Epidemiology and Dynamics of BK Polyomavirus Replication after Kidney Transplantation

BACKGROUND/OBJECTIVES

In the absence of an effective antiviral treatment for BK polyomavirus (BKPyV), a better understanding of the epidemiology and time course of BKPyV replication after kidney transplantation is needed to limit the virus's impact on the graft outcome.

METHODS

In a 7-year study, we screened more than 430 kidney transplant recipients and analyzed the time course and virological characteristics of BKPyV replication.

RESULTS

Urinary viral replication was observed in 116 (27%) of the 430 patients, and 90 of the 116 (78%) had viral DNAemia. Thirty-eight patients (8.8%) were presumed to have nephropathy (DNAemia > 4 log10 copies/mL). Of the patients with BKPyV replication, 48%, 60%, 71%, and 80% were first found to be positive one, two, three, and four months post-transplantation. The initial viral load in the urine was below 7 log10 copies/mL in 100% of the patients with viral replication first detected before the first month, and this proportion was 57% when viral replication was first detected after the first month. When the BKPyV replication was first detected in a urine sample at month 3 or later, 81.5% of patients had concomitant BKPyV DNAemia. The predominant viral subtype was Ib2 (60%), and there was no apparent relationship between the subtype and the time course of BKPyV replication.

CONCLUSIONS

Urinary BKPyV replication occurs early after renal transplantation and in most patients will increase to a level requiring therapeutic intervention. Close monitoring for BKPyV in the early post-transplantation period would enable the pre-emptive adjustment of the immunosuppression regimen.

Pendrin: linking acid base to blood pressure

Pendrin (SLC26A4) is an anion exchanger from the SLC26 transporter family which is mutated in human patients affected by Pendred syndrome, an autosomal recessive disease characterized by sensoneurinal deafness and hypothyroidism. Pendrin is also expressed in the kidney where it mediates the exchange of internal HCO3- for external Cl- at the apical surface of renal type B and non-A non-B-intercalated cells. Studies using pendrin knockout mice have first revealed that pendrin is essential for renal base excretion. However, subsequent studies have demonstrated that pendrin also controls chloride absorption by the distal nephron and that this mechanism is critical for renal NaCl balance. Furthermore, pendrin has been shown to control vascular volume and ultimately blood pressure. This review summarizes the current knowledge about how pendrin is linking renal acid-base regulation to blood pressure control.

Kidney Transplantation in Patients With AA Amyloidosis: Outcomes in a French Multicenter Cohort

RATIONALE & OBJECTIVE

Outcomes of kidney transplantation for patients with renal AA amyloidosis are uncertain, with reports of poor survival and high rates of disease recurrence. However, the data are inconclusive and mostly based on studies from the early 2000s and earlier.

STUDY DESIGN

Retrospective multicenter cohort study.

SETTING & PARTICIPANTS

We searched the French national transplant database to identify all patients with renal AA amyloidosis who underwent kidney transplantation between 2008 and 2018.

EXPOSURES

Age, cause of amyloidosis, use of biotherapies, and C-reactive protein levels.

OUTCOMES

Outcomes were all-cause mortality and allograft loss. We also reported amyloidosis allograft recurrence, occurrence of acute rejection episodes, as well as infectious, cardiovascular, and neoplastic disease events.

ANALYTICAL APPROACH

Kaplan-Meier estimator for mortality and cumulative incidence function method for allograft loss. Factors associated with patient and allograft survival were investigated using a Cox proportional hazards model and a cause-specific hazards model, respectively.

RESULTS

86 patients who received kidney transplants for AA amyloidosis at 26 French centers were included. The median age was 49.4 years (IQR, 39.7-61.1). The main cause of amyloidosis was familial Mediterranean fever (37 cases; 43%). 16 (18.6%) patients received biotherapy after transplantation. Patient survival rates were 94.0% (95% CI, 89.1-99.2) at 1 year and 85.5% (77.8-94.0) at 5 years after transplantation. Cumulative incidences of allograft loss were 10.5% (4.0-17.0) at 1 year and 13.0% (5.8-20.1) at 5 years after transplantation. Histologically proven AA amyloidosis recurrence occurred in 5 transplants (5.8%). An infection requiring hospitalization developed in 55.8% of cases, and there was a 27.9% incidence of acute allograft rejection. Multivariable analysis showed that C-reactive protein concentration at the time of transplantation was associated with patient survival (HR, 1.01; 95% CI, 1.00-1.02; P=0.01) and allograft survival (HR, 1.68; 95% CI, 1.10-2.57; P=0.02).

LIMITATIONS

The study lacked a control group, and the effect of biotherapies on transplantation outcomes could not be explored.

CONCLUSIONS

This relatively contemporary cohort of patients who received a kidney transplant for AA amyloidosis experienced favorable rates of survival and lower recurrence rates than previously reported. These data support the practice of treating these patients with kidney transplantation for end-stage kidney disease.

PLAIN-LANGUAGE SUMMARY

AA amyloidosis is a severe and rare disease. Kidney involvement is frequent and leads to end-stage kidney disease. Because of the involvement of other organs, these patients are often frail, which has raised concerns about their suitability for kidney transplantation. We reviewed all patients with AA amyloidosis nephropathy who underwent kidney transplantation in France in the recent era (2008-2018) and found that the outcomes after kidney transplantation were favorable, with 85.5% of patients still alive 5 years after transplantation, a survival rate that is comparable to the outcomes of patients receiving a transplant for other forms of kidney diseases. Recurrence of amyloidosis in the transplanted kidney was infrequent (5.8%). These data support the practice of kidney transplantation for patients with AA amyloidosis who experience kidney failure.

