Intracellular signaling pathways of muscarinic acetylcholine receptor-mediated detrusor muscle contractions.

Acetylcholine plays an essential role in the regulation of detrusor muscle contractions, and antimuscarinics are widely used in the management of overactive bladder syndrome. However, several adverse effects limit their application and patients' compliance. Thus, this study aimed to further analyze the signal transduction of M2 and M3 receptors in the murine urinary bladder to eventually find more specific therapeutic targets. Experiments were performed on adult male wild-type, M2, M3, M2/M3, or Gαq/11 knockout (KO), and pertussis toxin (PTX)-treated mice. Contraction force and RhoA activity were measured in the urinary bladder smooth muscle (UBSM). Our results indicate that carbamoylcholine (CCh)-induced contractions were associated with increased activity of RhoA and were reduced in the presence of the Rho-associated kinase (ROCK) inhibitor Y-27632 in UBSM. CCh-evoked contractile responses and RhoA activation were markedly reduced in detrusor strips lacking either M2 or M3 receptors and abolished in M2/M3 KO mice. Inhibition of Gαi-coupled signaling by PTX treatment shifted the concentration-response curve of CCh to the right and diminished RhoA activation. CCh-induced contractile responses were markedly decreased in Gαq/11 KO mice; however, RhoA activation was unaffected. In conclusion, cholinergic detrusor contraction and RhoA activation are mediated by both M2 and M3 receptors. Furthermore, whereas both Gαi and Gαq/11 proteins mediate UBSM contraction, the activation at the RhoA-ROCK pathway appears to be linked specifically to Gαi. These findings may aid the identification of more specific therapeutic targets for bladder dysfunctions.NEW & NOTEWORTHY Muscarinic acetylcholine receptors are of utmost importance in physiological regulation of micturition and also in the development of voiding disorders. We demonstrate that the RhoA-Rho-associated kinase (ROCK) pathway plays a crucial role in contractions induced by cholinergic stimulation in detrusor muscle. Activation of RhoA is mediated by both M2 and M3 receptors as well as by Gi but not Gq/11 proteins. The Gi-RhoA-ROCK pathway may provide a novel therapeutic target for overactive voiding disorders.

Actinomyces in Crohn's-like appendicitis.

AIMS: Appendicitis with a Crohn's-like histological appearance generally raises concern for Crohn's disease, Yersinia infection, and interval appendectomy. Actinomyces infection is a recognised cause of chronic appendicitis that can histologically mimic Crohn's disease. METHODS AND RESULTS: We report on 20 cases of appendicitis with Crohn's-like histological features that were due to Actinomyces. Most patients presented with acute or chronic abdominal pain. Imaging studies suggested a mass in five cases. Two patients had interval appendectomy. Histological features showed Crohn's-like appendicitis in 16 cases, with moderate to marked fibrosis and granulomas in seven cases. The other four cases had less consistent histological findings. None of the patients developed Crohn's disease during the follow-up interval (median, 37 months). CONCLUSIONS: Actinomyces can be associated with Crohn's-like appendicitis with marked fibrosis, transmural inflammation, lymphoid hyperplasia, and granulomas.

Histology and Glutamine Synthetase Immunoreactivity in Liver Biopsies From Patients With Congestive Heart Failure.

BACKGROUND: Long-standing congestive heart failure can induce a constellation of histopathology changes in the liver that can range from mild sinusoidal dilation to advanced fibrosis and loss of normal perivenular expression of glutamine synthetase (GS). Liver biopsies might be performed to assess the perioperative risk of these patients or to determine the need of synchronous liver transplant. We aimed to assess interobserver agreement in recognizing these liver histologic features in patients undergoing evaluation for heart transplantation and to examine whether immunohistochemistry of GS will aid the diagnosis of cardiac hepatopathy (CH). METHODS: Hematoxylin-eosin and trichrome-stained slides from 36 liver biopsies from patients undergoing evaluation for heart transplantation were reviewed by four liver pathologists. Histologic features of CH were reviewed and an overall fibrosis (stage) was assessed according to a recently proposed congestive hepatic fibrosis score (CHFS). In addition, 24 liver biopsies with a consensus diagnosis of CH and eight liver biopsies with no significant pathological changes were subjected to immunohistochemistry for GS. The Fleiss' kappa coefficient (K) analysis was performed to determine the interobserver agreement. Further, histologic features of CH were correlated with the staining pattern of GS. RESULTS: Sinusoidal dilation, centrilobular hepatocyte atrophy, centrilobular fibrosis and hemorrhage were the most common findings in this cohort with a substantial-to-fair level of interobserver agreement among four reviewers. The overall agreement on the diagnosis of CH and CHFS was moderate (K = 0.55, 95% confidence interval (CI): 0.32 - 0.73) and fair (K = 0.35, 95% CI: 0.24 - 0.49), respectively. Twelve (of 24, 50%) cases of CH showed loss of the normal perivenular GS staining, while the remaining 12 cases of CH and all eight controls showed retained GS expression. Histologic features of CH (presence of sinusoidal dilation, centrilobular hepatocyte atrophy, hemorrhage, and centrilobular fibrosis) and the stage of fibrosis (CHFS) were not correlated with the loss of GS staining. CONCLUSION: Most common features of CH can be interpreted with fair-to-substantial level of agreement by liver pathologists, with an overall moderate level agreement for the diagnosis and fair agreement for CHFS. Loss of normal perivenular expression of GS only occurs in 50% CH and thus is not a sensitive marker for CH.

