Association between Dental Scores and Saliva Uremic Toxins.

Dental health is frequently altered in patients with chronic kidney disease. We conducted a prospective study on dental health in CKD patients with a specific interest in the association between dental health issues and the accumulation of uremic toxins in the saliva. A total of 88 patients were included in the study, with chronic kidney disease stage 2 to 5 (without kidney replacement). We analysed the total concentrations of eight uremic toxins (trimethylamine N-oxide -TMAO-, Indoxyl Sulfate, P-cresyl-sulfate, Indole 3-acetic acid, 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid -CMPF-, Kynurenine, Hippuric acid and Phenylacetylglutamine) and three precursors of uremic toxins (Tyrosine, Phenylalanine and Tryptophan) in the saliva using LC-MS/MS. We observed, for the first time, the association between various dental scores: DMFT, FST, CPITN, and OHIS, and saliva uremic toxins and precursors: TMAO, indoxyl sulfate, or hippuric acid. Further prospective interventional studies are required to confirm our results.

Renal involvement is frequent in adults with primary mitochondrial disorders: an observational study.

Background: Mitochondrial functions are controlled by genes of both mitochondrial and nuclear DNA. Pathogenic variants affecting any of these are responsible for primary mitochondrial disorders (MIDs), which can be diagnosed during adulthood. Kidney functions are highly dependent on mitochondrial respiration. However, the prevalence of MID-associated nephropathies (MIDANs) is unknown in the adult population. We aimed to address this point and to provide a full characterization of MIDANs in this population. Methods: We retrospectively included for observational study adults (≥16 years of age) with genetically diagnosed MID between 2000 and 2020 in our tertiary care academic centre when they had a chronic kidney disease (CKD) evaluation. MIDANs were ascertained by CKD occurring in MIDs. The phenotypic, biological, histopathological and genotypic characteristics were recorded from the medical charts. Results: We included 80 MID-affected adults and ascertained MIDANs in 28/80 (35%). Kidney diseases under the care of a nephrologist occurred in only 14/28 (50%) of the adults with MIDAN. MIDANs were tubulointerstitial nephropathy in 14/28 patients (50%) and glomerular diseases in 9/28 (32.1%). In adults with MID, MIDAN was negatively associated with higher albumin levels {odds ratio [OR] 0.79 [95% confidence interval (CI) 0.67-0.95]} and vision abnormalities [OR 0.17 (95% CI 0.03-0.94)] and positively associated with hypertension [OR 4.23 (95% CI 1.04-17.17)]. Conclusion: MIDANs are frequent among adult MIDs. They are mostly represented by tubulointerstitial nephropathy or glomerular disease. Vision abnormalities, hypertension and albumin levels were independently associated with MIDANs. Our results pave the way for prospective studies investigating the prevalence of MIDANs among undetermined kidney disease populations.

Correlation between Saliva Levels and Serum Levels of Free Uremic Toxins in Healthy Volunteers.

The objective of the present study was to investigate the putative correlation between the saliva concentration and free serum concentration for 10 uremic toxins (UTs; eight protein-bound solutes: 3-carboxy-4-methyl-5-propyl-2-furanpropanoic acid (CMPF), hippuric acid (HA), indole-3-acetic acid (3-IAA), indoxyl sulfate (I3S), kynurenic acid (KA), kynurenine (KYN), p-cresyl glucuronide (pCG), and p-cresyl sulfate (pCS); two free, water-soluble, low-molecular weight solutes: phenylacetylglutamine (PAGN) and trimethylamine N-oxide (TMAO); and three precursors: tyrosine (Tyr), phenylalanine, and tryptophan). Saliva samples and blood samples were collected simultaneously from 18 healthy volunteers. After the addition of internal standards, 50 µL of saliva or serum were precipitated with methanol. UTs and precursors were quantified using a validated LC-MS/MS method. The saliva-serum correlation was statistically significant (according to Spearman's coefficient) for six UTs (TMAO, HA, I3S, pCS, 3-IAA, and CMPF). Tyr presented a weak saliva-serum correlation (p = 0.08), whereas the other two precursors did not show a saliva-serum correlation. For three UTs (KYN, KA and pCG), we were unable to test the correlation since the saliva or serum levels were too low in many of the volunteers. The present study is the first to report on the saliva concentrations of TMAO, KYN, HA, PAGN, pCG, and 3-IAA.