Statin therapy and the incidence of atherosclerotic cardiovascular events after kidney transplantation

BACKGROUND

Statins are recommended in kidney transplant recipients (KTRs) - a population with a high risk of major cardiovascular (CV) events. However, the literature data on the effectiveness of statins in KTRs are sparse and inconclusive. The present study's objective was to evaluate the association between statin exposure and atherosclerotic CV events in KTRs and the biochemical effectiveness of statins on the lipid profile.

METHODS

318 consecutive KTRs managed at a single center between 2006 and 2019 were retrospectively included. Those exposed to statins after transplantation were incident users. In all users, statins were indicated for primary CV prevention. Lipid profiles, the occurrence of any atherosclerotic CV events (stroke, myocardial infarction, other atherosclerotic CV events, and atherosclerotic CV deaths) were documented comprehensively. We applied Cox models that included statin exposure as a time-dependent covariate fitted with time-varying inverse probability treatment weighting (IPTW) to assess the effectiveness of statins on atherosclerotic CV events and on all CV events. We built linear mixed models to assess the biochemical effectiveness of statins.

RESULTS

During a median [interquartile range] follow-up period of 6.0 [3.9-10.0] years, 27 atherosclerotic CV events occurred in 26 patients. In the Cox models fitted with time-varying IPTW, exposure to statins was not associated with a decrease in atherosclerotic CV events; the hazard ratio (HR) [95% confidence interval (CI)] was 1.16 [0.53-2.53] (p=0.700). In the linear mixed models, statin exposure was associated with significant decrease over time in triglyceride and low-density lipoprotein cholesterol concentrations (p < 0.001). These results were consistent when stratified for the intensity of statin therapy.

CONCLUSION

Even though the lipid profile improved, statin exposure was not associated with a decrease in CV events in this real-life, single-center, retrospective, long-term follow-up study of a KTR cohort. Larger, controlled studies are needed to confirm or refute these results.

Factors That Predict a Sustained Humoral Response to COVID-19 Vaccines in Kidney Transplant Recipients

INTRODUCTION

Kidney transplant recipients (KTRs) produce a weak humoral response to coronavirus disease 2019 (COVID-19) vaccines. However, the factors associated with the quality of the serological response to three doses of COVID-19 vaccine have not been unambiguously identified.

METHODS

We included KTRs followed in the Nephrology Department at Amiens University Hospital (Amiens, France) between June and December 2021 who had received three doses of a COVID-19 mRNA vaccine (or two doses plus an episode of polymerase chain reaction-confirmed COVID-19). The lack of a humoral response was defined as an antibody titer below 7.1 binding antibody units (BAU)/mL, and an optimal response was defined as an antibody titer above 264 BAU/mL.

RESULTS

Of the 371 patients included, 246 (66.3%) were seropositive, and 97 (26.1%) had an optimal response. In a multivariate analysis, the only factor associated with seropositivity was a history of COVID-19 [odds ratio (OR) 87.2; 95% confidence interval (CI) (7.88-965.0); p < 0.0001], while the main factors associated with non-response were female sex [OR 0.28; 95%CI (0.15-0.51); p < 0.0001], less than 36 months between kidney transplantation and vaccination [OR 0.26; 95%CI (0.13-0.52); p < 0.0001], a higher creatinine level [OR 0.33; 95%CI (0.19-0.56); p < 0.0001], the use of tacrolimus [OR 0.23; 95%CI (0.12-0.45); p < 0.0001], the use of belatacept [OR 0.01; 95%CI (0.001-0.20); p = 0.002] and three-drug immunosuppression [OR 0.39; 95%CI (0.19-0.78); p = 0.015]. A history of COVID-19 was associated with an optimal response [OR 4.03; 95%CI (2.09-7.79); p < 0.0001], while an older age at vaccination [OR 0.97; 95%CI (0.95-0.99); p = 0.002], less than 36 months between kidney transplantation and vaccination [OR 0.35; 95%CI (0.18-0.69); p = 0.002], a higher creatinine level [OR 0.60; 95%CI (0.38-0.93); p = 0.02], three-drug immunosuppression [OR 0.45; 95%CI (0.27-0.76); p = 0.003] were associated with a poorer response.

CONCLUSION

We identified factors associated with a humoral response to a COVID-19 mRNA vaccine in KTRs. These findings might help physicians to optimize vaccination in KTRs.

Relationship between clinical phenotype and in vitro analysis of 13 NPT2c/SCL34A3 mutants

Biallelic pathogenic variants in the SLC34A3 gene, encoding for the NPT2c cotransporter, cause Hereditary Hypophosphatemic Rickets with Hypercalciuria (HHRH). However, the associated phenotype is highly variable. In addition, mice deleted for Slc34a3 exhibit a different phenotype compared to humans, without urinary phosphate leakage. The mechanisms by which SLC34A3 variants disrupt phosphate/calcium metabolism are un-completely understood. In this study we explored these mechanisms in vitro using SLC34A3 variants identified in patients with urinary phosphate leakage. We analyzed the consequences of these variants on NPT2c function and the link with the phenotype of the patients. We studied 20 patients with recurrent nephrolithiasis and low serum phosphate concentration harboring variants in the SLC34A3 gene. Half of the patients carried homozygous or composite heterozygous variants. Three patients had in addition variants in SLC34A1 and SLC9A3R1 genes. All these patients benefited from a precise analysis of their phenotype. We generated 13 of these mutants by site-directed mutagenesis. Then we carried out transient transfections of these mutants in HEK cells and measured their phosphate uptake capacity under different conditions. Among the 20 patients included, 3 had not only mutations in NPT2c but also in NPT2a or NHERF1 genes. Phosphate uptake was decreased in 8 NPT2c mutants studied and normal for 5. Four variants were initially categorized as variants of uncertain significance. Expression of the corresponding mutants showed that one did not modify phosphate transport, two reduced it moderately and one abolished it. Co-transfection of the NPT2c mutants with the wild-type plasmid of NPT2c or NPT2a did not reveal dominant negative effect of the mutants on NPT2c-mediated phosphate transport. A detailed analysis of patient phenotypes did not find a link between the severity of the disorder and the level of phosphate transport impairment. NPT2c mutations classified as ACMG3 identified in patients with renal phosphate leak should be characterized by in vitro study to check if they alter NPT2c-mediated phosphate transport since phosphate uptake capacity may not be affected. In addition, research for mutations in NHERF1 and NPT2a genes should always be associated to NPT2c sequencing.

