MO524CALCIMIMETIC ADHERENCE AND PREFERENCE IN THE MANAGEMENT OF SECONDARY HYPERPARATHYROIDISM IN EUROPE: A PILOT STUDY

Background and Aims

Oral cinacalcet (CIN) and IV-administered etelcalcetide (ETEL) are calcimimetics available for the management of secondary hyperparathyroidism (SHPT) in hemodialysis (HD) patients. This pilot study assessed patient adherence to calcimimetic therapy and calcimimetic preference of nephrologists and nurses based on adapted questionnaires.

Method

A cross-sectional survey was conducted with HD patients currently using a calcimimetic, and nephrologists and dialysis nurses who prescribed/administered calcimimetic in 7 European countries (Belgium, France, Germany, Italy, Spain, Sweden and the United Kingdom). Patient questionnaires were adapted from the Medication Adherence Report Scale (MARS), the Beliefs about Medicines Questionnaire (BMQ-specific Necessity and Concern), and Treatment Intrusiveness Scale (TIS) to understand patterns of adherence and perceptions of medications; questions about gastrointestinal (GI) symptoms were included. Questionnaires for nephrologists and nurses were adapted from the Treatment Rating Scale (TRS), Health Professional Preference Scale (HPPS), and Prescribing Comparator Scale (PCS) to understand calcimimetic preference. Questionnaires were translated and administered in the local language.

Results

Sixty HD patients (33 CIN and 27 ETEL), 16 nephrologists and 18 dialysis nurses participated in the survey. ETEL patients were younger than CIN patients (mean age: 57 vs. 59 yrs). ETEL patients also had a lower pill burden (mean no. of pills: 6 vs. 11) and had numerically fewer hospitalizations in the last 6 months (mean no. of days: 1.5 vs 3.9) than CIN patients. Self-reported adherence to CIN was high (mean MARS: 4.7±0.7). ETEL and CIN patients did not perceive medications (excluding dialysis, diet and dietary restrictions) as interfering with their life (mean TIS: 1.5±0.5 vs. 1.6±1.6) and neither calcimimetic group had a specific belief in medicines in terms of necessity (mean BMQ CIN: 2.4±0.6 and ETEL: 2.3±0.4) or concerns about potential side-effects (mean BMQ CIN: 3.1±0.6 and ETEL: 3.5±0.7). ETEL patients were less likely than CIN patients to experience GI symptoms in the prior month: nausea (11% vs. 49%), vomiting (11% vs. 24%), and diarrhea (15% vs. 33%). Overall, the adapted patient questionnaires showed good internal consistency for MARS (Cronbach’s α=0.99) and BMQ-Necessity and BMQ-Concerns scales (CIN: α=0.74 and ETEL: α=0.81) but lower consistency for TIS (α=0.3 for both CIN and ETEL).

Nephrologists and nurses had been practicing for a mean of 17 yrs. Nephrologists and nurses viewed ETEL to have more efficacy, lower risk of side effects, lower risk of non-adherence, lower burden for patients compared to CIN according to the TRS. According to HPPS, the top 3 treatment attributes for ETEL preference vs. CIN among nephrologists were encouraging patient adherence (93%; n=14/15), minimizing patient burden (87%; n=13/15) and having fewer side effects (80%; 12/15). Similar for nurses, encouraging patient adherence (88%; n=15/17) and minimizing patient burden (94%; n=16/17) were top attributes for ETEL preference as well as improving patient quality of life (82%; 14/17). Based on PCS, the majority of nephrologists agreed that compared to CIN, ETEL will ensure high adherence (100%), achieve better PTH control (93%; 14/15), reduce treatment burden for patients (87%; 13/15), improve patient’s quality of life (80%; 12/15), and improve effectiveness without increasing side-effects (80%; 12/15); they also agreed that ETEL created more work for nursing staff (80%; 12/15). Two thirds of nephrologists (n=10/15) agreed that ETEL would be more efficacious than CIN.

