RESUMO
Podocyte injury plays a key role in pathogenesis of many kidney diseases with increased podocyte foot process width (FPW), an important measure of podocyte injury. Unfortunately, there is no consensus on the best way to estimate FPW and unbiased stereology, the current gold standard, is time consuming and not widely available. To address this, we developed an automated FPW estimation technique using deep learning. A U-Net architecture variant model was trained to semantically segment the podocyte-glomerular basement membrane interface and filtration slits. Additionally, we employed a post-processing computer vision approach to accurately estimate FPW. A custom segmentation utility was also created to manually classify these structures on digital electron microscopy (EM) images and to prepare a training dataset. The model was applied to EM images of kidney biopsies from 56 patients with Fabry disease, 15 with type 2 diabetes, 10 with minimal change disease, and 17 normal individuals. The results were compared with unbiased stereology measurements performed by expert technicians unaware of the clinical information. FPW measured by deep learning and by the expert technicians were highly correlated and not statistically different in any of the studied groups. A Bland-Altman plot confirmed interchangeability of the methods. FPW measurement time per biopsy was substantially reduced by deep learning. Thus, we have developed a novel validated deep learning model for FPW measurement on EM images. The model is accessible through a cloud-based application making calculation of this important biomarker more widely accessible for research and clinical applications.
Assuntos
Aprendizado Profundo , Diabetes Mellitus Tipo 2 , Nefropatias Diabéticas , Humanos , Nefropatias Diabéticas/diagnóstico , Nefropatias Diabéticas/patologia , Membrana Basal Glomerular/patologia , BiópsiaRESUMO
BACKGROUND: Fabry disease (FD) is a rare lysosomal storage disorder caused by mutations in the GLA gene, resulting in reduced or lack of α-galactosidase A activity. This results in the accumulation of globotriaosylceramide (Gb3) and other glycosphingolipids in lysosomes causing cellular impairment and organ failures. While current therapies focus on reversing Gb3 accumulation, they do not address the altered cellular signaling in FD. Therefore, this study aims to explore Gb3-independent mechanisms of kidney damage in Fabry disease and identify potential biomarkers. METHODS: To investigate these mechanisms, we utilized a zebrafish (ZF) gla-/- mutant (MU) model. ZF naturally lack A4GALT gene and, therefore, cannot synthesize Gb3. We obtained kidney samples from both wild-type (WT) (n = 8) and MU (n = 8) ZF and conducted proteome profiling using untargeted mass spectrometry. Additionally, we examined mitochondria morphology and cristae morphology using electron microscopy. To assess oxidative stress, we measured total antioxidant activity. Finally, immunohistochemistry was conducted on kidney samples to validate specific proteins. RESULTS: Our proteomics analysis of renal tissues from zebrafish revealed downregulation of lysosome and mitochondrial-related proteins in gla-/- MU renal tissues, while energy-related pathways including carbon, glycolysis, and galactose metabolisms were disturbed. Moreover, we observed abnormal mitochondrial shape, disrupted cristae morphology, altered mitochondrial volume and lower antioxidant activity in gla-/- MU ZF. CONCLUSIONS: These results suggest that the alterations observed at the proteome and mitochondrial level closely resemble well-known GLA mutation-related alterations in humans. Importantly, they also unveil novel Gb3-independent pathogenic mechanisms in Fabry disease. Understanding these mechanisms could potentially lead to the development of innovative drug screening approaches. Furthermore, the findings pave the way for identifying new clinical targets, offering new avenues for therapeutic interventions in Fabry disease. The zebrafish gla-/- mutant model proves valuable in elucidating these mechanisms and may contribute significantly to advancing our knowledge of this disorder.
