Osteomalacia induced by vitamin D deficiency in hemodialysis patients: the crucial role of vitamin D correction

Vitamin D deficiency/insufficiency is significantly prevalent in chronic kidney disease. Data in the literature are however scarce about the effects of this deficiency on bone metabolism in hemodialysis (HD) patients. Moreover, it is still debated whether low vitamin D levels should be normalized in HD patients. In this paper, we report two cases showing the deleterious consequences of vitamin D deficiency in HD patients which is characterised by hypophosphatemia, hypocalcemia and osteomalacia (OM) leading to bone fractures. As vitamin D repletion is an easy way to treat OM, this report underlines the importance of monitoring and correction of vitamin D deficiency in this population.

Treating diabetes with islet transplantation: lessons from the past decade in Lille

Type 1 diabetes (T1D) is due to the loss of both beta-cell insulin secretion and glucose sensing, leading to glucose variability and a lack of predictability, a daily issue for patients. Guidelines for the treatment of T1D have become stricter as results from the Diabetes Control and Complications Trial (DCCT) demonstrated the close relationship between microangiopathy and HbA1c levels. In this regard, glucometers, ambulatory continuous glucose monitoring, and subcutaneous and intraperitoneal pumps have been major developments in the management of glucose imbalance. Besides this technological approach, islet transplantation (IT) has emerged as an acceptable safe procedure with results that continue to improve. Research in the last decade of the 20th century focused on the feasibility of islet isolation and transplantation and, since 2000, the success and reproducibility of the Edmonton protocol have been proven, and the mid-term (5-year) benefit-risk ratio evaluated. Currently, a 5-year 50% rate of insulin independence can be expected, with stabilization of microangiopathy and macroangiopathy, but the possible side-effects of immunosuppressants, limited availability of islets and still limited duration of insulin independence restrict the procedure to cases of brittle diabetes in patients who are not overweight or have no associated insulin resistance. However, various prognostic factors have been identified that may extend islet graft survival and reduce the number of islet injections required; these include graft quality, autoimmunity, immunosuppressant regimen and non-specific inflammatory reactions. Finally, alternative injection sites and unlimited sources of islets are likely to make IT a routine procedure in the future.

Dynamics of bubbles created by plasma in heptane for micro-gap conditions

The determination of the initial pressure at the bubble wall created by a discharge in heptane for micro-gap conditions cannot be determined straightforwardly by modeling the time-oscillations of the bubble. The resolution of the Gilmore equation gives the same solutions beyond 1 μs typically for various sets of initial parameters, making impossible the determination of the initial pressure at the bubble wall. Furthermore, the very first instant of the bubble formation is not easily accessible at very short time scales because of the plasma emission. Since the pressure waves propagate in the liquid, it is much easier to gain information on the first instants of the bubble formation by studying the pressure field far from the emission source. Then, it is possible to deduce by modeling what happened at the beginning of the emission of the pressure waves. The proposed solution consists in looking at the oscillations affecting another bubble located at least twice farther from the interelectrode gap than the maximum radius reached by the discharge bubble. The initial plasma pressure can be determined by this method.

Crohn's disease and nontropical endomyocardial fibrosis

The pathogenesis of endomyocardial fibrosis (EMF) is poorly understood. EMF may result from autoimmune scarring of the endocardium. Clinically, EMF presents as a restrictive cardiomyopathy. EMF is commonly reported in tropical countries. In Western countries, EMF is associated with hypereosinophilia and reported as Loeffler endocarditis. We report a Caucasian patient with Crohn's disease and EMF, and discuss a possible linkage between the two conditions.

Anti-viral therapy in haemodialysed HCV patients: efficacy, tolerance and treatment strategy

BACKGROUND

In end-stage renal disease (ESRD) patients, hepatitis C virus (HCV) eradication improves patient and graft survival.

AIM

To determine optimal use of erythropoietin (EPO) and ribavirin, to compare ribavirin concentrations with those of HCV patients having normal renal function and to evaluate sustained virological response (SVR) in a prospective observatory of ESRD candidates for renal transplantation.

METHODS

Thirty-two naïve patients were treated with Peg-IFN-α2a and ribavirin. Two different schedules of ribavirin and EPO administration were used: starting ribavirin at 600mg per week and adapting EPO when haemoglobin (Hb) fell below 10g/dL (adaptive strategy) or starting ribavirin at 1000mg per week while increasing EPO from the start of treatment (preventive strategy).