À qui un néphrologue doit-il prescrire un iSGLT2 ? Indications of SGLT2 inhibitors in kidney disease: who, why and when?

Inhibitors of sodium glucose co-transporter type 2 (iSGLT2) constitute a considerable advance in the management of patients with diabetes, heart failure and with chronic kidney disease (CKD). Randomized controlled studies have shown a significant reduction of cardiovascular risk in diabetic type 2 and/or heart failure with reduced ejection fraction patients. These studies observed a risk reduction of worsening nephropathy, leading to randomized controlled studies in CKD patients : CREDENCE, DAPA-CKD and EMPA-KIDNEY. iSGLT2 are associated with a slower progression toward end-stage kidney disease, a lower slope of GFR and a lower rate of albuminuria. In CKD patients with proteinuria either diabetic or not, the DAPA-CKD and the EMPA-KIDNEY studies have demonstrated a nephroprotective effect. This effect has not been found for patients without proteinuria. For the other nephropathies, further studies are required to confirm results obtained in patients without type 2 diabetes and macroalbuminuria. Therefore, the indication of iSGLT2, with appropriate dose of RAS inhibitor, seems undeniable to an optimal nephroprotection in CKD patients with type 2 diabetes and/or albuminuria and/or heart failure. They must be prescribed in addition to conventional nephroprotective and cardioprotective treatments and care. Side effects are limited. However, special education and monitoring concerning risks of genital infection and euglycemic ketoacidosis (diabetic patients) must be taken in mind. The therapeutic arsenal for CKD patients is expanding, leading to consider a personalized care according to the underlying nephropathy. © 2022 Published by Elsevier Masson SAS on behalf of Société francophone de néphrologie, dialyse et transplantation.

Vascularization of Cell-Laden Microfibres by Femtosecond Laser Processing.

To face the increasing demand for organ transplantation, currently the development of tissue engineering appears as the best opportunity to effectively regenerate functional tissues and organs. However, these approaches still face the lack of an efficient method to produce an efficient vascularization system. To answer these issues, the formation of an intra-volume channel within a three-dimensional, scaffold free, mature, and cell-covered collagen microfibre is here investigated through laser-induced cavitation. An intra-volume channel was formed upon irradiation with a near-infrared, femtosecond laser beam, focused with a high numerical aperture lens. The laser beam directly crossed the surface of a dense and living-cell bilayer and was focused behind the bilayer to induce channel formation in the hydrogel core while preserving the cell bilayer. Channel formation was assessed through confocal microscopy. Channel generation inside the hydrogel core was enhanced by the formation of voluminous cavitation bubbles with a lifetime longer than 30 s, which also improved intra-volume channel durability. Twenty-four hours after laser processing, cellular viability dropped due to a lack of sufficient hydration for processing longer than 10 min. However, the processing automation could drastically reduce the cellular mortality, this way enabling the formation of hollowed microfibres with a high density of living-cell outer bilayer.

Long-term health-related quality of life outcomes of adults with pediatric onset of frequently relapsing or steroid-dependent nephrotic syndrome.

BACKGROUND: Long-term psychosocial outcomes and health-related quality of life (HRQOL) in adults with pediatric onset of frequently relapsing or steroid-dependent idiopathic nephrotic syndrome (FRNS or SDNS) remain to be determined. METHODS: In this prospective cohort study, 59 adults with pediatric onset of FRNS/SDNS and persistent active glomerular disease in adulthood completed the GEDEPAC-2 questionnaire exploring 11 well-being domains. Data were compared to the French general population (FGP) with standardized incidence ratio ([SIR]; adjusted for period, age, gender). Regression models were performed to identify predictive factors of psychosocial well-being. RESULTS: In 82% of cases, the questionnaire was completed while the participants (n = 59; 47 men; median age = 32 years; median number of relapses = 13) were in complete remission (under specific therapy in 76% of cases). Participants had higher educational degree than in the FGP (SIR = 6.3; p < 0.01) and more frequently a managerial occupation (SIR = 3.1; p < 0.01). Social integration was acceptable with regard to marital status and experience of sexual intercourse, but experiences of discrimination were far more frequent (SIR = 12.5; p < 0.01). The SF-12 mental component summary (MCS) score was altered (Z-score = - 0.6; p < 0.01) and mean multidimensional fatigue inventory (MFI-20) global fatigue score appeared high (12). Transfer from pediatric to adult healthcare was followed by a period of discontinued care for 33% of participants. Multivariate analysis revealed a close relationship between MFI-20, physical health, and MCS. CONCLUSIONS: This study shows that pediatric onset FRNS and SDNS may have a long-term negative impact on mental HRQOL and highlights the impact of fatigue, which is often not adequately considered in routine care.