Conclusion

In this pilot study, CIN patients self-reported high adherence and both calcimimetic groups did not perceive medications to be concerning or intrusive. Nephrologists and nurses showed preference for ETEL than CIN. The questionnaires were validated and will be administered in a large study.

Fibroblast growth factor 23 as a risk factor for cardiovascular events and mortality in patients in the EVOLVE trial

INTRODUCTION

High mortality rates in patients with chronic kidney disease-mineral and bone disorder (CKD-MBD) receiving maintenance hemodialysis are largely due to cardiovascular (CV) events.

METHODS

We evaluated associations between MBD parameters, fibroblast growth factor 23 (FGF23) concentrations, and clinically adjudicated CV events from the Evaluation of Cinacalcet Hydrochloride Therapy to Lower Cardiovascular Events (EVOLVE) trial. Patients enrolled in EVOLVE, who had not experienced any study endpoints between randomization and week 20 with evaluable baseline and week 20 values for key laboratory parameters (parathyroid hormone, calcium, phosphate, and FGF23), were assessed. We used adjusted Cox proportional hazards regression models to estimate relative risk of outcomes (primary composite, all-cause mortality, and CV events) based on FGF23 and MBD parameters. Laboratory values were modeled with linear terms and using natural cubic splines with two degrees of freedom.

FINDINGS

For the primary endpoint, patients assessed (N = 2309) were followed up over a mean duration of 3.1 years, during which 1037 CV events (497 deaths, 540 nonfatal events) occurred. Adjusted models showed an association between FGF23 and the risk of CV events. Hazard ratio per log unit of FGF23 at week 20 was 1.09 [95% CI: 1.03-1.16], and the hazard ratio per log unit change in FGF23 from week 0 to week 20 was 1.09 [95% CI: 1.00-1.17].

DISCUSSION

Our data highlight FGF23 as an independent CV risk factor and potential biomarker and therapeutic target for patients with CKD-MBD receiving maintenance hemodialysis.

P0794A REAL-WORLD OBSERVATIONAL STUDY OF ETELCALCETIDE USE IN HEMODIALYSIS PATIENTS WITH SECONDARY HYPERPARATHYROIDISM IN EUROPE

Background and Aims

Intravenous etelcalcetide was approved in Europe in 2016 for treatment of secondary hyperparathyroidism (SHPT) in adult patients on hemodialysis (HD). Data on real-world use of etelcalcetide are needed to inform clinicians on routine clinical practice with this newly approved therapy.

Method

A multi-country observational medical chart review study was performed to describe clinical management of patients treated with etelcalcetide. Sites with at least 6 months of use of etelcalcetide were eligible for study participation. Chronic HD patients who had at least one record of etelcalcetide prescription were recruited. Abstracted data included demographics, clinical history, laboratory parameters and etelcalcetide use over time. Interim data are being reported.

Results

Medical charts for 238 HD patients who started etelcalcetide between December 24, 2016 and June 7, 2019 were reviewed. Data were obtained from 47 sites from 9 countries (Austria, Denmark, France, Germany, Greece, Netherlands, Russia, Slovenia, and Spain). Forty eight percent of patients (113/238) switched from cinacalcet to etelcalcetide (≤90 days from last cinacalcet prescription), whereas the remaining 125 patients were calcimimetic naive. Median (interquartile range, IQR) age was 62.5 (52-74) and dialysis vintage was 4.7 years (2.4-8.7). Twenty four percent of patients were diabetic and 17% of patients had a history of at least one cardiovascular event (heart failure, myocardial infarction, peripheral vascular disease, or stroke). Parathyroidectomy had been performed in 6% (13/238) of patients and 11% (26/238) had received a kidney transplant. Two-thirds of patients (63%) had a starting etelcalcetide dose of 5 mg and the median weekly dose was 7.5 mg (range: 2.5-15 mg). Table 1 summarizes the median and IQR for parathyroid hormone (PTH), calcium (Ca) and phosphate (P) levels at baseline, 3, 6 and 12 months following etelcalcetide initiation. At baseline, 85% (201/237) had normal Ca (≥2.1 mmol/L). Among patients who had a normal Ca at baseline, the cumulative incidence of hypocalcemia (<2.1 mmol) at 3, 6, 9 and 12 months was, 31%, 45%, 57% and 63%, respectively. Median time to first hypocalcemia event (Kaplan-Meier estimation) was 6.9 months (95% CI: 5.4, 8.9). Etelcalcetide persistence at 3, 6, 9 and 12 months was 96%, 94%, 91% and 87%, respectively. Of the 40 patients who discontinued etelcalcetide by 12 months, 10 patients discontinued for side effects (hypocalcemia=6, nausea=3, and vomiting=1), 5 for parathyroidectomy, 9 for low PTH, 1 for high PTH, and 15 for other reasons. More than half of the patients achieved a >30% reduction in PTH from baseline at 6-months (55.9%) and 73.5% at 12 months; and it was 63.2% and 80% for patients who were calcimimetic naive and 47.8% and 66.4% for patients who switched from cinacalcet to etelcalcetide, respectively.

