Visfatin as a therapeutic target for rheumatoid arthritis

Introduction: The rising prevalence of musculoskeletal pathologies in developed countries has caused a dramatic impact on social welfare. Amidst these musculoskeletal pathologies is Rheumatoid arthritis (RA), a chronic systemic autoimmune disease that mostly affects the synovium. RA metabolic-associated alterations, including distorted adipokine production, enhance RA inflammatory environment. Among the altered adipokines, visfatin is particularly involved in RA inflammation and catabolism and stands out as an essential enzyme linked to critical cell features.

Areas covered: We discuss the potential mechanism supporting the contribution of visfatin to RA and the association between RA and obesity. We discuss the repurposing of cancer-tested drugs to inhibit visfatin in the context of RA. Additionally, we address the possibility of combining these drugs with current RA therapy. Finally, we explore the future of visfatin as an RA biomarker or therapeutic target.

Expert opinion: Inhibition of visfatin has become an interesting therapeutic approach for RA pathology. Such a feat has already been attained in oncology using small molecule inhibitors, which suggest that a similar course of action would be worth pursuing in the RA context. Visfatin will become an important biomarker and therapeutic target for RA.     

Ischemic mitral valve regurgitation: the new challenge for magnetic resonance imaging.

Ischemic mitral valve regurgitation (IMVR) refers to mitral regurgitation in patients with ischemic heart disease (IHD) in the presence of a structurally normal mitral valve. IMVR contributes significantly to morbidity and mortality in patients with IHD. The thresholds for clinical management, surgical intervention, and the choice of surgical procedure continue to evolve and independent determinants for surgical success in the pre- and post-operative evaluation of IMVR are still controversial. Although echocardiography has been valued as the gold standard in the evaluation of IMVR, new technologies such as magnetic resonance imaging (MRI) may be seen as applicable to the investigation of this complex pathology. MRI may allow for detection of parameters that could help clinicians and surgeons to better assess IMVR and eventually guide appropriate treatment whenever necessary. The present article discusses the main parameters that should be routinely investigated while adopting MRI technology to assess patients with IMVR. The review is the result of a multidisciplinary approach to this complex etiopathogenic entity and involves expertise spanning from radiology, cardiology, to cardiac surgery.     

Characterization of granulosa cell subpopulations from avian preovulatory follicles by multiparameter flow cytometry

The objective of the present study was to characterize the granulosa cell populations from individual hen (Gallus domesticus) preovulatory follicles at defined stages of follicular maturation using multiparameter flow cytometry. Granulosa cells were fixed and stained with three fluorochromes that selectively bind to DNA (Hoechst 33342, blue), RNA (pyronin Y, red), or protein (fluorescein isothiocyanate, green). A flow cytometer equipped with a three-laser excitation system was used to analyze three colors of fluorescence from stained cells. Forward angle light scatter and axial light loss measurements were made on each cell to determine relative cell size. In addition, the ratios of RNA to protein and DNA to protein were measured. The major findings obtained from correlated measurements of cell cycle (DNA), protein, RNA, cell size, and ratios were: 1) the percentage of proliferating cells decreased while cell size increased during follicular maturation; 2) two subpopulations of granulosa cells were identified within each follicle based on relatively high and low protein contents; the fraction of cells in the high protein subpopulation increased, and the fraction of cells in the low protein subpopulation decreased during follicular maturation; 3) the high and low protein subpopulations also differed in cell cycle distribution, RNA content, and cell size; and 4) the distribution of cells into the two subpopulations and the degree of proliferation were influenced by stage of the ovulatory cycle, primarily in the most mature follicles. The results demonstrate the dynamic heterogeneity of the granulosa cell populations from individual ovarian follicles and show the influences of follicular maturation and stage of the ovulatory cycle on cell growth and metabolism.     

