Raimundo G. del Moral

Automatic quantification of liver fibrosis: design and validation of a new image analysis method: comparison with semi-quantitative indexes of fibrosis

BACKGROUND/AIMS Liver fibrosis is one of the most important and characteristic histologic alterations in progressive and chronic liver diseases. Thus, in both clinical and experimental practice, it is fundamental to have a reliable and objective method for its precise quantification. Several semi-quantitative scoring systems have been described. All are time-consuming and produce partially subjective fibrosis evaluations that are not very precise. This paper describes the design and validation of an original image analysis-based application, FibroQuant, for automatically and rapidly quantifying perisinusoidal, perivenular and portal-periportal and septal fibrosis and portal-periportal and septal morphology in liver histologic specimens. METHODS The implemented image-processing algorithms automatically segment interstitial fibrosis areas, while extraction of portal-periportal and septal region is carried out with an automatic algorithm and a simple interactive step. For validation, all automatically extracted areas were also manually segmented and quantified. RESULTS Statistical analysis showed significant intra- and interoperator variability in manual segmentation of all areas. Automatic quantifications did not significantly differ from mean manual evaluations of the same areas. Comparison of our image analysis quantifications with staging histologic evaluations of liver fibrosis showed significant correlations (Spearmans, 0.72<r<0.83; p<0.0001) and that the latter are based more on the distribution patterns than on the quantity of fibrosis. CONCLUSIONS FibroQuant is a sensitive, precise, objective and reproducible method of fibrosis quantification, which complements semi-quantitative histologic evaluation systems. This novel tool could be of special value in clinical trials and for improving the prognosis and follow-up among patients with fibrosis-inducing hepatic diseases.

Inhibition of Poly(ADP-Ribose) Polymerase Modulates Tumor-Related Gene Expression, Including Hypoxia-Inducible Factor-1 Activation, during Skin Carcinogenesis

Poly(ADP-ribose) polymerase (PARP)-1, an enzyme that catalyzes the attachment of ADP ribose to target proteins, acts as a component of enhancer/promoter regulatory complexes. In the present study, we show that pharmacologic inhibition of PARP-1 with 3,4-dihydro-5-[4-(1-piperidinyl)butoxyl]-1(2H)-isoquinolinone (DPQ) results in a strong delay in tumor formation and in a dramatic reduction in tumor size and multiplicity during 7,12-dimethylbenz(a)anthracene plus 12-O-tetradecanoylphorbol-13-acetate-induced skin carcinogenesis. This observation was parallel with a reduction in the skin inflammatory infiltrate in DPQ-treated mice and tumor vasculogenesis. Inhibition of PARP also affected activator protein-1 (AP-1) activation but not nuclear factor-kappaB (NF-kappaB). Using cDNA expression array analysis, a substantial difference in key tumor-related gene expression was found between chemically induced mice treated or not with PARP inhibitor and also between wild-type and parp-1 knockout mice. Most important differences were found in gene expression for Nfkbiz, S100a9, Hif-1alpha, and other genes involved in carcinogenesis and inflammation. These results were corroborated by real-time PCR. Moreover, the transcriptional activity of hypoxia-inducible factor-1alpha (HIF-1alpha) was compromised by PARP inhibition or in PARP-1-deficient cells, as measured by gene reporter assays and the expression of key target genes for HIF-1alpha. Tumor vasculature was also strongly inhibited in PARP-1-deficient mice and by DPQ. In summary, this study shows that inhibition of PARP on itself is able to control tumor growth, and PARP inhibition or genetic deletion of PARP-1 prevents from tumor promotion through their ability to cooperate with the activation AP-1, NF-kappaB, and HIF-1alpha.

