Changing of hepatitis C virus genotype patterns in France at the beginning of the third millenium: The GEMHEP GenoCII Study

This cross-sectional study aimed to investigate, during a short period between 2000 and 2001, in a large population of patients with chronic hepatitis C, the epidemiological characteristics of hepatitis C virus (HCV) genotypes in France. Data from 26 referral centres, corresponding to 1769 patients with chronic hepatitis C were collected consecutively during a 6-month period. HCV genotyping in the 5'-non-coding region (NCR) was performed in each center using the line probe assay (LiPA, in 63% of cases), sequencing (25%) or primer-specific polymerase chain reaction (PCR) (12%). HCV genotypes 1a, 1b, 2, 3, 4, 5, non-subtyped 1 and mixed infection were found in 18, 27, 9, 21, 9, 3, 11 and 1% of our population, respectively. HCV genotype distribution was associated with gender, age, source and duration of infection, alanine aminotransferase (ALT) levels, cirrhosis, alcohol consumption, hepatitis B virus (HBV) and human immunodeficiency virus (HIV) coinfection. In multivariate analysis, only the source of infection was the independent factor significantly associated with genotype (P = 0.0001). In conclusion, this study shows a changing pattern of HCV genotypes in France, with i.v. drug abuse as the major risk factor, an increase of genotype 4, and to a lesser extent 1a and 5, and a decrease of genotypes 1b and 2. The modification of the HCV genotype pattern in France in the next 10 years may require new therapeutic strategies, and further survey studies.

Peroxisome Proliferator-Activated Receptor β/δ Exerts a Strong Protection from Ischemic Acute Renal Failure

Ischemic acute renal failure is characterized by damages to the proximal straight tubule in the outer medulla. Lesions include loss of polarity, shedding into the tubule lumen, and eventually necrotic or apoptotic death of epithelial cells. It was recently shown that peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta) increases keratinocyte survival after an inflammatory reaction. Therefore, whether PPARbeta/delta could contribute also to the control of tubular epithelium death after renal ischemia/reperfusion was tested. It was found that PPARbeta/delta+/- and PPARbeta/delta-/- mutant mice exhibited much greater kidney dysfunction and injury than wild-type counterparts after a 30-min renal ischemia followed by a 36-h reperfusion. Conversely, wild-type mice that were given the specific PPARbeta/delta ligand L-165041 before renal ischemia were completely protected against renal dysfunction, as indicated by the lack of rise in serum creatinine and fractional excretion of Na+. This protective effect was accompanied by a significant reduction in medullary necrosis, apoptosis, and inflammation. On the basis of in vitro studies, PPARbeta/delta ligands seem to exert their role by activating the antiapoptotic Akt signaling pathway and, unexpectedly, by increasing the spreading of tubular epithelial cells, thus limiting potentially their shedding and anoikis. These results point to PPARbeta/delta as a remarkable new target for preconditioning strategies.

[Contribution of stem cells to renal repair after ischemia/reperfusion]

Repair of inflammatory and/or ischemic renal injury involves endothelial, mesangial and epithelial regeneration. These structures may be rebuilt by resident progenitor cells and bone marrow-derived stem cells. Resident progenitor cells in adult kidney have not yet been conclusively identified. They are likely to be slowly cycling cells located mainly in the outer medulla and renal papilla. In glomerulonephritis with mesangiolysis, mesangial regenera- tion involves progenitor cells migrating from the juxtaglomerular apparatus and also bone marrow-derived cells. In acute ischemic renal failure, epithelial regeneration of proximal tubules results from the migration, proliferation and differentiation of resident progenitor cells; bone marrow-derived cells may play an accessory role. Molecular mechanisms underlying these repair processes could be targets for new therapeutic approaches.

