor in a porcine model of kidney transplantation under DCD conditions. Landrace pigs received 1,000 IU/kg i.v. EPO 30 min before cardiac arrest. Kidneys were then subjected to 30 min of warm ischemia and were transplanted after 24 h of cold storage. Renal dysfunction, injury, and inflammation were evaluated 4 h after transplantation. Transplantation of kidneys from DCD resulted in significant renal dysfunction, injury, and inflammation. This study provides the first evidence that pretreatment of the donor with a single pharmacologically relevant dose of EPO causes substantial attenuation of the dysfunction and injury associated with the transplantation of kidneys recovered after cardiac death.

Effects of Hypericum Perforatum, in a rodent model of periodontitis

BACKGROUND

Hypericum perforatum is a medicinal plant species containing many polyphenolic compounds, namely flavonoids and phenolic acids. In this study we evaluate the effect of Hypericum perforatum in animal model of periodontitis.

METHODS

Periodontitis was induced in adult male Sprague-Dawley rats by placing a nylon thread ligature around the lower 1st molars. Hypericum perforatum was administered at the dose of 2 mg/kg os, daily for eight days. At day 8, the gingivomucosal tissue encircling the mandibular first molar was removed.

RESULTS

Periodontitis in rats resulted in an inflammatory process characterized by edema, neutrophil infiltration and cytokine production that was followed by the recruitment of other inflammatory cells, production of a range of inflammatory mediators such as NF-κB and iNOS expression, the nitration of tyrosine residues and activation of the nuclear enzyme poly (ADP-ribose) polymerase; apoptosis and the degree of gingivomucosal tissues injury. We report here that Hypericum perforatum exerts potent anti-inflammatory effects significantly reducing all of the parameters of inflammation as described above.

CONCLUSIONS

Taken together, our results clearly demonstrate that treatment with Hypericum reduces the development of inflammation and tissue injury, events associated with periodontitis.

An insight into the possible protective effect of pyrrolidine dithiocarbamate against lipopolysaccharide-induced oxidative stress and acute hepatic injury in rats

Lipopolysaccharide (LPS) is a major cell wall molecule of Gram-negative bacteria known to stimulate the synthesis and secretion of several toxic metabolites, such as reactive oxygen species. In this study, the effect of pyrrolidine dithiocarbamate (PDTC), an antioxidant with nuclear factor-κB inhibitor activity, was evaluated in LPS-induced oxidative stress and acute hepatic injury in rats. Animals were pretreated for 3 consecutive days with PDTC (200 mg/kg/day, i.p.) or saline and animals were then challenged with LPS (6 mg/kg, i.p.) or saline. Six hours after LPS injection, animals were decapitated and blood and liver samples were collected to assess the chosen biochemical parameters. Saline-pretreated animals challenged with LPS revealed extensive liver damage, as evidenced by increases in serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma glutamyl transferase (γ-GT). Also, LPS treatment resulted in significant increases in serum lactate dehydrogenase (LDH), tumor necrosis factor-alpha (TNF-α) and nitrite levels. Furthermore, LPS challenge caused oxidative stress as indicated by an increase in hepatic lipid peroxidation measured as thiobarbituric acid reactive substances (TBARS) and a decrease in hepatic reduced glutathione concentration (GSH) as well as decreased activities of superoxide dismutase (SOD) and catalase in hepatic tissues. The administration of PDTC prior to LPS challenge resulted in improved liver functions as evidenced by the decline in serum AST, ALT, γ-GT levels and reduction in serum LDH, TNF-α and nitrite levels. Moreover, PDTC reduced the chosen lipid peroxidation marker, TBARS and increased GSH concentration, and SOD and catalase activities in hepatic tissues. These results indicate that PDTC may be a useful pharmacological agent in alleviating LPS-induced oxidative stress and acute hepatic injury.

The role of nuclear factor-kappaB in the effect of angiotensin II in the paraventricular nucleus in protecting the gastric mucosa from ischemia-reperfusion injury in rats

BACKGROUND

The purpose of this study was to elucidate the role of nuclear factor kappaB (NF-kappaB) in the development of gastric ischemia-reperfusion (GI-R) injury and in mediating the effects of angiotensin II (Ang II) in the paraventricular nucleus (PVN) on GI-R injury.