Liver fibrosis assessment with semiquantitative indexes and image analysis quantification in sustained-responder and non-responder interferon-treated patients with chronic hepatitis C

BACKGROUND/AIMS The effect of interferon on the reduction of liver fibrosis is controversial. We aimed to compare semiquantitative methods with a quantitative digital image analysis system to assess liver fibrosis in biopsies from patients with chronic hepatitis and different responses to interferon. METHODS We studied 98 liver biopsies with chronic hepatitis C before and after recombinant interferon alfa-2 treatment, using conventional histological assessment, grading of histological activity, scoring/staging of fibrosis (Knodell and Scheuer), and quantification of fibrosis with image analysis (FibroQuant). RESULTS Sustained-responders to interferon showed a significant reduction in histological lesions and in their Knodell and Scheuer activity indexes. The semiquantitative systems showed no reduction in fibrosis. The FibroQuant application showed a significant reduction in porto-periportal and septal areas among sustained-responders (P < 0.001) and non-responders (P < 0.05), and in porto-periportal and septal fibrosis areas only in sustained-responders (P < 0.001), whereas the percentage of fibrosis increased in non-responders (P < 0.001). CONCLUSIONS The Scheuer system is useful for the daily evaluation of fibrosis, but the FibroQuant application provides more objective data on the anti-fibrogenic effects of interferon, which include a reduction in the porto-periportal area in sustained-responders and non-responders, accompanied by a reduction in the area of fibrosis only when the viral replication has ceased.

Anticonvulsant-induced toxic epidermal necrolysis: Monitoring the immunologic response

BACKGROUND Toxic epidermal necrolysis is a severe reaction with skin involvement induced by different drugs and other agents. The mechanisms implicated in the induction of the reaction are poorly understood. OBJECTIVE Our purpose was to study the involvement of T lymphocytes and other immunocompetent cells in the peripheral blood, blister fluid, and affected skin of 3 patients who had a severe reaction after receiving anticonvulsant medication. METHODS Quantification of T lymphocytes expressing the skin-homing receptor (cutaneous lymphocyte-associated antigen ¿CLA) in peripheral blood, skin, and skin blister fluid and assessment of other adhesion molecules, activation markers, and inflammatory interleukins by flow cytometry, immunohistochemistry, and reverse transcription-PCR. RESULTS An increase in CD3(+)CLA(+) cells paralleling the severity of the disease was observed in both peripheral blood and skin, tending to normalize as soon as patients conditions improved. E-selectin was detected in endothelial vessels in parallel with CLA expression on lymphocytes. An overexpression of TNFalpha, IFN-gamma, and IL-2 was also observed in PBMCs. The expression of the different markers changed over the course of the disease. CONCLUSIONS These data show an increase in activated T cells expressing the skin-homing receptor in both tissue and peripheral blood accompanying clinical symptoms, with a recruitment of macrophages and an overexpression of cytokines. All these results suggest an important role for T cells in the production of toxic epidermal necrolysis.

Altered Drug Membrane Permeability in a Multidrug- Resistant Leishmania tropica Line

We selected a Leishmania tropica cell line resistant to daunomycin (DNM) that presents a multidrug-resistant (MDR) phenotype characterized by overexpression of a P-glycoprotein of 150 kDa. The resistant line overexpressed an MDR-like gene, called ltrmdr1, located in an extrachromosomal circular DNA. DNM uptake experiments using laser flow cytometry showed a significant reduction in drug accumulation in the resistant parasites. The initial stages of the interaction of DNM with membranes from wild-type and DNM-resistant parasites were defined by a rapid kinetic stopped-flow procedure which can be described by two kinetic components. On the basis of a previous similar kinetic study with tumor cells, we ascribed the fast component to rapid interaction of DNM with membrane surface components and the slow component to passive diffusion of the drug across the membranes. The results reported here indicate that entrance of DNM into wild-type parasites was facilitated in respect to the resistant ones. We propose that resistance to DNM in L. tropica is a multifactorial event involving at least two complementary mechanisms. an altered drug membrane permeability and the overexpression of a protein related to P-glycoprotein that regulates drug efflux.