15-Deoxy-Δ12,14-Prostaglandin J2 Inhibits Glucocorticoid Binding and Signaling in Macrophages through a Peroxisome Proliferator-Activated Receptor γ-Independent Process

15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)) is involved in the control of inflammatory reaction. We tested the hypothesis that 15d-PGJ(2) would exert this control in part by modulating the sensitivity of inflammatory cells to glucocorticoids. Human U937cells and mouse RAW 264.7 cells were exposed to 15d-PGJ(2), and binding experiments were performed with [(3)H]dexamethasone as a glucocorticoid receptor (GR) ligand. 15d-PGJ(2) caused a transient and concentration-dependent decrease in [(3)H]dexamethasone-specific binding to either cells through a decrease in the number of GR per cell without significant modification of the K(d) value. These changes were related to functional alteration of the GR rather than to a decrease in GR protein. They did not require the engagement of peroxisome proliferator-activated receptor gamma (PPARgamma), because the response to 15d-PGJ(2) was neither mimicked by the PPARgamma agonist ciglitazone nor prevented by the PPARgamma antagonist bisphenol A diglycidyl ether. 15d-PGJ(2) altered GR possibly through the interaction of its cyclopentenone ring with GR cysteine residues because the cyclopentenone ring per se could mimic the effect of 15d-PGJ(2), and modification of GR cysteine residues with methyl methanethiosulfonate suppressed the response to 15d-PGJ(2). Finally, 15d-PGJ(2)-induced decreases in glucocorticoid binding to GR resulted in parallel decreases in the ability of GR to activate the transcription of a glucocorticoid-inducible reporter gene and to reduce the expression of monocyte chemoattractant protein-1. Together these data suggest that 15d-PGJ(2) limits glucocorticoid binding and signaling in monocytes/macrophages through a PPARgamma-independent and cyclopentenone-dependent mechanism. It provides a way in which 15d-PGJ(2) would exert proinflammatory activities in addition to its known anti-inflammatory activities.

Screening and management of patients with early chronic kidney disease

Diabetic nephropathy has become the most prevalent cause of end-stage renal disease (ESRD) in many countries. ESRD patients with diabetes have a particularly poor prognosis compared with patients without diabetes. The course of diabetic nephropathy can be modified with early management of the condition and it is important that diabetes patients are screened regularly for early signs of kidney damage. Blood pressure control and use of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers have been shown to slow the progression of chronic kidney disease. Patients with diabetes are at considerable risk of cardiovascular complications, and modifiable cardiovascular risk factors, such as anaemia and dyslipidaemia, should be treated at an early stage. Correction of anaemia with recombinant human erythropoietin is associated with improvements in quality of life, functional status, and cardiovascular morbidity and mortality, and may slow the progression of renal disease. Abnormalities in calcium and phosphate metabolism and acidosis may also occur in patients with diabetes and nephropathy and these should be monitored regularly. It is important that patients with kidney disease are detected promptly to allow intervention to slow renal disease progression and to treat modifiable cardiovascular risk factors. Improved collaboration between diabetologists and nephrologists will also ensure that patients receive optimal care.

Anemia management and the delay of chronic renal failure progression

Interstitial fibrosis plays a key role in the progression of chronic kidney diseases. Analysis of the biologic effects of erythropoietin and of the pathophysiology of interstitial fibrosis suggest that treatment with epoetin may slow the progression of chronic kidney disease, both by decreasing interstitial fibrosis and by protecting against its consequences. The results of two small prospective studies and of a retrospective one also suggest that treatment with epoetin may have such protective effects.

Transforming growth factor-beta 1 increases glucocorticoid binding and signaling in macrophages through a Smad- and activated protein-1-mediated process

BACKGROUND

Renal inflammation is regulated by a network of local and systemic mediators. Of them, transforming growth factor-beta1 (TGF-beta 1) and glucocorticoids play an important role in deactivating monocytes/macrophages. We examined the hypothesis that TGF-beta 1 effects may be partially achieved through modulation of the sensitivity of these cells to glucocorticoids.

METHODS

Human promonocytic U 937 cells differentiated to a mature macrophage-like phenotype were exposed to recombinant TGF-beta 1 before specific binding of [3H] dexamethasone was measured. The expression of glucocorticoid receptor (GR) was examined by RNase protection assay and Western blot analysis. The role of Smad 2/3 and activator protein 1 (AP-1) in the response to TGF-beta 1 was determined by introducing transdominant negative mutants and decoy oligodeoxynucleotides, respectively.