Assuntos
Doença de Fabry , Animais , Humanos , Antioxidantes , Mitocôndrias , Proteoma , Proteômica , Peixe-Zebra , alfa-Galactosidase/metabolismoRESUMO
Fabry disease is a rare disorder caused by variations in the alpha-galactosidase gene. To a degree, Fabry disease is manageable via enzyme replacement therapy (ERT). By understanding the molecular basis of Fabry nephropathy (FN) and ERT's long-term impact, here we aimed to provide a framework for selection of potential disease biomarkers and drug targets. We obtained biopsies from eight control individuals and two independent FN cohorts comprising 16 individuals taken prior to and after up to ten years of ERT, and performed RNAseq analysis. Combining pathway-centered analyses with network-science allowed computation of transcriptional landscapes from four nephron compartments and their integration with existing proteome and drug-target interactome data. Comparing these transcriptional landscapes revealed high inter-cohort heterogeneity. Kidney compartment transcriptional landscapes comprehensively reflected differences in FN cohort characteristics. With exception of a few aspects, in particular arteries, early ERT in patients with classical Fabry could lastingly revert FN gene expression patterns to closely match that of control individuals. Pathways nonetheless consistently altered in both FN cohorts pre-ERT were mostly in glomeruli and arteries and related to the same biological themes. While keratinization-related processes in glomeruli were sensitive to ERT, a majority of alterations, such as transporter activity and responses to stimuli, remained dysregulated or reemerged despite ERT. Inferring an ERT-resistant genetic module of expressed genes identified 69 drugs for potential repurposing matching the proteins encoded by 12 genes. Thus, we identified and cross-validated ERT-resistant gene product modules that, when leveraged with external data, allowed estimating their suitability as biomarkers to potentially track disease course or treatment efficacy and potential targets for adjunct pharmaceutical treatment.
Assuntos
Doença de Fabry , Nefropatias , Humanos , alfa-Galactosidase/genética , alfa-Galactosidase/metabolismo , Biomarcadores , Reposicionamento de Medicamentos , Terapia de Reposição de Enzimas , Doença de Fabry/tratamento farmacológico , Doença de Fabry/genética , Rim/metabolismo , Nefropatias/tratamento farmacológico , Nefropatias/genética , Análise de Sistemas , TranscriptomaRESUMO
While females can suffer serious complications of Fabry disease, most studies are limited to males to avoid confounding by mosaicism. Here, we developed a novel unbiased method for quantifying globotriaosylceramide (GL3) inclusion volume in affected podocytes (F+) in females with Fabry disease independent of mosaicism leading to important new observations. All podocytes in male patients with Fabry are F+. The probability of observing random profiles from F+ podocytes without GL3 inclusions (estimation error) was modeled from electron microscopic studies of 99 glomeruli from 40 treatment-naïve males and this model was applied to 28 treatment-naïve females. Also, podocyte structural parameters were compared in 16 age-matched treatment-naïve males and females with classic Fabry disease and 11 normal individuals. A 4th degree polynomial equation best described the relationship between podocyte GL3 volume density and the estimation error (R2 =0.94) and was confirmed by k-fold cross-validation. In females, this model showed that age related directly to F+ podocyte GL3 volume (correlation coefficient (r = 0.54) and podocyte volume (r = 0.48) and inversely to podocyte number density (r = -0.56), (all significant). F+ podocyte GL3 volume was significantly inversely related to podocyte number density (r = -0.79) and directly to proteinuria. There was no difference in F+ podocyte GL3 volume or volume fraction between age-matched males and females. Thus, in females with Fabry disease GL3 accumulation in F+ podocytes progresses with age in association with podocyte loss and proteinuria, and F+ podocyte GL3 accumulation in females with Fabry is similar to males, consistent with insignificant cross-correction between affected and non-affected podocytes. Hence, these findings have important pathophysiological and clinical implications.
Assuntos
Doença de Fabry , Podócitos , Doença de Fabry/complicações , Feminino , Humanos , Masculino , Proteinúria/etiologia , TriexosilceramidasRESUMO
BACKGROUND AND OBJECTIVES: Persons with intravenous drug use have a higher risk of developing CKD compared with the general population. In Norway, deposits of polyvinylpyrrolidone have been observed in kidney biopsies taken from persons with opioid addiction and intravenous drug use since 2009. Polyvinylpyrrolidone is an excipient commonly used in pharmaceuticals, and the polyvinylpyrrolidone deposits observed in these patients were caused by intravenous injection of a specific oral methadone syrup containing very high molecular weight polyvinylpyrrolidone. Here, we present the clinicopathologic findings from 28 patients with CKD associated with polyvinylpyrrolidone deposition in the kidney. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The 28 patients and their kidney biopsies were included when polyvinylpyrrolidone deposition was recognized, either retrospectively or at the time of diagnostic evaluation. Biopsies were taken between 2009 and 2016. We collected laboratory parameters and clinical data from digital patient charts. For each kidney biopsy, the glomerular volume, extent of polyvinylpyrrolidone deposition, and tubulointerstitial area with tubular atrophy were assessed quantitatively. RESULTS: All patients (mean age: 37 years) had CKD (mean eGFR: 33 ml/min per 1.73 m2) and normal urine protein or non-nephrotic-range proteinuria. Biopsies showed moderate to severe tubular atrophy (mean extent: 65%) and interstitial infiltrates of vacuolated macrophages containing polyvinylpyrrolidone (mean share of biopsy area: 1.5%). Underperfused and ischemic glomeruli were common findings. In 22 samples, ultrastructural investigation revealed polyvinylpyrrolidone-containing vacuoles in the mesangial or endothelial cells of glomeruli. At the last follow-up, most patients had stable or improved eGFR. Two patients had developed kidney failure and underwent hemodialysis. CONCLUSIONS: Intravenous injection of a specific oral methadone syrup caused polyvinylpyrrolidone deposition in the kidney in persons with opioid addiction and intravenous drug use. Kidney biopsy findings suggested an association between polyvinylpyrrolidone deposition and tubular atrophy.