METHODS

GI-R injury was induced in rats by clamping the celiac artery for 30 min and then reperfusing for 1 h. A cannula was inserted into the unilateral PVN for microinjection of Ang II. The expressions and levels of NF-kappaB (p65), IkappaB-alpha, and phosphorylated IkappaB-alpha in rat gastric mucosa were examined by Western blotting and immunohistochemistry. A laser Doppler flowmeter was used to assess gastric blood flow (GBF). Malondialdehyde (MDA) was determined using the thiobarbituric acid (TBA) method, and superoxide dismutase (SOD) activity was determined by the xanthine/xanthine oxidase method.

RESULTS

Microinjection of Ang II (3, 30, and 300 ng) into the PVN dose-dependently inhibited GI-R injury. The levels and expressions of NF-kappaB (p65) and phosphospecific IkappaB-alpha protein increased 1 h after GI-R and were markedly reduced by microinjection of Ang II into the PVN. In contrast, the level and expression of IkappaB-alpha protein decreased 1 h after ischemia-reperfusion and recovered to the normal level by microinjection of Ang II into the PVN. The effects of Ang II were prevented by pretreatment with the Ang II AT1 receptor antagonist losartan (5 microg) microinjected into the lateral cerebral ventricle. Inhibition of NF-kappaB activity by pyrrolidine dithiocarbamate (PDTC, 200 mg/kg) produced similar effects in rats subjected to ischemia-reperfusion with or without microinjection of Ang II into the PVN. Administration of PDTC attenuated gastric mucosal injury and suppressed the activation of NF-kappaB (p65). Ang II microinjection into the PVN increased GBF and decreased the MDA content but did not alter SOD activity in the gastric mucosa following ischemia-reperfusion.

CONCLUSIONS

NF-kappaB plays a role in PVN Ang II-mediated protection against GI-R injury. These central effects of Ang II are mediated by AT1 receptors.

Generation of endogenous hydrogen sulfide by cystathionine gamma-lyase limits renal ischemia/reperfusion injury and dysfunction

The generation of endogenous hydrogen sulfide may either limit or contribute to the degree of tissue injury caused by ischemia/reperfusion. A total of 74 male Wistar rats were used to investigate the effects of endogenous and exogenous hydrogen sulfide in renal ischemia/reperfusion. Administration of the irreversible cystathionine gamma-lyase (CSE) inhibitor, dL-propargylglycine, prevented the recovery of renal function after 45 min ischemia and 72 h reperfusion. The hydrogen sulfide donor sodium hydrosulfide attenuated the (renal, tubular, and glomerular) dysfunction and injury caused by 45 min ischemia and 6 h reperfusion. Western blot analysis of kidneys taken at 30 min reperfusion showed that sodium hydrosulfide significantly attenuated phosphorylation of mitogen-activated protein kinases (p-38, c-JUN N-terminal protein kinase 1/2, and extracellular signal-regulated kinase 1/2) and activation of nuclear factor-kappaB. At 6 h reperfusion, sodium hydrosulfide significantly attenuated the histological score for acute tubular necrosis, the activation of caspase-3 and Bid, the decline in the expression of anti-apoptotic Bcl-2, and the expression of nuclear factor-kappaB-dependent proteins (inducible nitric oxide synthase, cyclo-oxygenase-2, and intercellular adhesion molecule-1). These findings suggest that (1) the synthesis of endogenous hydrogen sulfide by CSE is essential to protect the kidney against ischemia/reperfusion injury and dysfunction and aids in the recovery of renal function following ischemia/reperfusion, (2) hydrogen sulfide generated by sodium hydrosulfide reduces ischemia/reperfusion injury and dysfunction, and morphological changes of the kidney, and (3) the observed protective effects of hydrogen sulfide are due to both anti-apoptotic and anti-inflammatory effects.

Pyrrolidine dithiocarbamate prevents deleterious effects of remote ischemia/reperfusion injury on healing of colonic anastomoses in rats

BACKGROUND

Pyrrolidine dithiocarbamate (PDTC) is a low-molecular-weight thiol antioxidant and potent inhibitor of nuclear factor-kappaB (NF-kappaB) activation. It has been shown to attenuate local harmful effects of ischemia/reperfusion (I/R) injury in many organs. In recent animal studies, a delaying effect of remote organ I/R injury on the healing of colonic anastomoses has been demonstrated. In this study we investigated whether PDTC prevents harmful systemic effects of superior mesenteric I/R on left colonic anastomosis in rats.

