Tubulointerstitial nephritis: diagnosis, treatment, and monitoring

Immunohistological analysis reveals IgG1-dominant immunophenotype of tubulointerstitial nephritis unassociated with IgG4-related diseases

PURPOSE

Tubulointerstitial nephritis (TIN) has various etiologies, including IgG4-related disease (IgG4-RD), autoimmune diseases, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), and others. IgG4-positive plasma cell infiltration can occasionally be found in TIN unrelated to IgG4-RD. Therefore, there may be problems with usage of IgG4 immunostaining to differentiate between TIN with and TIN without IgG4-RD. This study aimed to compare the proportion of plasma cells that are positive for each IgG subclass and to clarify the predominant IgG subclass trends and clinical characteristics associated with IgG4-RD and non-IgG4-related interstitial nephritis.

METHODS

The study enrolled 44 cases of TIN: 6 of IgG4-RD, 8 of autoimmune disease, 9 of AAV, and 21 of unknown disease group. In addition to clinical characteristics, IgG subclass composition of interstitial plasma cells was evaluated among 4 groups by immunohistochemistry.

RESULTS

IgG1 was the predominant IgG subclass in TIN unrelated to IgG4-RD. In the IgG4-RD group, the IgG subclass rate was high in both IgG1 and IgG4. The rate of average IgG4-positive cells was significantly lower in the autoimmune disease group and unknown disease group compared with the IgG4-RD group.

CONCLUSION

The present study revealed IgG1-dominant immune profiles of TIN unrelated to IgG4-RD. Further investigation is required to elucidate the clinicopathological differences between IgG1-dominant and IgG4-dominant groups in IgG4-RD.

Hospital registration of adverse drug reactions in electronic health records: importance and contribution to pharmacovigilance

BACKGROUND

Information on registered adverse drug reactions (ADRs) in hospitals may provide a large real-world data source that can be used to ensure patients' safety. This study aimed to assess the potential contribution of hospital registration of ADRs in electronic health records (EHR) to pharmacovigilance.

RESEARCH DESIGN AND METHODS

An observational retrospective descriptive study using data from the Jeroen Bosch Hospital in the Netherlands in 2019. 'Serious and/or severe' and 'previously unknown' ADRs registered systematically in the corresponding field of EHRs were assessed.

RESULTS

ADR data concerning 1010 patients were included. In total, 1630 ADRs were registered in EHRs. Fifty-eight serious and/or severe ADRs (5.2%) were registered. Tubulointerstitial nephritis was the most frequently registered severe ADR and was mainly associated with antibacterials for systemic use. A total of 82 previously unknown ADRs (5%) were registered. 'Migraine' and 'chest pain' were the most frequently registered unknown ADRs. Additionally, 25 ADRs (1.5%) were registered that may be attributable to 10 drugs 'under additional monitoring.'

CONCLUSIONS

Hospital registrations of ADRs in EHRs provide information on ADRs, which are challenging to assess during clinical trials. However, improvements are required to optimize this registration before it can serve as a valuable data source for pharmacovigilance purposes.

Diet and risk for acute tubulointerstitial nephritis

Uncertainty exists regarding the association between diet and acute tubulointerstitial nephritis. Dietary factors served as exposures, including intake of alcohol, beef, non-oily fish, fresh fruit, oily fish, dried fruit, coffee, salad/raw vegetable, cereal, tea, water, salt, cooked vegetable, cheese, poultry, pork, Lamb/mutton, bread, and processed meat were extracted from the UK Biobank. Acute tubulointerstitial nephritis served as the outcome extracted from the FinnGen biobank. The 3 main methods of this analysis were weighted median, inverse-variance-weighted (IVW), and MR-Egger methods. The heterogeneity was measured employing Cochran Q test. The MR-PRESSO method was employed to identify possible outliers. The robustness of the IVW method was evaluated by employing the leave-one-out analysis. According to the IVW method, processed meat intake (OR = 0.485; P = .00152), non-oily fish intake (OR = 0.396; P = .0454), oily fish intake (OR = 0.612; P = .00161), and dried fruit intake (OR = 0.536; P = .00648) reduced the risk of acute tubulointerstitial nephritis. Other dietary factors were not shown to be causally related to acute tubulointerstitial nephritis. This study revealed that intake of processed meat, non-oily fish, oily fish, and dried fruit all decreased the risk of acute tubulointerstitial nephritis.

Renal Proximal Tubule Cell-specific Megalin Deletion Does Not Affect Atherosclerosis But Induces Tubulointerstitial Nephritis in Mice Fed Western Diet

Background

Pharmacological inhibition of megalin (also known as low-density lipoprotein receptor-related protein 2: LRP2) attenuates atherosclerosis in hypercholesterolemic mice. Since megalin is abundant in renal proximal tubule cells (PTCs), the purpose of this study was to determine whether PTC-specific deletion of megalin reduces hypercholesterolemia-induced atherosclerosis in mice.

Methods

Female Lrp2 f/f mice were bred with male Ndrg1-Cre ERT2 +/0 mice to develop PTC-LRP2 +/+ and -/- littermates. To study atherosclerosis, all mice were to bred to an LDL receptor -/- background and fed a Western diet to induce atherosclerosis.

Results

PTC-specific megalin deletion did not attenuate atherosclerosis in LDL receptor -/- mice in either sex. Serendipitously, we discovered that PTC-specific megalin deletion led to interstitial infiltration of CD68+ cells and tubular atrophy. The pathology was only evident in male PTC-LRP2 -/- mice fed the Western diet, but not in mice fed a normal laboratory diet. Renal pathologies were also observed in male PTC-LRP2 -/- mice in an LDL receptor +/+ background fed the same Western diet, demonstrating that the renal pathologies were dependent on diet and not hypercholesterolemia. By contrast, female PTC-LRP2 -/- mice had no apparent renal pathologies. In vivo multiphoton microscopy demonstrated that PTC-specific megalin deletion dramatically diminished albumin accumulation in PTCs within 10 days of Western diet feeding. RNA sequencing analyses demonstrated the upregulation of inflammation-related pathways in kidney.

Conclusions

PTC-specific megalin deletion does not affect atherosclerosis, but leads to tubulointerstitial nephritis in mice fed Western diet, with severe pathologies in male mice.

Fluocinolone acetonide 0.2 µg/day intravitreal implant in non-infectious uveitis affecting the posterior segment: EU expert user panel consensus-based clinical recommendations

BACKGROUND

Non-infectious uveitis affecting the posterior segment of the eye (NIU-PS) is an inflammatory disease, which can significantly impair visual acuity if not adequately treated. Fluocinolone-acetonide sustained-release-0.2 µg/day intravitreal (FAc) implants are indicated for prevention of relapse in recurrent NIU-PS. The aim here was to provide treating clinicians with some consensus-based-recommendations for the clinical management of patients with NIU-PS with 0.2 µg/day FAc implants.

METHODS

A European-clinical-expert-group agreed to develop a consensus report on different issues related to the use of FAc implants in patients with NIU-PS.

RESULTS

The Clinical-expert-panel provided specific recommendations focusing on clinical presentation (unilateral/bilateral) of the NIU-PS; systemic involvement of NIU-PS and the lens status. Treatment algorithms were developed; one that refers to the management of patients with NIU-PS in clinical practice and another that establishes the best clinical scenarios for the use of FAc implants, both as monotherapy and as adjuvant therapy. Additionally, the Clinical-expert-panel has provided recommendations about the use of the FAc implants in a clinical-setting. The Clinical-expert-panel also considered the safety profile of FAc implants and their possible implications in the daily practice.

CONCLUSIONS

As more clinical experience has been gained using FAc implants, it was necessary to update the clinical recommendations that guide patient management in the clinic. The current consensus document addresses relevant issues related to the use of FAc implants on different types of patients with various etiologies of NIU-PS, and was conducted to standardize approaches to help specialists obtain better clinical outcomes.

Targeting immune cell glutamyl-prolyl-transfer RNA synthetase 1 (EPRS1) to prevent fibrosis after tubulointerstitial nephritis

Glutamyl-prolyl-transfer RNA synthetase 1 is an enzyme that connects glutamic acid and proline to transfer RNA during protein synthesis. In this issue, a study by Kang et al. examined the role of the immune cell glutamyl-prolyl-transfer RNA synthetase 1 in toxin-induced tubulointerstitial nephritis mice. The study demonstrated that blocking glutamyl-prolyl-transfer RNA synthetase 1 may be a therapeutic target to attenuate fibrosis after toxin-induced tubulointerstitial nephritis.