Assuntos
Transtornos Relacionados ao Uso de Opioides , Insuficiência Renal Crônica , Adulto , Atrofia/patologia , Biópsia , Células Endoteliais/patologia , Humanos , Rim/patologia , Metadona , Transtornos Relacionados ao Uso de Opioides/complicações , Transtornos Relacionados ao Uso de Opioides/patologia , Povidona/efeitos adversos , Insuficiência Renal Crônica/induzido quimicamente , Insuficiência Renal Crônica/etiologia , Insuficiência Renal Crônica/patologia , Estudos RetrospectivosRESUMO
Fabry disease (FD) is an X-linked inborn metabolic disorder due to partial or complete lysosomal α-galactosidase A deficiency. FD is characterized by progressive renal insufficiency and cardio- and cerebrovascular involvement. Restricted access on Gb3-independent tissue injury experimental models has limited the understanding of FD pathophysiology and delayed the development of new therapies. Accumulating glycosphingolipids, mainly Gb3 and lysoGb3, are Fabry specific markers used in clinical follow up. However, recent studies suggest there is a need for additional markers to monitor FD clinical course or response to treatment. We used a gla-knockout zebrafish (ZF) to investigate alternative biomarkers in Gb3-free-conditions. RNA sequencing was used to identify transcriptomic signatures in kidney tissues discriminating gla-mutant (M) from wild type (WT) ZF. Gene Ontology (GO) and KEGG pathways analysis showed upregulation of immune system activation and downregulation of oxidative phosphorylation pathways in kidneys from M ZF. In addition, upregulation of the Ca2+ signaling pathway was also detectable in M ZF kidneys. Importantly, disruption of mitochondrial and lysosome-related pathways observed in M ZF was validated by immunohistochemistry. Thus, this ZF model expands the pathophysiological understanding of FD, the Gb3-independent effects of gla mutations could be used to explore new therapeutic targets for FD.
Assuntos
Doença de Fabry , Animais , Doença de Fabry/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , alfa-Galactosidase/genética , Perfilação da Expressão Gênica , Transdução de Sinais , MutaçãoRESUMO
Background: Intravenous injection of oral opioid substitution drugs (OSD) is widespread among injecting drug users. Several OSDs contain the polymer polyvinylpyrrolidone (PVP) as an excipient. Parenterally administered PVP of high molecular weight may accumulate in tissues and organs. This phenomenon was first described in the 1950s, when PVP was utilised in medication for parenteral use. We report a case of an opioid-addicted patient with extensive PVP-deposition caused by repeated injections of OSDs. Case presentation: A 30-year-old male drug addicted patient in opioid substitution therapy (OST) was repeatedly referred to his local hospital in a poor general condition. Work-up revealed severe normocytic anaemia, renal insufficiency, pancreas insufficiency and pathological fractures. Biopsies from fractured bones, bone marrow and gastric mucosa showed extensive infiltrates of histiocytes with intracytoplasmic vacuoles. Vacuole content stained slightly bluish in hematoxylin and eosin stain, red in Congo red stain and black in periodic acid methenamine silver stain. The morphological appearance and staining properties were in accordance with the diagnosis of PVP deposition. The patient had been injecting both buprenorphine tablets and a specific methadone syrup for several years. The methadone syrup contained large amounts of high molecular weight PVP, making it the most likely cause of the deposition. His health quickly deteriorated and he died, impaired by multi-organ failure and cachexia, five years after the first diagnosis of PVP-deposition. The autopsy revealed extensive PVP-deposition in all sampled organs and tissues. Conclusions: Histological investigation and the correct identification of PVP in the biopsies led to the discovery of a severe adverse effect from long-standing misuse of a drug. The disseminated PVP deposition likely contributed to multi-organ dysfunction and cachexia with a fatal outcome. The deposited PVP likely originated from repeated injections of a certain methadone syrup.