Conclusion

To date, this is the largest study on real-world etelcalcetide use in Europe. Etelcalcetide switchers had higher PTH levels than calcimimetic naive patients at initiation. Persistence of etelcalcetide remained high at 12 months. As expected, we observed a substantial reduction in PTH, Ca, and P, and this was greater among patients who were calcimimetic naive than switchers (-43% vs. -32% at 12 months) for PTH. No new safety signals were observed.

Cinacalcet-induced hypocalcemia in a cohort of European haemodialysis patients: predictors, therapeutic approaches and outcomes

BACKGROUND

Calcimimetic treatment of secondary hyperparathyroidism in chronic dialysis patients is often followed by hypocalcemia.

METHODS

We investigated the frequency, predictors, consequences and therapeutic responses following cinacalcet-induced hypocalcemia in an incident European hemodialysis cohort of 1068 patients with a cinacalcet prescription.

RESULTS

Of 905 normocalcemic patients initiating cinacalcet, 67% developed hypocalcemia within 12 months: 68% mild, 23% moderate, 9% severe. Compared to persistently normocalcemic patients, those with severe hypocalcemia were more often diabetic, overweight, had cardiovascular disease, shorter dialysis vintage, used a catheter dialysis access, had fewer active vitamin-D sterols, and exhibited higher CRP and iPTH and lower calcium levels. Multivariate predictors of hypocalcemia included a catheter for vascular access, low albumin and high iPTH. Generally, no therapeutic intervention to prevent hypocalcemia was taken prior to cinacalcet initiation. After the hypocalcemic event, the most common clinical response was no change of the dialysis or medical regimen. Following the hypocalcemic event, iPTH remained low even in those with severe hypocalcemia. The number of deaths and cardiovascular events did not differ between patients with and without hypocalcemia within six months following cinacalcet initiation.

CONCLUSION

Two-thirds of cinacalcet initiated patients experienced hypocalcaemia with 9% being severe. Hypocalcemia was mostly asymptomatic, transient (with and without targeted intervention to correct it) and not associated with an increase in cardiovascular events or deaths.

Predictors of cinacalcet discontinuation and reinitiation in hemodialysis patients: results from 7 European countries

Background

The putative benefits of cinacalcet therapy for management of secondary hyperparathyroidism (SHPT) are thought to be most manifested when patients are taking it consistently and as prescribed. Real-world descriptions of cinacalcet prescription discontinuation and reinitiation in European hemodialysis patients are lacking. To address this knowledge gap, we used Dialysis Outcomes and Practice Patterns Study (DOPPS) data, based on dialysis facility medical records, from seven European countries to estimate rates and predictors of cinacalcet prescription discontinuation and reinitiation in hemodialysis patients and to describe the trajectories of CKD-MBD laboratory values after discontinuation.

Methods

Cox regression analyses were used to predict (1) cinacalcet discontinuation among 613 patients with ≥3 consecutive months without cinacalcet prescription immediately prior to a new cinacalcet prescription and (2) cinacalcet reinitiation among 415 patients with a newly discontinued cinacalcet prescription immediately after ≥3 consecutive months of prescribed use.

