Nonskeletal and skeletal effects of high doses versus low doses of vitamin D3 in renal transplant recipients: Results of the VITALE (VITamin D supplementation in renAL transplant recipients) study, a randomized clinical trial

Vitamin D sufficiency is associated with a reduced risk of fractures, diabetes mellitus, cardiovascular events, and cancers, which are frequent complications after renal transplantation. The VITALE (VITamin D supplementation in renAL transplant recipients) study is a multicenter double-blind randomized trial, including nondiabetic adult renal transplant recipients with serum 25-hydroxy vitamin D (25(OH) vitamin D) levels of <30 ng/mL, which is randomized 12 to 48 months after transplantation to receive high (100 000 IU) or low doses (12 000 IU) of cholecalciferol every 2 weeks for 2 months and then monthly for 22 months. The primary outcome was a composite endpoint, including diabetes mellitus, major cardiovascular events, cancer, and death. Of 536 inclusions (50.8 [13.7] years, 335 men), 269 and 267 inclusions were in the high-dose and low-dose groups, respectively. The serum 25(OH) vitamin D levels increased by 23 versus 6 ng/mL in the high-dose and low-dose groups, respectively (P < .0001). In the intent-to-treat analysis, 15% versus 16% of the patients in the high-dose and low-dose groups, respectively, experienced a first event of the composite endpoint (hazard ratio, 0.94 [0.60-1.48]; P = .78), whereas 1% and 4% of patients in the high-dose and low-dose groups, respectively, experienced an incident symptomatic fracture (odds ratio, 0.24 [0.07-0.86], P = .03). The incidence of adverse events was similar between the groups. After renal transplantation, high doses of cholecalciferol are safe but do not reduce extraskeletal complications (trial registration: ClinicalTrials.gov; identifier: NCT01431430).

Humoral response to a third injection of BNT162b2 vaccine in patients on maintenance haemodialysis

BACKGROUND

Humoral response against sudden acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after two doses of BNT162b2 (Pfizer-BioNTech) has been proven to be less intense in maintenance dialysis patients as compared with healthy subjects, leading the French authorities to recommend a third injection in this population. Here we investigated the response to the third injection in two cohorts of haemodialysis (HD) patients.

METHODS

Data from two prospective observational cohorts were collected. In the first ('systematic') cohort, patients from two HD centres (n = 66) received a third injection of BNT162b2, regardless of the response after two injections. In the second ('conditional') cohort, the injection was only prescribed to patients (n = 34) with no or low response to the previous two doses. In both cohorts, the third dose was injected 1-2 months after the second dose. Serology was performed after the second and third doses to assess anti-Spike immunoglobulin G (S IgG) antibody titre.

RESULTS

In the systematic cohort, anti-S IgG was found in 83.3 and 92.4% of patients after the second and third doses of BNT162b2, respectively. In this cohort, 6/11 (54.5%) and 20/21 (95.2%) patients switched from non-responder to low responder and from low responder to high responder, respectively. In low and high responders to two doses, 50/55 (90.9%) at least doubled their anti-S IgG titre. Similar trends were observed in the conditional cohort.

CONCLUSIONS

In maintenance HD patients, humoral response against SARS-CoV-2 was boosted after a third dose of BNT162b2, allowing seroconversion in more than half of non-responders. These data may support an intensified vaccination protocol with a third dose of BNT162b2 in dialysis patients.

Retrospective and Systematic Analysis of Causes and Outcomes of Thrombotic Microangiopathies in Routine Clinical Practice: An 11-Year Study

Background: Thrombotic microangiopathies (TMAs) are highly suspected in patients showing mechanical hemolytic anemia, thrombocytopenia, and haptoglobin consumption. Primary [thrombotic thrombocytopenic purpura (TTP) and atypical hemolytic uremic syndrome] and secondary TMA are considered. Even if ADAMTS13 measurements and alternative complement pathway explorations have greatly improved the ability to identify primary TMA, their diagnosis remains difficult, and their frequency relative to that of secondary TMA is undetermined. The objectives of the present study were, therefore, to describe the etiologies, management, and the outcomes of patients presenting with TMA in real-life clinical practice.

