Early decrease in the podocalyxin to synaptopodin ratio in urinary Fabry podocytes.

BACKGROUND: In Fabry nephropathy, podocyturia is an early event that may lead to glomerulosclerosis and chronic kidney disease. The glycocalyx is a potential podocyte damaged compartment in glomerulopathies. We investigated glycocalyx podocalyxin in urinary detached podocytes compared with cytoplasmic synaptopodin. METHODS: This was a cross-sectional study including 68 individuals: Controls (n = 20) and Fabry patients (n = 48), 15 untreated and 33 treated. Variables included age, gender, urinary protein/creatinine ratio (UPCR), estimated glomerular filtration rate (eGFR), lyso-triasocylsphingosine (lyso-Gb3) levels and enzyme replacement therapy (ERT). Podocyturia was assessed by immunofluorescence and podocyte subpopulations were analyzed. RESULTS: Fabry patients displayed higher podocyturia than controls. Fabry treated subjects (n = 33) presented significantly higher UPCR compared with untreated ones (n = 15); podocyturia, eGFR and lyso-Gb3 levels were not different. All control podocytes colocalized synaptopodin and podocalyxin; 13 Fabry patients (27%) colocalized these proteins, while 35 (73%) were only synaptopodin positive. No podocalyxin-positive/synaptopodin-negative cells were encountered. In Fabry patients, podocyturia was significantly higher and proteinuria lower in those that colocalized. CONCLUSION: Fabry patients present higher podocyturia and a presumably more damaged glycocalyx assessed by podocalyxin. Treated patients had significant higher proteinuria suggesting ERT is initiated late, at advanced stages. The degree of podocalyxin-negative podocytes was similar in both groups, but colocalization was associated with lower proteinuria. Podocyturia assessed by podocalyxin alone may be underestimated. The implications of podocyte glycocalyx damage deserve further investigations.

Parenteral Succinate Reduces Systemic ROS Production in Septic Rats, but It Does Not Reduce Creatinine Levels.

In sepsis, reactive oxygen species (ROS) production is increased. This process takes place mainly within the electron transport chain. ROS production is part of the pathophysiology of multiple organ failure in sepsis. Succinate yields Dihydroflavine-Adenine Dinucleotide (FADH2), which enters the chain through complex II, avoiding complex I, through which electrons are lost. The aim of this work is to determine if parenteral succinate reduces systemic ROS production and improves kidney function. Rats with cecal ligation and puncture were used as model of sepsis, and 4 groups were made: Control group; Succinate group, which only received parenteral succinate; Sepsis group; and Sepsis which received parenteral succinate. Systemic ROS are measured 24 hours after the procedure. Rats subjected to cecal puncture treated with succinate had less systemic ROS than Septic untreated rats (p = 0.007), while there were no differences in creatinine levels (p = 0.07). There was no correlation between creatinine and systemic ROS levels (p = 0.3). We concluded that parenteral succinate reduces ROS levels, but it does not reduce creatinine levels. Since there is no correlation between both levels, the processes would not be related.

In IgA Nephropathy, Glomerulosclerosis Is Associated with Increased Urinary CD80 Excretion and Urokinase-Type Plasminogen Activator Receptor-Positive Podocyturia.

BACKGROUND: Podocyturia may determine the evolution to podocytopenia, glomerulosclerosis, and renal failure. According to the Oxford classification of IgA nephropathy (IgAN), the S1 lesion describes glomerulosclerosis. Urokinase-type plasminogen activator receptor (uPAR) participates in podocyte attachment, while CD80 increases in glomerulosclerosis. We measured uPAR-positive urinary podocytes and urinary CD80 (uCD80) in controls and in IgAN subjects with M1E0S0T0 and M1E0S1T0 Oxford scores to assess a potential association between podocyturia, inflammation, and glomerulosclerosis. METHODS: The groups were as follows: controls (G1), n = 20 and IgAN group (G2), n = 39, subdivided into M1E0S0T0 (G2A), n = 21 and M1E0S1T0 (G2B), n = 18. Among the included variables, we determined uPAR-positive podocytes/gram of urinary creatinine (gUrCr) and uCD80 ng/gUrCr. Biopsies with interstitial fibrosis and tubular atrophy <10% were included. RESULTS: Groups were not different in age and gender; urinary protein-creatinine (uP/C) ratio, Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation, uPAR-positive podocytes/gUrCr, and uCD80 were significantly increased in G2 versus G1. G2A and G2B were not different in age, gender, hypertension, and follow-up. G2B displayed significantly higher uP/C, uPAR-positive podocytes, uCD80, and lower CKD-EPI versus G2A. Strong significant correlations were encountered between uCD80 and podocyturia in G2A and G2B. However, when G1 was compared to G2A and G2B separately, the differences with respect to uP/C, uPAR-positive podocytes, and podocyturia were significantly stronger versus G2B than versus G2A. CONCLUSIONS: IgAN presents elevated uCD80 excretion and uPAR-positive podocyturia, while CD80 correlates with podocyturia. Glomerulosclerosis (S1) at the time of biopsy is associated with higher uP/C, lower renal function, increased uPAR-positive podocyturia, and CD80 excretion, and is independent of M1. In IgAN, uPAR may participate in podocyte detachment.