Results

Cinacalcet was discontinued in 21 and 35% of new users after 6 and 12 months, respectively. Cinacalcet was reinitiated in 38 and 49% of newly-discontinued users after 6 and 12 months, respectively. Predictors of discontinuation included lower parathyroid hormone (PTH) in the previous month (< 150 pg/ml vs. 150–299, HR = 2.57 [95% CI: 1.52–4.33]) and lower serum calcium in the previous month (< 8.4 mg/dl vs. 8.4–10.19, HR = 1.67 [95% CI: 1.08–2.59]). Predictors of reinitiation included higher PTH in the previous month (300–599 pg/ml vs. 150–299, HR = 1.88 [95% CI = 1.19–2.97]; 600+ pg/ml, HR = 3.02 [95% CI = 1.92–4.76]). After cinacalcet discontinuation, mean serum PTH increased from 408 to 510 pg/ml, mean serum calcium briefly rose from 9.12 to 9.22 mg/dl before declining to 9.06 mg/dl, and mean serum phosphorus showed little change.

Conclusions

Nephrologist discontinuation of cinacalcet therapy is common in European countries. Additional research is needed to identify optimal cinacalcet treatment strategies for SHPT management, including comparisons of intermittent cinacalcet therapy versus sustained treatment with reduced dose or frequency.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1355-5) contains supplementary material, which is available to authorized users.

Effects of etelcalcetide on fibroblast growth factor 23 in patients with secondary hyperparathyroidism receiving hemodialysis

Background

Etelcalcetide is an intravenous calcimimetic approved for treatment of secondary hyperparathyroidism (sHPT) in patients receiving hemodialysis. Besides lowering parathyroid hormone (PTH), etelcalcetide also significantly reduces fibroblast growth factor 23 (FGF23), but the mechanisms are unknown.

Methods

To investigate potential mediators of etelcalcetide-induced FGF23 reduction, we performed secondary analyses of the 26-week randomized trials that compared the effects on PTH of etelcalcetide (n = 509) versus placebo (n = 514) and etelcalcetide (n = 340) versus cinacalcet (n = 343) in adults with sHPT receiving hemodialysis. We analyzed changes in FGF23 in relation to changes in PTH, calcium, phosphate and bone turnover markers. We also investigated how concomitant treatments aimed at mitigating hypocalcemia altered the FGF23-lowering effects of etelcalcetide.

Results

Etelcalcetide reduced FGF23 [median % change (quartile 1–quartile 3)] from baseline to the end of the trial significantly more than placebo [–56% (–85 to –7) versus +2% (–40 to +65); P < 0.001] and cinacalcet [–68% (–87 to –26) versus –41% (–76 to +25); P < 0.001]. Reductions in FGF23 correlated strongly with reductions in calcium and phosphate, but not with PTH; correlations with bone turnover markers were inconsistent and of borderline significance. Increases in concomitant vitamin D administration partially attenuated the FGF23-lowering effect of etelcalcetide, but increased dialysate calcium concentration versus no increase and increased dose of calcium supplementation versus no increase did not attenuate the FGF23-lowering effects of etelcalcetide.

Conclusion

These data suggest that etelcalcetide potently lowers FGF23 in patients with sHPT receiving hemodialysis and that the effect remains detectable among patients who receive concomitant treatments aimed at mitigating treatment-associated decreases in serum calcium.

Clinical Pharmacokinetics and Pharmacodynamics of Etelcalcetide, a Novel Calcimimetic for Treatment of Secondary Hyperparathyroidism in Patients With Chronic Kidney Disease on Hemodialysis