Interobserver Variability in Scoring Liver Biopsies with a Diagnosis of Alcoholic Hepatitis.

BACKGROUND: Alcoholic hepatitis (AH) is one of the most severe forms of alcoholic liver disease. Recently, a histologic scoring system for predicting prognosis in this patient cohort was proposed as Alcoholic Hepatitis Histologic Score (AHHS). We aimed to assess interobserver variability in recognizing histologic features of AH and the effect of this variability on the proposed AHHS categories. METHODS: Hematoxylin-eosin- and trichrome-stained slides from 32 patients diagnosed with AH with liver biopsies within 1 month of presentation (2000 to 2015) were reviewed by 5 pathologists including 3 liver pathologists and 2 gastrointestinal (GI) pathologists masked to the clinical findings or outcome. Histologic features of AH were assessed, the AHHS was calculated, and an AHHS category (mild, moderate, severe) was assigned. The Fleiss' kappa coefficient (κ) analysis was performed to determine the interobserver agreement. RESULTS: A slight-to-moderate level of interobserver agreement existed among 5 reviewers on histopathologic features of AH with κ value ranging from 0.20 (95% confidence interval (CI): 0.03 to 0.46, megamitochondria) to 0.52 [95% CI: 0.40 to 0.68, polymorphonuclear leukocyte (PMN) infiltration]. There was only a fair level of agreement in assigning AHHS category (κ = 0.33, 95% CI: 0.20 to 0.51). While overall fibrosis and neutrophilic inflammation were comparably evaluated by 3 liver pathologists and 2 GI pathologists, bilirubinostasis and megamitochondria were more consistently diagnosed by liver pathologists. Overall, 18 of 32 (56%) were uniformly assigned to an AHHS category by all liver pathologists with a κ value of 0.40 (95% CI: 0.22 to 0.60). CONCLUSIONS: In general, features of AH can be recognized with a slight-to-moderate level of interobserver agreement and there was fair interobserver agreement on assigning an AHHS category. Significant interobserver variability among pathologists revealed by the current study can limit its usefulness in everyday clinical practice.

PARP inhibition protects against alcoholic and non-alcoholic steatohepatitis.

BACKGROUND & AIMS: Mitochondrial dysfunction, oxidative stress, inflammation, and metabolic reprograming are crucial contributors to hepatic injury and subsequent liver fibrosis. Poly(ADP-ribose) polymerases (PARP) and their interactions with sirtuins play an important role in regulating intermediary metabolism in this process. However, there is little research into whether PARP inhibition affects alcoholic and non-alcoholic steatohepatitis (ASH/NASH). METHODS: We investigated the effects of genetic deletion of PARP1 and pharmacological inhibition of PARP in models of early alcoholic steatohepatitis, as well as on Kupffer cell activation in vitro using biochemical assays, real-time PCR, and histological analyses. The effects of PARP inhibition were also evaluated in high fat or methionine and choline deficient diet-induced steatohepatitis models in mice. RESULTS: PARP activity was increased in livers due to excessive alcohol intake, which was associated with decreased NAD+ content and SIRT1 activity. Pharmacological inhibition of PARP restored the hepatic NAD+ content, attenuated the decrease in SIRT1 activation and beneficially affected the metabolic-, inflammatory-, and oxidative stress-related alterations due to alcohol feeding in the liver. PARP1-/- animals were protected against alcoholic steatohepatitis and pharmacological inhibition of PARP or genetic deletion of PARP1 also attenuated Kupffer cell activation in vitro. Furthermore, PARP inhibition decreased hepatic triglyceride accumulation, metabolic dysregulation, or inflammation and/or fibrosis in models of NASH. CONCLUSION: Our results suggests that PARP inhibition is a promising therapeutic strategy in steatohepatitis with high translational potential, considering the availability of PARP inhibitors for clinical treatment of cancer. LAY SUMMARY: Poly(ADP-ribose) polymerases (PARP) are the most abundant nuclear enzymes. The PARP inhibitor olaparib (Lynparza) is a recently FDA-approved therapy for cancer. This study shows that PARP is overactivated in livers of subjects with alcoholic liver disease and that pharmacological inhibition of this enzyme with 3 different PARP inhibitors, including olaparib, attenuates high fat or alcohol induced liver injury, abnormal metabolic alteration, fat accumulation, inflammation and/or fibrosis in preclinical models of liver disease. These results suggest that PARP inhibition is a promising therapeutic strategy in the treatment of alcoholic and non-alcoholic liver diseases.