RESULTS

Patients treated with the adaptive strategy had lower median Hb levels (9.6 vs. 10.9g/dL, P=0.02) and more frequent median Hb levels below 10g/dL (58 vs. 5%, P=0.0007) despite lower median ribavirin doses (105 vs. 142mg/day, P<0.0001) than patients treated with the preventive strategy. There was a trend for more frequent transfusion in patients treated with the adaptive strategy than in patients treated with preventive strategy (50 vs. 20%, P=0.08). Compared to patients with normal renal function, ESRD patients had lower ribavirin concentrations during the first month (0.81 vs. 1.7mg/L, P=0.007) and similar concentrations thereafter. SVR was reached in 50%.

CONCLUSIONS

Pegylated interferon (Peg-IFN) and an adapted schedule of ribavirin are effective in ESRD patients. Increasing EPO from the start of treatment provides better haematological tolerance. The optimal dosage of ribavirin remains unresolved, in light of frequent side effects.

Diabetes cell therapy: a decade later

Type 1 diabetes is an intrinsically unstable condition because of the loss of both insulin secretion and glucose sensing. Guidelines to treat type 1 diabetes have become stricter since results from the Diabetes Control and Complications Trial (DCCT) demonstrated the close relationship between microangiopathy and HbA1c levels. Therapeutic strategies first require the treatment of underlying organic causes of the brittleness associated with the optimization of insulin therapy including continuous subcutaneous insulin infusion and glucose monitoring. Alternative approaches may still be needed for the most severely affected patients. During the last decade, islet transplantation has gone from an inconsistent 1-year rate of insulin independence of 10% to 80% and could reach 50% at 5 years, at the expense of non-negligible side effects. Among potential causes of islet transplantation success, sufficient islet mass and low levels of cellular autoimmunity are of critical importance. The main issues are currently the availability of an unlimited source of insulin-secreting cells, and the immunosuppressive drug side effects. Today, islet alone and islet after kidney transplantation are offered in a limited number of isolation centres, usually in clinical trials. Islet after kidney transplantation can be considered in type 1 diabetic patients with end-stage kidney disease that are ineligible for double kidney-pancreas transplantation. Islet transplantation alone is proposed to C-peptide negative adult diabetic patients with a body weight <80 kg or low daily insulin needs with creatinine clearance above 60 ml/min, albuminuria lower than 300mg/24H and without desire for pregnancy in women. Currently and until a more complete assessment of the 5- and probably 10-year overall benefit-risk ratio is available, islet transplantation remains a clinical research procedure.

[Management of renal atrophy in hypertensive patients: experience in Lille]

INTRODUCTION

In the absence of specific treatment, patients with renal vascular disease develop renal atrophy. This population frequently has hypertension refractory to medical treatment. The patients who may respond to revascularization or at the worst to a nephrectomy must be identified to optimize their therapeutic management.

METHODS

We conducted an observational retrospective study of hypertensive patients with unilateral renal atrophy (renal height < 9 cm) followed at the Lille University Hospital Center from 1998 to 2006. Hypertension, renal clearance (by scintigraphy with MAG3), and hypersecretion of renin (segmental/selective venous renin samples) were studied. We subsequently classified the patients into 3 groups. Medical treatment was optimized for all.

RESULTS

The mean follow-up period was 1.3+/-0.2 years. Eight patients were treated medically (group 1). Endovascular revascularization was used to treat the subjects for which atrophic kidney function accounted for more than 10% of their total renal function and with stenosis of the renal artery (>70%) (group 2, n=19). Those with a small nonfunctional kidney (<10% of total renal function) and hypersecretion of renin (ratio>1.5 in relation to the contralateral kidney) underwent a nephrectomy (group 3, n=8). The reduction in systolic blood pressure (SBP) was 27 mm Hg and diastolic blood pressure (DBP) 14 mm Hg for the overall study population (p < 0.001), without any significant aggravation of renal function. In group 1, the reduction in blood pressure was lower, with medical treatment alone; SBP fell by 13 mm Hg and DBP by 4mm Hg (p=ns) ; this group had the lowest initial blood pressure. In group 2, revascularization made it possible to improve SBP by 26 mm Hg and DBP by 14 mm Hg (p < 0.01) without significant impairment of renal function. Group 3 showed the most spectacular improvement in blood pressure, with SBP dropping by 40 mm Hg and DBP by 19 mm Hg (p=0.016). But it was also in this group that we observed an aggravation in the rate of glomerular filtration with a nonsignificant reduction of 12.8 mL/min, nonetheless superior to that expected according to the preoperative scintigraphy.

CONCLUSION

The results of this work underline the importance of multidisciplinary management of patients with small ischemic kidneys. Preselection of patients in unstable clinical situations (refractory hypertension, progressive kidney failure, flash pulmonary edema) by isotopic and endocrinal renal evaluation provides a basis for deciding on treatment. The existence of a renin ratio >1.5 can identify the patients most likely to respond to nephrectomy. The reduction of renal function following nephrectomy must be considered in the discussion about treatment. The functional threshold initially defined at 10% may be lowered to 5%, to limit this postoperative reduction.