Etelcalcetide, a d-amino acid peptide, is an intravenous calcimimetic approved for the treatment of secondary hyperparathyroidism. Etelcalcetide binds the calcium-sensing receptor and increases its sensitivity to extracellular calcium, thereby decreasing secretion of parathyroid hormone (PTH) by chief cells. Etelcalcetide and its low-molecular-weight transformation products are rapidly cleared by renal excretion in healthy subjects, but clearance is substantially reduced and dependent on hemodialysis in end-stage renal disease. The effective half-life is 3-5 days in patients undergoing hemodialysis 3 times a week. A clinical study using a single microtracer intravenous dose of [¹⁴ C]etelcalcetide indicated that 60% of the administered dose was eliminated in dialysate. Etelcalcetide undergoes reversible disulfide exchange with serum albumin to form a serum albumin peptide conjugate that is too large (67 kDa) to be dialyzed, until a subsequent exchange forms etelcalcetide or a low-molecular-weight transformation product. This exchange from albumin is apparent after hemodialysis, when it partially restores etelcalcetide concentrations in plasma. Etelcalcetide has no known risks for drug-drug interactions. In phase 3 studies, 74%-75% of hemodialysis patients with secondary hyperparathyroidism who received etelcalcetide achieved a >30% PTH reduction from baseline versus 8%-10% of patients who received placebo. The pharmacokinetics and pharmacodynamics of etelcalcetide in hemodialysis patients supports a 5-mg starting dose administered after hemodialysis and uptitration in 2.5- or 5-mg increments every 4 weeks to a maximum dose of 15 mg 3 times a week.

[Cinacalcet impact on calcium homeostasis and bone remodeling in 13 renal transplanted patients with hyperparathyroidism and hypercalcaemia]

The purpose of the study is to assess the impact of cinacalcet on calcium and bone remodeling, in post-renal transplanted patients with persistent hypercalcaemia secondary to hyperparathyroidism. Thirteen renal-transplanted adult recipients with a glomerular filtration rate over 30 ml/min/1.73 m(2), a total serum calcium>2.60 mmol/l with ionized calcium>1.31 mmol/l and a parathyroid hormone serum level over 70 pg/ml, were treated with cinacalcet for 4 months followed by a 15-day wash out. The results show that cinacalcet lowers significantly total and ionized calcium respectively from 2,73 (2,67-2,86) to 2,31 (2,26-2,37) mmol/l (P<0.05) and from 1,39 (1,37-1,47) to 1,21 (1,15-1,22) mmol/l (P<0.05) with no alteration of the 24-hour urine calcium/creatinine ratio and no significant expected PTH serum level suppression (153 [115-214,9] and 166 [122-174] pg/ml). On the other hand, fasting urine calcium was significantly decreased from 0,61 (0,27-1,02) to 0,22 (0,15-0,37) (P<0.05) and bone-specific alkaline phosphatases increased from 20,5 (13-46,6) to 33,8 (12-58,9) ng/ml, upon cinacalcet treatment. After its discontinuation, all these effects were reversible. In conclusion, cinacalcet normalizes total and ionized calcium in renal-transplanted recipients with hypercalcemia secondary to hyperparathyroidism through a mechanism that could be independent of PTH serum level suppression. The increase in bone-specific alkaline phosphatases, biochemical markers of bone accretion and the significant decrease in fasting urine calcium suggest the possibility of a beneficial impact of cinacalcet on bone remodeling.

Hemoglobin variability does not predict mortality in European hemodialysis patients

Patients with CKD exhibit significant within-patient hemoglobin (Hb) level variability, especially with the use of erythropoiesis stimulating agents (ESAs) and iron. Analyses of dialysis cohorts in the United States produced conflicting results regarding the association of Hb variability with patient outcomes. Here, we determined Hb variability in 5037 European hemodialysis (HD) patients treated over 2 years to identify predictors of high variability and to evaluate its association with all-cause and cardiovascular disease (CVD) mortality. We assessed Hb variability with various methods using SD, residual SD, time-in-target (11.0 to 12.5 g/dl), fluctuation across thresholds, and area under the curve (AUC). Hb variability was significantly greater among incident patients than prevalent patients. Compared with previously described cohorts in the United States, residual SD was similar but fluctuations above target were less frequent. Using logistic regression, age, body mass index, CVD history, dialysis vintage, serum albumin, Hb, angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) use, ESA use, dialysis access type, dialysis access change, and hospitalizations were significant predictors of high variability. Multivariable adjusted Cox regression showed that SD, residual SD, time-in-target, and AUC did not predict all-cause or CVD mortality during a median follow-up of 12.4 months (IQR: 7.7 to 17.4). However, patients with consistently low levels of Hb (<11 g/dl) and those who fluctuated between the target range and <11 g/dl had increased risks for death (RR 2.34; 95% CI: 1.24 to 4.41 and RR 1.74; 95% CI: 1.00 to 3.04, respectively). In conclusion, although Hb variability is common in European HD patients, it does not independently predict mortality.

