CYP3A4 is a crosslink between vitamin D and calcineurin inhibitors in solid organ transplant recipients: implications for bone health.

The use of calcineurin inhibitors (CNIs) and vitamin D deficiency may contribute to the pathogenesis of post-transplant bone disease. CNIs and 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) are substrates of the drug-metabolizing enzyme CYP3A4. This review summarizes the indications for the use of activated vitamin D analogs in post-transplant care and the current knowledge on the impact of CNIs on bone. We searched for clinical evidence of the interaction between CNIs and 1,25(OH)2D3. We also provide an overview of the literature on the interplay between vitamin D metabolism and CYP3A4 in experimental and clinical settings and discuss its possible implications for solid organ transplant recipients. In conclusion, there is a body of evidence on the interplay between vitamin D and the drug-metabolizing enzyme CYP3A4, which may have therapeutic implications.

Chronic norovirus infection among solid organ recipients in a tertiary care hospital, the Netherlands, 2006-2014.

OBJECTIVES: Immunocompromised patients can suffer prolonged norovirus symptoms and virus shedding for many years. Little is known about the prevalence of chronic norovirus infection among solid organ transplant (SOT) recipients. In this study, 2182 SOT recipients were retrospectively tested for chronic norovirus infection. METHODS: The first and last norovirus positive faecal samples of SOT recipients were sequenced to distinguish between persisting infection and re-infection. Patient charts were reviewed to obtain data on health status and treatments. RESULTS: In all, 101 of 2182 (4.6%) recipients were norovirus infected and 23 (22.8%) of these developed chronic norovirus infection. Chronic norovirus infection was found among allogeneic heart, kidney and lung transplant recipients. The median shedding period at the end of the study period was 218 days (range 32-1164 days). CONCLUSIONS: This study shows that chronic norovirus infection is not a rare phenomenon among SOT recipients in a tertiary-care hospital. Further research is needed to study the risk of norovirus transmission to other immunocompromised patients in the hospital and to the general population.

Outcome of pregnancies complicated by oligohydramnios or anhydramnios of renal origin.

OBJECTIVE: To evaluate the outcome of fetuses with oligohydramnios due to kidney anomalies. METHODS: A retrospective study was performed of all pregnancies diagnosed with oligohydramnios and associated kidney anomalies during the period 2000-2008. Outcome included pregnancy outcome, mortality, and morbidity. Morbidity included renal function based on the glomerular filtration rate (GFR) during follow-up. RESULTS: A total of 71 pregnancies were evaluated; 36 fetuses presented on ultrasound with cystic dysplasia, 15 with polycystic kidney disease (PKD) and 20 with hydronephrosis. Twenty-three (32%) had associated anomalies. In 49 fetuses (69%), the diagnosis had been made before 24 weeks of gestational age (GA); 41 of those pregnancies were terminated. Twenty-five neonates were live born: 10 survived, 15 died. Prognostic factors for survival included GA at diagnosis (32.2 weeks for survivors vs 28.1 weeks for non-survivors; P = 0.02), diagnosis of hydronephrosis (7 in the survivors vs 4 in the non-survivors: P = 0.05), isolated anomaly (9 in the survivors vs 7 in the non-survivors: P = 0.04). Severity of oligohydramnios (1 case of anhydramnios in the survivors vs 7 in the non-survivors: P = 0.08) was not significant. The 1-year GFR was below 50 mL/min.1.73 m(2) in four of the ten survivors. CONCLUSION: The prognosis of early onset renal oligohydramnios is poor. Predictive determinants of survival are: GA at diagnosis, nature of renal anomaly (hydronephrosis vs other), and presence of associated anomalies.

Disease activity patterns in juvenile systemic lupus erythematosus and its relation to early aggressive treatment.

This study aimed to determine disease activity patterns in juvenile systemic lupus erythematosus (jSLE) and its relation to early treatment. All jSLE patients who visited the outpatient departments of three Dutch university hospitals for at least 6 months were included. Data were retrospectively collected from each patient visit and hospitalization. Patient characteristics, clinical and laboratory findings categorized in organ systems, flare rate, medication use and disease course were analysed. Included were 35 patients (female 77%; White 47%) with a total follow-up of 142 years. Median age at diagnosis was 12.8 years. Flare rate was 0.45/ patient-year. An organ system not earlier involved was affected in 34% of flares. Identifiable disease activity patterns were: chronic active (49%), relapse remitting (14%) and long quiescence (37%), with no significant difference in organ involvement at diagnosis. Positive anti-Sm and non-White ethnicity were significantly associated with a chronic active pattern. In 14 patients with severe symptoms at diagnosis, treatment with intravenous cyclophosphamide and/or biologics and/or intravenous methylprednisone in the first 6 months resulted in a long quiescence pattern in seven patients. In conclusion, distinct disease activity patterns are identifiable in children. Suppression of disease with early aggressive treatment may decrease the rate of progression.

