Phytochemical analysis and immunomodulatory activities in vitro and in vivo of Aframomum melegueta K Schum seed extracts.

Aframomum melegueta K Schum (A. melegueta), an herbaceous plant renowned for its medicinal seeds, was investigated for its potential immunomodulatory effects in vitro and in vivo using ethanolic and methanolic extracts. The immunomodulatory effect was evaluated by measuring antibody titers using the agglutination technique, while anti-inflammatory activity was assessed in a carrageenan-induced mouse paw edema model. In vitro immunomodulatory activity was measured by lysozyme release from neutrophils. Additionally, white blood cell counts were analyzed post-extracts treatment. The MTT assay was employed to determine cytotoxicity, and the biochemical parameters of liver toxicity were evaluated. Remarkably, both extracts exhibited a dose-dependent reduction in paw edema (p < 0.001), with the most significant reduction observed at 1 g/kg (78.13 and 74.27% for ethanolic and methanolic extracts, respectively). Neutrophil degranulation was significantly inhibited in a dose-dependent manner (p < 0.003), reaching maximal inhibition at 100 µg/mg (60.78 and 39.7% for ethanolic and methanolic extracts, respectively). In comparison to the control group, both antibody production and white blood cell counts were reduced. Neither of the extracts showcased any cytotoxicity or toxicity. These findings suggest that A. melegueta extracts exhibit immunosuppressive and anti-inflammatory activities due to the presence of various biomolecules.

Antitumoral activity of Caralluma europaea on colorectal and prostate cancer cell lines.

Caralluma europaea is a medicinal plant used in Moroccan popular medicine, which has been employed as a remedy attributed to its anti-inflammatory, antipyretic, antinociceptive, antidiabetic, neuroprotective, and antiparasitic properties. The aim of the present study was to investigate the antitumor activity of both the methanolic and aqueous extract of C. europaea. The effects of increasing concentrations of aqueous and methanolic extracts on human colorectal cancer HT-29 and HCT116 cell lines and human prostate cancer PC3 and DU145 cell lines were examined on cell proliferation using MTT assay and cell cycle analysis. The induction of apoptosis was also assessed by determining protein expression of caspase-3 and poly-ADP-ribose polymerase (PARP) cleavage by western blot. The methanolic extract of C. europaea exerted significant antiproliferative effects on HT-29 (IC50 values 73 µg/ml), HCT116 (IC50 values 67 µg/ml), PC3 (IC50 values 63 µg/ml) and DU145 cells (IC50 values 65 µg/ml) after 48 hr treatment. Further, incubation with methanolic extract of C. europaea induced cell cycle arrest in G1 phase and an apoptotic process for all treated cell lines. In conclusion, the present results suggest that C. europaea, exhibited that these natural compounds are significant apoptosis inducers which may have considerable potential for development of effective natural product anticancer agents.

An Update of Research Animal Models of Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a group of chronic disorders that includes two main disease forms, Crohn's disease, and ulcerative colitis. The understanding of the intestinal inflammation occurring in IBD has been immeasurably advanced by the development of the now numerous murine models of intestinal inflammation. The usefulness of this research tool in IBD arises from a convergence of underlying genetic susceptibility, immune system dysfunction, environmental factors, and shifts in gut microbiota. Due to the multifactorial feature of these diseases, different animal models have been used to investigate the underlying mechanisms and develop potential therapeutic strategies. The results of preclinical efficacy studies often inform the progression of therapeutic strategies. This review describes the distinct feature and limitations of each murine IBD model and discusses the previous and current lessons from the IBD models.

Amino acid substitutions in the Hepatitis C virus core region of genotype 1b in Moroccan patients.