The Impact of ABCC2 -24C>T Gene Polymorphism on Graft Survival in Kidney Transplant Recipients

Personalized medicine in kidney transplantation has the potential to improve outcomes and reduce complications. The aim of this study was to investigate the influence of single nucleotide polymorphisms in genes encoding metabolizing enzymes (CYP3A5) and transporters (ABCC2) on clinical outcomes (acute graft failure and/or acute tubular necrosis (ATN)) in kidney transplant recipients (KTR). This was a multicenter, retrospective cohort study where adult KTR who had undergone kidney transplantation between 2020 and 2021 and received tacrolimus-mycophenolate treatment were enrolled in the study. DNA was extracted from collected blood samples using a commercially available kit. CYP3A5*3, ABCC2 -24C>T and ABCC2 3972C>T SNP were determined by polymerase chain reaction. Of the total 39 patients included, nine (23.1%) KTR had an incidence of acute graft failure and/or ATN. A multiple logistic regression showed wildtype ABCC2 -24C>T C allele had a higher risk of developing acute graft rejection and/or ATN compared to the variant allele carriers (adjusted Odd Ratios [aOR]: 27.675, p = 0.038). Recipients who had delayed graft function (aOR: 49.214, p = 0.012) and a history of CMV infection (aOR: 18.097, p = 0.009) were at 49.2 and 18.1-times increased risk for acute graft failure and/or ATN, respectively. The large aOR was inevitable due to the small sample size and required cautious interpretation. This is the first study to determine the effect of the ABCC2 -24C>T genetic polymorphism on clinical outcomes in Malaysian KTR and forms the basis for further work on ABCC2 -24C>T effects in long-term KTR.

Tubulointerstitial Nephritis and Uveitis: A Case Report

Tubulointerstitial nephritis and uveitis (TINU) is a rare disease of unknown pathogenesis that is characterized by tubulointerstitial nephritis and uveitis. Currently, there are over 250 reported cases of TINU syndrome. TINU syndrome typically presents with mild uveitis and nephritis that is self-limited; however, in this case, the symptoms were severe making it different from previous case reports. We present a case of a 29-year-old female with a history of cytomegalovirus (CMV) with a recent diagnosis of bilateral uveitis who was admitted for worsening systemic symptoms. Laboratory testing revealed acute renal insufficiency along with hematuria and proteinuria. A kidney biopsy revealed tubulointerstitial nephritis, and the patient was initiated on corticosteroids for the diagnosis of TINU. The patient's renal function recovered to baseline after a prolonged three-month course of systemic steroids but had a recurrence of her uveitis with steroid taper requiring initiation of steroid-sparing therapies. TINU syndrome should be considered in patients presenting with uveitis and renal dysfunction. Prompt diagnosis is necessary to preserve renal function with corticosteroids. The prognosis for patients with TINU is variable, with a frequently recurring and relapsing course. More research is needed to determine the optimal treatment.

New-Onset Acute Interstitial Nephritis Post-SARS-CoV-2 Infection and COVID-19 Vaccination: A Panoramic Review

The 2019 coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) has posed a considerable challenge to global healthcare. Acute interstitial nephritis (AIN) post SARS-CoV-2 infection and vaccination has been reported, but its clinical features and pathogenesis remained unclear. We reviewed so far the largest 22 cases of AIN post SARS-CoV-2 infection and 36 cases of AIN following COVID-19 vaccination. The onset of AIN was mainly related to messenger RNA vaccines (52.8%). Apart from fever, proteinuria (45.5%) was the main manifestation of AIN post SARS-CoV-2 infection, left acute kidney injury (AKI, 63.9%) in patients post COVID-19 vaccination. The potential mechanism of vaccination induced AIN was conjugating vaccines with proteins to form a hapten, which activated dendritic cells and promoted a cascade immunological reaction leading to AIN.

Automated evaluation with deep learning of total interstitial inflammation and peritubular capillaritis on kidney biopsies

BACKGROUND

Interstitial inflammation and peritubular capillaritis are observed in many diseases on native and transplant kidney biopsies. A precise and automated evaluation of these histological criteria could help stratify patients' kidney prognoses and facilitate therapeutic management.

METHODS

We used a convolutional neural network to evaluate those criteria on kidney biopsies. A total of 423 kidney samples from various diseases were included; 83 kidney samples were used for the neural network training, 106 for comparing manual annotations on limited areas to automated predictions, and 234 to compare automated and visual gradings.

RESULTS

The precision, recall and F-score for leukocyte detection were, respectively, 81%, 71% and 76%. Regarding peritubular capillaries detection the precision, recall and F-score were, respectively, 82%, 83% and 82%. There was a strong correlation between the predicted and observed grading of total inflammation, as for the grading of capillaritis (r = 0.89 and r = 0.82, respectively, all P < .0001). The areas under the receiver operating characteristics curves for the prediction of pathologists' Banff total inflammation (ti) and peritubular capillaritis (ptc) scores were respectively all above 0.94 and 0.86. The kappa coefficients between the visual and the neural networks' scores were respectively 0.74, 0.78 and 0.68 for ti ≥1, ti ≥2 and ti ≥3, and 0.62, 0.64 and 0.79 for ptc ≥1, ptc ≥2 and ptc ≥3. In a subgroup of patients with immunoglobulin A nephropathy, the inflammation severity was highly correlated to kidney function at biopsy on univariate and multivariate analyses.

CONCLUSION

We developed a tool using deep learning that scores the total inflammation and capillaritis, demonstrating the potential of artificial intelligence in kidney pathology.

[Acute interstitial nephritis and hantavirus infection]

Acute interstitial nephritis (AIN) is a cause of acute kidney injury and characterized by an inflammation of the tubulointerstitial space, leading to a decline in kidney function. Multiple etiologies can cause AIN including medications, autoimmune diseases and infections. A multiplicity of drugs is associated with AIN, while antibiotics (especially beta-lactams), proton-pump inhibitors (PPI) and non-steroidal anti-inflammatory agents (NSAIDs) are the most common. The pathognomonic triad of exanthema, fever and eosinophilia is rarely present in AIN patients. Treatment of medication-associated AIN is based upon the discontinuation of the provoking drug. Glucocorticoids can be considered in severe cases.Nephropathia epidemica (NE) is a disease caused by an infection with the Puumula-virus (PUUV) in northern and central Europe. Small rodents (mostly mice) are the host of the virus accountable for a rising number of infections during spring and summer. It is causing a syndrome consisting of AIN, fever and often thrombocytopenia. There is a good chance of complete recovery of kidney function following NE.

Ocular involvement in allergic drug reactions

PURPOSE OF REVIEW

Many systemic medications have been observed to cause ocular toxicity. A subset of these reactions is thought to involve immunomodulation or a hypersensitivity reaction. As new medications are developed, ocular adverse effects are becoming increasingly prevalent. Herein we review immune-mediated drug reactions affecting they eye with special attention to the hypersensitivity mechanisms leading to ocular toxicity.

RECENT FINDINGS

Recent work has focused on mechanisms and risk of immune-mediated ocular adverse drug reactions including genetic susceptibility and loss of ocular immune privilege.

SUMMARY

Given the consequences of immune-mediated ocular adverse drug reactions, clinicians must be aware of these to facilitate early recognition and management. The prompt involvement of an ophthalmologist for diagnosis and management is often essential to preserve vision and avoid long-term morbidity.

Diagnostic and Management Strategies of Tubulointerstitial Nephritis and Uveitis Syndrome (TINU): Current Perspectives

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare autoimmune disease with unclear pathogenesis but probably related to a combination of genetic predisposition and environmental triggers. Diagnosis is challenging due to the asynchronous onset of renal and ocular symptoms, and it is necessary to exclude other causes of nephritis and uveitis. It affects both sexes, with an overall predominance of females and a median age of onset of 15 years. TINU syndrome is characterized by bilateral, non-granulomatous anterior uveitis and tubulointerstitial nephritis, which can cause acute renal failure in severe cases. Several triggers have been identified including concurrent infections, medications, or endocrine diseases. The diagnosis of TINU is mainly based on clinical and analytical findings, and although urinary β2-microglobulin is a useful parameter no specific diagnostic test is available. Current perspectives intend to facilitate its diagnosis identifying susceptibility HLA genotypes, serologic markers and imaging tools to avoid renal biopsy. Treatment options for TINU syndrome include corticosteroids, immunosuppressive agents, and intravenous immunoglobulins, but relapses are frequent, and management can be challenging. The purpose of this review is to provide an updated summary of the diagnostic and treatment strategies of TINU syndrome, helping clinicians recognize and manage this rare autoimmune disorder.