RESULTS

U 937 cell exposure to TGF-beta 1 caused a dose- and time-dependent increase in [3H] dexamethasone binding to these cells, with a < or =twofold increase in the number of binding sites per cell, without modification of the affinity. The changes in glucocorticoid binding were associated with identical changes in GR protein and mRNA levels, that were explained by an increase in GR gene transcription rather than by posttranscriptional mechanisms. Functional inactivation of Smad 2/3 and AP-1 limited the response to TGF-beta 1, indicating a role for these transcription factors. Finally, increases in glucocorticoid binding to GR were responsible for increases in the ability of GR to transactivate minimal promoters containing glucocorticoid-responsive elements (GRE) [MMTV-Luc and (GRE)2 TK-Luc].

CONCLUSION

TGF-beta 1 increases glucocorticoid binding and signaling in inflammatory cells through a Smad 2/3- and AP-1-mediated process. This may represent a new target for intervention to increase glucocorticoid responsiveness.

[Calpains participate in inflammatory reaction development]

Calpains are cysteine proteases first identified 50 years ago. Because they are present in the cytosol of mammalian cells and because they are activated in response to Ca2+ mobilization, they are thought to be involved mainly in cell signalling pathways. They could participate in cellular responses such as apoptosis, proliferation, extracellular matrix adhesion and motility, that have relevance to pathophysiological issues in ischemia, inflammation, repair and tumor progression. Here we consider calpain functions in inflammatory reaction. We report the recent observation that calpain inhibitors reduce the development of acute and chronic inflammation. This has opened the door for understanding how these enzymes are effective in inflammation. We present data suggesting that calpains are primarily responsible for the activation of nuclear factor-kappa B, a transcription factor with a pivotal role in inflammation. They are involved in inflammatory cell adhesion and migration, pro-inflammatory mediator release and anti-inflammatory hormone resistance as well. In addition, we emphasize the intriguing possibility that calpains are externalized during inflammatory process and that they play a role in the microenvironment of inflammatory cells. Thus, both intracellular and extracellular calpains would offer novel therapeutic targets in inflammation.

Fanconi syndrome and renal failure induced by tenofovir: a first case report

Although nephrotoxicity of cidofovir and adefovir is well established, no renal side effects have been observed yet with tenofovir, which is the third member of this family. The authors report the case of a patient who had Fanconi syndrome, nephrogenic diabetes insipidus, and acute renal failure during treatment with tenofovir, a nucleotide reverse transcriptase inhibitor that recently has been approved by the Food and Drug Administration for treatment of patients infected with human immunodeficiency virus.

Recovery of plasma volume after 1 week of exposure at 4,350 m

Plasma volume (PV) decreases at high altitude, but is rapidly restored upon return to sea-level (RSL). The aim of this study was (1) to describe PV recovery upon RSL with concomitant changes in major fluid regulating hormones, and (2) to test the hypothesis that PV recovery is promoted by the administration of a plasma expander. Ten male subjects were evaluated at rest and during submaximal exercise at sea-level (SL), after 7 days at 4,350 m (H7), and on RSL, on day 1 (RSL1, rest only) and day 2 (RSL2). PV (measured by carbon monoxide rebreathing), plasma renin (Ren), aldosterone (Aldo), atrial natriuretic factor (ANF) and arginine vasopressin (AVP) were measured at rest and during exercise. The subjects were divided into two groups 1 h before RSL, one group receiving PV expansion (475+/-219 ml) to ensure normovolemia (PVX, n=6), the others serving as controls (Control, n=4). PV decreased by 13.6% in H7 ( n=10), but was restored in RSL2, regardless of PVX. Ren, Aldo and AVP, which were similar in both groups, were reduced in H7, but were higher in RSL2 (rest or exercise). ANF was modified neither by hypoxia nor by PVX. Total water intake was reduced in H7, but remained normal in RSL in both groups, whereas water output dropped in RSL. PVX increased urine flow rate in RSL1 compared with subjects not given PVX. The present results suggest that PV recovery during early RSL is mainly due to a decreased diuresis, promoted at least in part by changes in fluid regulating hormones. However, neither PV recovery, nor hormonal responses were altered with PVX-induced normovolemia upon RSL.