Adaptation of the cerebrocortical circulation to carotid artery occlusion involves blood flow redistribution between cortical regions and is independent of eNOS.

Cerebral circulation is secured by feed-forward and feed-back control pathways to maintain and eventually reestablish the optimal oxygen and nutrient supply of neurons in case of disturbances of the cardiovascular system. Using the high temporal and spatial resolution of laser-speckle imaging we aimed to analyze the pattern of cerebrocortical blood flow (CoBF) changes after unilateral (left) carotid artery occlusion (CAO) in anesthetized mice to evaluate the contribution of macrovascular (circle of Willis) vs. pial collateral vessels as well as that of endothelial nitric oxide synthase (eNOS) to the cerebrovascular adaptation to CAO. In wild-type mice CoBF reduction in the left temporal cortex started immediately after CAO, reaching its maximum (-26%) at 5-10 s. Thereafter, CoBF recovered close to the preocclusion level within 30 s indicating the activation of feed-back pathway(s). Interestingly, the frontoparietal cerebrocortical regions also showed CoBF reduction in the left (-17-19%) but not in the right hemisphere, although these brain areas receive their blood supply from the common azygos anterior cerebral artery in mice. In eNOS-deficient animals the acute CoBF reduction after CAO was unaltered, and the recovery was even accelerated compared with controls. These results indicate that 1) the Willis circle alone is not sufficient to provide an immediate compensation for the loss of one carotid artery, 2) pial collaterals attenuate the ischemia of the temporal cortex ipsilateral to CAO at the expense of the blood supply of the frontoparietal region, and 3) eNOS, surprisingly, does not play an important role in this CoBF redistribution.

Prevalence of Helicobacter pylori in Gastric Hyperplastic Polyps.

Hyperplastic polyps of the stomach are routinely encountered during upper endoscopy and often arise in the setting of abnormal surrounding mucosa, particularly Helicobacter pylori, autoimmune gastritis, and reactive gastropathy. Not infrequently gastroenterologists fail to biopsy the surrounding mucosa, thus determining the underlying etiology of the gastric hyperplastic polyp can be difficult. Recently, the Rodger C. Haggitt Gastrointestinal Pathology Society published guidelines on the use of special stains. The society guidelines indicate that H pylori are not usually present in hyperplastic polyps and special stains in this setting may have limited utility. We analyzed the histologic features of 32 gastric hyperplastic polyps in which the nonpolypoid mucosa demonstrated H pylori gastritis. A consecutive series of 50 hyperplastic polyps in which no surrounding mucosa was sampled was also analyzed. When H pylori are identified in biopsies of the nonpolypoid mucosa, it is also commonly present within the polyp tissue (22/32, 69%). The majority of H pylori organisms were identified on routine hematoxylin and eosin stain (16/22, 72%). In contrast, H pylori were only seen in 2/50 consecutive hyperplastic polyps in which the surrounding mucosa was not sampled. Compared with the hyperplastic polyps that lack the organisms, H pylori associated hyperplastic polyps more commonly had dense lymphoplasmacytic inflammation (P = .0001) and neutrophils within gastric epithelium (P = .036). Polyp location, number, size, and presence of intestinal metaplasia was not associated with H pylori These results provide empirical data to guide evaluation of hyperplastic polyps for H pylori.

Expression of p53 predicts risk of prevalent and incident advanced neoplasia in patients with Barrett's esophagus and epithelial changes indefinite for dysplasia.