METHODS

Anastomosis of the left colon was performed in 40 rats randomly allocated into the following four groups: (1) Sham-operated group (group I, n = 10)-simultaneously with colonic anastomosis, the superior mesenteric artery and collateral branches divided from the celiac axis and the inferior mesenteric artery were isolated but not occluded. (2) Sham+PDTC group (group II, n = 10)-identical to sham-operated rats except for the administration of PDTC (100 mg/kg IV bolus) 30 minutes prior to commencing the experimental period. (3) I/R group (group III, n = 10)-60 minutes of intestinal I/R by superior mesenteric artery occlusion. (4) PDTC-treated group (group IV, n = 10)-PDTC 100 mg/kg before and after the I/R. On postoperative day 6, all animals were sacrificed, and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for investigation of anastomotic hydroxyproline (HP) contents, perianastomotic malondialdehyde (MDA) levels, myeloperoxidase activity (MPO), and glutathione (GSH) level.

RESULTS

There was a statistically significant decrease in anastomotic bursting pressure values, tissue HP content and GSH level, along with an increase in MDA level and MPO activity in group III, when compared to groups I, II, and IV (p < 0.05). However, PDTC treatment led to a statistically significant increase in anastomotic bursting pressure values, tissue HP content and GSH level, along with a decrease in MDA level and MPO activity in group IV (p < 0.05).

CONCLUSIONS

This study showed that PDTC treatment significantly prevented the delaying effect of remote organ I/R injury on anastomotic healing in the colon. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent for increasing the safety of the anastomosis during particular operations where remote organ I/R injury occurs.

Renal protection by delayed ischaemic preconditioning is associated with inhibition of the inflammatory response and NF-kappaB activation

Brief and sublethal ischaemia renders an organ tolerant to subsequent prolonged ischaemia, which is called ischaemic preconditioning (IPC). In regard to the beneficial effects and endogenous mechanisms of renal delayed IPC, few data are available. In this study, we aim at determining reno-protective effects of delayed IPC against ischaemia-reperfusion (I/R) injury, and illustrating whether these effects are associated with suppressing inflammation and nuclear factor-kappaB (NF-kappaB) activation. I/R injury was induced by clamping both renal pedicles for 40 min, followed by 24 h of reperfusion. The rats were subjected to ischaemia for 20 min (preconditioning) or sham surgery (non- preconditioning) at day 4 before I/R. Functional and morphological parameters were evaluated at 24 h after reperfusion. At the same time, macrophage (ED-1(+)) infiltration, and the expression of intercellular adhesion molecule-1 (ICAM-1) and tumor necrosis factor-alpha (TNF-alpha) were assessed by immunohistochemistry. Moreover, I kappa B-alpha degradation and NF-kappaB/DNA binding activity were analyzed. Compared with rats exposed to I/R injury, preconditioned rats had a significant decrease in levels of serum creatinine (Scr, 384.3 +/- 21.8 micromol/L vs. 52.5 +/- 21.7 micromol/L; p<0.001), blood urea nitrogen (BUN, 40.4 +/- 2.7 mmol/L vs. 15.9 +/- 4.2 mmol/L; p<0.001) and serum aspartate aminotransferase (AST, 486.7 +/- 58.6 IU/L vs. 267.3 +/- 43.9 IU/L; p<0.001). Parallel to the above changes, preconditioned rats preserved structural integrity and decreased tubulointerstitial damage scores (3.4 +/- 0.3 vs. 0.2 +/- 0.05; p<0.001) and ED-1(+) cell infiltration (25.3 +/- 3.5 vs. 6.2 +/- 1.2 cells/HPF, p<0.01). Furthermore, our results showed that the expression of ICAM-1 and TNF-alpha, the degree of I kappa B-alpha degradation, and NF-kappaB/DNA binding activity were reduced by IPC. Taken together, our results demonstrated that delayed IPC offered both functional and histological protection, which may be related to suppression of inflammation in preconditioned kidneys.

Novel pharmacological approaches to the treatment of renal ischemia-reperfusion injury: a comprehensive review