Induction of urokinase receptor expression in nephrotoxic nephritis

The urokinase receptor (uPAR) is a multifunctional molecule involved in pericellular, fibrinolytic, and proteolytic activities, as well as in cell adhesion and chemotaxis and may play a role in the pathogenesis of tissue remodeling occurring during glomerulonephritis. We analyzed sequentially the expression of uPAR by immunohistochemistry and in situ hybridization in an accelerated model of nephrotoxic nephritis in rats. A strong induction of uPAR mRNA expression was observed in glomeruli as soon as 1 h after nephrotoxic serum injection. The intensity of glomerular uPAR mRNA and antigen expression increased and peaked at 24 h. At that time, numerous glomerular fibrin deposits, monocyte/marcrophage infiltration, and heavy proteinuria were observed. Fibrin deposition was detected at 6 h, peaked at 24 h, and progressively declined over the next 3 weeks, while uPAR antigen expression remained elevated until the end of the study (3 weeks). By double labeling, we showed that the expression of uPAR was mediated by both intrinsic glomerular cells and infiltrating macrophages. Severe podocytic lesions developed within 3 days after antiserum injection, and glomerulosclerosis rapidly progressed within 2-3 weeks. These results show that glomerular uPAR expression is induced in nephrotoxic nephritis and suggest that uPAR may promote local proteolysis and also tissue remodeling, leading to the late development of glomerulosclerosis.

[Inflammation, prelude to renal sclerosis: the importance of NF-kappa B]

NF-kappa B comprises a family of transcription factors. These are thought to have a central role in the expression of genes involved in cell mobilization, cell proliferation and cell differentiation, and, hence, in inflammation, repair and fibrosis processes. In particular, NF-kappa B activation appears to drive a number of inflammatory diseases of the kidney and their progression to end-stage renal failure. Thus, targeting NF-kappa B activation would lead to the development of new pharmaceutical compounds that would provide novel treatment for these diseases.

Haemodynamic changes and vasopressin release are not consistently associated with carbon dioxide pneumoperitoneum in humans

BACKGROUND

Conflicting haemodynamic changes, suggested to be caused by vasopressin release, have been reported during carbon dioxide (CO2) pneumoperitoneum. However, peritoneal stimulations including open surgery cause both a systemic vasopressor response and a vasopressin release, which are suppressed by opiate administration. Also, a decreased venous return of blood to the heart causes vasopressin release. Furthermore, previous haemodynamic assessments of laparoscopic surgery have been conducted using various anaesthetic regimens, which are likely to have caused various haemodynamic effects. We hypothesised that intraoperative haemodynamic and/or humoral changes would not be observed in association with laparoscopic surgery provided that, (a) normovolaemia is continuously maintained using transoesophageal echocardiographic (TEE) assessment, and (b) adequate depth of general anaesthesia is continuously maintained by bispectral index (BIS) monitoring and high plasma Ievel opiate administration.

METHODS

Twenty ASA 1 women undergoing laparoscopic surgery received 10 ml. kg-1 lactated Ringer's solution and thereafter were randomly allocated to receive intraoperatively either 8 ng. ml-1 or 4 ng. ml-1 plasma remifentanil concentrations while BIS was maintained at 50+/-5 by isoflurane alteration. The group receiving 4 ng. ml-1 remifentanil was used as control. Expired CO2 was maintained within a 32-38 kPa range throughout the investigation. Complete TEE haemodynamic investigation was performed before pneumoperitoneum (PP) (T1), and during PP horizontal (T2), with a head-up tilt (T3), with a head-down tilt (T4), horizontal (T5), and PP released (T6). Plasma vasopressin, epinephrine and norepinephrine levels were measured at T1, T3, and T6. ANOVA, Student's t-test and Mann-Whitney U-test were used for statistical analysis.