Methods: We conducted a retrospective study between 01/01/2008 and 31/12/2018 that included all consecutive patients presenting with biological TMA syndrome at admission or developing during hospitalization. Patients were identified from the laboratory databases, and their medical files were reviewed to confirm TMA diagnosis, to determine etiology, and to analyze their therapeutic management and outcomes.

Results: During this period, 239 patients with a full TMA biological syndrome were identified, and the TMA diagnosis was finally confirmed in 216 (90.4%) after the cases were reviewed. Primary TMAs (thrombotic thrombocytopenic purpura or atypical hemolytic uremic syndrome) were diagnosed in 20 of 216 patients (9.3%). Typical HUS was diagnosed in eight patients (3.7%), and the most frequent secondary TMAs were HELLP syndrome (79/216, 36.6%) and active malignancies (30/219, 13.9%). ADAMTS13 measurements and alternative complement pathway analyses were performed in a minority of patients. Multiple factors identified as TMA triggers were present in most patients, in 55% of patients with primary TMA, vs. 44.7% of patients with secondary TMA (p = 0.377). Death occurred in 57 patients (23.4%) during follow-up, and dialysis was required in 51 patients (23.6%). Active malignancies [odds ratio (OR) 13.7], transplantation (OR 4.43), male sex (OR 2.89), and older age (OR 1.07) were significantly associated with death.

Conclusion: Secondary TMAs represent many TMA causes in patients presenting a full TMA biological syndrome during routine clinical practice. Multiple factors favoring TMA are present in about half of primary or secondary TMA. ADAMTS13 and complement pathway were poorly explored in our cohort. The risk of death is particularly high in patients with malignancies as compared with patients with other TMA.

Incidence and Risk Factors of Venous Thromboembolic Events in Patients with ANCA-Glomerulonephritis: A Cohort Study from the Maine-Anjou Registry

(1) Introduction: The incidence of venous thromboembolisms (VTE) has not been extensively analyzed in patients with antineutrophil cytoplasmic antibody (ANCA)-glomerulonephritis (ANCA-GN). Thus, the aim of the present study was to assess the frequency and the risk factors of VTE in patients with ANCA-GN. (2) Methods: Patients from the Maine-Anjou ANCA-associated vasculitis (AAV) registry with a biopsy showing pauci-immune glomerulonephritis were included. VTE events, site, and interval from AAV diagnosis were analyzed. (3) Results: 133 patients fulfilled the inclusion criteria of the study and were analyzed. VTE episodes were diagnosed in 23/133 (17.3%) patients at a median delay of 3 months from ANCA-GN diagnosis. Patients with VTE had lower serum albumin (p = 0.040), were less frequently on statin therapy (p = 0.009) and had less frequently proteinase-3 (PR3)-ANCAs (p = 0.078). Univariate analysis identified higher age (p = 0.022), lower serum albumin (p = 0.030), lack of statin therapy (p = 0.009), and rituximab treatment (p = 0.018) as significant risk factors of VTE. In multivariate analysis, only lack of statin therapy (HR 4.873; p = 0.042) was significantly associated with VTE. (4) Conclusion: Patients with ANCA-GN are at high risk of VTE, especially within the first months following AAV diagnosis. Our results suggest that statin therapy is associated with a lower risk of VTE in ANCA-GN patients.

Renal biopsy in very elderly patients (over 80 years): clinical presentation, histological diagnosis, and long-term outcome

PURPOSE

Data regarding the long-term outcome of very elderly (VE) patients undergoing renal biopsy (RB) are lacking. The objective of this study was to analyse the outcome of VE patients undergoing RB.

METHODS

All patients over 65 years that underwent native RB between 2004 and 2016 in our center were included. Among the 206 included patients, those over 80 years (VE, 46 patients) were analysed and compared to those aged 65-80 years (160 patients). The outcomes of the VE group were analysed.

RESULTS

Baseline characteristics, renal presentation, safety of RB and RB-related diagnosis were not different between VE patients and 65-80-year-old patients. Survival of VE patients was 73.1, 50.6 and 21.8% at 2, 4 and 6 years after RB, significantly poorer than those of 65-80-year-old group. Early death (< 1 year) occurred in 10 VE patients, was associated with a higher proteinuria-to-creatininuria ratio and tended to be associated with a more frequent dialysis need at RB. Of the 46 VE patients, 31 (67.4%) were diagnosed with a potentially reversible kidney disease, of whom 17 (40%) were started on immunosuppressive regimens. Survival of patients with a reversible kidney disease tended to be better than those with other diseases.