Assuntos
Buprenorfina , Preparações Farmacêuticas , Adulto , Analgésicos Opioides , Humanos , Masculino , Povidona/efeitos adversosRESUMO
The polymer polyvinylpyrrolidone (PVP) is an excipient widely used in prescription drugs. Depending on the molecular weight (MW), parenterally administered PVP may accumulate in various tissues. Consequently, moderate and high MW PVP have only been used in oral preparations since the late 1970s. Surprisingly, starting in 2009, pathology departments in Norway received biopsies revealing PVP deposition, all from patients with a history of intravenous drug use. We identified 13 patients with PVP deposition and re-evaluated 31 biopsies and two autopsies. Common indications for biopsy were renal insufficiency, anemia, pathological fractures, and abdominal complaints. We observed PVP deposits in all biopsies (kidney, hematopoietic bone marrow, bone, gastrointestinal tract, lymph node, and skin) and all sampled tissue from the autopsies. Overall, the clinical findings could be related to PVP deposits in the biopsies. In the most seriously affected patients, PVP deposition caused severe organ dysfunction and contributed to the fatal outcomes of two patients. All patients except for one were prescribed opioid substitution drugs (OSDs), and most of the patients admitted to having injected such medications. Several OSDs contain PVP. One methadone formulation that was marketed in Norway from 2007 to 2014 contained large amounts of very high MW PVP, making it the most likely source of PVP deposition. Although the presumed source of PVP in these patients has now been withdrawn from the market, pathologists should be aware of PVP deposits when evaluating biopsies from this patient group.
Assuntos
Excipientes/efeitos adversos , Tratamento de Substituição de Opiáceos/efeitos adversos , Povidona/efeitos adversos , Adulto , Anemia/induzido quimicamente , Feminino , Fraturas Ósseas/induzido quimicamente , Humanos , Nefropatias/induzido quimicamente , Masculino , Pessoa de Meia-Idade , Transtornos Relacionados ao Uso de OpioidesRESUMO
INTRODUCTION: Published data on hypertension incidence and management in Anderson-Fabry disease are scant and the contribution of elevated blood pressure to organ damage is not well recognized. AIM: Therefore, we have assessed blood pressure values and their possible correlations with clinical findings in a well described cohort of Fabry patients. METHODS: Between January 2015 and May 2019, all adult Fabry patients (n = 24 females, n = 8 males) referred to our institute were prospectively enrolled. During the first examination patient's genotype and clinical characteristics were recorded. Blood pressure data were obtained by standard observed office measurements followed, within 6 months, by ambulatory blood pressure monitoring and home self-recordings. Organ involvement, including kidneys, heart and brain, was monitored over time. Consequently, patients were defined as clinically stable or progressive through the Fabry Stabilization Index. RESULTS: The standard office measurements have diagnosed hypertension in three (9.37%) patients, but the ambulatory monitoring showed elevated blood pressure in six (18.75%) patients, revealing three cases of masked hypertension. All the hypertensive patients were females and, compared with normotensive subjects, they presented a lower glomerular filtration rate (p < 0.05) and a more advanced cardiac hypertrophy (p < 0.05). Four (66.7%) of them were diagnosed with a progressive form of the disease through the Fabry Stabilization Index while the majority of the normotensive group (84.6%, n = 19) was stable over time. No correlation was found between the prevalence of hypertension and the type of mutations causing Fabry disease. CONCLUSION: Hypertension can be found in a restricted portion of clinically stable Fabry patients. In contrast, patients presenting with a progressive organ involvement, particularly renal impairment, have a major risk of developing uncontrolled blood pressure, and should be followed carefully. Moreover, the ambulatory blood pressure monitoring proved to be useful to reveal masked hypertension, which can contribute to the progressive worsening of the organ damage. Therefore, a proper diagnosis and therapy of hypertension may improve the outcome of Fabry patients.
Assuntos
Monitorização Ambulatorial da Pressão Arterial , Pressão Sanguínea , Doença de Fabry/complicações , Hipertensão/etiologia , Adulto , Idoso , Progressão da Doença , Doença de Fabry/fisiopatologia , Feminino , Humanos , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-IdadeRESUMO
Nephropathy represents a major complication of Fabry Disease and its accurate characterization is of paramount importance in predicting the disease progression and assessing the therapeutic responses. The diagnostic process still relies on performing renal biopsy, nevertheless many efforts have been made to discover early reliable biomarkers allowing us to avoid invasive procedures. In this field, proteomics offers a sensitive and fast method leading to an accurate detection of specific pathological proteins and the discovery of diagnostic and prognostic biomarkers that reflect disease progression and facilitate the evaluation of therapeutic responses. Here, we report a review of selected literature focusing on the investigation of several proteomic techniques highlighting their advantages, limitations and future perspectives in their application in the routine study of Fabry Nephropathy.