Renal ischemia-reperfusion (I-R) contributes to the development of ischemic acute renal failure (ARF). Multi-factorial processes are involved in the development and progression of renal I-R injury with the generation of reactive oxygen species, nitric oxide and peroxynitrite, and the decline of antioxidant protection playing major roles, leading to dysfunction, injury, and death of the cells of the kidney. Renal inflammation, involving cytokine/adhesion molecule cascades with recruitment, activation, and diapedesis of circulating leukocytes is also implicated. Clinically, renal I-R occurs in a variety of medical and surgical settings and is responsible for the development of acute tubular necrosis (a characteristic feature of ischemic ARF), e.g., in renal transplantation where I-R of the kidney directly influences graft and patient survival. The cellular mechanisms involved in the development of renal I-R injury have been targeted by several pharmacological interventions. However, although showing promise in experimental models of renal I-R injury and ischemic ARF, they have not proved successful in the clinical setting (e.g., atrial natriuretic peptide, low-dose dopamine). This review highlights recent pharmacological developments, which have shown particular promise against experimental renal I-R injury and ischemic ARF, including novel antioxidants and antioxidant enzyme mimetics, nitric oxide and nitric oxide synthase inhibitors, erythropoietin, peroxisome-proliferator-activated receptor agonists, inhibitors of poly(ADP-ribose) polymerase, carbon monoxide-releasing molecules, statins, and adenosine. Novel approaches such as recent research involving combination therapies and the potential of non-pharmacological strategies are also considered.

Pyrrolidine dithiocarbamate prevents 60 minutes of warm mesenteric ischemia/reperfusion injury in rats

BACKGROUND

Pyrrolidine dithiocarbamate (PDTC) is a low-molecular-weight thiol antioxidant and potent inhibitor of nuclear factor-kappaB (NF-kappaB) activation. It has been shown to attenuate harmful effects of ischemia/reperfusion (I/R) injury in many organs. In recent animal studies, destructive effects of reperfusion injury has been demonstrated. In this study, we aimed to investigate whether PDTC prevents harmful effects of superior mesenteric I/R injury in rats.

METHODS

Wistar-albino rats were randomly allocated into the following 4 groups: (1) sham-operated group--these animals underwent laparotomy without I/R injury (group I, n = 12); (2) sham+PDTC group--identical to sham-operated rats except for the administration of PDTC (100 mg/kg intravenous bolus) 30 minutes prior to the commencement of the experimental period (group II, n = 12); (3) I/R group--these animals underwent laparotomy and 60 minutes of ischemia followed by 120 minutes of reperfusion (group III, n = 12); (4) PDTC-treated group (100 mg/kg, intravenously, before the I/R, group IV, n = 12). All animals were killed, and intestinal tissue samples were obtained for investigation of intestinal mucosal injury, myeloperoxidase (MPO) activity, malondialdehyde (MDA) levels, glutathione (GSH) levels, and intestinal edema.

RESULTS

There was a statistically significant decrease in GSH levels, along with an increase in intestinal mucosal injury scores, MPO activity, MDA levels, and intestinal tissue wet-to-dry weight ratios in group III when compared to groups I, II, and IV (P < .05). However, PDTC treatment led to a statistically significant increase in GSH levels, along with a decrease in intestinal mucosal injury scores, MPO activity, MDA levels, and intestinal tissue wet-to-dry weight ratios in group IV (P < .05).

CONCLUSIONS

This study showed that PDTC treatment significantly prevented the reperfusion injury caused by superior mesenteric I/R. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent to use in particular operations where the reperfusion injury occurs.

Pyrrolidine Dithiocarbamate Reduces Lung Injury Caused by Mesenteric Ischemia/Reperfusion in a Rat Model

BACKGROUND

Pyrrolidine dithiocarbamate (PDTC) is a low-molecular thiol antioxidant and potent inhibitor of nuclear factor-kappaB (NF-kappaB) activation. It has been shown to attenuate local harmful effects of ischemia/reperfusion (I/R) injury in many organs. In this study, we aimed to study the effect of PDTC on lung reperfusion injury induced by superior mesenteric occlusion.

METHODS

Male Wistar-albino rats randomized into three groups: (1) sham-operated control group (n = 12), laparotomy without I/R injury; (2) intestinal ischemia/reperfusion (I/R) group (n = 12), 60 min of ischemia by superior mesenteric occlusion followed by 2 h of reperfusion; and (3) I/R+PDTC-treated group (n = 12), 100 mg/kg injection of PDTC intravenously, 30 min after the commencement of reperfusion. Evans blue dye was injected to half of rats in all groups before the induction of I/R. We assessed the degree of pulmonary tissue injury biochemically by measuring malondialdehyde (MDA), glutathione (GSH), and nitric oxide (NO) levels, and histopathologically by establishing pulmonary neutrophil sequestration and acute lung injury scoring. Pulmonary edema was evaluated by Evans blue dye extravasation, as well as lung tissue wet/dry weight ratios.