Gypenosides suppress fibrosis of the renal NRK-49F cells by targeting miR-378a-5p through the PI3K/AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The incidence of renal fibrosis caused by chronic kidney disease is increasing year by year. Preventing the activation and conversion of kidney-intrinsic fibroblasts to a myofibroblast phenotype is an important target for blocking the development of renal interstitial fibrosis. Our team established a stable renal interstitial fibrosis cell model in the early stage, and the screening results showed that GPs has good anti-fibrosis potential. At this stage, only a few literatures have reported its anti-fibrosis effect, and the mechanism of action is still unclear.

AIM OF THE STUDY

The massive synthesis and secretion of extracellular-matrix (ECM) components by activated fibroblasts in the kidneys causes irreversible renal interstitial fibrosis. Gypenosides (GPs) have been shown to decelerate this process, in which micro RNAs (miRNAs) play an important regulatory role. This study aimed to evaluate the mechanism underlying the suppressive effect of GPs on renal fibrosis.

MATERIALS AND METHODS

This study used TGF-β1-stimulated NRK-49F renal cells as an in-vitro model of renal interstitial fibrosis. First, the concentration range of GPs that significantly affects the cytoactive was determined. Then, the anti-fibrotic effects of various concentrations of GPs in the in-vitro model were assessed via immunofluorescence, western blotting, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Non-coding-RNA sequencing combined with bioinformatics was used to predict the mechanistic basis of the anti-fibrotic effect of GPs, and qRT-PCR was used to verify the sequencing results and bioinformatic predictions. The identified relationships of the anti-fibrotic effect of GPs with miR-378a-5p and the PI3K/AKT signaling were evaluated using a miR-NC mimic and the PI3K inhibitor LY294002 as controls, respectively.

RESULTS

TGF-β1 stimulation up-regulated α-SMA, COL1, and COL3 in NRK-49F cells, and this effect was suppressed by GPs. Additionally, TGF-β1 stimulation significantly changed the expression levels of 151 miRNAs, and GPs significantly suppressed the effect of TGF-β1 on the levels of 18 of these miRNAs. Among them, miR-3588 and miR-378a-5p were down-regulated, and miR-135b-5p and miR-3068-5p were up-regulated upon TGF-β1 induction. Of these miRNAs, miR-378a-5p was predicted to target the mRNAs of numerous proteins mainly enriched in the PI3K/AKT signaling pathway. The miRNA transfection experiments with the miR-NC mimic and PI3K inhibitor as controls showed that miR-378a-5p overexpression could suppress the TGF-β1-induced up-regulation of α-SMA, COL1, PI3K, and AKT, including the phosphorylated form (p-AKT).

CONCLUSION

GPs inhibit the PI3K/AKT signaling by up-regulating miR-378a-5p in TGF-β1-stimulated NRK-49F cells and thereby reduce their massive secretion of ECM components. Given that this in-vitro model of renal interstitial fibrosis closely mimics the in-vivo pathogenesis, our results most likely apply to the in-vivo conditions.

Age at Mortality in Patients with Type 2 Diabetes Who Underwent Kidney Transplantation: An Analysis of Data from the Korean National Health Insurance and Statistical Information Service, 2006 to 2018

BACKGROUND

Although the clinical outcomes of diabetes have improved, diabetes remains the principal cause of end-stage renal disease. The aim of the study is to investigate whether mortality trends in individuals with type 2 diabetes and kidney transplantation (KT) have changed.

METHODS

This study analyzed data from the National Health Insurance Service claims database linked to death records from the National Statistical Information Service in Korea. Information from a total of 2521 deaths of KT recipients was collected from 2006 to 2018.

RESULTS

The age at death of KT recipients increased from 57.4 years in 2006 to 65.2 years in 2018, with a mean change of +0.65 years/year (p < 0.001). The overall age at death increased by 0.55 and 0.66 years/year in the type 2 diabetes and non-diabetes populations, respectively. The age at death was significantly higher in the type 2 diabetes group, and was maintained during the study period. The proportion of death due to malignancy and cerebrovascular and heart disease was maintained, that due to type 2 diabetes decreased and that due to pneumonia increased. Neither diabetes nor hypertension determined the age at death, and the age at KT was the most prominent factor affecting age at death in KT recipients.

CONCLUSIONS

The age at death in KT recipients increased over the 12 years between 2006 and 2018, with similar trends in the type 2 diabetes and non-diabetes groups. The age at KT was higher in patients with type 2 diabetes, and was the main contributor to the age at death in KT recipients.

Sarcoid-like Uveitis with or without Tubulointerstitial Nephritis during COVID-19

PURPOSE

To report sarcoid-like uveitis with or without tubulointerstitial nephritis (TIN) during coronavirus disease 2019 (COVID-19) and to discuss diagnostic evaluation and treatment.

METHODS

Detailed information on the subject's demographics, medical history, ophthalmic examination findings, and laboratory results were obtained from medical records. Fluorescein angiography (FA) and indocyanine green angiography (ICGA) images were evaluated.

RESULTS

All seven patients aged between 8 and 17 had bilateral granulomatous panuveitis. TIN preceded in four patients. Thorax computed tomography of patient 1 was found to be compatible with COVID-19, patients 2 and 3 were in contact with Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive parents, patients 4 and 5 were found to be SARS-CoV-2 PCR positive, and patients 6 and 7 were positive for SARS-CoV-2 IgG antibodies. ICGA revealed hypofluorescent dots in six patients. Intraocular inflammation was controlled with corticosteroid and/or immunomodulatory therapy. Visual acuity was maintained or improved in all.

CONCLUSION

SARS-CoV-2 infection may be related to sarcoid-like uveitis and acute tubulointerstitial nephritis.

Clinical Characteristics of Children With Acute Tubulointerstitial Nephritis: A Single-Center Experience

OBJECTIVE

Acute tubulointerstitial nephritis (ATIN) is an infiltration of the kidney interstitium with inflammatory cells. Medications are most frequently blamed for the etiology. Patients may present with non-specific signs and symptoms. Therefore, the diagnosis of ATIN is often delayed. In this study, clinical characteristics, treatment protocols, and outcomes of children diagnosed with ATIN were presented.

METHODS

This is a retrospective study based on the data of 18 patients diagnosed with ATIN between 2017 and 2022 at Gazi University. Patients were divided into two groups: steroid-treated (n=13) and non-steroid-treated (n=5). Clinical features and laboratory evaluations were compared between the groups.

RESULTS

The mean age of the patients was 14.4±2.6 years, and the great majority were girls (88.9%, n=16). ATIN was mostly medication-related (n=17, 94.4%). Steroids were started in one-third of patients using non-steroidal anti-inflammatory drugs. Steroids were started in 45.4% of the patients with eosinophilia, 75% of those with pyuria, 66.6% of those with hematuria, and half of the patients with increased kidney echogenicity. The kidney functions returned to normal ranges in all patients. In steroid-treated patients, although recovery times for serum creatinine were longer (7.2±2.5 vs. 71.2±100.7 days), blood eosinophil count reached normal values more rapidly (5.4±2.3 vs. 3.1±1.0 days).

CONCLUSION

ATIN can be associated with diverse clinical presentations. The first and most important step of treatment is to discontinue the medication responsible for the etiology. Steroid treatment improves eosinophilia more rapidly. However, randomized controlled studies are needed to determine further treatment steps and establish a more definite treatment protocol.

Prepubertal to adulthood exposure to low doses of glyphosate-based herbicide increases the expression of the Havcr1 (Kim1) biomarker and causes mild kidney alterations

Glyphosate is a nonselective and postemergent herbicide used to combat weeds in several crops, which raises concerns about risks to human health since residues are detected in urine, human milk, surface water and several types of food. Feces and urine are the major routes of elimination of glyphosate, making the kidney a sensitive target for the development of toxicity. In fact, farmers are at high risk of developing chronic kidney disease. In this sense, this study aims to investigate kidney function by measuring the serum levels of urea and creatinine, examining the histological morphology, and analyzing the mRNA expression of genes related to tubular transport of ions, urea and urates and the biomarker of kidney disease Kim1, and the levels of lead in the kidney in male Wistar rats orally exposed to low levels of glyphosate-based herbicide (GBH: 0, 0.5 or 5 mg/kg) from weaning to adult life by gavage. GBH0.5 showed reduced serum urea concentration, presence of tubulointerstitial swelling and mononuclear cell infiltration into the interstitium, increased gene expression of Kim1 and reduced gene expression of Slc14a1. GBH5 showed reduced serum urea and increased serum creatinine concentrations, tubulointerstitial swelling, interstitial fibrosis, and reduced expression of Trpm6 and Trpv5. Exposure to GBH did not affect the levels of Pb in the kidneys of animals. In conclusion, glyphosate at low doses may cause mild kidney damage. It is necessary to evaluate whether the long-term effects of this constant injury may contribute to the development of chronic kidney disease of uncertain etiology.