Assuntos
Doença de Fabry/diagnóstico , Proteínas/genética , Proteoma/genética , Proteômica/métodos , Biomarcadores/metabolismo , Progressão da Doença , Doença de Fabry/genética , Doença de Fabry/patologia , Humanos , Proteínas/isolamento & purificaçãoRESUMO
OBJECTIVES: The PRoposing Early Disease Indicators for Clinical Tracking in Fabry Disease (PREDICT-FD) initiative aimed to reach consensus among a panel of global experts on early indicators of disease progression that may justify FD-specific treatment initiation. DESIGN AND SETTING: Anonymous feedback from panellists via online questionnaires was analysed using a modified Delphi consensus technique. Questionnaires and data were managed by an independent administrator directed by two non-voting cochairs. First, possible early indicators of renal, cardiac and central/peripheral nervous system (CNS/PNS) damage, and other disease and patient-reported indicators assessable in routine clinical practice were compiled by the cochairs and administrator from panellists' free-text responses. Second, the panel scored indicators for importance (5-point scale: 1=not important; 5=extremely important); indicators scoring ≥3 among >75% of panellists were then rated for agreement (5-point scale: 1=strongly disagree; 5=strongly agree). Indicators awarded an agreement score ≥4 by >67% of panellists achieved consensus. Finally, any panel-proposed refinements to consensus indicator definitions were adopted if >75% of panellists agreed. RESULTS: A panel of 21 expert clinicians from 15 countries provided information from which 83 possible current indicators of damage (kidney, 15; cardiac, 15; CNS/PNS, 13; other, 16; patient reported, 24) were compiled. Of 45 indicators meeting the importance criteria, consensus was reached for 29 and consolidated as 27 indicators (kidney, 6; cardiac, 10; CNS/PNS, 2; other, 6; patient reported, 3) including: (kidney) elevated albumin:creatinine ratio, histological damage, microalbuminuria; (cardiac) markers of early systolic/diastolic dysfunction, elevated serum cardiac troponin; (CNS/PNS) neuropathic pain, gastrointestinal symptoms suggestive of gastrointestinal neuropathy; (other) pain in extremities/neuropathy, angiokeratoma; (patient-reported) febrile crises, progression of symptoms/signs. Panellists revised and approved proposed chronologies of when the consensus indicators manifest. The panel response rate was >95% at all stages. CONCLUSIONS: PREDICT-FD captured global opinion regarding current clinical indicators that could prompt FD-specific treatment initiation earlier than is currently practised.
Assuntos
Doença de Fabry , Consenso , Técnica Delphi , Progressão da Doença , Doença de Fabry/diagnóstico , Doença de Fabry/tratamento farmacológico , Humanos , Inquéritos e QuestionáriosRESUMO
BACKGROUND: In males with classic Fabry disease, the processes leading to the frequent outcome of ESKD are poorly understood. Defects in the gene encoding α-galactosidase A lead to accumulation of globotriaosylceramide (GL3) in various cell types. In the glomerular podocytes, accumulation of GL3 progresses with age. Of concern, podocytes are relatively resistant to enzyme replacement therapy and are poorly replicating, with little ability to compensate for cell loss. METHODS: In this study of 55 males (mean age 27 years) with classic Fabry disease genotype and/or phenotype, we performed unbiased quantitative morphometric electron microscopic studies of biopsied kidney samples from patients and seven living transplant donors (to serve as controls). We extracted clinical information from medical records and clinical trial databases. RESULTS: Podocyte GL3 volume fraction (proportion of podocyte cytoplasm occupied by GL3) increased with age up to about age 27, suggesting that increasing podocyte GL3 volume fraction beyond a threshold may compromise survival of these cells. GL3 accumulation was associated with podocyte injury and loss, as evidenced by increased foot process width (a generally accepted structural marker of podocyte stress and injury) and with decreased podocyte number density per glomerular volume. Worsening podocyte structural parameters (increasing podocyte GL3 volume fraction and foot process width) was also associated with increasing urinary protein excretion-a strong prognosticator of adverse renal outcomes in Fabry disease-as well as with decreasing GFR. CONCLUSIONS: Given the known association between podocyte loss and irreversible FSGS and global glomerulosclerosis, this study points to an important role for podocyte injury and loss in the progression of Fabry nephropathy and indicates a need for therapeutic intervention before critical podocyte loss occurs.