Serum iPTH, calcium and phosphate, and the risk of mortality in a European haemodialysis population

Background. A number of US observational studies reported an increased mortality risk with higher intact parathyroid hormone (iPTH), calcium and/or phosphate. The existence of such a link in a European haemodialysis population was explored as part of the Analysing Data, Recognising Excellence and Optimising Outcomes (ARO) Chronic Kidney Disease (CKD) Research Initiative.

Methods. The association between the markers of mineral and bone disease and clinical outcomes was examined in 7970 patients treated in European Fresenius Medical Care facilities over a median of 21 months. Baseline and time-dependent (TD) Cox regression were performed using Kidney Disease Outcomes Quality Initiative (KDOQI) target ranges as reference categories, adjusting for demographics, medical history, dialysis parameters, inflammation, medications and laboratory parameters. Fractional polynomial (FP) models were also used.

Results. Hazard ratio (HR) estimates from baseline analysis for iPTH were U-shaped [>600 pg/mL, HR = 2.10, 95% confidence interval (CI) 1.62–2.73; <75 pg/mL, HR = 1.46, 95% CI 1.17–1.83]. TD analysis confirmed the results for iPTH. Baseline analysis showed that calcium >2.75 mmol/L increased risk of death (HR = 1.70, 95% CI 1.19–2.42). TD analysis showed that both low (HR = 1.19, 95% CI 1.04–1.37) and high calcium (HR = 1.74, 95% CI 1.30–2.34) increased risk of death. Baseline analysis for phosphate showed a U-shaped pattern (<1.13 mmol/L, HR = 1.18, 95% CI 1.01–1.37; >1.78 mmol/L, HR = 1.32, 95% CI 1.13–1.55). TD analysis confirmed the results for phosphate <1.13 mmol/L. HR estimates were higher in patients with diabetes versus those without diabetes for baseline analysis only (P-value = 0.014). FP analysis confirmed the results of baseline and TD analyses.

Conclusion. Patients with iPTH, calcium and phosphate levels within the KDOQI target ranges have the lowest risk of mortality compared with those outside the target ranges.

Timing of onset of CKD-related metabolic complications

Chronic kidney disease (CKD) guidelines recommend evaluating patients with GFR <60 ml/min per 1.73 m(2) for complications, but little evidence supports the use of a single GFR threshold for all metabolic disorders. We used data from the NephroTest cohort, including 1038 adult patients who had stages 2 through 5 CKD and were not on dialysis, to study the occurrence of metabolic complications. GFR was measured using renal clearance of (51)Cr-EDTA (mGFR) and estimated using two equations derived from the Modification of Diet in Renal Disease study. As mGFR decreased from 60 to 90 to <20 ml/min per 1.73 m(2), the prevalence of hyperparathyroidism increased from 17 to 85%, anemia from 8 to 41%, hyperphosphatemia from 1 to 30%, metabolic acidosis from 2 to 39%, and hyperkalemia from 2 to 42%. Factors most strongly associated with metabolic complications, independent of mGFR, were younger age for acidosis and hyperphosphatemia, presence of diabetes for acidosis, diabetic kidney disease for anemia, and both male gender and the use of inhibitors of the renin-angiotensin system for hyperkalemia. mGFR thresholds for detecting complications with 90% sensitivity were 50, 44, 40, 39, and 37 ml/min per 1.73 m(2) for hyperparathyroidism, anemia, acidosis, hyperkalemia, and hyperphosphatemia, respectively. Analysis using estimated GFR produced similar results. In summary, this study describes the onset of CKD-related complications at different levels of GFR; anemia and hyperparathyroidism occur earlier than acidosis, hyperkalemia, and hyperphosphatemia.