BACKGROUND AND AIMS: Patients with Barrett's esophagus (BE) are at an increased risk for developing esophageal adenocarcinoma (EAC); thus they may undergo regular endoscopic surveillance. If epithelial changes cannot be unequivocally classified as negative or positive for dysplasia, a diagnosis of indefinite for dysplasia (IND) is recommended. Several biomarkers have been proposed as markers or predictors of neoplasia in the general BE population; however, their significance is not clear in patients with BE-IND. We therefore performed a retrospective study to determine whether expression of these biomarkers was associated with the development of neoplasia in BE-IND patients. METHODS: We searched our archives to identify all cases of BE-IND diagnosed between January 1992 and December 2007. Immunohistochemical analyses were used to semi-quantify the expression of p53, α-methylacyl-CoA racemase (AMACR), and cyclin D1. A univariate analysis was used to identify predictors for prevalent and incident neoplasia and advanced neoplasia. RESULTS: Among the 103 patients with an index diagnosis of BE-IND who were included in this study, 81 (78.6%) underwent a follow-up biopsy within 12 months of diagnosis; 10 (12.3%) had neoplasia, including four (4.9%) with advanced neoplasia. Among 79 patients without prevalent neoplasia who underwent more than 1 year of follow-up, 18 (22.8%) had developed neoplasia, including four (5.1%) with advanced neoplasia. AMACR and cyclin D1 expression levels were not correlated with prevalent or incident neoplasia; however, high p53 expression (>5%) was associated with prevalent advanced neoplasia on surveillance biopsy (P = 0.04) and with an increased risk of progression to advanced neoplasia (HR = 12; P = 0.03). CONCLUSION: In this study, p53 expression was found to be predictive of prevalent advanced neoplasia and progression to advanced neoplasia in patients with BE-IND.

Overexpression of p53 predicts colorectal neoplasia risk in patients with inflammatory bowel disease and mucosa changes indefinite for dysplasia.

BACKGROUND AND AIMS: We previously demonstrated a significant colorectal neoplasia risk in inflammatory bowel disease (IBD) patients with mucosal changes indefinite for dysplasia (IND) and the potential diagnostic utility of p53 and cytokeratin 7 immunohistochemistry in IBD-associated neoplasia. The primary aim of this exploratory study was to determine the predictive value of the two markers for neoplasia risk in the IBD-IND population. METHODS: We identified 44 eligible cases with IBD and IND in colon biopsy from our pathology database. We semi-quantified the expression of p53 and cytokeratin 7 in the colon biopsies by immunohistochemistry and correlated their expression, demographic information, and clinical features with colorectal neoplasia outcome. RESULTS: The mean age of the cohort was 46.6 ± 15.1 years, with 25 (56.8%) being male. The median follow-up was 101 months (range: 6-247) after IND diagnosis. Among these 44 patients, 11 (25%) progressed to neoplasia (low-grade dysplasia = 6; high-grade dysplasia = 2; cancer 3) at a median follow-up of 66 months (range: 19-145). Univariate analysis demonstrated that age and p53 overexpression were associated with progression to neoplasia. CONCLUSIONS: Twenty-five percent of patients with IBD and IND developed colorectal dysplasia or cancer. Overexpression of p53 and age are associated with neoplastic progression.

Syndromic and sporadic inflammatory/hyperplastic small-bowel polyps: a comparative study.

BACKGROUND: Inflammatory/hyperplastic small-bowel polyps (SBPs) occur either sporadically or in patients with a polyposis syndrome; however, comparison between these two settings of the histological features of SBPs has not been reported and the etiology of sporadic inflammatory/hyperplastic SBPs remains unclear. METHOD: Twenty-eight cases of sporadic inflammatory/hyperplastic SBPs and nine cases of syndromic SBPs were retrieved from the Department of Anatomic Pathology at the Cleveland Clinic. Clinico-demographics and histological features were compared between the two groups. RESULTS: Patients with syndromic inflammatory/hyperplastic SBPs were younger (48 vs. 63 years; P = 0.007) and had higher rates of hemorrhagic telangiectasia (55.6% vs. 0%; P = 0.000), gastric polyps (87.5% vs. 21.4%; P = 0.001), and family history of colon cancer (62.5% vs. 11.1%; P = 0.014). Sporadic cases were more frequently associated with gastro-esophageal reflux (35.7% vs. 0%; P = 0.079) and anti-reflux medication use (55.6% vs. 11.1%; P = 0.026). Histologically, the syndromic SBPs were more often of pure intestinal type (45.4% vs. 3.8%; P = 0.005) and had prominent vessels (81.8% vs. 42.3%; P = 0.036). CONCLUSIONS: Patients with syndromic SBPs are younger and have higher rates of hemorrhagic telangiectasia, gastric polyps, and family history of colon cancer. Histologically, syndromic inflammatory/hyperplastic SBPs are more likely to be of pure intestinal type and to have prominent vessels.

Risk for colorectal neoplasia in patients with inflammatory bowel disease and mucosa indefinite for dysplasia.