Drugs associated with incident fragility fractures in kidney transplant recipients

Background

The risk of fragility fractures is high in kidney transplant recipients, and steroids are reportedly a major cause. Other drugs known to induce fragility fractures have been studied in the general population but not in kidney transplant recipients. Here, we investigated the association between exposure over time to drugs that can injure bone (namely vitamin K antagonists, insulin, loop diuretics, proton pump inhibitors, opioids, selective serotonin reuptake inhibitors, antiepileptics and benzodiazepines) and incident fractures and changes over time in T-scores in this population.

Methods

A total of 613 consecutive kidney transplant recipients were included between 2006 and 2019. Drug exposures and incident fractures during the study period were comprehensively documented, and dual-energy X-ray absorptiometry was performed regularly. The data were analyzed using Cox proportional hazards models with time-dependent covariates and linear mixed models.

Results

Incident fractures occurred in 63 patients, giving a fracture incidence of 16.9 per 1000 person-years. Exposures to loop diuretics [hazard ratio (95% confidence interval) 2.11 (1.17-3.79)] and opioids [5.94 (2.14-16.52)] were associated with incident fractures. Exposure to loop diuretics was associated with a decrease over time in the T-score for the lumbar spine (P = .022) and for the wrist (P = .028).

Conclusions

This study suggests that the exposure to loop diuretics and opioids increases the risk of fracture in kidney transplant recipients.

[Management of iron deficiency in chronic kidney disease: Review and proposed algorithm]

Iron deficiency is very common in chronic kidney disease, even before the dialysis stage. It is an independent factor of morbidity and mortality in patients with non-dialysis chronic kidney disease. During chronic kidney disease, iron deficiency is defined by a transferrin saturation <20% and/or a serum ferritin <100 μg/L. In France, about half of non-dialysis chronic kidney disease patients have absolute iron deficiency (transferrin saturation <20% and serum ferritin <100 μg/L) and/or functional iron deficiency (transferrin saturation <20% and serum ferritin >100 μg/L). Despite this, iron deficiency is usually not investigated. In fact, more than 60% of nephrologists do not assess iron status at least once a year. In addition, iron deficiency is rarely treated: only 12% of patients are prescribed oral or intravenous iron. Early detection and treatment are fundamental and should be systematic. In order to help improve the management of iron deficiency among non-dialysis chronic kidney disease patients, we propose an algorithm that takes into account current recommendations and the most recent data from the literature. Initial blood test requires the measurement of hemoglobin concentration, transferrin saturation and serum ferritin. A transferrin saturation <20% establishes the diagnosis of iron deficiency and the serum ferritin level points towards an absolute or functional deficiency. The combination of both values makes it possible to adapt the treatment, particularly in an inflammatory context where oral iron is not effective.

Long-term renal outcome in methylmalonic acidemia in adolescents and adults

BACKGROUND

Chronic kidney disease (CKD) is one of the main long-term prognosis factors in methylmalonic acidemia (MMA), a rare disease of propionate catabolism. Our objective was to precisely address the clinical and biological characteristics of long-term CKD in MMA adolescent and adult patients.

PATIENTS AND METHODS

In this retrospective study, we included MMA patients older than 13 years who had not received kidney and/or liver transplantation. We explored tubular functions, with special attention to proximal tubular function. We measured glomerular filtration rate (mGFR) by iohexol clearance and compared it to estimated glomerular filtration rate (eGFR) by Schwartz formula and CKD-EPI.

RESULTS

Thirteen patients were included (M/F = 5/8). Median age was 24 years (13 to 32). Median mGFR was 57 mL/min/1.73 m2 (23.3 to 105 mL/min/1.73 m2). Ten out of 13 patients had mGFR below 90 mL/min/1.73 m2. No patient had significant glomerular proteinuria. No patient had complete Fanconi syndrome. Only one patient had biological signs suggestive of incomplete proximal tubulopathy. Four out of 13 patients had isolated potassium loss, related to a non-reabsorbable anion effect of urinary methylmalonate. Both Schwartz formula and CKD-EPI significantly overestimated GFR. Bias were respectively 16 ± 15 mL/min/1.73 m2 and 37 ± 22 mL/min/1.73 m2.

CONCLUSION

CKD is a common complication of the MMA. Usual equations overestimate GFR. Therefore, mGFR should be performed to inform therapeutic decisions such as dialysis and/or transplantation. Mild evidence of proximal tubular dysfunction was found in only one patient, suggesting that other mechanisms are involved.

Early steroid withdrawal has a positive effect on bone in kidney transplant recipients: a propensity score study with inverse probability-of-treatment weighting

Background:

Long-term corticosteroid use after kidney transplantation is associated with a decrease in bone mineral density (BMD) and a high fracture risk. We hypothesized that patients with early steroid withdrawal (ESW) would display a gain in BMD in the year following kidney transplantation, when compared with patients on long-term corticosteroid therapy.

Methods:

In a cohort of kidney transplant recipients, 356 patients were included between 2012 and 2019. Dual-energy X-ray absorptiometry was performed 1 and 12 months after transplantation. The data were analyzed using linear regression with inverse probability-of-treatment weighting (based on a propensity score).