Pitfalls of measuring total blood calcium in patients with CKD

Disorders of mineral and bone metabolism are prevalent in patients with chronic kidney disease (CKD). The recent National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) guidelines recommend that blood calcium (Ca) be regularly measured in patients with stages 3 to 5 CKD. The Kidney Disease: Improving Global Outcomes (KDIGO) position states that the measurement of ionized Ca (iCa) is preferred and that if total Ca (tCa) concentration is used instead, then it should be adjusted in the setting of hypoalbuminemia. In 691 consecutive patients with stages 3 to 5 CKD, we compared the ability of noncorrected and albumin-corrected tCa concentration to identify low, normal, or high iCa concentration. The agreement between noncorrected or albumin-corrected tCa and iCa was only fair. The risk for underestimating ionized calcium was independently increased by a low total CO(2) concentration when either noncorrected or albumin-corrected Ca was used and by a low albumin concentration only when noncorrected tCa was used. The risk for overestimating iCa was increased by a low albumin concentration only when albumin-corrected Ca was used. In conclusion, albumin-corrected tCa does not predict iCa better than noncorrected tCa. Moreover, both noncorrected and albumin-corrected tCa concentrations poorly predict hypo- or hypercalcemia in patients with CKD.

Partial fanconi syndrome induced by imatinib therapy: a novel cause of urinary phosphate loss

Imatinib mesylate (Gleevec, Glivec; Novartis, Basel, Switzerland) is a specific tyrosine kinase inhibitor that has become the gold-standard treatment for patients with chronic myeloid leukemia. Several tyrosine kinases inhibited by imatinib are expressed in the kidney, and although the drug is usually well tolerated, several cases of acute renal failure were reported. We describe for the first time a case of a patient treated by imatinib for chronic myeloid leukemia who developed partial Fanconi syndrome with mild renal failure, which leads to a discussion of the pathophysiological characteristics of imatinib-induced renal toxicity. Patients on long-term imatinib treatment should be monitored for renal failure, as well as proximal tubule dysfunction, including hypophosphatemia.

Effect of Early Correction of Anemia on the Progression of CKD

BACKGROUND

This study is designed to assess the effect of early and complete correction of anemia by using recombinant human erythropoietin (epoetin) alfa on the progression of chronic kidney disease (CKD).

METHODS

Patients were randomly assigned to achieve high (13 to 15 g/dL [130 to 150 g/L]) or low (11 to 12 g/dL [110 to 120 g/L]) hemoglobin-level targets during 4 months of stabilization, followed by 36 months of maintenance. Glomerular filtration rate (GFR) decrease was measured by using iohexol clearance. Quality of life, nutrition, and safety also were monitored.

RESULTS

Because of labeling changes for subcutaneous administration of epoetin alfa (Eprex; Johnson and Johnson, Schaffhausen, Switzerland), the study was terminated prematurely. There were 195 patients enrolled in each group; 108 high-hemoglobin and 133 low-hemoglobin patients entered the maintenance phase. Mean maintenance duration was 7.4 months for the high-hemoglobin group and 8.3 months for the low-hemoglobin group. GFR decrease was numerically, but not statistically significantly, lower with the high-hemoglobin group (0.058 versus 0.081 mL/min/1.73 m2/mo [< 0.01 mL/s/1.73 m2/mo]). Physical quality-of-life measures showed trends (Role-Physical, P = 0.055; Physical Function, P = 0.083) or statistically significant improvement (Vitality, P = 0.042) with high hemoglobin levels at the end of the stabilization phase. Adverse events were similar between groups. Cardiovascular adverse events occurred in 25% of the high-hemoglobin and 18% of the low-hemoglobin patients (P = 0.137). Neither epoetin dosage nor hemoglobin level was associated with cardiovascular adverse events or death.

CONCLUSION

These data suggest that normalization of hemoglobin levels in patients with CKD is safe. Longer duration studies are needed to clarify efficacy benefits with high hemoglobin levels.

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.