BACKGROUND: The management of colonic epithelial changes indefinite for dysplasia (IND) in patients with inflammatory bowel disease (IBD) remains controversial because of a paucity of published outcome data. METHODS: We analyzed data from 93 patients with IBD who were IND and 52 IBD patients without dysplasia (controls) from the Department of Anatomic Pathology database at the Cleveland Clinic from 1989 to 2004. Pathology reports, histologic slides, clinical features, and outcomes were reviewed. RESULTS: Twenty-two patients (23.7%) had surgical resections within 6 months of the IND assignment; of these, 6 had dysplasia (27.3%; 1 low-grade dysplasia and 5 high-grade dysplasia [HGD]). The remaining 71 patients received regular colonoscopy examinations for a mean period of 98.6 months; 18 patients developed dysplasia or carcinoma (25.2%; 10 low-grade dysplasia, 5 HGD, and 3 colorectal cancer). There was a mean interval of 53.9 months between an IND assignment and identification of dysplasia or carcinoma. Histology review of 59 cases revealed 3.2 cases per 100 person-years for neoplasia (low-grade dysplasia, HGD, or colorectal cancer) and 1.5 cases per 100 person-years for advanced neoplasia (HGD or colorectal cancer); these values were higher than those for controls (1.9 cases per 100 person-years for neoplasia and 0.7 cases per 100 person-years for advance neoplasia; P = 0.1 and P = 0.2, respectively, for IND versus controls). Patients aged more than 44 years when they were found to be IND were more likely than younger patients to develop neoplasia (hazard ratio, 6.7; P = 0.01). CONCLUSIONS: Patients with IBD and IND are at significant risk for colorectal dysplasia and cancer. These patients should be closely followed.

Risk for esophageal neoplasia in Barrett's esophagus patients with mucosal changes indefinite for dysplasia.

BACKGROUND AND AIM: Patients with Barrett's esophagus (BE) are at increased risk for esophageal adenocarcinoma (EAC) and therefore require surveillance. Biopsies are classified as indefinite for dysplasia (IND) when the significance of epithelial abnormalities is uncertain due to inflammation or sampling. Our aim was to characterize the neoplastic risk of IND in BE patients and to identify predictors of neoplastic risk. METHODS: Our pathology database from 1992 to 2007 was searched for BE and IND. Progression rates were calculated and univariate analysis was performed to identify predictors for neoplasia progression in BE-IND patients. RESULTS: Among 85 patients who had a follow-up (FU) biopsy within 1 year, 11 (12.9%) patients had prevalent neoplasia (seven low-grade dysplasia [LGD], two high-grade dysplasia [HGD], and two EAC). Among 82 patients who did not have prevalent neoplasia but had ≥ 1 year FU, 17 progressed to dysplasia (14 LGD, 3 HGD) and 2 developed EAC during a mean FU period of 59 months. The incidence of neoplasia (LGD, HGD, or EAC) and advanced neoplasia (HGD + EAC) was 4.5 and 1.2 cases per 100 patient-years, respectively. Longer length of BE and multi-focal IND on index biopsy were associated with progression to neoplasia. CONCLUSION: Patients with BE-IND carry a significant risk of harboring prevalent dysplasia, but the risk of incident dysplasia is similar to the general BE population. The length of BE and the multifocal IND might tentatively help to identify a patient subpopulation at higher risk of neoplastic progression before more definitive data becomes available.

Poly (ADP-ribose) polymerase-1 is a key mediator of liver inflammation and fibrosis.

UNLABELLED: Poly (ADP-ribose) polymerase 1 (PARP-1) is a constitutive enzyme, the major isoform of the PARP family, which is involved in the regulation of DNA repair, cell death, metabolism, and inflammatory responses. Pharmacological inhibitors of PARP provide significant therapeutic benefits in various preclinical disease models associated with tissue injury and inflammation. However, our understanding the role of PARP activation in the pathophysiology of liver inflammation and fibrosis is limited. In this study we investigated the role of PARP-1 in liver inflammation and fibrosis using acute and chronic models of carbon tetrachloride (CCl4 )-induced liver injury and fibrosis, a model of bile duct ligation (BDL)-induced hepatic fibrosis in vivo, and isolated liver-derived cells ex vivo. Pharmacological inhibition of PARP with structurally distinct inhibitors or genetic deletion of PARP-1 markedly attenuated CCl4 -induced hepatocyte death, inflammation, and fibrosis. Interestingly, the chronic CCl4 -induced liver injury was also characterized by mitochondrial dysfunction and dysregulation of numerous genes involved in metabolism. Most of these pathological changes were attenuated by PARP inhibitors. PARP inhibition not only prevented CCl4 -induced chronic liver inflammation and fibrosis, but was also able to reverse these pathological processes. PARP inhibitors also attenuated the development of BDL-induced hepatic fibrosis in mice. In liver biopsies of subjects with alcoholic or hepatitis B-induced cirrhosis, increased nitrative stress and PARP activation was noted. CONCLUSION: The reactive oxygen/nitrogen species-PARP pathway plays a pathogenetic role in the development of liver inflammation, metabolism, and fibrosis. PARP inhibitors are currently in clinical trials for oncological indications, and the current results indicate that liver inflammation and liver fibrosis may be additional clinical indications where PARP inhibition may be of translational potential.