Results:

At 1 year after transplantation, the gain in BMD was significantly greater in recipients with ESW than in recipients on long-term corticosteroid therapy for the lumbar spine (+0.036 g/cm², p < 0.001) and the femoral neck (+0.020 g/cm², p = 0.035). Among patients with ESW, (i) none had osteoporosis, (ii) the percentage with normal BMD increased from 33.3% at month 1 to 54.4% at month 12, and (iii) the percentage with osteopenia fell from 56.2% to 45.6%. In patients undergoing long-term corticosteroid therapy, the fracture incidence was 13.5 per 1000 person-years. None of the patients in the ESW group experienced a fracture.

Conclusion:

ESW has a positive effect on bone in kidney transplant recipients.

Severe erosive gingivostomatitis in a patient treated by vedolizumab

Vedolizumab is a humanized monoclonal antibody that binds to the human a4β7 integrin and is approved for use in inflammatory bowel diseases. We describe a patient with severe, refractory erosive gingivostomatitis, which appeared a few days after the first dose of vedolizumab and resolved after discontinuation of the drug. We believe the gingivostomatitis to be a direct side effect of vedolizumab, rather than an extraintestinal manifestation of the underlying inflammatory bowel diseases. The clinicians need to be aware of this adverse event, which could be mistakenly considered as an extraintestinal manifestation of inflammatory bowel diseases.

P0879EARLY STEROID WITHDRAWAL HAS A POSITIVE EFFECT ON BONE KIDNEY TRANSPLANT RECIPIENTS: A PROPENSITY SCORE STUDY WITH INVERSE PROBABILITY-OF-TREATMENT WEIGHTING

Background and Aims

Long-term corticosteroid use after kidney transplantation is associated with a decrease in bone mineral density and a high fracture risk. We hypothesized that patients with early steroid withdrawal (ESW) would display a gain in bone mineral density in the year following kidney transplantation, when compared with patients on long-term corticosteroid therapy (LTCT).

Method

In a cohort of kidney transplant recipients, 317 patients were included between 2012 and 2018. Dual-energy X-ray absorptiometry was performed 1 and 12 months after transplantation. The data were analyzed using linear regression with inverse probability-of-treatment weighting based on a propensity score.

Results

One year after transplantation, the gain in bone mineral density was significantly greater in recipients with ESW than in recipients on LTCT for the lumbar spine (+0.027 g/cm, P &lt; 0.001) and the femoral neck (+0.021 g/cm, P = 0.035). Among patients with ESW, (i) none had osteoporosis, (ii) the percentage with normal bone mineral density increased from 35.0% at month 1 to 56.4% at month 12, and (ii) the percentage with osteopenia fell from 52.5% to 43.6%. In patients undergoing LTCT, the fracture incidence was 14.5 per 1000 person-years. None of the patients in the ESW group experienced a fracture. Cardiovascular risk factors were more prominent in the LTCT group relative to the ESW group: patients in LTCT group (i) were more likely to have high blood pressure (p&lt;0.001), (ii) gained more weight gain (p=0.032) and (iii) displayed a greater increase in serum triglyceride levels (p=0.004).The acute rejection rate was similar in the two groups.

Conclusion

Early steroid withdrawal is associated with a spontaneous increase in bone mineral density at 12 months post-transplantation (relative to patients on long-term steroid therapy), with a reduction in several cardiovascular risk factors and does not appear to harm the graft.

Natural History of Perianal Fistulising Lesions in Patients With Elderly-onset Crohn's Disease: A Population-based Study

INTRODUCTION

Most studies of elderly-onset Crohn's disease [CD; diagnosed in patients aged 60 or over] have described a mild course. However, data on the natural history of perianal fistulising CD [pfCD] in this population are scarce. In a population-based cohort study, we described the prevalence, natural history, and treatment of pfCD in patients with elderly-onset CD vs patients with paediatric-onset CD.

METHOD

All patients diagnosed with CD at or after the age of 60 between 1988 and 2006, were included [n = 372]. Logistic regression, Cox models, and a nested case-control method were used to identify factors associated with pfCD.

RESULTS

A total of 34 elderly patients [9% of the 372] had pfCD at diagnosis. After a median follow-up of 6 years (interquartile range [IQR]: 3; 10), 59 patients [16%] had pfCD; the same prevalence [16%] was observed in paediatric-onset patients. At last follow-up, anal incontinence was more frequent in elderly patients with pfCD than in elderly patients without pfCD [22% vs 4%, respectively; p < 10-4]. Rectal CD at diagnosis was associated with pfCD: hazard ratio (95% confidence interval [CI] = 2.8 [1.6-5.0]). Although 37% of the patients received immunosuppressants and 17% received anti-tumour necrosis factor agents, 24% [14 out of 59] had a definitive stoma at last follow-up.

CONCLUSION

During the first 6 years of disease, the prevalence of pfCD was similar in elderly and paediatric patients. Rectal involvement was associated with the appearance of pfCD in elderly-onset patients. Around a quarter of patients with elderly-onset CD will have a stoma. Our results suggest that treatment with biologics should be evaluated in these patients.

Association of blood bicarbonate and pH with mineral metabolism disturbance and outcome after kidney transplantation

In kidney transplant recipients (KTRs), scarce evidence has associated low blood bicarbonate levels with mineral metabolic disturbance and reduced allograft survival. However, the contribution of the blood pH to these observations remains unassessed. Equally, little is known about the influence of the blood provenance (arteriovenous fistula vs peripheral vein) on bicarbonate values. We analyzed blood gas parameters in a single-center cohort of 1260 stable KTRs, 3 months after transplantation. Inspection of pO₂ distribution allowed the unambiguous identification of the arterial (N = 914) or venous (N = 346) origin of the samples. In patients with arterial blood samples, 435 (46%) had bicarbonate levels below 22 mmol/L. Among them, 196 (40%) were acidemic (blood pH <7.38). In multivariate analysis, low arterial blood pH was associated with increased blood ionized calcium and phosphate and reduced fibroblast growth factor 23 and calcitriol, but not with outcome. In contrast, low bicarbonate concentration predicted allograft loss independently of measured glomerular filtration rate and other potential confounders (hazard ratio [HR] 1.70; 95% confidence interval [CI] 1.04-2.80). In KTRs, reduced arterial blood bicarbonate levels predict outcome while acidemia is associated with altered mineral metabolism.