Therapeutic effect of cortistatin on experimental arthritis by downregulating inflammatory and Th1 responses

Background: Rheumatoid arthritis is a chronic autoimmune disease of unknown aetiology characterised by chronic inflammation in the joints and subsequent destruction of the cartilage and bone. Aim: To propose a new strategy for the treatment of arthritis based on the administration of cortistatin, a newly discovered neuropeptide with anti-inflammatory actions. Methods: DBA/1J mice with collagen-induced arthritis were treated with cortistatin after the onset of disease, and the clinical score and joint histopathology were evaluated. Inflammatory response was determined by measuring the levels of various inflammatory mediators (cytokines and chemokines) in joints and serum. T helper cell type 1 (Th1)-mediated autoreactive response was evaluated by determining the proliferative response and cytokine profile of draining lymph node cells stimulated with collagen and by assaying the content of serum autoantibodies. Results: Cortistatin treatment significantly reduced the severity of established collagen-induced arthritis, completely abrogating joint swelling and destruction of cartilage and bone. The therapeutic effect of cortistatin was associated with a striking reduction in the two deleterious components of the disease—that is, the Th1-driven autoimmune and inflammatory responses. Cortistatin downregulated the production of various inflammatory cytokines and chemokines, decreased the antigen-specific Th1-cell expansion, and induced the production of regulatory cytokines, such as interleukin 10 and transforming growth factor β1. Cortistatin exerted its effects on synovial cells through both somatostatin and ghrelin receptors, showing a higher effect than both peptides protecting against experimental arthritis. Conclusion: This work provides a powerful rationale for the assessment of the efficacy of cortistatin as a novel therapeutic approach to the treatment of rheumatoid arthritis.

Bisphenol A Exposure during Adulthood Alters Expression of Aromatase and 5α-Reductase Isozymes in Rat Prostate

The high incidence of prostate cancer (PCa) and benign prostatic hypertrophy (BPH) in elderly men is a cause of increasing public health concern. In recent years, various environmental endocrine disruptors, such as bisphenol A (BPA), have been shown to disrupt sexual organs, including the prostate gland. However, the mechanisms underlying these effects remain unclear. Because androgens and estrogens are important factors in prostate physiopathology, our objective was to examine in rat ventral prostate the effects of adult exposure to BPA on 5α-Reductase isozymes (5α-R types 1, 2, and 3) and aromatase, key enzymes in the biosynthesis of dihydrotestosterone and estradiol, respectively. Adult rats were subcutaneously injected for four days with BPA (25, 50, 300, or 600 µg/Kg/d) dissolved in vehicle. Quantitative RT-PCR, western blot and immunohistochemical analyses showed lower mRNA and protein levels of 5α-R1 and 5α-R2 in BPA-treated groups versus controls but higher mRNA levels of 5α-R3, recently proposed as a biomarker of malignancy. However, BPA treatment augmented mRNA and protein levels of aromatase, whose increase has been described in prostate diseases. BPA-treated rats also evidenced a higher plasma estradiol/testosterone ratio, which is associated with prostate disease. Our results may offer new insights into the role of BPA in the development of prostate disease and may be of great value for studying the prostate disease risk associated with exposure to BPA in adulthood.

PARP-1 regulates metastatic melanoma through modulation of vimentin-induced malignant transformation

PARP inhibition can induce anti-neoplastic effects when used as monotherapy or in combination with chemo- or radiotherapy in various tumor settings; however, the basis for the anti-metastasic activities resulting from PARP inhibition remains unknown. PARP inhibitors may also act as modulators of tumor angiogenesis. Proteomic analysis of endothelial cells revealed that vimentin, an intermediary filament involved in angiogenesis and a specific hallmark of EndoMT (endothelial to mesenchymal transition) transformation, was down-regulated following loss of PARP-1 function in endothelial cells. VE-cadherin, an endothelial marker of vascular normalization, was up-regulated in HUVEC treated with PARP inhibitors or following PARP-1 silencing; vimentin over-expression was sufficient to drive to an EndoMT phenotype. In melanoma cells, PARP inhibition reduced pro-metastatic markers, including vasculogenic mimicry. We also demonstrated that vimentin expression was sufficient to induce increased mesenchymal/pro-metastasic phenotypic changes in melanoma cells, including ILK/GSK3-β-dependent E-cadherin down-regulation, Snail1 activation and increased cell motility and migration. In a murine model of metastatic melanoma, PARP inhibition counteracted the ability of melanoma cells to metastasize to the lung. These results suggest that inhibition of PARP interferes with key metastasis-promoting processes, leading to suppression of invasion and colonization of distal organs by aggressive metastatic cells.