Role of endocannabinoids and cannabinoid-1 receptors in cerebrocortical blood flow regulation.

BACKGROUND: Endocannabinoids are among the most intensively studied lipid mediators of cardiovascular functions. In the present study the effects of decreased and increased activity of the endocannabinoid system (achieved by cannabinoid-1 (CB1) receptor blockade and inhibition of cannabinoid reuptake, respectively) on the systemic and cerebral circulation were analyzed under steady-state physiological conditions and during hypoxia and hypercapnia (H/H). METHODOLOGY/PRINCIPAL FINDINGS: In anesthetized spontaneously ventilating rats the CB1-receptor antagonist/inverse agonist AM-251 (10 mg/kg, i.v.) failed to influence blood pressure (BP), cerebrocortical blood flow (CoBF, measured by laser-Doppler flowmetry) or arterial blood gas levels. In contrast, the putative cannabinoid reuptake inhibitor AM-404 (10 mg/kg, i.v.) induced triphasic responses, some of which could be blocked by AM-251. Hypertension during phase I was resistant to AM-251, whereas the concomitant CoBF-increase was attenuated. In contrast, hypotension during phase III was sensitive to AM-251, whereas the concomitant CoBF-decrease was not. Therefore, CoBF autoregulation appeared to shift towards higher BP levels after CB1-blockade. During phase II H/H developed due to respiratory depression, which could be inhibited by AM-251. Interestingly, however, the concomitant rise in CoBF remained unchanged after AM-251, indicating that CB1-blockade potentially enhanced the reactivity of the CoBF to H/H. In accordance with this hypothesis, AM-251 induced a significant enhancement of the CoBF responses during controlled stepwise H/H. CONCLUSION/SIGNIFICANCE: Under resting physiological conditions CB1-receptor mediated mechanisms appear to have limited influence on systemic or cerebral circulation. Enhancement of endocannabinoid levels, however, induces transient CB1-independent hypertension and sustained CB1-mediated hypotension. Furthermore, enhanced endocannabinoid activity results in respiratory depression in a CB1-dependent manner. Finally, our data indicate for the first time the involvement of the endocannabinoid system and CB1-receptors in the regulation of the cerebral circulation during H/H and also raise the possibility of their contribution to the autoregulation of CoBF.

Mitochondrial reactive oxygen species generation triggers inflammatory response and tissue injury associated with hepatic ischemia-reperfusion: therapeutic potential of mitochondrially targeted antioxidants.

Mitochondrial reactive oxygen species generation has been implicated in the pathophysiology of ischemia-reperfusion (I/R) injury; however, its exact role and its spatial-temporal relationship with inflammation are elusive. Herein we explore the spatial-temporal relationship of oxidative/nitrative stress and inflammatory response during the course of hepatic I/R and the possible therapeutic potential of mitochondrial-targeted antioxidants, using a mouse model of segmental hepatic ischemia-reperfusion injury. Hepatic I/R was characterized by early (at 2 h of reperfusion) mitochondrial injury, decreased complex I activity, increased oxidant generation in the liver or liver mitochondria, and profound hepatocellular injury/dysfunction with acute proinflammatory response (TNF-α, MIP-1α/CCL3, MIP-2/CXCL2) without inflammatory cell infiltration, followed by marked neutrophil infiltration and a more pronounced secondary wave of oxidative/nitrative stress in the liver (starting from 6 h of reperfusion and peaking at 24 h). Mitochondrially targeted antioxidants, MitoQ or Mito-CP, dose-dependently attenuated I/R-induced liver dysfunction, the early and delayed oxidative and nitrative stress response (HNE/carbonyl adducts, malondialdehyde, 8-OHdG, and 3-nitrotyrosine formation), and mitochondrial and histopathological injury/dysfunction, as well as delayed inflammatory cell infiltration and cell death. Mitochondrially generated oxidants play a central role in triggering the deleterious cascade of events associated with hepatic I/R, which may be targeted by novel antioxidants for therapeutic advantage.

Cisplatin nephrotoxicity involves mitochondrial injury with impaired tubular mitochondrial enzyme activity.