Osmoregulation Performance and Kidney Transplant Outcome

BACKGROUND

Kidney transplant recipients have an impaired ability to dilute urine but seldom develop baseline hyponatremia before ESRD. Although hyponatremia is a risk factor for adverse events in CKD and in kidney transplant recipients, it remains unclear whether subtler alterations in osmoregulation performance are associated with outcome.

METHODS

We studied a single-center prospective cohort of 1258 kidney transplant recipients who underwent a water-loading test 3 months after transplant to determine osmoregulation performance. Measured GFR (mGFR) was performed at the same visit. A group of 164 healthy candidates for kidney donation served as controls. We further evaluated the association of osmoregulation performance with transplantation outcomes and subsequent kidney function.

RESULTS

Unlike controls, most kidney transplant recipients failed to maintain plasma sodium during water loading (plasma sodium slope of -0.6±0.4 mmol/L per hour in transplant recipients versus -0.12±0.3 mmol/L per hour in controls; P<0.001). Steeper plasma sodium reduction during the test independently associated with the composite outcome of all-cause mortality and allograft loss (hazard ratio [HR], 1.73 per 1 mmol/L per hour decrease in plasma sodium; 95% confidence interval [95% CI], 1.23 to 2.45; P=0.002) and allograft loss alone (HR, 2.04 per 1 mmol/L per hour decrease in plasma sodium; 95% CI, 1.19 to 3.51; P=0.01). The association remained significant in a prespecified sensitivity analysis excluding patients with hyperglycemia. In addition, a steeper plasma sodium slope 3 months after transplantation independently correlated with lower mGFR at 12 months (β=1.93; 95% CI, 0.46 to 3.41; P=0.01).

CONCLUSIONS

Reduced osmoregulation performance occurs frequently in kidney transplant recipients and is an independent predictor of renal outcome.

Cellular and molecular mechanisms associated with ischemic stroke severity in female mice with chronic kidney disease

Ischemic stroke is highly prevalent in chronic kidney disease (CKD) patients and has been associated with a higher risk of neurological deterioration and in-hospital mortality. To date, little is known about the processes by which CKD worsens ischemic stroke. This work aimed to investigate the cellular and molecular mechanism associated with ischemic stroke severity in an in vivo model of CKD. CKD was induced through right kidney cortical electrocautery in 8-week-old female C57BL/6 J mice followed by left total nephrectomy. Transient middle cerebral artery occlusion (tMCAO) was performed 6 weeks after left nephrectomy. Twenty-four hours after tMCAO, the infarct volumes were significantly wider in CKD than in SHAM mice. CKD mice displayed decreased neuroscore, impaired ability to remain on rotarod device, weaker muscular strength and decreased prehensile score. Apoptosis, neuronal loss, glial cells recruitment and microglia/macrophages M₁ signature genes CD32, CD86, IL-1β, IL-6, MCP1 and iNOS were significantly increased within ischemic lesions of CKD mice. This effect was associated with decreased AMP kinase phosphorylation and increased activation of the NFΚB pathway. Pharmacological targeting of AMP kinase activity, which is known to block microglia/macrophages M₁ polarization, appears promising to improve stroke recovery in CKD.

Hepatic Production of Fibroblast Growth Factor 23 in Autosomal Dominant Polycystic Kidney Disease

CONTEXT

The bone-derived hormone fibroblast growth factor (FGF) 23 controls phosphate homeostasis and urinary phosphate excretion. FGF23 plasma levels increase in the early stage of renal insufficiency to prevent hyperphosphatemia. Recent evidence suggests that this increase has effects on cardiac and immune cells that compromise patients' health. Patients with autosomal dominant polycystic kidney disease (ADPKD) have been reported to have higher FGF23 concentrations than other patients with similar renal function. The significance of this finding has remained unknown.

METHODS AND RESULTS

Analyzing the FGF23 plasma levels in 434 patients with ADPKD and 355 control subjects with a measured glomerular filtration rate (mGFR) between 60 and 120 mL/min per 1.73 m2, we confirmed that patients with ADPKD had higher FGF23 plasma concentrations than controls. Remarkably, this difference did not translate into renal phosphate leakage. Using different assays for FGF23, we found that this discrepancy was explained by a predominant increase in the cleaved C-terminal fragment of FGF23, which lacks phosphaturic activity. We found that FGF23 plasma concentration independently correlated with the severity of cystic liver disease in ADPKD. We observed that, in contrast to control liver tissues, the cystic liver from patients with ADPKD markedly expressed FGF23 messenger RNA and protein. In line with this finding, the surgical reduction of polycystic liver mass was associated with a decrease in FGF23 plasma levels independently of any modification in mGFR, phosphate, or iron status.

CONCLUSION

Our findings demonstrate that severely polycystic livers produce FGF23 and increase levels of circulating FGF23 in patients with ADPKD.

Cost-effectiveness analysis of stent type in endoscopic treatment of gastric leak after laparoscopic sleeve gastrectomy

Background

Gastric leak is the most feared surgical postoperative complication after sleeve gastrectomy. An endoscopic procedure is usually required to treat the leak. No data are available on the cost-effectiveness of different stent types in this procedure.