Crosstalk between PARP-1 and NF-jB modulates the promotion of skin neoplasia

Poly (ADP-ribose) polymerase-1 (PARP-1)-deficient mice are protected against septic shock, type I diabetes, stroke and inflammation. It is now accepted that inflammation and related events, such as activation of NF-κB, are key components in the initiation and progression of epithelial cancer and in particular in the neoplastic transformation of keratinocytes and skin carcinogenesis. Here, we report that PARP-1-deficient mice display a strikingly reduced susceptibility to skin carcinogenesis. In parp-1−/− mice, development of papilloma-like premalignant lesions induced with DMBA and TPA, is strongly delayed and the final number of tumor-bearing mice and total tumor number were significantly reduced. In addition, epidermis of parp-1−/− mice did not show increased proliferation rates after treatment with carcinogen. Deregulated NF-κB is a hallmark for tumorigenesis together with the concomitant release of early inflammatory mediators. In the absence of PARP-1, NF-κB activation and induction κB-target genes did not take place during the promotion of tumor development. These results suggest that PARP-1 abolition impairs the promotion of skin carcinogenesis interfering with the activation of NF-κB and might have an important implication in targeting PARP-1 as a new antineoplastic therapeutic approach.

P Glycoprotein: A New Mechanism to Control Drug-Induced Nephrotoxicity

The role of P glycoprotein (P-gp) in kidney is now being explored, and under physiological conditions, this protein is thought to be an excretory pump of cationic xenobiotics and metabolites. Functionally, two different types of P-gp have been described, but only the class I has been related to drug transport, and its overexpression confers the multidrug resistance phenotype in tumoral cells. It has been proposed that P-gp is involved in the energy-dependent transport of substrates through the cell membrane (toxic metabolites, toxins, nutrients, ions, peptides, etc.) – like a ‘hydrophobic molecule vacuum cleaner’. Several physiological functions have been attributed to P-gp: defense against xenobiotic aggression and transmembrane transport of prenylcysteine methyl esters, removing these cytotoxic metabolites from cells. A variety of substrates ranging from chemotherapeutics to steroid hormones, antibiotics, and calcium channel blockers can be transported by P-gp, suggesting the possible involvement of this protein in other unknown functions. Results from our group and others have suggested that overexpression of P-gp in renal tubular and mesangial cells prevents pharmacological nephrotoxicity by cyclosporin A (CsA). On the other hand CsA, a substrate of the pump, could act as a blocker in tubular cells by competitive inhibition. One relevant aspect in kidney is the possible relationship between P-gp and protein kinase C. Several reports suggest that protein kinase C may play a role in inducing the P-gp overexpression in cells under xenobiotic pressure, through activation of the ras oncoprotein family. This could be mediated directly by angiotensin II as a ras activator. This way, the detoxicant function of P-gp against products of the ras catabolism could mediate their accumulation when the ‘vacuum cleaner’ function is blocked by CsA or tacrolimus, contributing to the initial development of fibroblastic activation that leads to interstitial fibrosis associated with nephrotoxicity by these immunosuppressor drugs. In conclusion, P-gp expression could be an important component of a complex detoxifying system in kidney against xenobiotics or regulating the traffic of endogenous metabolites responsible for the susceptibility of subjects to the development of nephrotoxicity against different drugs.