The presence of intraperitoneal, retroperitoneal and pleural fluid in acute Puumala hantavirus infection

BACKGROUND

Puumala hantavirus (PUUV) causes most cases of haemorrhagic fever with renal syndrome (HFRS) in Europe. PUUV infection is characterised by acute kidney injury, thrombocytopenia and increased capillary leakage. Typical symptoms are fever, headache, nausea, abdominal and back pain. This study aimed to evaluate the amount and distribution of intraperitoneal, retroperitoneal and pleural fluid and the association of fluid collections to the symptoms and clinical findings in patients with acute PUUV infection.

METHODS

Abdominal magnetic resonance imaging (MRI) was performed on 27 hospitalised patients with acute PUUV infection. The clinical and laboratory findings and patients' symptoms were analysed in relation to the imaging findings. The thickness of the fluid collections was measured in millimetres (mm) from axial images.

RESULTS

Fluid collections were found in all patients. The amount of intraperitoneal fluid correlated positively with plasma C-reactive protein (CRP) level (r = 0.586, p = .001), while it had an inverse correlation with serum creatinine concentration (r = -0.418, p = .030). Retroperitoneal fluid also correlated inversely with serum creatinine and cystatin C concentrations (r = -0.501, p = .008 and r = -0.383, p = .048, respectively). The amount of fluid was not greater in patients with abdominal or back pain. Patients with back pain had higher serum creatinine compared with patients without back pain, 452 µmol/L (range 88-1071) vs. 83 µmol/L (range 60-679), p = .004.

CONCLUSIONS

Fluid collections were found in all patients. A greater amount of intraperitoneal fluid associates with higher CRP concentrations but not with higher serum creatinine levels. Back pain associates with higher creatinine level but not with the presence of fluids.

Urine alpha 1-microglobulin-to-creatinine ratio and beta 2-microglobulin-to-creatinine ratio for detecting CAKUT with kidney dysfunction in children

BACKGROUND

The leading cause of advanced chronic kidney disease (CKD) in children is congenital anomalies of the kidney and urinary tract (CAKUT). However, the most appropriate parameters of biochemical urine analysis for detecting CAKUT with kidney dysfunction are not known.

METHODS

The present observational study analyzed data on children with CAKUT (stage 2-4 CKD) and the general pediatric population obtained from school urine screenings. The sensitivity and specificity of urine alpha 1-microglobulin-, beta 2-microglobulin-, protein-, and the albumin-to-creatinine ratios (AMCR, BMCR, PCR, ACR, respectively) in detecting CAKUT with kidney dysfunction were compared with those of the conventional urine dipstick, and the most appropriate of these four parameters were evaluated.

RESULTS

In total, 77 children with CAKUT and 1712 subjects in the general pediatric population fulfilled the eligibility criteria. Conventional dipstick urinalysis was insufficient due to its low sensitivity; even when the threshold of proteinuria was +/-, its sensitivity was only 29.7% for stage 2 and 44.1% for stage 3 CKD. Among the four parameters assessed, the AMCR and BMCR were adequate for detecting CAKUT in children with stage 3-4 CKD (the respective sensitivity and specificity of the AMCR for detecting CAKUT in stage 3 CKD was 79.4% and 97.5% while that of BMCR was 82.4% and 97.5%). These data were validated using national cohort data.

CONCLUSION

AMCR and BMCR are superior to dipstick urinalysis, PCR, and ACR in detecting CAKUT with kidney dysfunction, particularly stage 3 CKD. However, for AMCR, external validation is required. A higher resolution version of the Graphical abstract is available as Supplementary information.

Randomized control trial of prednisolone and doxycycline in patients with acute interstitial nephritis of unknown aetiology

BACKGROUND

Patients presenting with acute interstitial nephritis (AIN) of unknown aetiology, probably the earliest presentation of chronic kidney disease of unknown aetiology (CKDu), have been treated with oral prednisolone and doxycycline by physicians in Sri Lanka. This trial assessed the effectiveness of prednisolone and doxycycline based on eGFR changes at 6 months in patients with AIN of unknown aetiology.

METHOD

A randomized clinical trial with a 2 × 2 factorial design for patients presenting with AIN of unknown aetiology (n = 59) was enacted to compare treatments with; A-prednisolone, B-doxycycline, C-both treatments together, and D-neither. The primary outcome was a recovery of patients' presenting renal function to eGFR categories: 61-90 ml/min/1.73m² (complete remission- CR) to 31-60 ml/min/1.73m² (partial remission- PR) and 0-30 ml/min/1.73m² no remission (NR) by 6 months. A secondary outcome was progression-free survival (not reaching < 30 ml/min/1.73m² eGFR), by 6-36 months. Analysis was by intention to treat.

RESULTS

Seventy patients compatible with a clinical diagnosis of AIN were biopsied for eligibility; 59 AIN of unknown aetiology were enrolled, A = 15, B = 15, C = 14 and D = 15 randomly allocated to each group. Baseline characteristics were similar between groups. The number of patients with CR, PR and NR, respectively, by 6 months, in group A 3:8:2, group B 2:8:3 and group C 8:5:0 was compared with group D 8:6:1. There were no significant differences found between groups A vs. D (p = 0.2), B vs. D (p = 0.1) and C vs. D (p = 0.4). In an exploratory analysis, progression-free survival in prednisolone-treated (A + C) arms was 0/29 (100%) in comparison to 25/30 (83%) in those not so treated (B + D) arms, and the log-rank test was p = 0.02, whereas no such difference found (p = 0.60) between doxycycline-treated (B + C) arms 27/29 (93%) vs those not so treated (A + D) arms 27/30 (90%).

CONCLUSION

Prednisolone and doxycycline were not beneficial for the earliest presentation of CKDu at 6 months. However, there is a potential benefit of prednisolone on the long-term outcome of CKDu. An adequately powered steroid trial using patients reaching < 30 ml/min/1.73m² eGFR by 3 years, as an outcome is warranted for AIN of unknown aetiology.

TRIAL REGISTRATION

Sri Lanka Clinical Trial Registry SLCTR/2014/007, Registered on the 31st of March 2014.

Acute interstitial nephritis manifesting as a persistent nephogram

We report a case of a 61-year-old woman who presented to the emergency department with high inflammatory parameters and acute renal failure. Marked enlarged kidneys with persistent nephrogram were found on contrast-enhanced computed tomography . Renal biopsy showed acute interstitial nephritis. Acute interstitial nephritis must be included in the differential diagnosis in patients presenting with a persistent nephrogram.

Diuretic resistance in patients with kidney disease: Challenges and opportunities

Edema caused by kidney disease is called renal edema. Edema is a common symptom of many human kidney diseases. Patients with renal edema often need to take diuretics.However, After taking diuretics, patients with kidney diseases are prone to kidney congestion, decreased renal perfusion, decreased diuretics secreted by renal tubules, neuroendocrine system abnormalities, abnormal ion transporter transport, drug interaction, electrolyte disorder, and hypoproteinemia, which lead to ineffective or weakened diuretic use and increase readmission rate and mortality. The main causes and coping strategies of diuretic resistance in patients with kidney diseases were described in detail in this report. The common causes of DR included poor diet (electrolyte disturbance and hypoproteinemia due to patients' failure to limit diet according to correct sodium, chlorine, potassium, and protein level) and poor drug compliance (the patient did not take adequate doses of diuretics. true resistance occurs only if the patient takes adequate doses of diuretics, but they are not effective), changes in pharmacokinetics and pharmacodynamics, electrolyte disorders, changes in renal adaptation, functional nephron reduction, and decreased renal blood flow. Common treatment measures include increasing in the diuretic dose and/or frequency, sequential nephron blockade,using new diuretics, ultrafiltration treatment, etc. In clinical work, measures should be taken to prevent or delay the occurrence and development of DR in patients with kidney diseases according to the actual situation of patients and the mechanism of various causes. Currently, there are many studies on DR in patients with heart diseases. Although the phenomenon of DR in patients with kidney diseases is common, there is a relatively little overview of the mechanism and treatment strategy of DR in patients with kidney diseases. Therefore, this paper hopes to show the information on DR in patients with kidney diseases to clinicians and researchers and broaden the research direction and ideas to a certain extent.