RESULTS

Haemodynamic indices and humoral values did not change significantly within and between remifentanil groups throughout the investigation (all P<0.05).

CONCLUSION

Continuous adequate depth of anaesthesia and normovolaemia may have prevented both a humoral and a haemodynamic response, initiated in the peritoneum by the contact with CO2 in previous investigations.

Transforming growth factor-beta inhibits interleukin-10 synthesis by human monocytic cells

Transforming growth factor-beta (TGF-beta1) enhances interleukin-10 (IL-10) synthesis by mouse monocytes/macrophages, suggesting a potential role of IL-10 in mediating some of the anti-inflammatory properties of TGF-beta1. Since differences exist between the transcriptional regulation of human and mouse IL-10, the studies reported here examined whether TGF-beta1 up-regulated IL-10 production by human monocytes/macrophages as well. Exposure of PMA-differentiated U-937 promonocytic cells to TGF-beta1 resulted in an unexpected, dose-dependent decrease in IL-10 production as assessed by specific ELISA. TGF-beta1 was effective when added at the time of the PMA stimulus or 6 hours after. In addition, TGF-beta1 suppressed induction of IL-10 by three different stimuli other than PMA. TGF-beta1 inhibition of IL-10 protein release was associated with proportional changes in IL-10 mRNA accumulation as assessed by quantitative kinetic ELISA PCR. This would result from a decrease in IL-10 gene transcription as TGF-beta1 did not affect IL-10 mRNA stability, and TGF-beta1 limited the luciferase activity in cells transfected with reporter gene constructs containing 1,308 bp of the 5' non-coding sequence of human IL-10 gene. Blocking tumour necrosis factor-alpha (TNF-alpha) with neutralizing anti-TNF-alpha antibody did not modify the response to TGF-beta1, indicating the involvement of TNF-alpha-independent mechanisms in the overall process. Thus, the present study provides the first evidence that TGF-beta1 prevents IL-10 production by human monocytic cells at a transcriptional level.

Cytokines and hormones with anti-inflammatory effects: new tools for therapeutic intervention

The inflammation that is involved in the development of glomerulonephritis is tightly regulated by the expression of anti-inflammatory factors. These include circulating hormones, such as glucocorticoids, and mediators that are produced by intrinsic cells and infiltrating leucocytes. The present review focuses on these anti-inflammatory factors, summarizing in particular their activities in existing models of glomerulonephritis. In addition, experimental evidence is presented that anti-inflammatory mediators are able to increase glucocorticoid binding or signalling in target cells. These data help to explain the in-vivo efficacy of anti-inflammatory mediators, and offer a promising new avenue for therapeutic intervention.

Nephrotoxic nephritis and obstructive nephropathy: evaluation with MR imaging enhanced with ultrasmall superparamagnetic iron oxide-preliminary findings in a rat model

PURPOSE

To evaluate the role of magnetic resonance (MR) imaging enhanced with ultrasmall superparamagnetic iron oxide (USPIO) in the evaluation and differentiation of different types of nephropathies.

MATERIALS AND METHODS

Two experimental rat models of nephropathies were studied: a model of nephrotoxic nephritis induced by means of intravenous injection of sheep anti-rat glomerular basement membrane serum (n = 43) and a model of obstructive nephropathy (n = 6). Imaging sessions were performed with a spectrometer operating at 4.7 T with fast low-angle shot, or FLASH, sequences. Signal intensity was measured in each kidney compartment before and 24 hours after intravenous injection of USPIO (90 micromol of iron per kilogram of body weight). MR findings were compared with histologic data and urine protein levels.