The aim of the present study was to identify basic amino acid in the core region in subtype 1b-infected, treatment-naive patients from Morocco and to search for their eventual association with liver cancer. The survey included 151 patients (86 patients with chronic hepatitis and 65 patients with hepatocellular carcinoma, HCC). We performed direct sequencing, and compared the data obtained with the consensus sequence of core protein. Several recurrent amino acid substitutions were observed. The Arg70 was changed for a Gln in 22 of 112 patients (19.6%) and Leu91 was changed to Met in 23 of 112 patients (20.5%). Besides, the threonine at position 75 (Thr75) was mutated for alanine or serine in 43 (38.4%) and 40 (35.7%) of the patients, respectively. Overall, there was no significant difference between patients with chronic hepatitis and those with HCC regarding amino acids substitution number (24% vs. 33%, respectively, P = 0.457). Our study provides the first inventory of predominant amino acid substitutions in the HCV core region genotype 1b. The impact of single or combined mutations on the resistance to treatment or on disease progression is still unknown and deserves more attention in the future.

Morocco underwent a drift of circulating hepatitis C virus subtypes in recent decades.

Hepatitis C virus (HCV) isolates circulating in Morocco are poorly documented. To determine the subgenotype distribution of HCV in chronically infected patients, serum samples from 185 anti-HCV-positive patients were analyzed. Determination of the HCV genotype and subtype was performed by sequencing the 5'UTR, NS5B and core regions. According to the NS5B phylogeny, the HCV strains primarily belonged to subtypes 1b (75.2%), 2i (19.1%) and 2k (2.8%). Using a Bayesian approach, the mean date of appearance of the most recent common ancestor was estimated to be 1910 for HCV-1b and 1854 for HCV-2i. Although it is currently the most frequent genotype in Morocco and the dominant form in hepatocellular carcinoma, it thus appears that HCV-1b was introduced into the population subsequently to HCV-2i.

Neutrophils stimulated by apolipoprotein(a) generate fragments that are stronger inhibitors of plasmin formation than apo(a).

Apolipoprotein(a), the plasminogen-like component of lipoprotein(a), is transformed into fragments by polymorphonuclear neutrophils (PMNs) elastase. Since stimulated PMNs express urokinase-type plasminogen activator (uPA), we sought to investigate the relevance of apo(a) fragmentation on plasminogen activation by neutrophils. Freshly isolated human PMNs stimulated by a 10 kringle recombinant apo(a), r-apo(a), activate plasminogen in a specific and saturable manner (Km = 476 +/- 42 nM, Vmax = 896 +/- 18 pmol min(-1)). This activation is prevented by amiloride, an inhibitor of u-PA, and epsilon-aminocaproic acid, epsilon-ACA, a lysine analogue that blocks plasminogen binding to PMNs. Stimulation of PMNs by apo(a) results in the formation of elastase-derived apo(a) fragments. These fragments produce a concentration-dependent decrease in the formation of plasmin. Addition of elastase inhibitors to PMNs prevented degradation of apo(a) and partially restored the formation of plasmin. In a similar manner, isolated r-apo(a) fragments were able to produce a 100% decrease in plasmin generation as compared to intact r-apo(a). These data indicate that apo(a) fragments produce a more pronounced inhibition in the generation of cell-bound plasmin by uPA than the parent apo(a). These effects of apo(a) and its fragments were neutralised by a monoclonal antibody directed against the lysine-binding site of apo(a). This mechanism may be of biological relevance to the effects of Lp(a) in conditions where PMNs accumulate and release elastase, i.e. thrombus lysis and inflammatory lesions.

Role of leukocyte elastase in preventing cellular re-colonization of the mural thrombus.