Marked reduction of proteinuria after removal of a growth hormone-producing pituitary adenoma in a patient with focal segmental glomerulosclerosis: a case report and literature review

Focal segmental glomerulosclerosis is a rare complication of acromegaly. A 74-year-old man was found to have acromegaly features such as enlargement of the forehead, nose, and hands. Laboratory tests showed a urine protein/creatinine ratio of 3.16 g/gCr and serum creatinine of 1.34 mg/dL. The levels of growth hormone and insulin-like growth factor I were markedly elevated, and the growth hormone level was not suppressed after 75 g oral glucose loading. Magnetic resonance imaging revealed a pituitary tumor with a diameter of 1.2 cm. Renal biopsy confirmed the diagnosis of focal segmental glomerulosclerosis. Transsphenoidal resection of the pituitary tumor led to remission of acromegaly and reduction in proteinuria highlighting the causal link between growth hormone overproduction and proteinuria. Treatment of acromegaly may be effective for acromegaly-associated focal segmental glomerulosclerosis.

Tubulointerstitial Nephritis and Uveitis Syndrome (TINU): A Case Series in a Tertiary Care Uveitis Setting

Background: Tubulointerstitial nephritis and uveitis syndrome (TINU) is a rare disorder typically characterized by sudden-onset non-granulomatous anterior uveitis associated with tubulointerstitial nephritis (TIN). However, the prevalence and clinical features of TINU are still a matter of debate. To add information about TINU, we describe here the clinical features of a series of patients affected by TINU in a retrospective study. Methods: A total of 9358 clinical records of both adult and pediatric patients up to 21 years of age, referred to the Uveitis Center of the Sapienza University of Rome, were examined. The medical records covered a period from 1990 to 2020. Various demographic and clinical features were analyzed in patients who met the criteria for TINU. Results: Twenty-one patients with TINU were identified. TINU was classified as definite, possible, or probable by the currently recognized international criteria. The median age at diagnosis was 14 years (interquartile range 12–35). Females were predominant (15/21, 71.4%). In most cases (14/21, 66.6%), patients developed ocular disease concurrently with renal disease. The most frequent type of ocular involvement was bilateral anterior uveitis (9/21, 42.8%). In two cases, patients presented with bilateral intermediate uveitis; in three cases, they presented with bilateral or unilateral alternating posterior uveitis; and in four cases, they presented with bilateral panuveitis. In one case, the uveitis was anterior in the right eye (OD) and posterior in the left eye (OS), and two cases presented with bilateral asynchronous or unilateral alternating anterior uveitis. All patients received treatment with systemic corticosteroids and topical ocular therapy. At the end of the follow-up, a significant improvement in ocular signs and symptoms with a return to normal visual acuity was generally observed. In all patients, acute kidney injury (AKI) reverted completely and none progressed to chronic kidney disease (CKD). Conclusions: Patients with TINU may often present with atypical uveitis. We suggest that patients with sudden-onset uveitis, even if not bilateral anterior, should be referred to a nephologist for an assessment of the possible presence of renal disease.

Primary biliary cholangitis presenting with Fanconi syndrome: an important phenotype

A woman in her 50s was referred to nephrology clinic due to progressive chronic kidney disease. She exhibited features of proximal renal tubulopathy, namely Fanconi syndrome, including normoglycaemic glycosuria, normal anion gap metabolic acidosis, and intermittent hypouricaemia and hypophosphataemia. Kidney biopsy showed tubulointerstitial inflammation and focal chronic damage. In addition, antimitochondrial antibodies were present and she had abnormal liver blood tests. A unifying diagnosis of primary biliary cholangitis with an associated renal tubulopathy and interstitial nephritis was made. She was commenced on sodium bicarbonate, ursodeoxycholic acid and oral prednisolone, leading to an improvement in liver biochemistry. Kidney function was stabilised, but a sustained improvement was not seen. This case acts as a reminder of the rare association of tubulointerstitial nephritis and Fanconi syndrome with primary biliary cholangitis, which may be an under-recognised phenotype.

'A disease of disparity': chronic kidney disease of unknown aetiology in endemic immigrant communities

Chronic kidney disease (CKD) of unknown aetiology is a form of tubulointerstitial CKD in the absence of traditional and known predisposing risk factors. Since the early 2000s, there is an emerging trend in marginalised agricultural communities among workers exposed to occupational and environmental hazards. CKD of unknown aetiology has received significant attention in recent years and is becoming increasingly relevant to the Australian medical community with the growing migrant population, which this case‐based communication illustrates.

Renal sarcoidosis

Renal sarcoidosis (RS) is a rare form of sarcoidosis that results in granulomatous inflammation of renal parenchyma. We describe the epidemiology, pathogenesis, clinical features, diagnostic approach, treatment strategies and outcomes of this condition. RS occurs most commonly at the time of initial presentation of sarcoidosis but can at any time along the course of the disease. The most common presenting clinical manifestations of RS are renal insufficiency or signs of general systemic inflammation. End-stage renal disease requiring dialysis is a rare initial presentation of RS. The diagnosis of RS should be considered in patients who present with renal failure and have either a known diagnosis of sarcoidosis or have extra-renal features consistent with sarcoidosis. A renal biopsy helps to establish the diagnosis of RS, with interstitial non-caseating granulomas confined primarily to the renal cortex being the hallmark pathological finding. However, these histologic findings are not specific for sarcoidosis, and alternative causes for granulomatous inflammation of the renal parenchyma should be excluded. Corticosteroids are the drug of choice for RS. Although RS usually responds well to corticosteroids, the disease may have a chronic course and require long-term immunosuppressive therapy. The risk of progression to ESRD is rare.

Distribution of kidney diseases in Joinville, Santa Catarina: analysis of a kidney biopsy data bank between 2008 and 2019

INTRODUCTION

Studies based on kidney biopsies are important for the epidemiological understanding of nephropathies.

OBJECTIVE

To describe the main nephropathies diagnosed through renal biopsies, and compare them with regards to gender, time, healthcare insurance and age.

METHODS

A population-based retrospective study that reviewed all kidney disease diagnoses obtained by biopsy of a native kidney from pathology services between 2008 and 2019 in Joinville, Brazil.

RESULTS

Of 778 biopsies performed, 44.5% were primary nephropathies and 28.5% were secondary. The highest prevalence was focal segmental glomerulosclerosis (FSGS) [18.1%], followed by tubulointerstitial nephropathy (TIN) [15.9%] and IgA nephropathy (IgAN) [9.1%]. There was a growing increase in the prevalence of TIN among elderly and uninsured patients over the period. In the multivariate analysis, among the primary glomerulopathies, males had a higher risk for the occurrence of IgAN [OR=2.02; 95% CI 1.13-3.61; p=0.018], as well as being a protective factor for the occurrence of lupus glomerulonephritis (LGN) [OR=0.20, 95% CI 0.08-0.49; p<0.001]. Advancing age and dependence on a public healthcare decreased the likelihood of having a diagnosis of LGN [OR=0.91, 95% CI 0.88-0.94, p < 0.001 and OR=0.45, CI 95 % 0.21-0.96; p = 0.036, respectively]. Patients without private healthcare insurance were more likely to have TIN [OR=1.77, 95%CI 1.16-2.70; p = 0.008].

CONCLUSION

Sex, age and type of medical healthcare insurance may be related to the occurrence of some nephropathies. The increased risk of TIN in individuals without a private healthcare plan may be an indication of inequalities in health care.

Assessment of renal microcirculation in biopsy-proven tubulointerstitial nephritis in patients with and without glomerular disease: the role of resistive index

BACKGROUND

Renal resistive index (RRI) measured by Doppler sonography is a marker of microvascular status and it is associated with changes in renal function. Aim of the study was to assess RRI in biopsy-proven tubulointerstitial nephritis (TIN) in patients with and without glomerular disease.

METHODS

132 consecutive patients underwent to native renal biopsy with diagnosis of isolated TIN or in association with glomerulonephritis. Estimated glomerular filtration rate (eGFR), 24-hour urinary protein excretion and renal ecocolorDoppler ultrasonography with RRI assessment were performed at time of enrollment.

RESULTS

Patients with isolated-TIN had significantly higher RRI than both patients with non-immunoglobulin A glomerulonephritis (non-IgA-TIN) [0.73 (0.68-0.77) vs 0.64 (0.60-0.67), p < 0.001] and patients with IgA nephropathy (IgAN) [0.73 (0.68-0.77) vs 0.66 (0.60-0.71), p < 0.01]. Patients with isolated-TIN had mainly RRI ≥ 0.70 (n = 15, 65.2%) with the respect to patients with non-IgA-TIN (n = 7, 12.3%) and patients with IgAN (n = 17, 32.7%). A negative linear correlation was found between RRI and hemoglobin (r = 0.233, p < 0.01) and between RRI and eGFR (r = 0.537, p < 0.001).

CONCLUSION

Tubulointerstitial damage is the most accurate histological lesion that correlates with eGFR and renal impairment. RRI can be a useful parameter to detect tubulointerstitial lesions.