Plasma creatinine below limit of quantification in a patient with acute kidney injury.

BACKGROUND: Acute kidney injury (AKI) is an infrequent complication of inflammatory bowel disease and can be exceptionally linked to interstitial nephritis secondary to anti-inflammatory drugs, such as Pentasa® (5-ASA). CASE PRESENTATION: We present an case of an 80-year-old man who presented chronic diarrheas treated by Pentasa®. He developed AKI, evidenced by high plasma creatinine dosed in his local laboratory. At the hospital admission, plasma creatinine was exceptionally undetectable by the enzymatic method while Jaffe's method successfully determined it. Creatinine measurement by the enzymatic method was gradually restored during hospital stay, concomitant with the discontinuation of 5-ASA administration, suggesting that this drug could interfere with creatinine enzymatic assay. Creatinine enzymatic assays combine serial reactions. The last one called Trinder reaction, catalyzed by a peroxidase, uses H2O2 to convert uncolored dye in a colored compound, proportionally to creatinine concentration. We showed that AKI related-plasma accumulation of 5-ASA, could participate in the negative interference observed on creatinine measurement, by scavenging H2O2. Interestingly, all Trinder reaction-based measurements (uric acid, lipase, lactate, triglycerides and cholesterol) were affected. Negative interference of 5-ASA was confirmed by interferogram experiments on all Trinder reaction-dependent assays. CONCLUSION: All Trinder-dependent parameters should be interpreted with the patient's treatment knowledge, in particular salicylate derivatives.

Contactin-1 is a novel target antigen in membranous nephropathy associated with chronic inflammatory demyelinating polyneuropathy.

Primary membranous nephropathy (MN) is an autoimmune glomerular disease in which autoantibodies are directed against podocyte proteins. In about 80% of cases the main targeted antigen is the phospholipase A2 receptor 1 (PLA2R1). Anti-PLA2R1 antibodies are mainly immunoglobulin G type 4 (IgG4). However, the antigenic target remains to be defined in 20% of cases. MN can be associated with chronic inflammatory demyelinating polyneuropathy, an autoimmune disease of the peripheral nervous system where a common antigenic target has yet to be identified. To ascertain a possible novel target antigen, we analyzed kidney biopsies from five patients positive for anti-contactin 1 antibodies and presenting with MN combined with chronic inflammatory demyelinating polyneuropathy. Eluted IgG from biopsy sections against contactin 1 and nerve tissue were screened. Western blot revealed contactin 1 expression in normal kidney glomeruli. Confocal microscopic analysis showed the presence and colocalization of contactin 1 and IgG4 on the glomerular basement membrane of these patients. Glomerular contactin 1 was absent in patients with anti-PLA2R1-associated MN or membranous lupus nephritis or a healthy control. The eluted IgG from contactin 1-positive biopsy sections but not the IgG eluted from patients with PLA2R1 MN bound contactin 1 with the main eluted subclass IgG4. Eluted IgG could bind paranodal tissue (myelinated axon) and colocalized with commercial anti-contactin 1 antibody. Thus, contactin 1 is a novel common antigenic target in MN associated with chronic inflammatory demyelinating polyneuropathy. However, the precise pathophysiology remains to be elucidated.

Incidence, prognostic impact and clinical outcomes of renal impairment in patients with multiple myeloma: a population-based registry.