Who should benefit from diabetes cell therapy?

Type 1 diabetes are intrinsically unstable conditions because of the loss of both insulin secretion and glucose sensing. Guidelines to treat type 1 diabetes have become stricter since the Diabetes Control and Complications Trial (DCCT) results demonstrated the close relationship between microangiopathy and HbA1c levels, whereas the deleterious role of glucose variability on macroangiopathy has been more recently suspected. Therapeutic strategies first require the treatment of underlying organic causes of the brittleness whenever possible and, secondly, the optimization of insulin therapy using analogues, multiple injections and consideration of continuous subcutaneous insulin infusion. Alternative approaches may still be needed for the most severely affected patients, including islet transplantation. We propose islet after kidney transplantation in diabetic patients with end-stage kidney disease ineligible for double kidney-pancreas transplantation (i.e C peptide negative patients over 45 years of age or with severe macroangiopathy) if creatinine blood levels are stable below 20mg/l at least six months after kidney transplantation and steroid discontinuation. Islet transplantation alone is proposed to (1) C peptide negative diabetic patients, (2) aged 18-65 with a duration of diabetes of at least five years, (3) treated with intensive subcutaneous insulin therapy, but unable to obtain a glycated hemoglobin level below 7% without hypoglycemia and / or with brittleness and unpredictable hyper- and hypoglycemia altering quality of life, (4) with normal body weight (< 80 kg) and / or low daily insulin needs (the lower, the better), (5) with renal function close to normal (creatinine clearance above 60 ml/min with albuminuria lower than 300 mg/24 h), (6) with no desire for pregnancy in women. Currently and until more complete assessment of the 5-year overall benefit-risk ratio, islet transplantation remains a clinical research procedure. As already provided for other types of transplantation, and once recognized as a "routine" procedure, prioritization of enlisted patients for islet transplantation could be aided by the calculation of a score that should be determined by a multidisciplinary team.

Primary graft function, metabolic control, and graft survival after islet transplantation

OBJECTIVE To investigate the influence of primary graft function (PGF) on graft survival and metabolic control after islet transplantation with the Edmonton protocol. RESEARCH DESIGN AND METHODS A total of 14 consecutive patients with brittle type 1 diabetes were enrolled in this phase 2 study and received median 12,479 islet equivalents per kilogram of body weight (interquartile range 11,072-15,755) in two or three sequential infusions within 67 days (44-95). PGF was estimated 1 month after the last infusion by the beta-score, a previously validated index (range 0-8) based on insulin or oral treatment requirements, plasma C-peptide, blood glucose, and A1C. Primary outcome was graft survival, defined as insulin independence with A1C < or =6.5%. RESULTS All patients gained insulin independence within 12 days (6-23) after the last infusion. PGF was optimal (beta-score > or =7) in nine patients and suboptimal (beta-score < or =6) in five. At last follow-up, 3.3 years (2.8-4.0) after islet transplantation, eight patients (57%) remained insulin independent with A1C < or =6.5%, including seven patients with optimal PGF (78%) and one with suboptimal PGF (20%) (P = 0.01, log-rank test). Graft survival was not significantly influenced by HLA mismatches or by preexisting islet autoantibodies. A1C, mean glucose, glucose variability (assessed with continuous glucose monitoring system), and glucose tolerance (using an oral glucose tolerance test) were markedly improved when compared with baseline values and were significantly lower in patients with optimal PGF than in those with suboptimal PGF. CONCLUSIONS Optimal PGF was associated with prolonged graft survival and better metabolic control after islet transplantation. This early outcome may represent a valuable end point in future clinical trials.

Conversion to sirolimus for chronic renal allograft dysfunction: risk factors for graft loss and severe side effects

We retrospectively reviewed our experience with 45 kidney transplant recipients (KTR) that were switched from CNI to SRL, mainly for chronic allograft dysfunction (CAD) (41/45). The mean serum creatinine at switch was 2.5 ± 0.8 mg/dl. At 1 year, patient survival was 93%. Death-censored graft survival was 67% at 1 year and 54% at 2 years. SRL was stopped because of severe side effects in 15 patients. Among these, eight patients developed ‘de novo’ high-grade proteinuria. Univariate analysis revealed that (1) a higher SRL level at 1 month was a predictor of SRL withdrawal due to severe side effects (P = 0.006), and (2) predictors of graft failure after SRL conversion were low SRL loading dose (P = 0.03) and a higher creatinine level at conversion (P = 0.003).

In conclusion, the therapeutic index of SRL in patients suffering from CAD is narrow, with high exposure triggering serious adverse events that may mandate SRL discontinuation, while too low exposure may expose patients to under-immunosuppression and graft loss.