Assuntos
Doença de Fabry/metabolismo , Doença de Fabry/patologia , Podócitos/metabolismo , Podócitos/patologia , Triexosilceramidas/metabolismo , Adolescente , Adulto , Fatores Etários , Estudos de Casos e Controles , Criança , Pré-Escolar , Taxa de Filtração Glomerular , Humanos , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Masculino , Pessoa de Meia-Idade , Adulto JovemAssuntos
Doença de Fabry , Nefropatias , Diagnóstico Precoce , Terapia de Reposição de Enzimas , Doença de Fabry/diagnóstico , Doença de Fabry/epidemiologia , Doença de Fabry/genética , Doença de Fabry/terapia , Predisposição Genética para Doença , Humanos , Isoenzimas/uso terapêutico , Nefropatias/diagnóstico , Nefropatias/epidemiologia , Nefropatias/genética , Nefropatias/terapia , Mutação , Fenótipo , Valor Preditivo dos Testes , Prognóstico , Proteínas Recombinantes/uso terapêutico , Medição de Risco , Fatores de Risco , alfa-Galactosidase/genética , alfa-Galactosidase/uso terapêuticoRESUMO
BACKGROUND: The burden of kidney diseases is reported to be higher in lower- and middle-income countries as compared to developed countries, and countries in sub-Saharan Africa are reported to be most affected. Health systems in most sub-Sahara African countries have limited capacity in the form of trained and skilled health care providers, diagnostic support, equipment and policies to provide nephrology services. Several initiatives have been implemented to support establishment of these services. METHODS: This is a situation analysis to examine the nephrology services in Tanzania. It was conducted by interviewing key personnel in institutions providing nephrology services aiming at describing available services and international collaborators supporting nephrology services. RESULTS: Tanzania is a low-income country in Sub-Saharan Africa with a population of more than 55 million that has seen remarkable improvement in the provision of nephrology services and these include increase in the number of nephrologists to 14 in 2018 from one in 2006, increase in number of dialysis units from one unit (0.03 unit per million) before 2007 to 28 units (0.5 units per million) in 2018 and improved diagnostic services with introduction of nephropathology services. Government of Tanzania has been providing kidney transplantation services by funding referral of donor and recipients abroad and has now introduced local transplantation services in two hospitals. There have been strong international collaborators who have supported nephrology services and establishment of nephrology training in Tanzania. CONCLUSION: Tanzania has seen remarkable achievement in provision of nephrology services and provides an interesting model to be used in supporting nephrology services in low income countries.
Assuntos
Atenção à Saúde/tendências , Países em Desenvolvimento/estatística & dados numéricos , Nefrologia/estatística & dados numéricos , Diálise Renal/estatística & dados numéricos , Insuficiência Renal Crônica/terapia , Biópsia , Atenção à Saúde/organização & administração , Humanos , Cooperação Internacional , Rim/patologia , Transplante de Rim , Rins Artificiais/provisão & distribuição , Nefrologistas/provisão & distribuição , Nefrologia/educação , Diálise Peritoneal , Insuficiência Renal Crônica/diagnóstico , TanzâniaRESUMO
OBJECTIVE: Chronic kidney disease (CKD) is a serious medical condition characterized by gradual loss of kidney function. Early detection and diagnosis is mandatory for adequate therapy and prognostic improvement. Hence, in the current pilot study we explore the use of image registration methods for detecting renal morphologic changes in patients with CKD. METHODS: Ten healthy volunteers and nine patients with presumed CKD underwent dynamic T1 weighted imaging without contrast agent. From real and simulated dynamic time series, kidney deformation fields were estimated using a poroelastic deformation model. From the deformation fields several quantitative parameters reflecting pressure gradients, and volumetric and shear deformations were computed. Eight of the patients also underwent a kidney biopsy as a gold standard. RESULTS: We found that the absolute deformation, normalized volume changes, as well as pressure gradients correlated significantly with arteriosclerosis from biopsy assessments. Furthermore, our results indicate that current image registration methodologies are lacking sensitivity to recover mild changes in tissue stiffness. CONCLUSION: Image registration applied to dynamic time series correlated with structural renal changes and should be further explored as a tool for invasive measurements of arteriosclerosis. SIGNIFICANCE: Under the assumption that the proposed framework can be further developed in terms of sensitivity and specificity, it can provide clinicians with a non-invasive tool of high spatial coverage available for characterization of arteriosclerosis and potentially other pathological changes observed in chronic kidney disease.