RESULTS

In the nephrotoxic nephritis model 24 hours after injection of USPIO, a significant signal intensity decrease (P: <.05) was present only in the cortex where the glomerular lesions were located. In the obstructive nephropathy model, the signal intensity decrease (P: <.05) was located in all kidney compartments in response to diffuse interstitial lesions. The decrease in signal intensity was due to iron uptake by either macrophages or mesangial cells gaining endocytic activity and was correlated, in the nephrotoxic nephritis model, to the degree of proteinuria.

CONCLUSION

Twenty-four-hour delayed USPIO-enhanced MR imaging may help identify and differentiate various types of nephropathies.

Glomerulosclerosis in mice transgenic for human insulin-like growth factor-binding protein-1

BACKGROUND

The growth hormone (GH)/insulin-like growth factor (IGF) system is thought to participate in the glomerulosclerosis process. Because IGF-binding proteins (IGFBPs) modulate IGF actions and hence GH secretion, this study assessed whether mice transgenic for human IGFBP-1 have altered susceptibility to glomerulosclerosis.

METHODS

A line of transgenic mice that express human IGFBP-1 mRNA in the liver under the control of the alpha1-antitrypsin promoter has been obtained, and morphological changes in the kidney tissue were assessed. Glomerulosclerosis was identified using light microscopy, light microscopic morphometry, and electron microscopy. Extracellular matrix components were analyzed by immunohistochemistry.

RESULTS

There was a marked increase in mesangial extracellular matrix area in homozygous transgenic mice at three months of age as compared with heterozygous transgenic mice and nontransgenic littermates. These changes were not associated with alterations in glomerular volume or cellularity. The expansion of extracellular matrix area was related to a marked increase in laminin and type IV collagen and to the appearance of type I collagen.

CONCLUSIONS

These observations indicate that the enhanced expression of IGFBP-1 may result in the development of glomerulosclerosis without glomerular hypertrophy. The changes are potentially related to a decrease in IGF-I availability and/or to an IGF-I-independent role of IGFBP-1.

[Interactions between glucocorticoids and anti-inflammatory peptides]

Both pro- and anti-inflammatory mediators regulate the anti-inflammatory actions of glucocorticoids, in part by modifying the binding of glucocorticoids to specific receptors. For instance, somatostatin has been shown to increase glucocorticoid binding and signaling in macrophages. The mechanism of this regulation does not require an increased expression of glucocorticoid receptors but, rather, a stabilization of glucocorticoid receptor-associated heat shock protein 90. This is related to a decrease in calpain activity. Thus calpain inhibition may offer a new and exciting possibility for enhancing the anti-inflammatory efficiency of glucocorticoids.

Somatostatin increases glucocorticoid binding and signaling in macrophages by blocking the calpain-specific cleavage of Hsp 90

Somatostatin has direct anti-inflammatory actions and participates in the anti-inflammatory actions of glucocorticoids, but the mechanisms underlying this regulation remain poorly understood. The objective of this study was to evaluate whether somatostatin increases glucocorticoid responsiveness by up-regulating glucocorticoid receptor (GR) expression and signaling. Somatostatin promoted a time- and dose-dependent increase in [(3)H]dexamethasone binding to RAW 264.7 macrophages. Cell exposure to 10 nM somatostatin for 18 h promoted a 2-fold increase in the number of GR sites per cell without significant modification of the affinity. Analysis of GR heterocomplex components demonstrated that somatostatin increased the level of heat shock protein (Hsp) 90, whereas the level of GR remained almost unchanged. The increase in Hsp 90 was associated with a decrease in the cleavage of its carboxyl-terminal domain. Evidence for the involvement of calpain inhibition in this process was obtained by the demonstration that 1) somatostatin induced a dose-dependent decrease in calpain activity and 2) calpain inhibitors, calpain inhibitor I and calpeptin, both abolished the cleavage of Hsp 90 and induced a dose-dependent increase in [(3)H]dexamethasone binding. Increases in glucocorticoid binding after somatostatin treatment were associated with similar increases in the ability of GR to transactivate a minimal promoter containing two glucocorticoid response elements (GRE) and to interfere with the activation of nuclear factor-kappaB (NF-kappaB). Thus, the present findings indicate that somatostatin increases glucocorticoid binding and signaling by limiting the calpain-specific cleavage of GR-associated Hsp 90. This mechanism may represent a novel target for intervention to increase glucocorticoid responsiveness.