Acute interstitial nephritis after COVID-19 vaccination

A woman in her 70s presented to the hospital being generally unwell 8 days following the first dose of the AstraZeneca COVID-19 vaccination. She was in stage III acute kidney injury (AKI) with hyperkalaemia and metabolic acidosis. Urinalysis showed haematoproteinuria. Renal immunology screen was negative. She subsequently underwent two renal biopsies. The second biopsy showed features consistent with acute tubulointerstitial nephritis. She was commenced on oral steroids, which led to marked improvement of her renal function.There are reasons why AKI can occur post vaccination such as prerenal AKI from reduced oral intake postvaccination due to feeling unwell or developing vomiting or diarrhoea. Intravenous fluids were given to this patient but with no meaningful improvement in renal function. She developed a possible reaction to the AstraZeneca COVID-19 vaccine, which led to AKI as supported by the interstitial inflammation and presence of eosinophils on renal biopsy.

Environmentally Persistent Free Radical Promotes Lung Cancer Progression by Regulating the Expression Profile of miRNAs

Background: Environmentally persistent free radicals (EPFRs) are generated in the combustion processes of solid waste and can cause adverse influences on human health, especially lung diseases. Lung cancer is one of the most serious malignancies in recent years, which the global deaths rate is about 1.6 million every year. Methods and Results: In this study, we verified that ZnO/MCB EPFRs promote cell proliferation and migration, impedes cell apoptosis in lung cancer. Furthermore, we found that ZnO/MCB could influence the expression of miRNAs (miR-18a and miR-34a). In vivo, ZnO/MCB and ZnO EPFRs can reduce the weight and survival rate of BALB/c male mice more than that of BALB/c female mice. In the ZnO/MCB exposed group, male mice lung became even smaller, while the female mice the lung increased significantly. Taken together, our results provide evidence for assessing the potential health risks of persistent free radicals on fine particles. Conclusions: This study linked toxicity of EPFRs with miRNAs revealed the potential health hazard to human lung cancer.

Recurrent Hypokalemia and Adrenal Steroids in Patients With APECED

CONTEXT

Hypokalemia is a common finding in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) but its exact cause often remains unknown.

OBJECTIVE

To explore the prevalence and etiology of hypokalemia and the role of adrenal steroids therein in a cohort of patients with APECED.

METHODS

We performed a cross-sectional assessment and retrospective data collection on 44 Finnish patients with APECED to identify subjects with episodes of hypokalemia. Also 68 healthy matched controls attended the cross-sectional evaluation. Factors associating with a tendency for hypokalemia were analyzed by reviewing medical records during 1960-2021 and performing a cross-sectional analysis of serum adrenal steroids.

RESULTS

In total 14 of the 44 APECED patients (32%) had episodes of hypokalemia; 2 presented with hypokalemia at cross-sectional evaluation and 12 had a history of hypokalemia before the cross-sectional evaluation. Hypokalemic episodes started at the median age of 14.1 years; 12/14 (86%) had primary adrenal insufficiency (PAI). The median number of hypokalemic periods per year was 0.3 (range 0.04-2.2); the frequency correlated positively with the number of clinical APECED manifestations at the time of cross-sectional evaluation (r=0.811, p<0.001). Etiologies of hypokalemia varied but episodes often occurred when new clinical manifestations developed and during hospitalizations. Three patients had kidney defects, also associated with electrolyte imbalances. Severity of hypokalemia varied (range 2.2-3.2 mmol/L), but no severe complications were observed. At cross-sectional evaluation, patients with PAI (n = 30) had significantly lower median plasma potassium and higher sodium concentration than controls, suggesting that fludrocortisone treatment contributed to hypokalemia. Detailed analysis of adrenal steroids provided no conclusive differences between patients with and without episodes of hypokalemia.

CONCLUSIONS

In APECED, hypokalemia is common and varies in terms of frequency, etiology, and severity. PAI and kidney disease predispose to hypokalemia. In addition, hypokalemic periods seem to be more common in patients with more severe phenotype of APECED.

Pediatric uveitis: Role of the pediatrician

The challenges of childhood uveitis lie in the varied spectrum of its clinical presentation, the often asymptomatic nature of disease, and the evolving nature of the phenotype alongside normal physiological development. These issues can lead to delayed diagnosis which can cause significant morbidity and severe visual impairment. The most common ocular complications include cataracts, band keratopathy, glaucoma, and macular oedema, and the various associated systemic disorders can also result in extra-ophthalmic morbidity. Pediatricians have an important role to play. Their awareness of the various presentations and etiologies of uveitis in children afford the opportunity of prompt diagnosis before complications arise. Juvenile Idiopathic Arthritis (JIA) is one of the most common associated disorders seen in childhood uveitis, but there is a need to recognize other causes. In this review, different causes of uveitis are explored, including infections, autoimmune and autoinflammatory disease. As treatment is often informed by etiology, pediatricians can ensure early ophthalmological referral for children with inflammatory disease at risk of uveitis and can support management decisions for children with uveitis and possible underling multi-system inflammatory disease, thus reducing the risk of the development of irreversible sequelae.

Renal replacement therapy-requiring acute kidney injury due to tubulointerstitial nephritis and uveitis syndrome: case report

BACKGROUND

Acute kidney injury is a major challenge for today's healthcare systems around the globe. Renal replacement therapy has been shown to be beneficial in acute kidney injury, but treatment highly depends on the cause of the acute kidney injury. One less common cause is tubulointerstitial nephritis, which comes in different entities. A very rare type of tubulointerstitial nephritis is tubulointerstitial nephritis and uveitis syndrome, in which the patient presents with additional uveitis.

CASE PRESENTATION

A 19-year-old caucasian male presented with mild dyspnea, lack of appetite, weight loss, and moderate itchiness. Lab results showed an acute kidney injury with marked increase of serum creatinine. The patient was started on prednisolone immediately after admission. As the patient in this case showed symptoms of uremia on admission, we decided to establish renal replacement therapy, which is unusual in tubulointerstitial nephritis and uveitis syndrome. During his course of dialysis, the patient developed symptoms of sepsis probably due to a catheter-related infection requiring intensive care and antibiotic treatment, which had to be terminated early as the patient developed a rash. Intensified immunosuppression, combined with antibiotics, significantly resolved excretory kidney dysfunction.

CONCLUSIONS

Since both the primary inflammatory process and the secondary infectious complication significantly impaired excretory kidney function, kidney function of younger individuals with new-onset anterior uveitis should be monitored over time and during follow-up.

Rifampicin-Induced Nephrotoxicity in a Tuberculosis Patient: Treatment Dilemma?

Acute kidney injury related to rifampin is usually a clinical diagnosis. We report a case of a man being treated for pulmonary tuberculosis with acute tubulointerstitial nephritis related to rifampicin.

LEARNING POINTS

Rifampicin can cause acute kidney injury.Renal impairment may develop weeks after rifampicin administration was started.

Urinary concentrations of neonicotinoid insecticides were related to renal tubular dysfunction and neuropsychological complaints in Dry-zone of Sri Lanka

Neonicotinoids are systemic insecticides used since the 1990’s , that possess renal tubular toxicity. We conducted a field-based descriptive study in the North Central Dry-zone of Sri Lanka, where chronic kidney disease (CKD) of unknown etiology has been increasing since the 1990’s. To elucidate the relationship between renal tubular dysfunctions and urinary neonicotinoids concentrations, we collected spot urine samples from15 CKD patients, 15 family members, and 62 neighbors in 2015, analyzed two renal tubular biomarkers, Cystatin-C and L-FABP, quantified seven neonicotinoids and a metabolite N-desmethyl-acetamiprid by LC–MS/MS; and we investigated their symptoms using a questionnaire. Cystatin-C and L-FABP had a positive correlation (p < 0.001). N-Desmethyl-acetamiprid was detected in 92.4% of the urine samples, followed by dinotefuran (17.4%), thiamethoxam (17.4%), clothianidin (9.8%), thiacloprid and imidacloprid. Dinotefuran and thiacloprid have never been registered in Sri Lanka. In High Cystatin-C group (> 70 μg/gCre, n = 7), higher urinary concentration of dinotefuran (p = 0.009), and in Zero Cystatin-C group (< LOQ, n = 7), higher N-desmethyl-acetamiprid (p = 0.013), dinotefuran (p = 0.049), and thiacloprid (p = 0.035), and more complaints of chest pains, stomachache, skin eruption and diarrhea (p < 0.05) were found than in Normal Cystatin-C group (n = 78). Urinary neonicotinoids may be one of the potential risk factors for renal tubular dysfunction in this area.