RESULTS

Pyrrolidine dithiocarbamate treatment significantly reduced the MDA and NO levels, and increased the GSH levels in the lung parenchyma, biochemically (p < 0.05), and atteneuated the pulmonary parenchymal damage, histopathologically (p < 0.05). However, pulmonary neutrophil sequestration was not affected by postischemic treatment with PDTC (p > 0.05). Pyrrolidine dithiocarbamate administration also significantly alleviated the formation of pulmonary edema, as evidenced by the decreased Evans blue dye extravasation and organ wet/dry weight ratios (p < 0.05).

CONCLUSIONS

This study showed that postischemic treatment with PDTC significantly attenuated the lung reperfusion injury. Further clinical studies are needed for better understanding of the specific mechanisms of PDTC protection against I/R-related organ injury and to clarify whether PDTC may be a useful therapeutic agent during particular operations where remote organ I/R injury occurs.

Ameliorative effect of pyrrolidinedithiocarbamate on acetic acid-induced colitis in rats

Ulcerative colitis is a chronically recurrent inflammatory bowel disease of unknown origin. The present study examined the effect of NF-kappaB inhibitor and antioxidant, pyrrolidinedithiocarbamate (PDTC) on experimental ulcerative colitis in rats. Animals were randomly divided into 4 groups, each consisting of 6 animals; normal control group, acetic acid group, PDTC-treated group and sulfasalazine-treated group as a positive control group. Induction of colitis by intracolonic administration of 3% acetic acid produced severe macroscopic inflammation in the colon 24 h after acetic acid administration as assessed by the colonic damage score. Microscopically, colonic tissues showed ulceration, oedema and inflammatory cells infiltration. Biochemical studies revealed increased serum levels of lactate dehydrogenase (LDH), and nitrite/nitrate and colonic concentrations of tumor necrosis factor-alpha (TNF-alpha) and the neutrophil infiltration index, myeloperoxidase (MPO). Oxidative stress was indicated by elevated lipid peroxides formation and depleted reduced glutathione concentrations (GSH) in colonic tissues. Immunohistochemical studies of colonic sections revealed upregulation of inducible nitric oxide synthase (iNOS). Pretreatment with PDTC at a dose of (200 mg/kg/day, i.p.), three days before induction of colitis decreased serum LDH, nitrite/nitrate and TNF-alpha levels, colonic concentrations of MPO and lipid peroxides while increased colonic GSH concentration. Moreover, PDTC pretreatment attenuated colonic iNOS expression. Finally, histopathological changes were nearly restored by PDTC pretreatment. The findings of the present study provide evidence that PDTC may be beneficial in patients with inflammatory bowel disease.

Pyrrolidine dithiocarbamate reduced experimental periodontitis

Nuclear factor-kappaB (NF-kappaB) is a transcription factor which plays a pivotal role in the induction of genes involved in physiological processes as well as in the response to injury and inflammation. Dithiocarbamates are antioxidants which are potent inhibitors of NF-kappaB. We postulated that pyrrolidine dithiocarbamate (PDTC) would attenuate inflammation. In the present study, we have investigated the effects of PDTC, in a rat model of periodontitis. Periodontitis was induced in rats by placing around the lower left first molar a 2/0 braided silk. At day eight the gingivomucosal tissue encircling the mandibular first molar was removed for biochemical and histological analysis. At day eight ligations significantly induced an increase neutrophil infiltration as well as the gingivomucosal tissue expression of TNF-alpha and iNOS as well as nitrotyrosine formation and poly (ADP-ribose) polymerase activation. Ligation significantly increased Evans blue extravasation in gingivomucosal tissue and alveolar bone destruction. Intraperitonial injection of PDTC (10 mg/kg daily for eight days) significantly reduced all of the parameters of inflammation as described above. These data demonstrate that PDTC exerts an anti-inflammatory role during experimental periodontitis and is able to ameliorate the tissue damage associated with ligature-induced periodontitis.

Nuclear factor-kappaB inhibition by pyrrolidinedithiocarbamate attenuates gastric ischemia-reperfusion injury in rats