BACKGROUND: Renal impairment (RI), a severe complication in multiple myeloma (MM), is considered as a poor prognostic factor. Patient survival has increased with the use of novel drugs and autologous stem-cell transplantation (ASCT). However, specific evolution of the incidence of RI in MM and its impact on prognosis remain unclear. METHODS: Using a population-based registry of 1038 newly diagnosed MM in Gironde, France, we evaluated the incidence trends of RI in MM patients and assessed net survival according to factors of interest using Pohar-Perme indicator and excess mortality rate regression. We also reviewed 114 cases of MM with RI to describe their clinical outcomes. RESULTS: In our population-based study, 24.6% of MM patients presented with RI (12.9% required haemodialysis). Median survival time was 21 months in patients with RI versus not reached at 3 years for other patients (P < 0.01). Age >73 years, RI, comorbidities and non-use of drugs or ASCT were associated with excess mortality risk. The effect of RI on excess mortality rates was maximum in the first 6 months after diagnosis. In the observational study, median follow-up time was 22.5 months; factors associated with renal response were haematologic response [odds ratio (OR) 6.81; P < 0.01] and previous chronic kidney disease (OR 0.26; P = 0.04). Factors associated with 1-year overall survival were haematological [hazard ratio (HR) 0.13; P < 0.01] and renal response (HR 0.27; P = 0.03). CONCLUSIONS: RI represents an independent negative prognostic factor in MM in the first 6 months after diagnosis. Renal recovery and haematologic response are the strongest markers associated with patient survival.

Intra-volume processing of gelatine hydrogel by femtosecond laser-induced cavitation.

Cell oxygenation and nutrition are crucial for the viability of tissue-engineered constructs, and different alternatives are currently being developed to achieve an adequate vascularisation of the engineered tissue. One of the alternatives is the generation of channel-like patterns in a bioconstruct. Here, the formation of full-formed channels inside hydrogels by laser-induced cavitation was investigated. A near-infrared, femtosecond laser beam focused with a high numerical aperture was employed to obtain intra-volume modifications of a block of gelatine hydrogel. Characterisation of the laser-processed gelatine was carried out by optical microscopy and epifluorescence microscopy right after and 24 h after the laser process. Rheology analyses on the unprocessed gelatine blocks were conducted to better understand the cavitation mechanism taking place during the intense laser interaction. Different cavitation patterns were observed at varying dose values by changing the repetition rate and the overlap between successive pulses while keeping the laser fluence and the number of passes fixed. This way, cavitation bubble features and behaviour can be controlled to optimise the formation of intra-volume channels in the gelatine volume. Results showed that the generation of fully formed channels was linked to the formation of large non-spherical cavitation bubbles during the laser interaction at high dose and low repetition rates. In conclusion, the formation of fully formed channels was made possible with a near-infrared, femtosecond laser beam strongly focused inside gelatine hydrogel blocks through laser-induced cavitation at high dose and low repetition rates.

Description of a multidisciplinary model of care in a French cohort of adult patients with tuberous sclerosis complex.

BACKGROUND: Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disorder. Due to the various manifestations of TSC and their potential complications, a multidisciplinary care approach is recommended by consensus guidelines. OBJECTIVES: Our study aimed to give a complete description of our TSC adult cohort and to evaluate the multidisciplinary and interdisciplinary management model. METHODS: Data on each adult patient diagnosed with TSC, including disease manifestations, interventions and outcomes, were collected at baseline and updated annually. A multidisciplinary TSC approach with all the recommended explorations was carried out annually. RESULTS: 90 patients were enrolled in Centre Hospitalier Universitaire de Bordeaux, between January 2000 and September 2018. Median age of patients at inclusion was 37 years (range, 27-47) and 20 years old at diagnosis of TSC. Regarding the occurrence of TSC manifestations, 97% of the patients had cutaneous lesions, 89% had neurological manifestations, 83% had renal manifestations and 100% had dental lesions with pits. More than half the patients had sclerotic bone lesions (68%), TSC-associated neuropsychiatric disorders (64%) and lymphangioleiomyomatosis (59%). A TSC multidisciplinary approach was developed including a global follow-up and an evaluation of TSC targeting organs, according to the recommendations. A satisfaction survey revealed global and entire satisfaction of patients with TSC. CONCLUSION: We obtained an accurate description of a cohort of adult patients with TSC. Our multidisciplinary approach model allowed us to provide optimal management of patients with TSC with a high level of patient satisfaction.