A 3-year old girl with seizures, hypokalemia and metabolic alkalosis.

A 3-year-old girl presented to the emergency department with seizures, low-grade fever and vomiting. She had tachycardia and a slow capillary refill. Blood pressure could not be measured. Because of suspected sepsis and/or meningo-encephalitis, broad spectrum antibiotics and antiviral medication were given together, along with volume expansion and anticonvulsive therapy. A few hours later, after a second seizure, the blood pressure was extremely high (156/116 mm Hg). The girl was treated with anticonvulsants and intravenous antihypertensive agents. MRI of the brain showed signs of posterior reversible encephalopathy syndrome. Cultures of blood and cerebrospinal fluid remained sterile. Further investigation into the cause of the malignant hypertension revealed hypokalemia, metabolic alkalosis and extremely high plasma renin activity, caused by a rare renal abnormality: bilateral renal segmental hypoplasia or Ask-Upmark kidneys.

Renin-induced hypertension in Wilms tumor patients.

BACKGROUND: Since the report that hypertension associated with Wilms tumor (WT) may be renin-induced, no larger series than 13 patients have been published. Nevertheless, angiotensin converting enzyme (ACE) inhibitors have become treatment of choice for hypertension in WT patients. The purpose of this study was to investigate the correlation between plasma renin levels and blood pressure in a larger cohort of WT patients. PROCEDURE: In this retrospective, single-center study, data on blood pressure and plasma renin were analyzed in 86 WT patients treated according to the consecutive SIOP protocols 6, 9, 93-01, and 2001. RESULTS: At diagnosis, 47 WT patients suffered from hypertension (55%). In 31 of these patients plasma renin levels were analyzed; increased plasma renin levels were found in 25/31 patients (81%). In contrast, normal plasma renin levels were measured in 8/13 of the patients with a normal blood pressure (P = 0.012). Twenty-eight children received antihypertensive treatment before surgery, in 25 of them blood pressure normalized before surgery. Blood pressure was normal directly after surgery in all patients but 4, in whom blood pressure recovered to normal within a few weeks. CONCLUSIONS: This retrospective study shows that hypertension in WT patients is associated with elevated plasma renin levels, indicating that ACE inhibitors may be a good therapeutic option in at least a subset of WT patients with hypertension before nephrectomy.

Kidney transplantation without prior dialysis in children: the Eurotransplant experience.

Kidney transplantation without prior dialysis may prevent dialysis-associated morbidity. We analyzed the outcome of 1113 first kidney transplants in children performed between 1990 and 2000 in the Eurotransplant community. Enlistment for a deceased donor kidney before start of dialysis (127/895, 14%) made dialysis redundant in 55% of cases. Mean residual creatinine clearance at transplantation of these patients was 8 mL/min/1.73 m(2). Pre-emptive transplantations of deceased donor kidneys showed less acute rejections (52% vs. 37% rejection-free at 3 years, p = 0.039), compared to transplantations following dialysis. The difference in graft survival between non-dialyzed and dialyzed patients (82% vs. 69% at 6 year) did not reach statistical significance (p = 0.055). No differences were noted after living donor transplantation. Multivariate analysis showed that the period of transplantation was the strongest predictor of graft survival (p < 0.001). Congenital structural abnormalities such as primary kidney disease predominated in nondialyzed patients as compared to dialyzed patients (p < 0.001); this factor did not influence graft survival. Based on our conclusion that pre-emptive transplantation is at least as good as post-dialysis transplantation, as well as on quality of life arguments, we recommend to consider pre-emptive transplantation in children with end-stage renal failure.

Pediatric renal transplantation in the Netherlands.