Analysis of tetanus toxin peptide/DR recognition by human T cell receptors reconstituted into a murine T cell hybridoma

We have previously reported that human T cell receptors (TcR) selected in the class II-restricted (HLA-DRB1*1302) response to a tetanus toxin peptide (tt830-843) frequently used the Vβ2 germ-line segment which paired with several Vα segments and that the putative CDR3 of both α and β chains showed remarkable heterogeneity. To analyze the structural basis for recognition of the tt830-843/DR complex, five of these TcR were reconstituted into a murine T cell hybridoma, 58 α^?β^?, by expressing the human α and β variable regions joined to the mouse α and β constant regions, respectively. The chimeric TcR, expressing the same Vβ germ-line segment (Vβ2), two expressing Vα21.1, twoVα17.1 and one Vα8.1 were shown to have the expected antigen specificity and DR restriction. Two lines of evidence suggested that the putative CDR3, although not conserved in these TcR, played a key role in recognition. First, two TcR with identical V germ-line segments but distinct CDR3 showed large differences in their capacity to react with the ligand. Second, interchanging the α and β chains from tt830-843/DR1302-specific TcR which differed in their CDR3 sequences invariably led to loss of recognition. We also asked whether germ-line Vα17.1 could functionally replace Vα21.1, as they appear to be related in their primary sequence. However, as in the case of CDR3 exchanges, Vα replacement abrogated TcR reactivity. Taken together, these data underline the fine interdependence of the structural components of the TcR binding site in defining a given specificity. Four of the TcR studied displaying promiscuous recognition were also tested against different DR alleles and site-directed mutants. The results of these experiments suggested that, in spite of their structural heterogeneity, anti-tt830-843 TcR may have a similar orientation with respect to the peptide/DR complex. The reconstitution system described herein should represent a valuable tool for detailed studies of human TcR specificity.     

Purification and characterization of Par o I, major allergen of Parietaria officinalis pollen.

Par o I, a major allergen of Parietaria officinalis, was purified from the pollen extract. The purified allergen was obtained by ultrafiltration, Sephadex gel filtration and DE-52 ion exchange chromatography: the purified preparation yields a single band in polyacrylamide gel isoelectric focusing (PAG-IEF), sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting, a single immunoprecipitation arc in crossed immunoelectrophoresis (CIE) and crossed radioimmunoelectrophoresis (CRIE) and a single peak in size exclusion high-performance liquid chromatography (HPLC). Par o I is a glycoprotein with a protein to carbohydrate ratio of 100:21. The molecular weight, determined by SDS-PAGE, Sephadex G-50 gel filtration and size exclusion HPLC, varied between 13.5 and 14.5 kDa according to the method employed. The isoelectric point was 4.6. The amino acid composition and the sequence of the first twelve N-terminal residues were determined. The allergenicity was assayed in vivo and in vitro. 29/29 Parietaria-allergic patients were skin positive to Par o I and possessed high level of specific serum IgE antibody as it determined by radioallergosorbent test (RAST). Par o I contained dominant epitopes for human IgE as inhibited to 85% the pollen extract RAST performed with a pool of sera of allergic patients. The RAST inhibitory activity was not abolished by deglycosylation.     

Respiration in NREM and REM sleep after upper airway surgery for obstructive sleep apnoea

SUMMARY  To verify whether upper airway surgery in obstructive sleep apnoea syndrome affects differently respiration in NREM and REM sleep, 22 patients were studied by polysomnography before and three months after surgical treatment. On the average, treatment improved respiration during both sleep states, but no significant interaction was found between sleep state and effect of surgical treatment. According to the response to treatment, three groups of patients were identified: the first group ( N = 6), with an improvement in apnoea-hypopnoea index (AHI), percentage of sleep time spent in apnoea and hypopnoea (time in AH) and mean oxyhaemoglobin saturation (SaO₂) in both NREM and REM sleep; the second group ( N = 5), with an improvement in AHI only in NREM sleep, associated with improvement in mean SaO₂ in both sleep states; the third group ( N = 11), without any improvement in AHI and time in AH, either associated ( N = 5) or not ( N = 6) with an improvement in mean SaO₂ in both sleep states. An increase in the percentage of hypopnoeas out of the total AHI after treatment could partly account for the apparent discrepancy between AHI and mean SaO₂ behaviour in the subjects of the second group, but not in the patients of the third group who improved their mean SaO₂. Mixed apnoeas occurred before surgery in six subjects; they remained numerous after surgery only in two subjects who did not show any SaO₂ improvement. In conclusion, the degree of improvement in respiration after upper airway surgery was similar in every patient in NREM and REM sleep.     