To explore possible mechanisms responsible for the absence of cell re-colonization of mural thrombi in aneurysms, we analyzed the release and storage of leukocyte proteases in the most luminal layer versus intermediate and abluminal layers of 10 mural thrombi of human abdominal aortic aneurysms. The luminal layer contained many polymorphonuclear leukocytes (PMNs), which released pro-matrix metalloproteinase (MMP)-9 and MMP-8. Leukocyte elastase was also stored and released by the luminal layer (immunohistochemistry, activity on synthetic substrates, and casein zymography). Acid buffer allowed extraction of leukocyte elastase from the luminal layer, which was inhibited by elastase inhibitors. Casein zymography of luminal extracts and conditioned medium from formyl-methionyl-leucyl-phenylalanine (fMLP)-stimulated PMNs exhibited a similar lysis pattern, corresponding to elastase activity. Smooth muscle cell (SMC) seeding resulted in colonization of the intermediate thrombus layer ex vivo but not of the luminal layer. Extracts of the luminal layer induced loss of anchorage of both cultured human smooth muscle cells and stromal cells of bone marrow origin (anoikis). This anoikis was prevented by preincubation of the extracts with serine protease inhibitors. Moreover, adhesion of human SMCs and stromal bone marrow cells on fibrin gels was strongly inhibited when the gel was preincubated with pure elastase, medium of fMLP-stimulated PMNs, or extracts of luminal layers of mural thrombi. This loss of cell anchorage was prevented by the preincubation of the medium or extracts with alpha(1)-antitrypsin, but not when alpha(1)-antitrypsin was added after binding of elastase to the fibrin gel. In conclusion, elastase released by PMNs trapped within the mural thrombus impairs the spontaneous anchorage of mesenchymal cells to a fibrin matrix. This phenomenon could be one mechanism by which cellular healing of the mural thrombus in aneurysms is prevented.

IL-10 inhibits vascular smooth muscle cell activation in vitro and in vivo.

The anti-inflammatory cytokine IL-10 inhibits intimal hyperplasia after stent implantation via a powerful inactivation of monocytes. We tested the hypothesis that IL-10 may also inhibit vascular smooth muscle cell (SMC) activation via the inhibition of the NF-kappaB/I-kappaB system. The IL-10 receptor was detected in rat SMCs in vitro and in vivo. In LPS-stimulated rat SMCs, 1 ng/ml recombinant murine IL-10 (mIL-10) reduced I-kappaBalpha and I-kappaBbeta degradation, NF-kappaB activation, as well as the expression of the NF-kappaB-dependent gene IL-6 by 32%, 31%, 75%, and 19%, respectively (P < 0.05 for all). Similar results were obtained in vivo 6 h and 4 days after balloon abrasion of the rat aorta, a model in which intimal hyperplasia results essentially from SMC activation. Moreover, mIL-10 reduced SMC proliferation and migration in vitro (by 60% for both, P < 0.0001), resulting in reduced SMC proliferation and intimal growth 14 days after balloon abrasion of the rat aorta (by 76% and 75%, respectively; P < 0.005). In conclusion, mIL-10 has a direct inhibitory effect on SMCs in vitro and in vivo. This effect is mediated in part by NF-kappaB inactivation and may participate in the overall protective effect of IL-10 on postangioplasty restenosis.

Pharmacological potentiation of natriuretic peptide limits polymorphonuclear neutrophil-vascular cell interactions.

OBJECTIVE: Activated polymorphonuclear neutrophils (PMNs) are the main source of circulating neutral endopeptidase (NEP). We tested the hypothesis that NEP inhibition could potentiate the effect of atrial natriuretic peptide (ANP) on PMN-vascular cell interactions in vitro. METHODS AND RESULTS: ANP alone and its potentiation by retrothiorphan, the NEP inhibitor, significantly inhibited superoxide, lysozyme, and matrix metalloproteinase (MMP)-9 release by N-formyl-Met-Leu-Phe-stimulated PMNs. Activated PMNs degraded exogenous ANP, which was prevented by NEP inhibition. Hypoxia significantly increased the adhesion of PMNs to endothelial cells and their subsequent MMP-9 release by 60% and 150%, respectively (P<0.01). ANP and its potentiation by retrothiorphan limited PMN adhesion to hypoxic endothelial cells and thus decreased their MMP-9 release (P<0.01). Smooth muscle cells (SMCs) incubated with conditioned medium of N-formyl-Met-Leu-Phe-stimulated PMNs exhibited morphological and biochemical changes characteristic of apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling positivity, nuclear condensation/fragmentation, poly ADP-ribose polymerase cleavage, and DNA laddering). SMC detachment and subsequent apoptosis could be related to leukocyte elastase-induced pericellular proteolysis, inasmuch as both events are inhibited by elastase inhibitors. ANP and its potentiation by retrothiorphan were able to limit elastase release, fibronectin degradation, and SMC apoptosis. CONCLUSIONS: ANP potentiation by NEP inhibition could limit PMN activation and its consequences on vascular cells.