Methods

Between April 2005 and July 2016, patients with a confirmed gastric leak undergoing endoscopic treatment using a covered stent (CS) or double-pigtail stent (DPS) were included. The primary objective of the study was to assess overall costs of the stent types after primary sleeve gastrectomy. Secondary objectives were the cost-effectiveness of each stent type expressed as an incremental cost-effectiveness ratio (ICER); the incremental net benefit; the probability of efficiency, defined as the probability of being cost-effective at a threshold of €30 000, and identification of the key drivers of ICER derived from a multivariable analysis.

Results

One hundred and twelve patients were enrolled. The overall mean costs of gastric leak were €22 470; the mean(s.d.) cost was €24 916(12 212) in the CS arm and €20 024(3352) in the DPS arm (P = 0·018). DPS was more cost-effective than CS (ICER €4743 per endoscopic procedure avoided), with an incremental net benefit of €25 257 and a 27 per cent probability of efficiency. Key drivers of the ICER were the inpatient ward after diagnosis of gastric leak (surgery versus internal medicine), type of institution (private versus public) and duration of hospital stay per endoscopic procedure.

Conclusion

DPS for the treatment of gastric leak is more cost-effective than CS and should be proposed as the standard regimen whenever possible.

Dramatic Increase in Incidence of Ulcerative Colitis and Crohn's Disease (1988-2011): A Population-Based Study of French Adolescents

OBJECTIVES

Few data are available to describe the changes in incidence of pediatric-onset inflammatory bowel disease (IBD). The aim of this study was to describe changes in incidence and phenotypic presentation of pediatric-onset IBD in northern France during a 24-year period.

METHODS

Pediatric-onset IBD (<17 years) was issued from a population-based IBD study in France between 1988 and 2011. Age groups and digestive location were defined according to the Paris classification.

RESULTS

1,350 incident cases were recorded (8.3% of all IBD) including 990 Crohn's disease (CD), 326 ulcerative colitis (UC) and 34 IBD unclassified (IBDU). Median age at diagnosis was similar in CD (14.4 years (Q1=11.8-Q3=16.0)) and UC (14.0 years (11.0-16.0)) and did not change over time. There were significantly more males with CD (females/males=0.82) than UC (females/males=1.25) (P=0.0042). Median time between onset of symptoms and IBD diagnosis was consistently 3 months (1-6). Mean incidence was 4.4/10⁵ for IBD overall (3.2 for CD, 1.1 for UC and 0.1 for IBDU). From 1988-1990 to 2009-2011, a dramatic increase in incidences of both CD and UC were observed in adolescents (10-16 years): for CD from 4.2 to 9.5/10⁵ (+126%; P<0.001) and for UC, from 1.6 to 4.1/10⁵ (+156%; P<0.001). No modification in age or location at diagnosis was observed in either CD or UC.

CONCLUSIONS

In this population-based study, CD and UC incidences increased dramatically in adolescents across a 24-year span, suggesting that one or more strong environmental factors may predispose this population to IBD.

Extra-intestinal Manifestations at Diagnosis in Paediatric- and Elderly-onset Ulcerative Colitis are Associated With a More Severe Disease Outcome: A Population-based Study

BACKGROUND AND AIMS

Data on extra-intestinal manifestations [EIM] and their impact on the disease course of ulcerative colitis [UC] in population-based cohorts are scarce, particularly in paediatric- and elderly-onset UC patients. The aims of this population-based study were to assess: 1] the occurrence of EIM in paediatric- and elderly-onset UC; 2] the factors associated with EIM; and 3] their impact on long-term disease outcome.

METHODS

Paediatric-onset [< 17 years at diagnosis] and elderly-onset UC patients [> 60 years at diagnosis] from a French prospective population-based registry [EPIMAD] were included. Data on EIM and other clinical factors at diagnosis and at maximal follow-up were collected.

RESULTS

In all, 158 paediatric- and 470 elderly-onset patients were included [median age at diagnosis 14.5 and 68.8 years, median follow-up 11.2 and 6.2 years, respectively]. EIM occurred in 8.9% of childhood- and 3% of elderly-onset patients at diagnosis and in 16.7% and 2.2% of individuals during follow-up [p < 0.01], respectively. The most frequent EIM was joint involvement [15.8% of paediatric onset and 2.6% of elderly-onset]. Presence of EIM at diagnosis was associated with more severe disease course [need for immunosuppressants or biologic therapy or colectomy] in both paediatric- and elderly-onset UC (hazard ratio [HR] = 2.0, 95% confidence interval [CI]: 1.0-4.2; and HR = 2.8, 0.9-7.9, respectively). Extensive colitis was another independent risk factor in both age groups.

CONCLUSIONS

Elderly-onset UC patients had lower risk of EIM either at diagnosis or during follow-up than paediatric-onset individuals. EIM at diagnosis predicted more severe disease outcome, including need for immunosuppressive or biologic therapy or surgery, in both paediatric- and elderly-onset UC.

How the reference values for serum parathyroid hormone concentration are (or should be) established?