Down-regulation of nitric oxide synthase-2 and cyclooxygenase-2 pathways by p53 in squamous cell carcinoma

The goal of this study was to analyze the correlation between inducible nitric oxide synthase (iNOS) and COX-2 activities and p53 gene status in head and neck squamous cell carcinomas (HNSCCs) in vivo and in vitro. In a series of 43 HNSCCs we observed an up-regulation of both iNOS and COX-2 pathways in tumor tissues and both activities were correlated each other (rs = 0.612 and P = 0.0002). We also found that p53-mutated HNSCCs (25 cases, 58.1%) showed higher levels of iNOS activity and cGMP in comparison with wild-type p53 tumors (18 cases, 41.9%) (P = 0.0005 and P = 0.01), as well as higher iNOS immunohistochemical expression (P = 0.03). Analogously, higher PgE2 levels were documented in p53-mutated HNSCCs when compared with wild-type p53 tumors (P = 0.015) and COX-2 protein expression was higher in p53-mutated HNSCCs (P = 0.007). A431 cancer cells expressing a p53 temperature-sensitive mutant showed an approximately 1.9- and 2.6-fold decrease in spontaneous NO(2-)/NO(3-) and PgE2 synthesis at permissive temperature, respectively, when compared with the same cells at nonpermissive temperature (P 相似文献   

Endogenous levels of mRNA for IFNs and IFN-related genes in hepatic biopsies of chronic HCV-infected and non-alcoholic steatohepatitis patients

To investigate the intra-hepatic activation of the IFN system in patients affected by chronic HCV-infection in comparison with that observed in a non-infectious liver disease such as non-alcoholic steatohepatitis, we measured the liver steady state mRNA levels of interferon-alpha, interferon-beta and interferon-gamma as well as of IFN-related genes (IFNAR-1, STAT1alpha, PKR, 2-5 AS, IRF-1, ICE and IL-18). In HCV-infected subjects, possible correlations of these parameters with viral load and liver injury were also analyzed. Twenty-four chronic untreated HCV-infected subjects and seven patients with non-alcoholic steatohepatitis were enrolled in the study. Liver biopsies were graded according to Knodell scores. Intra-hepatic mRNA levels of IFNs and related genes were assessed by semi-quantitative RT-PCR. In comparison with non-alcoholic steatohepatitis, in HCV-infected subjects IFN-alpha and -beta mRNA levels were significantly lower, whereas IFN-gamma, IFNAR-1, STAT1alpha IRF-1, and IL-18 mRNA were upregulated. Moreover, IFN-gamma mRNA steady state levels were correlated positively with those of IFNAR-1, IRF-1, and IL-18, suggesting a coordinated induction of these genes. Although plasma viral load was correlated inversely with IL-18-specific mRNA, viral load was not related to liver injury. IFN-gamma and IRF-1 mRNA levels were correlated positively with ALT, but not with the grading or staging. Conversely, IFN-alpha and -beta mRNA levels were higher in livers with lower staging scores. These findings support the hypothesis that in chronic HCV infection there is an imbalance between an upregulated IFN-gamma system and a downregulated IFN-alpha and -beta system, probably due to a mixed effect exerted by HCV-specific and inflammatory non-specific factors.