Immunomodulation and TNF-α inhibition for tubulointerstitial nephritis and uveitis syndrome: a case series

BACKGROUND

Tubulointerstitial nephritis and uveitis (TINU) syndrome combines acute inflammatory nephritis (AIN) and uveitis. Uveitis in TINU often requires systemic immunomodulatory therapy (IMT), including steroid-sparing agents. Although common for other noninfectious uveitides, the use of tumor necrosis factor-α inhibitors (TNFi) in TINU has seldom been described.

METHODS

This retrospective case series included patients <18 years of age with TINU followed at our tertiary care pediatric hospital. Disease characteristics at time of diagnosis and subsequent ophthalmological and rheumatologic evaluations were extracted from the record. AIN was defined as the presence of abnormal renal function and urinalysis or renal biopsy findings consistent with TINU. Uveitis grading, site of inflammation, inactivity, and flare were defined according to Standardization of Uveitis Nomenclature.

RESULTS

A total of 10 patients (median age, 12.3 years; 6 females) were included. AIN preceded uveitis onset in 6 patients. Uveitis was bilateral at onset in 7 patients. Uveitis inactivity was achieved with systemic corticosteroids (CS) in 2 and with mycophenolate mofetil (MMF) in 3 patients. Because of persistent ocular inflammation, despite CS and IMT, 4 patients were treated with TNFi. All rapidly achieved uveitis quiescence and maintained prolonged inactivity under combined treatment with TNFi and MMF.

CONCLUSIONS

Most patients in our study cohort required a steroid-sparing immunomodulator to achieve and maintain uveitis control. In the 50% of the cohort in whom conventional IMTs were inadequate, TNFi were able to maintain quiescence. TNF inhibition might be a useful treatment in IMT-refractory uveitis in TINU patients.

Tubulointerstitial nephritis and uveitis syndrome following meningitis and systemic lymphadenopathy with persistent Toxoplasma immunoglobulin M: a case report

Background

Tubulointerstitial nephritis and uveitis syndrome is a rare lymphocyte-related oculorenal inflammatory disease presumed to be associated with drug use and infectious agents. Toxoplasma gondii is one of such pathogens that could exhibit encephalitis, meningitis, and uveitis in immunocompromised or in some immunocompetent individuals. If the immunoglobulin M of Toxoplasma is positive on screening, the interpretation of the result is not simple, especially when immunoglobulin M stays positive persistently.

Case presentation

A 34-year-old Asian male developed fever, headache, and lymphadenopathy with tenderness, which was initially diagnosed as meningitis. Antibiotics were started, and diclofenac sodium was used for the fever. Although his symptoms were alleviated in a week by the treatment, gradual decline in renal function was noted, prompting a renal biopsy that indicated acute granulomatous interstitial nephritis. A week later, tenderness in both eyes with blurred vision appeared and revealed iritis and keratic precipitations in both eyes; hence, the diagnosis of acute tubulointerstitial nephritis and bilateral uveitis syndrome was made. Toxoplasma gondii-specific immunoglobulin G and immunoglobulin M titers were both positive. Although we could not rule out recent infection of Toxoplasma gondii, which may cause uveitis initially, Toxoplasma immunoglobulin G avidity test indicated a distant infection, which allowed us to rule out meningitis and uveitis as responsible for the complication of recent Toxoplasma gondii infection. Drug-induced lymphocyte stimulation test, or lymphocyte transformation test of diclofenac sodium, was solely positive among the tested drugs. Uveitis was alleviated only with ophthalmic steroid, and renal function returned to normal without administration of systemic steroid.

Conclusions

We experienced a case of diclofenac-induced tubulointerstitial nephritis and uveitis syndrome. In ruling out infections, Toxoplasma immunoglobulin M was persistently positive, and Toxoplasma immunoglobulin G avidity test indicated a “distant” infection. From these two results, we ruled out recent infection. However, it should be noted that “distant” infection indicated by commercial immunoglobulin G avidity is still a multiplex profile consisting of reinfection, reactivation, and latent infection. Narrowing down the infection profile of Toxoplasma is challenging in some cases. Therefore, careful diagnosis and extended follow-up of such patients are needed.

Tubulointerstitial nephritis and uveitis syndrome in an adolescent female: a case report

BACKGROUND

Tubulointerstitial nephritis with uveitis syndrome is a rare disease affecting mainly children and young women. Tubulointerstitial nephritis with uveitis is a diagnosis of exclusion, requiring a high degree of clinical suspicion. Studies report recent infections or certain drugs as precipitating factors of a lymphocytic oculorenal immune response. The prognosis is usually favorable with topical and systemic corticosteroid therapy.

CASE PRESENTATION

We report a literature review and the case of a 14-year-old white girl, who presented to the ophthalmology department with features of one-sided uveitis. Upon transfer of patient to nephrological care, diagnostic work-up revealed renal involvement. Renal biopsy showed a mixed-cell and granulomatous tubulointerstitial nephritis with some noncaseating granulomas, leading to a diagnosis of tubulointerstitial nephritis with uveitis syndrome. With topical ocular and systemic corticosteroid therapy, the patients' condition improved over several weeks.

CONCLUSIONS

Our case highlights the importance of early recognition and treatment of this syndrome, where cross-specialty care typically leads to a favorable outcome.

Strong Associations Between Early Tubular Damage and Urinary Cytokine, Chemokine, and Growth Factor Levels in Elderly Males and Females

Acute tubular necrosis is associated with high mortality rates and it is important to develop new biomarkers for tubular damage. The aim of this study was to investigate the effect of early tubular damage on a large number of urinary cytokines, chemokines, and growth factors. We selected 90 urine samples from the Prospective Investigation of the Vasculature in Uppsala Seniors Study (41 males and 49 females). The tubular damage markers cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule-1 (KIM-1) were analyzed in the urine samples and urinary cytokine levels were analyzed with 2 multiplex assays (proximity extension assay). After adjustment for sex, body mass index, estimated glomerular filtration rate, smoking, and multiplicity testing using the false discovery rate approach, there remained 26 cytokines that correlated significantly with urine cystatin C, 27 cytokines that correlated with NGAL, and 66 cytokines that correlated with KIM-1. Tubular damage shows a strong association with urinary cytokines, chemokines, and growth factors. Our findings indicate that multiplex proteomics could be a promising new approach to explore the complex effects of tubular damage.

Correlation between renal distribution of leptospires during the acute phase and chronic renal dysfunction in a hamster model of infection with Leptospira interrogans

BACKGROUND

Leptospirosis has been described as a biphasic disease consisting of hematogenous dissemination to major organs in the acute phase and asymptomatic renal colonization in the chronic phase. Several observational studies have suggested an association between leptospirosis and chronic kidney disease (CKD). We investigated the dynamics of leptospires and histopathological changes in the kidney to understand the relationship between them, and also investigated the extent of renal dysfunction in the acute and chronic phases of leptospirosis using a hamster model.

FINDINGS

Hamsters (n = 68) were subcutaneously infected with 1 × 104 cells of the Leptospira interrogans serovar Manilae strain UP-MMC-SM. A total of 53 infected hamsters developed fatal acute leptospirosis, and the remaining 15 hamsters recovered from the acute phase, 13 of which showed Leptospira colonization in the kidneys in the chronic phase. Five asymptomatic hamsters also had renal colonization in the chronic phase. Immunofluorescence staining showed that leptospires were locally distributed in the renal interstitium in the early acute phase and then spread continuously into the surrounding interstitium. The kidneys of the surviving hamsters in the chronic phase showed patchy lesions of atrophic tubules, a finding of chronic tubulointerstitial nephritis, which were substantially consistent with the distribution of leptospires in the renal interstitium. The degree of atrophic tubules in kidney sections correlated statistically with the serum creatinine level in the chronic phase (rs = 0.78, p = 0.01).

CONCLUSION

Subcutaneous infection with pathogenic leptospires could cause acute death or chronic leptospirosis in hamsters after surviving the acute phase. We suggest that the renal distribution of leptospires during the acute phase probably affected the extent of tubular atrophy, leading to CKD.

Clinical characteristics of childhood acute tubulointerstitial nephritis

BACKGROUND

Acute tubulointerstitial nephritis (ATIN) is a rare cause of acute kidney injury in children that can lead to chronic kidney disease. The aim of this study was to describe the presenting features, etiology, and clinical characteristics of childhood ATIN, and to evaluate treatment modalities and renal outcomes.

METHODS

The study included 38 patients who had been diagnosed with ATIN, were younger than 18 years old, and were admitted for at least 6 months of follow up.