Well-validated reference values are necessary for a correct interpretation of a serum PTH concentration. Establishing PTH reference values needs recruiting a large reference population. Exclusion criteria for this population can be defined as any situation possibly inducing an increase or a decrease in PTH concentration. As recommended in the recent guidelines on the diagnosis and management of asymptomatic primary hyperparathyroidism, PTH reference values should be established in vitamin D-replete subjects with a normal renal function with possible stratification according to various factors such as age, gender, menopausal status, body mass index, and race. A consensus about analytical/pre-analytical aspects of PTH measurement is also needed with special emphasis on the nature of the sample (plasma or serum), the time and the fasting/non-fasting status of the blood sample. Our opinion is that blood sample for PTH measurement should be obtained in the morning after an overnight fast. Furthermore, despite longer stability of the PTH molecule in EDTA plasma, we prefer serum as it allows to measure calcium, a prerequisite for a correct interpretation of a PTH concentration, on the same sample. Once a consensus is reached, we believe an important international multicentre work should be performed to recruit a very extensive reference population of apparently healthy vitamin D-replete subjects with a normal renal function in order to establish the PTH normative data. Due to the huge inter-method variability in PTH measurement, a sufficient quantity of blood sample should be obtained to allow measurement with as many PTH kits as possible.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

Levels of Indoxyl Sulfate in Kidney Transplant Patients, and the Relationship With Hard Outcomes

BACKGROUND

Indoxyl sulfate (IS) is a protein-bound uremic toxin that is known to be associated with the risk of cardiovascular (CV) disease and death in both predialysis and dialysis patients. Data on levels of protein-bound uremic toxins in kidney transplant patients are scarce. The study's objective was to evaluate the levels of IS in kidney transplant patients and the relationship with hard outcomes.

METHODS AND RESULTS

In 311 kidney transplant patients, IS levels were measured immediately before transplantation (T0), and 1 month (M1) and 12 months (M12) afterwards. Over a mean±standard deviation follow-up period of 113±29 months, a total of 55 deaths, 70 CV events and 71 graft losses were recorded. We observed a rapid significant decrease (below or near the normal value) in IS levels after kidney transplantation. Total and free IS levels at M12 were significantly higher in non-transplant patients than in transplant patients (P=0.003 and <0.0001 respectively), despite having similar estimated glomerular filtration rates. Lastly, IS levels were not associated with overall mortality, CV events or graft loss at T0, M1 or M12.

CONCLUSIONS

IS levels were significantly lower in kidney transplant receipts than in non-recipients suggesting that kidney transplantation protects against an increase in IS levels. IS levels were not associated with hard outcomes in kidney transplant patients. (Circ J 2016; 80: 722-730).

Neurological disorders in a murine model of chronic renal failure

Cardiovascular disease is highly prevalent in patients with chronic renal failure (CRF). However, data on the impact of CRF on the cerebral circulatory system are scarce—despite the fact that stroke is the third most common cause of cardiovascular death in people with CRF. In the present study, we examined the impact of CRF on behavior (anxiety), recognition and ischemic stroke severity in a well-defined murine model of CRF. We did not observe any significant increases between CRF mice and non-CRF mice in terms of anxiety. In contrast, CRF mice showed lower levels of anxiety in some tests. Recognition was not impaired (vs. controls) after 6 weeks of CRF but was impaired after 10 weeks of CRF. Chronic renal failure enhances the severity of ischemic stroke, as evaluated by the infarct volume size in CRF mice after 34 weeks of CRF. Furthermore, neurological test results in non-CRF mice tended to improve in the days following ischemic stroke, whereas the results in CRF mice tended to worsen. In conclusion, we showed that a murine model of CRF is suitable for evaluating uremic toxicity and the associated neurological disorders. Our data confirm the role of uremic toxicity in the genesis of neurological abnormalities (other than anxiety).

Surgical conservative treatment of recurrent bleeding duodenal ulcer

BACKGROUND/AIMS

Endoscopic hemostasis and proton pump inhibitors (PPI) have decreased the incidence of rebleeding and reduced the need for surgery for bleeding duodenal ulcer (BDU). The gold standard surgical treatment of BDU remains vagotomy-antrectomy. Currently, no recommendation is made on the best procedure when emergency surgery is necessary. The aim of this study was to assess the results of a systematic conservative treatment (CT): under-running bleeding gastroduodenal artery (GDA) and ulcer suture through a duodenotomy with (CT+L group) or without (CT group) GDA double ligation along with continuous intravenous PPI.

METHODOLOGY

From 1995 to 2006, 22 consecutive patients (11 per group) underwent emergency surgery for BDU. Mean age was 63 +/- 18 years, ASA score 2.64 +/- 0.7. Ten patients (45%) presented collapse. Mean transfusion number was 11 +/- 9, number of therapeutic endoscopies 1.7 +/- 1, and Rockall score 6 +/- 2.

RESULTS

Overall, 2 patients (9%) had rebleeding and 5 patients (22%) died. No death was reported secondary to rebleeding. In the CT+L group, 9 patients (82%) had intravenous PPI, no patient had rebleeding and 2 patients died (22%).

CONCLUSIONS

Surgical CT of BDU with continuous PPI is effective, with a low rate of rebleeding. The standard use of vagotomy-antrectomy is questionable.

[Self expanding metallic stent in the management of malignant colonic obstruction]

INTRODUCTION

Fifteen to thirty percent of colonic cancers are diagnosed at acute colic obstruction stage. In this situation surgery is associated with a high morbi-mortality. The self-expandable metallic stents (SEM) have two objectives: (a) resolution of the obstructive to allow secondary planified radical surgical procedure; (b) palliative in the event of advanced disease.

PATIENTS AND METHODS

From May 2001 to December 2002, 11 patients, mean age 75 +/- 8 years, presenting with acute colic obstruction were initially treated by SEM placed by endoscopy. Four patients were classified score ASA 4. Ten patients had a colonic cancer, and a patient presented a peritoneal carcinomatosis from an ovarian carcinoma. Overall five patients had a carcinomatosis. Stenosis, mean length 4 +/- 3 cm, were located on the left colon. In five patients the SEM was proposed as a palliative treatment.

RESULTS

Successfully placement of SEM was obtained in 10 (91%) patient without perforation. Three complications (bleeding, reobstruction, migration) were observed. Clinical success (colonic decompression within 96 h without endoscopic or surgical reintervention) was observed in nine out of ten (90%) patients. Six patients had a SEM with curative attempt allowing (i) colonic resection (9 +/- 2 days) without stomy (one postoperative death) in five patients; (ii) a colo-colic derivation for diffuse carcinomatosis discovered peroperatively. A diverting colostomy was carried out in two of the four patients (j6, j30) (reobstruction, migration) for whom the SEM had been proposed as palliative treatment.