Cisplatin is a widely used antineoplastic agent. However, its major limitation is dose-dependent nephrotoxicity whose precise mechanism is poorly understood. Recent studies have suggested that mitochondrial dysfunction in tubular epithelium contributes to cisplatin-induced nephrotoxicity. Here the authors extend those findings by describing the role of an important electron transport chain enzyme, cytochrome c oxidase (COX). Immunohistochemistry for COX 1 protein demonstrated that, in response to cisplatin, expression was mostly maintained in focally damaged tubular epithelium. In contrast, COX enzyme activity in proximal tubules (by light microscopy) was decreased. Ultrastructural analysis of the cortex and outer stripe of the outer medulla showed decreased mitochondrial mass, disruption of cristae, and extensive mitochondrial swelling in proximal tubular epithelium. Functional electron microscopy showed that COX enzyme activity was decreased in the remaining mitochondria in the proximal tubules but maintained in distal tubules. In summary, cisplatin-induced nephrotoxicity is associated with structural and functional damage to the mitochondria. More broadly, using functional electron microscopy to measure mitochondrial enzyme activity may generate mechanistic insights across a spectrum of renal disorders.

ß-Caryophyllene ameliorates cisplatin-induced nephrotoxicity in a cannabinoid 2 receptor-dependent manner.

(E)-ß-caryophyllene (BCP) is a natural sesquiterpene found in many essential oils of spice (best known for contributing to the spiciness of black pepper) and food plants with recognized anti-inflammatory properties. Recently it was shown that BCP is a natural agonist of endogenous cannabinoid 2 (CB(2)) receptors, which are expressed in immune cells and mediate anti-inflammatory effects. In this study we aimed to test the effects of BCP in a clinically relevant murine model of nephropathy (induced by the widely used antineoplastic drug cisplatin) in which the tubular injury is largely dependent on inflammation and oxidative/nitrative stress. ß-caryophyllene dose-dependently ameliorated cisplatin-induced kidney dysfunction, morphological damage, and renal inflammatory response (chemokines MCP-1 and MIP-2, cytokines TNF-α and IL-1ß, adhesion molecule ICAM-1, and neutrophil and macrophage infiltration). It also markedly mitigated oxidative/nitrative stress (NOX-2 and NOX-4 expression, 4-HNE and 3-NT content) and cell death. The protective effects of BCP against biochemical and histological markers of nephropathy were absent in CB(2) knockout mice. Thus, BCP may be an excellent therapeutic agent to prevent cisplatin-induced nephrotoxicity through a CB(2) receptor-dependent pathway. Given the excellent safety profile of BCP in humans it has tremendous therapeutic potential in a multitude of diseases associated with inflammation and oxidative stress.

Cannabinoid 1 receptor promotes cardiac dysfunction, oxidative stress, inflammation, and fibrosis in diabetic cardiomyopathy.

Endocannabinoids and cannabinoid 1 (CB(1)) receptors have been implicated in cardiac dysfunction, inflammation, and cell death associated with various forms of shock, heart failure, and atherosclerosis, in addition to their recognized role in the development of various cardiovascular risk factors in obesity/metabolic syndrome and diabetes. In this study, we explored the role of CB(1) receptors in myocardial dysfunction, inflammation, oxidative/nitrative stress, cell death, and interrelated signaling pathways, using a mouse model of type 1 diabetic cardiomyopathy. Diabetic cardiomyopathy was characterized by increased myocardial endocannabinoid anandamide levels, oxidative/nitrative stress, activation of p38/Jun NH(2)-terminal kinase (JNK) mitogen-activated protein kinases (MAPKs), enhanced inflammation (tumor necrosis factor-α, interleukin-1ß, cyclooxygenase 2, intracellular adhesion molecule 1, and vascular cell adhesion molecule 1), increased expression of CB(1), advanced glycation end product (AGE) and angiotensin II type 1 receptors (receptor for advanced glycation end product [RAGE], angiotensin II receptor type 1 [AT(1)R]), p47(phox) NADPH oxidase subunit, ß-myosin heavy chain isozyme switch, accumulation of AGE, fibrosis, and decreased expression of sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA2a). Pharmacological inhibition or genetic deletion of CB(1) receptors attenuated the diabetes-induced cardiac dysfunction and the above-mentioned pathological alterations. Activation of CB(1) receptors by endocannabinoids may play an important role in the pathogenesis of diabetic cardiomyopathy by facilitating MAPK activation, AT(1)R expression/signaling, AGE accumulation, oxidative/nitrative stress, inflammation, and fibrosis. Conversely, CB(1) receptor inhibition may be beneficial in the treatment of diabetic cardiovascular complications.

Δ8-Tetrahydrocannabivarin prevents hepatic ischaemia/reperfusion injury by decreasing oxidative stress and inflammatory responses through cannabinoid CB2 receptors.