CONCLUSION

RB appears as a safe and valuable procedure to assess diagnosis of kidney disease in VE patients. Our data suggest that RB is critical for the identification and treatment decision of patients with potentially reversible diseases and may translate in clinical improvement.

Spontaneous resurgence of conditioned fear weeks after successful extinction in brain injured mice

Mild traumatic brain injury (TBI) is a major risk factor for post-traumatic stress disorder (PTSD), and both disorders share common symptoms and neurobiological defects. Relapse after successful treatment, known as long-term fear resurgence, is common in PTSD patients and a major therapeutic hurdle. We induced a mild focal TBI by controlled cortical impact (CCI) in male C57BL/6 J mice and used fear conditioning to assess PTSD-like behaviors and concomitant alterations in the fear circuitry. We found for the first time that mild TBI, and to a lesser extent sham (craniotomy), mice displayed a spontaneous resurgence of conditioned fear when tested for fear extinction memory recall, despite having effectively acquired and extinguished conditioned fear 6 weeks earlier in the same context. Other characteristic symptoms of PTSD are risk-taking behaviors and cognitive deficits. CCI mice displayed risk-taking behaviors, behavioral inflexibility and reductions in processing speed compared to naïve mice. In conjunction with these changes there were alterations in amygdala morphology 3 months post-trauma, and decreased myelin basic protein density at the primary lesion site and in distant secondary sites such as the hippocampus, thalamus, and amygdala, compared to sham mice. Furthermore, activity-dependent brain-derived neurotrophic factor (BDNF) transcripts were decreased in the prefrontal cortex, a key region for fear extinction consolidation, following fear extinction training in both TBI and, to a lesser extent, sham mice. This study shows for the first time that a mild brain injury can generate a spontaneous resurgence of conditioned fear associated with defective BDNF signalling in the prefrontal cortex, PTSD-like behaviors, and have enduring effects on the brain.

Cost-Minimisation Analysis of Erythropoiesis-Stimulating Agents in the Treatment of Anaemia in Dialysed Patients: A Pilot Study

OBJECTIVE

This study aimed to assess the cost impact of administering erythropoiesis-stimulating agents once every 4 weeks instead of one to three times a week to treat anaemia in patients undergoing dialysis.

METHODS

This was a monocentric retrospective study involving 27 patients who underwent haemodialysis between 2009 and 2013 in a university hospital in Angers, France. The study was a cost-minimisation analysis from the hospital perspective. Only direct medical costs were considered.

RESULTS

This study demonstrated that therapeutic management of anaemia with methoxy polyethylene glycol-epoetin beta would save medical and nurse time (7 days and 15 days per year, respectively) and reduce costs by €59,960 a year for an active file of 40 patients undergoing haemodialysis, assuming a 100% occupancy rate in the above-mentioned hospital.

CONCLUSION

This study indicated that treating anaemia by administering erythropoiesis-stimulating agents once every 4 weeks instead of one to three times a week in patients undergoing haemodialysis would be beneficial for the hospital.

Total Artificial Heart and Chronic Haemodialysis: A Possible Bridge to Transplantation?

BACKGROUND

Total artificial heart (TAH) device is sometimes necessary to treat end stage heart failure (HF). After surgery, renal impairment can occur with the need of renal replacement therapy.

METHOD

We report the case of a 51-year-old man who was treated with conventional hemodialysis (HD) while on support with TAH.

RESULTS

The patient underwent HD while on TAH support during 14 months. He benefited from conventional HD, 6 sessions per week. HD sessions were well tolerated, and patient's condition and quality of life improved significantly. The main difficulty was to maintain red blood cell level because of chronic hemolysis due to TAH, which required repetitive blood transfusions, resulting in a high rate of human leukocyte antigen sensitization. Unfortunately, the patient died of mesenteric ischemia due to anticoagulation under dosing.