Characterization of acute kidney injury in critically ill patients with severe coronavirus disease 2019.

BACKGROUND: Coronavirus disease 2019 (COVID-19)-associated acute kidney injury (AKI) frequency, severity and characterization in critically ill patients has not been reported. METHODS: Single-centre cohort performed from 3 March 2020 to 14 April 2020 in four intensive care units in Bordeaux University Hospital, France. All patients with COVID-19 and pulmonary severity criteria were included. AKI was defined using Kidney Disease: Improving Global Outcomes (KDIGO) criteria. A systematic urinary analysis was performed. The incidence, severity, clinical presentation, biological characterization (transient versus persistent AKI; proteinuria, haematuria and glycosuria) and short-term outcomes were evaluated. RESULTS: Seventy-one patients were included, with basal serum creatinine (SCr) of 69 ± 21 µmol/L. At admission, AKI was present in 8/71 (11%) patients. Median [interquartile range (IQR)] follow-up was 17 (12-23) days. AKI developed in a total of 57/71 (80%) patients, with 35% Stage 1, 35% Stage 2 and 30% Stage 3 AKI; 10/57 (18%) required renal replacement therapy (RRT). Transient AKI was present in only 4/55 (7%) patients and persistent AKI was observed in 51/55 (93%). Patients with persistent AKI developed a median (IQR) urine protein/creatinine of 82 (54-140) (mg/mmol) with an albuminuria/proteinuria ratio of 0.23 ± 20, indicating predominant tubulointerstitial injury. Only two (4%) patients had glycosuria. At Day 7 after onset of AKI, six (11%) patients remained dependent on RRT, nine (16%) had SCr >200 µmol/L and four (7%) had died. Day 7 and Day 14 renal recovery occurred in 28% and 52%, respectively. CONCLUSION: Severe COVID-19-associated AKI is frequent, persistent, severe and characterized by an almost exclusive tubulointerstitial injury without glycosuria.

CD154 Induces Interleukin-6 Secretion by Kidney Tubular Epithelial Cells under Hypoxic Conditions: Inhibition by Chloroquine.

Inflammation is a major contributor to tubular epithelium injury in kidney disorders, and the involvement of blood platelets in driving inflammation is increasingly stressed. CD154, the ligand of CD40, is one of the mediators supporting platelet proinflammatory properties. Although hypoxia is an essential constituent of the inflammatory reaction, if and how platelets and CD154 regulate inflammation in hypoxic conditions remain unclear. Here, we studied the control by CD154 of the proinflammatory cytokine interleukin- (IL-) 6 secretion in short-term oxygen (O2) deprivation conditions, using the HK-2 cell line as a kidney tubular epithelial cell (TEC) model. IL-6 secretion was markedly stimulated by CD154 after 1 to 3 hours of hypoxic stress. Both intracellular IL-6 expression and secretion were stimulated by CD154 and associated with a strong upregulation of IL-6 mRNA and increased transcription. Searching for inhibitors of CD154-mediated IL-6 production by HK-2 cells in hypoxic conditions, we observed that chloroquine, a drug that has been repurposed as an anti-inflammatory agent, alleviated this induction. Therefore, CD154 is a potent early stimulus for IL-6 secretion by TECs in O2 deprivation conditions, a mechanism likely to take part in the deleterious inflammatory consequences of platelet activation in kidney tubular injury. The inhibition of CD154-induced IL-6 production by chloroquine suggests the potential usefulness of this drug as a therapeutic adjunct in conditions associated with acute kidney injury.

Chronic interstitial nephritis in agricultural communities is a toxin-induced proximal tubular nephropathy.