Assuntos
Interpretação de Imagem Assistida por Computador/métodos , Rim/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Insuficiência Renal Crônica/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Biópsia , Elasticidade/fisiologia , Feminino , Humanos , Rim/patologia , Rim/fisiopatologia , Masculino , Pessoa de Meia-Idade , Insuficiência Renal Crônica/patologia , Insuficiência Renal Crônica/fisiopatologia , Adulto JovemRESUMO
BACKGROUND: In a recent study we demonstrated that low birth weight (LBW) was associated with increased risk of progressive IgA nephropathy (IgAN). In the present study we investigate whether this could be explained by differences in glomerular morphological parameters. METHODS: The Medical Birth Registry of Norway has registered all births since 1967 and the Norwegian Kidney Biopsy Registry has registered all kidney biopsies since 1988. Patients diagnosed with IgAN, registered birth weight and estimated glomerular filtration rate above 60 ml/min/1.73m2 at time of diagnosis were eligible for inclusion. Patients were included in a case-control manner based on whether or not they had LBW or were small for gestational age (SGA). Glomerular area, volume and density were measured using high resolution digital images and differences were compared between groups. RESULTS: We included 51 IgAN patients with a mean age of 23.6 years, 47.1% male. Compared to IgAN patients without LBW or SGA, IgAN patients with LBW and/or SGA had larger glomerular area (16,235 ± 3744 vs 14,036 ± 3502 µm2, p-value 0.04). This was significant for total cohort and male but not female. On separate analysis by gender, glomerular area was significantly larger only in males (17,636 ± 3285 vs 13,346 ± 2835 µm2, p-value 0.004). Glomerular density was not different between groups. In adjusted linear regression analysis, glomerular area was negatively associated with birth weight. CONCLUSION: Among young adult IgAN patients, low birth weight is associated with having larger glomerular area, especially in males. Larger glomeruli may be a sign of congenital nephron deficit that may explain the increased risk of progressive IgAN.
Assuntos
Glomerulonefrite por IGA/diagnóstico , Glomerulonefrite por IGA/fisiopatologia , Recém-Nascido de Baixo Peso/fisiologia , Glomérulos Renais/patologia , Adolescente , Adulto , Feminino , Glomerulonefrite por IGA/epidemiologia , Humanos , Masculino , Noruega/epidemiologia , Sistema de Registros , Adulto JovemRESUMO
BACKGROUND/AIMS: A previous case report found stereomicroscopic changes typical for Fabry disease in a kidney biopsy. This case series evaluates an expanded diagnostic capacity of the method. METHODS: Bedside stereomicroscopy was performed in a cross-sectional prospective study of 31 consecutive enzyme-treated or treatment-naïve male (n = 14) and female Fabry disease patients. The burden of glomerular storage material was scored semiquantitatively on a visual analog scale (range 0-3) and a blinded comparison was done with a reference histologic method. RESULTS: Significant correlations (p < 0.001) were found between the stereomicroscopic scoring of glomerular characteristic white storage material and the amount of podocyte globotriaosylceramide (Gb3) deposits scored by standardized light microscopy. The bedside method correctly identified the variability of podocyte Gb3 accumulation after 10 years of identical agalsidase therapy in 2 brothers aged 24 and 27 years, and also identified tubular cell deposits. Stereomicroscopy correctly verified the absence of sphingolipid deposits in the biopsy of a female index patient with a genetic variant of unknown significance, and the diagnosis of Fabry disease was finally discarded. CONCLUSIONS: Bedside stereomicroscopy of kidney biopsies is an easily available, low-cost microscopy method handled by the clinician. The method carries a high diagnostic sensitivity for Fabry disease, reducing the risk of misdiagnosis in previously unknown cases. An expanded yield of the method is suggested, including the grading of the podocyte Gb3 burden and assessment of effectiveness of enzyme replacement therapy. We recommend the method as complementary to current standard histologic evaluation of Fabry kidney biopsies.