Hepatitis C virus genotypes in France: relationship with epidemiology, pathogenicity and response to interferon therapy. The GEMHEP

The aim of this study was to investigate the following in a large population of French patients with chronic hepatitis C: the geographical distribution of hepatitis C virus (HCV) genotypes; the relationship between HCV genotypes and epidemiological characteristics; severity of the disease; and response to interferon (IFN) therapy. Data from 14 tertiary referral centres, corresponding to 1872 patients with chronic hepatitis C, were prospectively collected from 1989 to 1997. HCV genotyping was performed using the line probe assay (LiPA). HCV genotypes 1b, 3, 1a, 2, 4 and a mixed infection were found in 41%, 22%, 16%, 11%, 4% and 4% of our population, respectively. HCV genotype distribution was homogeneous, except for genotype 2 that was found more frequently in the southwest than in the other regions (21% vs 9.2%) (P=0.001). HCV distribution was associated with gender, age, and source and duration of infection. In multivariate analysis, these correlations were related to the source of infection, which was the only independent factor significantly associated with genotype (P=0.001). Genotype 1b was significantly more common in patients with cirrhosis, but in multivariate analysis cirrhosis was independently related to older age at exposure and longer duration of infection (P=0.001). A sustained response to IFN therapy was observed in 11% of patients infected with genotypes 1a or 1b vs 32% of those infected with genotypes 2 or 3 (P=0.001). This study shows that HCV genotype is mainly related to the source infection, but not to the intrinsic pathogenicity of HCV, and is a strong predictor of sustained response to therapy.

Reactive oxygen and nitrogen intermediates increase transforming growth factor-beta1 release from human epithelial alveolar cells through two different mechanisms

Transforming growth factor (TGF)-beta1 is a growth factor involved in the mechanisms of lung repair and fibrosis that follow inflammatory processes. We sought to examine the link between the generation of reactive oxygen intermediates (ROI) or reactive nitrogen intermediates (RNI) by inflammatory cells and the expression of TGF-beta1 by alveolar epithelial cells. Exposure of the A549 lung epithelial cell line to either an ROI generating system (xanthine and xanthine oxidase) or an RNI donor (S-nitroso-N-acetyl-penicillamine [SNAP]) promoted a time- and dose-dependent increase in TGF-beta1 release, as measured by a specific enzyme-linked immunosorbent assay. At the peak, the levels of TGF-beta1 were twice the control values. The induction of TGF-beta1 release by ROI was blunted by catalase and unaffected by superoxide dismutase, indicating the involvement of hydrogen peroxide. The response was also blunted by 5, 6-dichloro-1-beta-D-ribofuranosyl benzimidazole (DRB), a specific RNA polymerase II inhibitor, and accompanied by a corresponding increase in TGF-beta1 messenger RNA, as measured by quantitative/competitive reverse transcription polymerase chain reaction, suggesting the involvement of transcriptional mechanisms and possibly other downstream mechanisms. In contrast, RNI-induced TGF-beta1 release was unaffected by DRB and blunted by the protein synthesis inhibitor cycloheximide, suggesting the involvement of translational and post-translational mechanisms. This response required cyclic guanosine monophosphate (cGMP)- mediated processes because (1) immunoreactive cGMP accumulated in the culture medium of SNAP-treated cells; (2) SNAP-induced TGF-beta1 release was blunted by KT 5823, an inhibitor of cGMP-dependent protein kinase; and (3) similar increase in TGF-beta1 release was obtained by cell exposure to membrane-permeable dibutyryl-cGMP or to atrial natriuretic factor, a known agonist of particulate guanylate cyclase. These data suggest that in vitro exposure of human alveolar epithelial cells to ROI and RNI enhances TGF-beta1 release through different mechanisms. In vivo, this control may constitute a molecular link between inflammatory and fibrotic processes.