BACKGROUND AND PURPOSE: Activation of cannabinoid CB(2) receptors protects against various forms of ischaemia-reperfusion (I/R) injury. Δ(8) -Tetrahydrocannabivarin (Δ(8) -THCV) is a synthetic analogue of the plant cannabinoid Δ(9) -tetrahydrocannabivarin, which exhibits anti-inflammatory effects in rodents involving activation of CB(2) receptors. Here, we assessed effects of Δ(8) -THCV and its metabolite 11-OH-Δ(8) -THCV on CB(2) receptors and against hepatic I/R injury. EXPERIMENTAL APPROACH: Effects in vitro were measured with human CB(2) receptors expressed in CHO cells. Hepatic I/R injury was assessed in mice with 1h ischaemia and 2, 6 or 24h reperfusion in vivo. KEY RESULTS: Displacement of [(3) H]CP55940 by Δ(8) -THCV or 11-OH-Δ(8) -THCV from specific binding sites in CHO cell membranes transfected with human CB(2) receptors (hCB(2) ) yielded K(i) values of 68.4 and 59.95 nM respectively. Δ(8) -THCV or 11-OH-Δ(8) -THCV inhibited forskolin-stimulated cAMP production by hCB(2) CHO cells (EC(50) = 12.95 and 14.3 nM respectively). Δ(8) -THCV, given before induction of I/R, attenuated hepatic injury (measured by serum alanine aminotransferase and aspartate aminotransferase levels), decreased tissue protein carbonyl adducts, 4-hydroxy-2-nonenal, the chemokines CCL3 and CXCL2,TNF-α, intercellular adhesion molecule 1 (CD54) mRNA levels, tissue neutrophil infiltration, caspase 3/7 activity and DNA fragmentation. Protective effects of Δ(8) -THCV against liver damage were still present when the compound was given at the beginning of reperfusion. Pretreatment with a CB(2) receptor antagonist attenuated the protective effects of Δ(8) -THCV, while a CB(1) antagonist tended to enhance it. CONCLUSIONS AND IMPLICATIONS: Δ(8) -THCV activated CB(2) receptors in vitro, and decreased tissue injury and inflammation in vivo, associated with I/R partly via CB(2) receptor activation. LINKED ARTICLES: This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and Medicine visit http://dx.doi.org/10.1111/bph.2011.163.issue-7.

A new cannabinoid CB2 receptor agonist HU-910 attenuates oxidative stress, inflammation and cell death associated with hepatic ischaemia/reperfusion injury.

BACKGROUND AND PURPOSE: Cannabinoid CB(2) receptor activation has been reported to attenuate myocardial, cerebral and hepatic ischaemia-reperfusion (I/R) injury. EXPERIMENTAL APPROACH: We have investigated the effects of a novel CB(2) receptor agonist ((1S,4R)-2-(2,6-dimethoxy-4-(2-methyloctan-2-yl)phenyl)-7,7-dimethylbicyclo[2.2.1]hept-2-en-1-yl)methanol (HU-910) on liver injury induced by 1 h of ischaemia followed by 2, 6 or 24 h of reperfusion, using a well-established mouse model of segmental hepatic I/R. KEY RESULTS: Displacement of [(3) H]CP55940 by HU-910 from specific binding sites in CHO cell membranes transfected with human CB(2) or CB(1) receptors (hCB(1/2) ) yielded K(i) values of 6 nM and 1.4 µM respectively. HU-910 inhibited forskolin-stimulated cyclic AMP production by hCB(2) CHO cells (EC(50) = 162 nM) and yielded EC(50) of 26.4 nM in [(35) S]GTPγS binding assays using hCB(2) expressing CHO membranes. HU-910 given before ischaemia significantly attenuated levels of I/R-induced hepatic pro-inflammatory chemokines (CCL3 and CXCL2), TNF-α, inter-cellular adhesion molecule-1, neutrophil infiltration, oxidative stress and cell death. Some of the beneficial effect of HU-910 also persisted when given at the beginning of the reperfusion or 1 h after the ischaemic episode. Furthermore, HU-910 attenuated the bacterial endotoxin-triggered TNF-α production in isolated Kupffer cells and expression of adhesion molecules in primary human liver sinusoidal endothelial cells stimulated with TNF-α. Pretreatment with a CB(2) receptor antagonist attenuated the protective effects of HU-910, while pretreatment with a CB(1) antagonist tended to enhance them. CONCLUSION AND IMPLICATIONS: HU-910 is a potent CB(2) receptor agonist which may exert protective effects in various diseases associated with inflammation and tissue injury. LINKED ARTICLES: This article is part of a themed section on Cannabinoids in Biology and Medicine. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-8. To view Part I of Cannabinoids in Biology and Medicine visit http://dx.doi.org/10.1111/bph.2011.163.issue-7.