Pyrrolidinedithiocarbamate (PDTC) is a potent antioxidant and an inhibitor of nuclear factor-kappaB (NF-kappaB). The present study examined the impact of PDTC preconditioning on gastric protection in response to ischemia-reperfusion (I/R) injury to the rat stomach. Male Wistar rats were recruited and divided into 3 groups (n = 7). One group was subjected to gastric ischemia for 30 min and reperfusion for 1 hour. The second group of rats was preconditioned with PDTC (200 mg/kg body mass i.v.) 15 min prior to ischemia and before reperfusion. The third group of rats was sham-operated and served as the control group. Gastric I/R injury increased serum lactate dehydrogenase level, vascular permeability of gastric mucosa (as indicated by Evans blue dye extravasation) and gastric content of inflammatory cytokine; tumor necrosis factor-alpha (TNF-alpha). Moreover, oxidative stress was increased as indicated by elevated lipid peroxides formation (measured as thiobarbituric acid reactive substances) and depleted reduced glutathione in gastric tissues. NF-kappaB translocation was also detected by electrophoretic mobility shift assay. Microscopically, gastric tissues subjected to I/R injury showed ulceration, hemorrhages, and neutrophil infiltration. Immunohistochemical studies of gastric sections revealed increased expression of p53 and Bcl-2 proteins. PDTC pretreatment reduced Evans blue extravasation, serum lactate dehydrogenase levels, gastric TNF-alpha levels, and thiobarbituric acid reactive substances content, and increased gastric glutathione content. Moreover, PDTC pretreatment abolished p53 expression and inhibited NF-kappaB translocation. Finally, histopathological changes were nearly restored by PDTC pretreatment. These results clearly demonstrate that NF-kappaB activation and pro-apoptotic protein p53 induction are involved in gastric I/R injury. PDTC protects against gastric I/R injury by an antioxidant, NF-kappaB inhibition, and by reduction of pro-apoptotic protein p53 expression, which seems to be downstream to NF-kappaB, thus promoting cell survival.

Inhibitors of calpain activation (PD150606 and E-64) and renal ischemia-reperfusion injury

Calpain activation has been implicated in the development of ischemia-reperfusion (I-R) injury. Here we investigate the effects of two inhibitors of calpain activity, PD150606 and E-64, on the renal dysfunction and injury caused by I-R of rat kidneys in vivo. Male Wistar rats were administered PD150606 or E-64 (3mg/kg i.p.) or vehicle (10%, v/v, DMSO) 30min prior to I-R. Rats were subjected to bilateral renal ischemia (45min) followed by reperfusion (6h). Serum and urinary biochemical indicators of renal dysfunction and injury were measured; serum creatinine (for glomerular dysfunction), fractional excretion of Na(+) (FE(Na), for tubular dysfunction) and urinary N-acetyl-beta-d-glucosaminidase (NAG, for tubular injury). Additionally, kidney tissues were used for histological analysis of renal injury, immunohistochemical analysis of intercellular adhesion molecule-1 (ICAM-1) expression and nitrotyrosine formation. Renal myeloperoxidase (MPO) activity (for polymorphonuclear leukocyte infiltration) and malondialdehyde (MDA) levels (for tissue lipid peroxidation) were determined. Both PD150606 and E-64 significantly reduced the increases in serum creatinine, FE(Na) and NAG caused by renal I-R, indicating attenuation of renal dysfunction and injury and reduced histological evidence of renal damage caused by I-R. Both PD150606 and E-64 markedly reduced the evidence of oxidative stress (ICAM-1 expression, MPO activity, MDA levels) and nitrosative stress (nitrotyrosine formation) in rat kidneys subjected to I-R. These findings provide the first evidence that calpain inhibitors can reduce the renal dysfunction and injury caused by I-R of the kidney and may be useful in enhancing the tolerance of the kidney against renal injury associated with aortovascular surgery or renal transplantation.

Future strategies in the treatment of acute renal failure: growth factors, stem cells, and other novel therapies

PURPOSE OF REVIEW

Acute renal failure remains a significant cause of morbidity and mortality in adults and children. Despite advances in understanding the pathophysiology of acute renal failure, little progress has been made in its treatment. This review assesses the recent data on current and promising new therapies for acute renal failure.

RECENT FINDINGS

The first section of the review describes the recent therapies that have been used in humans, all of whom have been adults. The second section evaluates the use of agents given in experimental animal models during or after the onset of acute renal failure. The third section describes the many animal studies using therapies before the onset of experimental renal failure. The final section discusses how the emerging field of stem cell research might be used to treat acute renal failure.

SUMMARY

Among the recent studies in humans, the most intriguing have been the use of atrial natriuretic peptide in patients with nonoliguric renal failure and isotonic sodium bicarbonate infusions to prevent radiocontrast medium-induced renal failure. Among the agents used in animal studies, those with the greatest potential were hepatocyte growth factor and ethyl pyruvate, because they seem to protect against or accelerate recovery from acute renal failure after the renal insult. Finally, stem cell therapy may someday offer the best option for recovery from acute renal failure.