In the Netherlands, pediatric kidney transplantation programs are available in four centers. We retrospectively analyzed the results obtained over the past decade. Between 1985 and 1995, 231 patients (139 boys) received 269 transplants, including 61 repeat. The recipients were aged 1.9-21.8 yrs (mean 10.9), the donors 0.3-63.3 yrs (median 11.4, mean 19.7). Immunosuppression consisted of corticosteroids, cyclosporin A and azathioprine, in various combinations and dosages. The patient survival during follow-up was 97%. The overall graft survival was 73% at 1 yr and 60% at 5 yrs after transplantation. Major causes of graft loss were acute rejection (21%), thrombosis (12%) and chronic rejection (28%). Acute rejection episodes were noted in 74% of all grafts. First acute rejection episodes had a moderate predictive value for graft loss (relative risk (RR), compared to rejection-free grafts, 5.9). First rejection episodes occurring later than 3 months after transplantation were considerably more predictive (RR 18.3) than early ones. Grafts from living related donors (n = 35) yielded a superior 5-yr graft survival (77%) and remained free of rejection more often than grafts from adult cadaveric donors(43% vs. 25%). The results of pre-emptive transplants were excellent (n = 13, 5-yr survival 100%). Repeat transplants had the same results as primary transplants. Recipients younger than 4 yrs showed a poor 5-yr graft survival of 38% (n = 13). Single kidney grafts from donors younger than 4 yrs (n = 35) had a 5-yr graft survival of 44%. In contrast, kidneys from these young donors did well if transplanted en bloc (n = 10, 5-yr graft survival 89%). These overall results are in line with those of others. The results may be improved by expansion of immunosuppressive therapy in the first year and by thrombosis prophylaxis in high-risk patient-donor combinations. Better results may be expected from more extensive use of living related donations, pre-emptive transplantation and en bloc transplantation instead of single kidneys of young donors.

Four cases of hemolytic uremic syndrome--source contaminated swimming water?

In June '93, 4 children, aged 1.5-3.5 years, all living in one town, were admitted to our hospital with the diagnosis hemolytic uremic syndrome (HUS) within one week. In cooperation with the local health authorities a common source was searched for. Questionnaires indicated that the single condition shared by all patients was swimming water. The patients were not acquainted, visited different daycares, and had no food resources in common. All 4 patients bathed in the same, shallow, recreational lake within a period of 5 days. During this time the air temperature was high according to Dutch standards (around 27 degrees C), and many people visited the lake, estimated several hundreds a day. The water level was lower than normal. Diarrhea followed 3-11 days after swimming and the first clinical symptoms of HUS developed 6-7 days after the onset of diarrhea. The lake was closed for swimming when the fourth HUS patient was diagnosed and the possibility of transmission by way of the lake was mentioned. E. coli O157: H7 was demonstrated in the fecal samples of 2 index patients. The samples were taken 9-20 days after the start of diarrhea. Antibodies to O157 and verotoxin 2 were strongly positive in all patients. A local outbreak of diarrheal illness was not registered. Of 16 family members who also swam in the same lake, 7 developed symptoms of enteritis, 3 had positive cultures of their fecal samples and 5 had positive serology. Pulsed-field gel electrophoresis of the E. coli isolates of the patients and family members showed an identical pattern. No O157: H7-DNA could be detected in filter concentrated lake water samples using polymerase chain reaction (PCR) enhancement. These samples were, however, taken 16 days after the latest possible date of contamination of our patients, 15 days after decrease of the air temperature to 15-17 degrees C, and 14 days after the inlet from water from the environment. It could thus very well be that the microorganism was no longer present. This third report of swimming water associated HUS should direct environmental surveys in similar cases of local HUS outbreaks.

Reduction of a centrally induced pressor response by neurohypophyseal peptides: the involvement of lower brainstem mechanisms.

Pressor and bradycardiac responses induced by electrical stimulation of the mesencephalic reticular formation in urethane-anesthetized rats were used as model of neurogenic hypertension. Oxytocin (OXT) and prolyl-leucyl-glycinamide (OXT-(7-9] administered into the fourth cerebral ventricle markedly attenuated the magnitude of the pressor response. OXT-(7-9) was somewhat more potent than OXT and its effect was dose-dependent. Microinjection of OXT-(7-9) into the dorsal raphe nucleus reduced the pressor response as well. [Arg8]vasopressin (AVP) did not affect the pressor response when administered via this route, while prolyl-arginyl-glycinamide (AVP-(7-9] had an action that was similar to that of OXT-(7-9). None of these peptides affected the magnitude of the bradycardiac response. It is suggested that OXT and related fragments modulate neurogenic hypertensive responses through lower brainstem mechanisms.

Effect of low-frequency stimulation of the pituitary stalk on neurohypophysial hormone release in vivo.

Because of the usually low spontaneous activity of oxytocin producing cells, the effect of low frequency (6 Hz) electrical stimulation of the pituitary stalk in vivo upon plasma oxytocin concentration, uterine contractions and intramammary pressure was studied. 30 min of stimulation increased plasma oxytocin concentration. The same type of stimulation elicited both uterine contractions in early post partum rats and milk ejection in the lactating rat, but the latter phenomenon was not considered to mimic physiological events as contrasted with the former. It was concluded that in contrast to previous data, below 10 Hz stimulation of the pituitary stalk in vivo is also effective in producing hormone release and, furthermore, that it may have physiological consequences.