Assuntos
Biópsia/métodos , Doença de Fabry/metabolismo , Doença de Fabry/patologia , Rim/patologia , Testes Imediatos , Esfingolipídeos/metabolismo , Adulto , Estudos Transversais , Doença de Fabry/diagnóstico , Feminino , Globosídeos/metabolismo , Humanos , Rim/metabolismo , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Túbulos Renais/metabolismo , Túbulos Renais/patologia , Masculino , Microscopia , Pessoa de Meia-Idade , Podócitos/patologia , Estudos Prospectivos , Triexosilceramidas/metabolismo , Adulto JovemRESUMO
BACKGROUND: The non-ionic agent iohexol is increasingly used as the marker of choice for glomerular filtration rate (GFR) measurement. Estimates of GFR in children have low accuracy and limiting the number of blood-draws in this patient population is especially relevant. We have performed a study to evaluate different formulas for calculating measured GFR based on plasma iohexol clearance with blood sampling at only one time point (GFR1p) and to determine the optimal sampling time point. METHODS: Ninety-six children with chronic kidney disease (CKD) stage 1-5 (median age 9.2 years; range 3 months to 17.5 years) were examined in a cross-sectional study using iohexol clearance and blood sampling at seven time points within 5 h (GFR7p) as the reference method. Median GFR7p was 66 (range 6-153) mL/min/1.73 m2. The performances of six different single time-point formulas (Fleming, Ham and Piepsz, Groth and Aasted, Stake, Jacobsson- and Jacobsson-modified) were validated against the reference. The two-point GFR (GFR2p) was calculated according to the Jødal and Brøchner-Mortensen formula. RESULTS: The GFR1p calculated according to Fleming with sampling at 3 h (GFR1p3h-Fleming) had the best overall performance, with 82% of measures within 10% of the reference value (P10). In children with a GFR ≥ 30 mL/min/1.73 m2 (n = 78), the GFR1p3h-Fleming had a P10 of 92.3%, which is not significantly different (p = 0.29) from that of GFR2p (P10 = 96.2%). Considerable differences within and between the different formulas were found for different CKD stages and different time points for blood sampling. CONCLUSIONS: For determination of mGFR in children with CKD and an assumed GFR of ≥ 30 mL/min/1.73 m2 we recommend GFR1p3h-Fleming as the preferred single-point method as an alternative to GFR2p. For children with a GFR < 30 mL/min/1.73 m2, we recommend the slope-GFR with at least two blood samples. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov , Identifier NCT01092260, https://clinicaltrials.gov/ct2/show/NCT01092260?term=tondel&rank=2.
Assuntos
Taxa de Filtração Glomerular/fisiologia , Iohexol/farmacocinética , Insuficiência Renal Crônica/fisiopatologia , Adolescente , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Lactente , Rim/fisiopatologia , Masculino , Taxa de Depuração MetabólicaRESUMO
BACKGROUND AND OBJECTIVES: Dose-dependent clearing of podocyte globotriaosylceramide has previously been shown in patients with classic Fabry disease treated with enzyme replacement. Our study evaluates the dose-dependent effects of agalsidase therapy in serial kidney biopsies of patients treated for up to 14 years. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Twenty patients with classic Fabry disease (12 men) started enzyme replacement therapy at a median age of 21 (range =7-62) years old. Agalsidase-α or -ß was prescribed for a median of 9.4 (range =5-14) years. The lower fixed dose group received agalsidase 0.2 mg/kg every other week throughout the follow-up period. The higher dose group received a range of agalsidase doses (0.2-1.0 mg/kg every other week). Dose changes were made due to disease progression, suboptimal effect, or agalsidase-ß shortage. Serial kidney biopsies were performed along with clinical assessment and biomarkers and scored according to recommendations from the International Study Group of Fabry Nephropathy. RESULTS: No statistical differences were found in baseline or final GFR or albuminuria. Kidney biopsies showed significant reduction of podocyte globotriaosylceramide in both the lower fixed dose group (-1.39 [SD=1.04]; P=0.004) and the higher dose group (-3.16 [SD=2.39]; P=0.002). Podocyte globotriaosylceramide (Gb3) reduction correlated with cumulative agalsidase dose (r=0.69; P=0.001). Arterial/arteriolar intima Gb3 cleared significantly in the higher dose group, all seven patients with baseline intimal Gb3 cleared the intima, one patient gained intimal Gb3 inclusions (P=0.03), and medial Gb3 did not change statistically in either group. Residual plasma globotriaosylsphingosine levels remained higher in the lower fixed dose group (20.1 nmol/L [SD=11.9]) compared with the higher dose group (10.4 nmol/L [SD=8.4]) and correlated with cumulative agalsidase dose in men (r=0.71; P=0.01). CONCLUSIONS: Reduction of podocyte globotriaosylceramide was found in patients with classic Fabry disease treated with long-term agalsidase on different dosing regimens, correlating with cumulative dose. Limited clearing of arterial/arteriolar globotriaosylceramide raises concerns regarding long-term vascular effects of current therapy. Residual plasma globotriaosylsphingosine correlated with cumulative dose in men.