CONCLUSION

We conclude that HD treatment is possible despite TAH and should be considered in patients with both end stage renal and HF.

[Type 2 diabetes and eating disorders]

Patients with type 2 diabetes are expected to follow numerous dietary recommendations which can be difficult to adhere to in the long-term. However, to improve the balance of their diabetes and avoid complications, it is important to lose weight and restore a healthy relationship with food. A dietary approach combining therapeutic education principles and a bio-psycho-sensorial approach can be useful in this context.

Thrombotic microangiopathy due to acquired ADAMTS13 deficiency in a patient receiving interferon-beta treatment for multiple sclerosis

Thrombotic microangiopathies (TMAs) can be due to inherited or acquired ADAMTS13 deficiency. Acquired deficiency is mainly associated with autoantibodies directed to ADAMTS13, including drug-induced forms. A few cases of TMA have been reported in association with interferon-alpha treatment and more rarely with interferon-beta. We report the case of a 52-year-old male with TMA-associated severe renal failure secondary to severe ADAMTS13 deficiency due to an anti-ADAMTS13 IgG antibody which developed after interferon-beta treatment for multiple sclerosis. Treatment included interferon-beta discontinuation, immediate plasma exchange therapy, corticosteroids, and hemodialysis. After an initial hematologic improvement, early hemolysis relapse led us to introduce rituximab allowing durable hematologic recovery. This is the first reported case of interferon-beta-induced TMA due to acquired ADAMTS13 deficiency that was treated by rituximab.

An unexpected cause of progressive renal failure in a 66-year-old male after liver transplantation: secondary hyperoxaluria

BACKGROUND

Hyperoxaluria is a rare metabolic disorder characterized by calcium oxalate deposition in different tissues. It is caused either by an inherited disease of oxalate metabolism [primary hyperoxalurias (PH)] or by an acquired disturbance (secondary hyperoxaluria).

CASE

We report here an atypical presentation of enteric hyperoxaluria-induced renal failure that occurred after liver transplantation. Despite adapted treatment and intensive haemodialysis, the patient did not recover. This case allows the reviewing of the multiple pathophysiological mechanisms involved in this disease.

CONCLUSION

Oxalate nephropathy should be considered in the differential diagnosis of acute renal failure, especially when previous renal impairment and fat malabsorption are present. We suggest performing renal biopsy early to allow a prompt diagnosis and therapeutic intervention.

Cre/loxP-mediated chromosome engineering of the mouse genome

Together with numerous other genome modifications, chromosome engineering offers a very powerful tool to accelerate the functional analysis of the mammalian genome. The technology, based on the Cre/loxP system, is used more and more in the scientific community in order to generate new chromosomes carrying deletions, duplications, inversions and translocations in targeted regions of interest. In this review, we will present the basic principle of the technique either in vivo or in vitro and we will briefly describe some applications to provide highly valuable genetic tools, to decipher the mammalian genome organisation and to analyze human diseases in the mouse.

Effects of tetrahydrofolate polyglutamates on the kinetic parameters of serine hydroxymethyltransferase and glycine decarboxylase from pea leaf mitochondria

Plant tissues contain highly conjugated forms of folate. Despite this, the ability of plant folate-dependent enzymes to utilize tetrahydrofolate polyglutamates has not been examined in detail. In leaf mitochondria, the glycine-cleavage system and serine hydroxymethyltransferase, present in large amounts in the matrix space and involved in the photorespiratory cycle, necessitate the presence of tetrahydrofolate as a cofactor. The aim of the present work was to determine whether glutamate chain length (one to six glutamate residues) influenced the affinity constant for tetrahydrofolate and the maximal velocities displayed by these two enzymes. The results show that the affinity constant decreased by at least one order of magnitude when the tetrahydrofolate substrate contained three or more glutamate residues. In contrast, maximal velocities were not altered in the presence of these substrates. These results are consistent with analyses of mitochondrial folates which revealed a pool of polyglutamates dominated by tetra and pentaglutamates. The equilibrium constant of the serine hydroxymethyltransferase suggests that, during photorespiration, the reaction must be permanently pushed toward the formation of serine (the unfavourable direction) to allow the recycling of tetrahydrofolate necessary for the operation of the glycine decarboxylase T-protein.