CONCLUSIONS

This study confirms that SEM and surgery are not competitive but complementary techniques. When the SEM is placed with curative attempt, it allows resolution of the obstructive syndrome and secondary planified radical surgical procedure under better conditions. The results observed in the palliative SEM group suggested to reconsider this indication.

Traitement de la sténose biliaire par prothèse métallique

A patient presented with a cholangiocarcinoma of the common bile duct; it was initially considered unresectable leading to the placement of the metallic stent whose upper end extended beyond the convergence of the hepatic ducts. The metallic biliary stent became obstructed and so encrusted as to be unremovable; the patient required a left hepatectomy with resection of the stent and the biliary convergence in addition to a pancreatoduodenectomy in order to resect his primary lesion This difficult situation emphasizes that, whenever there is doubt as to the resectability of a biliary lesion, the decision to place a metallic stent should be the fruit of a thorough medico-surgical discussion; where there is any doubt, a plastic stent which is more easily removable should be placed.

[Fistulisation of a tubercular adenopathy in the oesophagus. About a paucisymptomatic form]

The authors present the case of a cervico-mediastinal mass which disappeared spontaneously. The clinical presentation and the image of a fistula during the oesophagoscopy are in favour of the fistulisation of a tubercular adenopathy in the oesophagus. This pathology is rare. This observation is original by the delay of diagnosis due to a dysphagie summarizing the clinical signs and the spontaneously favorable evolution of the fistula.

[Physiology of intestinal absorption]

Hydrolysis of dietary constituents is necessary to allow nutrients absorption by the small intestinal enterocytes. The digestion process takes place in the intestinal lumen, in the brush border membrane, in the enterocyte, and is mediated by a large number of hydrolases secreted in the gastrointestinal tract or produced by the epithelial cells and localized in the brush border. Nutrients are essentially absorbed via a transcellular route across enterocyte cell membranes to enter bloodstream or lymphatic circulation. Transport of nutrients across apical or basolateral membranes occur by active or facilitated mechanisms involving specific transporters. Water, electrolytes and small molecules can be partly absorbed via paracellular pathway. Tight junction permeability is regulated by osmolarity of intercellular space, definite nutrient concentrations in lumen, and activity of brush border membrane transporters.

Aortic thrombosis and ulcerative colitis

Arterial thrombotic accidents in the course of inflammatory bowel disease are rare. They generally affect young adults whose disease is active. We observed a case of aortic and renal arterial thrombosis in a 40-year-old woman who was suffering from ulcerative colitis. Surgical thrombectomy ensured good postoperative results, without any ischemic or renal sequelae. Six days later the patient presented with distal thrombosis of the splenic artery, which receded under anticoagulant treatment. The physiopathology of thromboembolic events in the course of inflammatory bowel disease is uncertain. Such events result from a state of hypercoagulability of various mechanisms, which can be observed in active inflammatory bowel disease. This possibility of serious arterial thrombosis argues in favor of long-term anticoagulant treatment when inflammatory bowel disease is active.

[Hepatic disorders related to Lyme disease. Study of two cases and a review of the literature]

We report two cases of Lyme disease, revealed by hepatic damage in a 71- and a 59-year old man. In the first case, the disease was revealed by febrile jaundice whereas, in the second case, results of liver tests showed cytolytic and cholestatic abnormalities with fever. Lyme disease is a zoonosis due to infection by Borrelia burdorferi transmitted by ticks. The multiple phases of the disease explain the polymorphism of the clinical manifestations. Usually, extrahepatic symptoms are first observed, including neurological tropisms of Borrelia burdorferi. On the contrary, hepatic impairment due to Lyme disease is rare, often asymptomatic and with biological manifestations only.

Low sensitivity of invasive tests for the detection of Helicobacter pylori infection in patients with bleeding ulcer

BACKGROUND

A high false negative rate for antral infection with Helicobacter pylori when assessed by rapid urease test has recently been reported in patients with bleeding ulcer. This result could partly explain the differing prevalence of H. pylori infection in bleeding and non-bleeding ulcers.

AIMS

To evaluate the accuracy of a rapid urease test (UT), histology and culture for detection of H. pylori in antral biopsies from acute bleeding peptic ulcer patients using a serological test as reference.

PATIENTS AND METHODS

All consecutive patients with active bleeding gastric or duodenal ulcer at endoscopic examination admitted in six university hospitals in France were considered for inclusion. Five antral biopsies were taken during the diagnostic endoscopy for UT, culture and histology. A blood sample was taken for H. pylori serology.

RESULTS

One hundred and eighty one patients were included and 129 (71%) had a positive serology. The sensitivity of UT, histology and culture for detection of H. pylori infection were 41%, 33% and 34%, respectively. The sensitivity and specificity of the combination of the three invasive tests were 48.8% (95% CI: 40.2-57.4) and 90.6% (95% CI: 82. 6-99) respectively. In the 52 serologically negative patients, only 5 had at least one invasive positive test. The sensitivity of the invasive tests decreased significantly with age but was not influenced by NSAIDs intake. Of 80 patients with a positive serological test and negative histological evaluation for H. pylori, chronic antral inflammation was found in 70 patients (87%). In 46 patients with both negative serological test and H. pylori negative test according to histology, only 13 (28%) had chronic antral inflammation.

CONCLUSIONS

The sensitivity of invasive tests for detection of H. pylori is low during acute ulcer bleeding, and they should be used with caution in this condition. A serological test is recommended to identify patients with H. pylori infection in spite of negative invasive tests.