RESULTS

The median age at diagnosis was 13.1 years (range 1.2-16.6 years). The female / male ratio was 1.37. The most common symptoms were abdominal pain (65.7%) and nausea / vomiting (55.2%). Twenty-three of the patients had a history of drug intake (60.5%), and the most active drugs in the etiology were non-steroidal anti-inflammatory drugs (56.5%). Eleven patients were given steroid therapy due to severe kidney involvement and rapid increases in serum creatinine values, and ten of those patients were drug-related ATIN cases. Other patients were given symptomatic treatment. Four patients needed several sessions of dialysis due to the severity of their acute renal failure. The follow-up creatinine and estimated glomerular filtration rate levels were not statistically different between the symptomatic and corticosteroid treated groups (P > 0.05).

CONCLUSIONS

Although our study was unable to show the beneficial effect of corticosteroid therapy on the extent of renal recovery, the use of steroids may be preferable in severe nephritis because of the rapid recovery of estimated glomerular filtration rate with corticosteroid therapy.

A Systematic Review of Renal Pathology in Chronic Kidney Disease of Uncertain Etiology

INTRODUCTION

Despite much research on chronic kidney disease of uncertain etiology (CKDu) in Sri Lanka and the Mesoamerican nephropathy, the etiology and pathogenesis of this disease remains elusive. The pathology has broadly been described as chronic tubulointerstitial nephritis and no specific signature lesions have been identified.

METHODS

A scoping review was conducted through MEDLINE and Google Scholar databases for peer-reviewed publications on biopsy studies related to CKDu - Sri Lanka and Mesoamerican nephropathy to develop a comparative and critical analysis of the renal pathology found in these patients.

RESULTS

Thirteen studies met the selection criteria. Interstitial fibrosis was the predominant lesion in all the studies. Tubulointerstitial and glomerular abnormalities showed a more variable distribution. No characteristic histopathological feature was reported other than a proximal tubular lysosomal inclusion body which was claimed to indicate a toxic etiology. Three main pathogenetic mechanisms were postulated: repeated acute insults leading to scarring, low-grade chronic insults leading to non-inflammatory fibrosis, and tubulointerstitial damage in combination with glomerular injury. The main limitations in the interpretation and comparative analysis of these studies were the heterogeneity in case selection and biopsy reporting.

CONCLUSIONS

Although no characteristic histopathological feature could be found in CKDu-Sri Lanka or Mesoamerican nephropathy, there are noticeable differences between these two groups in the frequency and severity of the glomerular and tubulointerstitial changes which warrant more explorative studies preferably on kidneys in early stages of the disease. Future strategies should ensure that more uniform selection criteria and reporting methods are used.

Aetiology, course and treatment of acute tubulointerstitial nephritis in paediatric patients: a cross-sectional web-based survey

BACKGROUND

Acute tubulointerstitial nephritis (TIN) is a significant cause of acute renal failure in paediatric and adult patients. There are no large paediatric series focusing on the aetiology, treatment and courses of acute TIN.

PATIENTS, DESIGN AND SETTING

We collected retrospective clinical data from paediatric patients with acute biopsy-proven TIN by means of an online survey. Members of four professional societies were invited to participate.

RESULTS

Thirty-nine physicians from 18 countries responded. 171 patients with acute TIN were included (54% female, median age 12 years). The most frequent causes were tubulointerstitial nephritis and uveitis syndrome in 31% and drug-induced TIN in 30% (the majority of these caused by non-steroidal anti-inflammatory drugs). In 28% of patients, no initiating noxae were identified (idiopathic TIN). Median estimated glomerular filtration rate (eGFR) rose significantly from 31 at time of renal biopsy to 86 mL/min/1.73 m² 3-6 months later (p<0.001). After 3-6 months, eGFR normalised in 41% of patients (eGFR ≥90 mL/min/1.73 m²), with only 3% having severe or end-stage impairment of renal function (<30 mL/min/1.73 m²). 80% of patients received corticosteroid therapy. Median eGFR after 3-6 months did not differ between steroid-treated and steroid-untreated patients. Other immunosuppressants were used in 18% (n=31) of patients, 21 of whom received mycophenolate mofetil.

CONCLUSIONS

Despite different aetiologies, acute paediatric TIN had a favourable outcome overall with 88% of patients showing no or mild impairment of eGFR after 3-6 months. Prospective randomised controlled trials are needed to evaluate the efficacy of glucocorticoid treatment in paediatric patients with acute TIN.

The Differential Diagnosis of Sterile Pyuria in Pediatric Patients: A Review

Sterile pyuria is a common finding in pediatric patients. Literature describing the diagnoses as well as clinical characteristics of children with sterile pyuria is lacking. This review was performed to establish an evidence-based approach to the differential diagnosis by way of an extensive literature search. The definition of pyuria is inconsistent. The various causes of pediatric sterile pyuria identified were classified as either Infectious or Non-Infectious. Sub-categories of Infectious causes include: Viral Infection, Bacterial Infection, Other Infections (tuberculosis, fungal, parasitic), Sexually Transmitted Infections, Recent Antibiotic Therapy. Non-Infectious causes include: Systemic Disease, Renal Disease, Drug Related, Inflammation adjacent to Genitourinary Tract. Clinicians that encounter pediatric patients with sterile pyuria and persistent symptoms should consider the substantial differential diagnosis described in this study.

Prednisolone treatment in acute interstitial nephritis (PRAISE) - protocol for the randomized controlled trial

BACKGROUND

Acute interstitial nephritis (AIN) is an important and common cause of acute renal failure. There are no generally accepted guidelines for the treatment of AIN, due to the lack of prospective randomized trials. Since AIN is characterized by an enhanced immune response, immunosuppressive treatment could potentially improve prognosis by attenuating inflammation and subsequent fibrosis. Despite the limited evidence of effects of steroids and potential adverse effects, prednisolone is frequently used in the treatment of AIN and there is a strong need for clinical trials on the effects of immunosuppression, including steroids, in the treatment of AIN. We aimed to evaluate the effectiveness of prednisolone treatment in AIN, and hypothesized a positive effect of prednisolone treatment on renal function in AIN.

METHODS

The study is a randomized, controlled, prospective, open label multicenter study, including incident adult patients with biopsy proven AIN. Patients will be randomized 1:1 to one of 2 treatment regimens: A. No prednisolone treatment (control group) and B. B) Oral prednisolone treatment staring with 60 mg daily tapered over 8 weeks. One hundred ten patients (55 in each group) are planned to be included and followed for 1 year. Primary outcome is renal function estimated by eGFR 3 months after inclusion. Secondary outcomes are renal function after 12 months and need for renal replacement therapy and quality of life after 3 and 12 months. In addition, with-in prednisolone group analysis are performed to estimate the importance of treatment delay. Exploratory analyses include analysis of biomarkers in urine and plasma and the evaluation of these biomarkers in relation to renal prognosis and re-evaluation of renal biopsies to identify possible renal prognostic factors.

DISCUSSION

Strengths and possible limitations in the design are evaluated. The study will provide important information on the effects of prednisolone treatment in AIN and as well as prognostic information relevant for future use of biomarkers and histology. Ultimately, this would lead to improved and evidence based clinical guidelines for the treatment of AIN.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT04376216 (Retrospectively registered on May 6, 2020).

More than ancillary records: clinical implications of renal pathology examination in tumor nephrectomy specimens

Background

Nephrectomy is the management of choice for the treatment of renal tumors. Surgical pathologists primarily focus on tumor diagnosis and investigations relating to prognosis or therapy. Pathological changes in non-neoplastic tissue may, however, be relevant for further management and should be thoroughly assessed.

Methods

Here, we examined the non-neoplastic renal parenchyma in 206 tumor nephrectomy specimens for the presence of glomerular, tubulo-interstitial, or vascular lesions, and correlated them with clinical parameters and outcome of renal function.

Results

We analyzed 188 malignant and 18 benign or pseudo-tumorous lesions. The most common tumor type was clear cell renal cell carcinoma (CCRCC, n = 106) followed by papillary or urothelial carcinomas (n = 25). Renal pathology examination revealed the presence of kidney disease in 39 cases (18.9%). Glomerulonephritis was found in 15 cases (7.3%), and the most frequent was IgA nephropathy (n = 6; 2.9%). Vasculitis was found in two cases (0.9%). In 15 cases we found tubulo-interstitial nephritis, and in 9 severe diabetic or hypertensive nephropathy. Partial nephrectomy was not linked to better eGFR at follow-up. Age, vascular nephropathy, glomerular scarring and interstitial fibrosis were the leading independent negative factors influencing eGFR at time of surgery, whereas proteinuria was associated with reduced eGFR at 1 year.

Conclusion

Our large study population indicates a high incidence of renal diseases potentially relevant for the postoperative management of patients with renal neoplasia. Consistent and systematic reporting of non-neoplastic renal pathology in tumor nephrectomy specimens should therefore be mandatory.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40620-021-01030-0.