Almost 30 years after the detection of chronic interstitial nephritis in agricultural communities (CINAC) its etiology remains unknown. To help define this we examined 34 renal biopsies from Sri Lanka, El Salvador, India and France of patients with chronic kidney disease 2-3 and diagnosed with CINAC by light and electron microscopy. In addition to known histopathology, we identified a unique constellation of proximal tubular cell findings including large dysmorphic lysosomes with a light-medium electron-dense matrix containing dispersed dark electron-dense non-membrane bound "aggregates". These aggregates associated with varying degrees of cellular/tubular atrophy, apparent cell fragment shedding and no-weak proximal tubular cell proliferative capacity. Identical lysosomal lesions, identifiable by electron microscopy, were observed in 9% of renal transplant implantation biopsies, but were more prevalent in six month (50%) and 12 month (67%) protocol biopsies and in indication biopsies (76%) of calcineurin inhibitor treated transplant patients. The phenotype was also found associated with nephrotoxic drugs (lomustine, clomiphene, lithium, cocaine) and in some patients with light chain tubulopathy, all conditions that can be directly or indirectly linked to calcineurin pathway inhibition or modulation. One hundred biopsies of normal kidneys, drug/toxin induced nephropathies, and overt proteinuric patients of different etiologies to some extent could demonstrate the light microscopic proximal tubular cell changes, but rarely the electron microscopic lysosomal features. Rats treated with the calcineurin inhibitor cyclosporine for four weeks developed similar proximal tubular cell lysosomal alterations, which were absent in a dehydration group. Overall, the finding of an identical proximal tubular cell (lysosomal) lesion in CINAC and calcineurin inhibitor nephrotoxicity in different geographic regions suggests a common paradigm where CINAC patients undergo a tubulotoxic mechanism similar to calcineurin inhibitor nephrotoxicity.

Towards an in vitro model of the glomerular barrier unit with an innovative bioassembly method.

BACKGROUND: The development of an artificial glomerular unit may be pivotal for renal pathophysiology studies at a multicellular scale. Using a tissue engineering approach, we aimed to reproduce in part the specific glomerular barrier architecture by manufacturing a glomerular microfibre (Mf). METHODS: Immortalized human glomerular cell lines of endothelial cells (GEnCs) and podocytes were used. Cells and a three-dimensional (3D) matrix were characterized by immunofluorescence with confocal analysis, Western blot and polymerase chain reaction. Optical and electron microscopy were used to study Mf and cell shapes. We also analysed cell viability and cell metabolism within the 3D construct at 14 days. RESULTS: Using the Mf manufacturing method, we repeatedly obtained a cellularized Mf sorting human glomerular cells in 3D. Around a central structure made of collagen I, we obtained an internal layer composed of GEnC, a newly formed glomerular basement membrane rich in α5 collagen IV and an external layer of podocytes. The cell concentration, optimal seeding time and role of physical stresses were modulated to obtain the Mf. Cell viability and expression of specific proteins (nephrin, synaptopodin, vascular endothelial growth factor receptor 2 (VEGFR2) and von Willebrandt factor (vWF)) were maintained for 19 days in the Mf system. Mf ultrastructure, observed with EM, had similarities with the human glomerular barrier. CONCLUSION: In summary, with our 3D bio-engineered glomerular fibre, GEnC and podocytes produced a glomerular basement membrane. In the future, this glomerular Mf will allow us to study cell interactions in a 3D system and increase our knowledge of glomerular pathophysiology.

Adult onset tubulo-interstitial nephropathy in MT-ND5-related phenotypes.

Kidney is a highly adenosine triphosphate dependent organ in human body. Healthy and functional mitochondria are essential for normal kidney function. Clinical and genetic variability are the hallmarks of mitochondrial disorders. We report here the involvement of two MT-ND5 pathogenic variants encoding for ND5 subunit of respiratory chain complex I, the m.13513G>A and the m.13514A>G, in adult-onset kidney disease in three unrelated patients. The first patient had myopathy encephalopathy lactic acidosis and stroke syndrome, left ventricular hypertrophy with Wolff-Parkinson-White syndrome and tubulo-interstitial kidney disease. The second presented Leber hereditary optic neuropathy associated with tubulo-interstitial kidney disease. The third presented with an isolated chronic tubulo-interstitial kidney disease. These mutations have never been associated with adulthood mitochondrial nephropathy. These case reports highlight the importance to consider mitochondrial dysfunction in tubulo-interstitial kidney disease.