Expression of uPAR in Urinary Podocytes of Patients with Fabry Disease.

Background. Despite enzyme replacement therapy, Fabry nephropathy still progresses. Podocyturia is an irreversible event that antedates proteinuria and leads to chronic renal failure. We evaluated a potential mechanism of podocyte detachment via the expression of the urokinase-type Plasminogen Activator Receptor (uPAR) in urinary podocytes of Fabry patients. Methods. This is a cross-sectional study that included controls (n = 20) and Fabry patients (n = 44) either untreated (n = 23) or treated with agalsidase-ß (n = 21). Variables. Variables are estimated glomerular filtration rate (eGFR), urinary protein : creatinine ratio, and urinary uPAR+ podocyte : creatinine ratio. uPAR mRNA expression in response to lyso-Gb3, a bioactive glycolipid accumulated in Fabry disease, was studied in cultured human podocytes. Results. Controls and Fabry patients had similar age, gender, and renal function. Urinary uPAR+ podocytes were higher in patients than in controls. Untreated patients were significantly younger; had more females, and presented lower urinary protein : creatinine ratios and significantly higher urinary uPAR+ podocytes than treated subjects. In treated patients, urinary uPAR+ podocytes correlated with urinary protein : creatinine ratio (ρ = 0.5; p = 0.02). Lyso-Gb3 at concentrations found in the circulation of Fabry patients increased uPAR expression in cultured podocytes. Conclusions. Urinary podocytes expressing uPAR are increased in Fabry patients, especially in untreated patients. The potential contribution of uPAR expression to podocyte detachment merits further studies.

Biomarcadores en la lesión renal aguda: ¿ paradigma o evidencia ? / Biomarkers in acute kidney injury: Evidence or paradigm?

La lesión renal aguda en los pacientes críticos representa un factor de riesgo independiente de la morbilidad y la mortalidad a corto y a largo plazo, con un tremendo impacto económico en cuanto a los costes en salud pública. Por el momento, el diagnóstico de la lesión renal aguda sigue basándose en la presencia de oliguria o en un aumento gradual de la creatinina sérica, hecho que retrasa el diagnóstico, en detrimento de la llamada «ventana terapéutica». La aparición de nuevos biomarcadores de lesión renal aguda podría mejorar esta situación y contribuir a la detección de la «lesión renal aguda subclínica», lo que permitiría el uso precoz de múltiples estrategias de tratamiento con el objetivo de preservar la funcionalidad renal. No obstante, los nuevos biomarcadores presentan características que podrían vulnerar su capacidad de acción, centrada concretamente en aportar un valor añadido al abordaje precoz de la enfermedad, dada la falta de tratamientos específicos validados para la lesión renal aguda. Esta revisión tiene como objetivo analizar los puntos fuertes y débiles de esta nueva herramienta para el diagnóstico temprano de la lesión renal aguda (AU)

Acute kidney injury in the critically ill represents an independent risk factor of morbidity and mortality in the short and long terms, with significant economic impacts in terms of public health costs. Currently its diagnosis is still based on the presence of oliguria and/or a gradual increase in serum creatinine, which make the diagnosis a delayed event and to detriment of the so-called ‘therapeutic window’. The appearance of new biomarkers of acute kidney injury could potentially improve this situation, contributing to the detection of ‘subclinical acute kidney injury’, which could allow the precocious employment of multiple treatment strategies in order to preserve kidney function. However these new biomarkers display sensitive features that may threaten their full capacity of action, which focus specifically on their additional contribution in the early approach of the situation, given the lack of specific validated treatments for acute kidney injury. This review aims to analyze the strengths and weaknesses of these new tools in the early management of acute kidney injury (AU)

Heterogeneidad en los fenotipos inflamatorios de los pacientes con EPOC: rol del recuento celular diferencial en esputo / Heterogeneity of Inflammatory Phenotypes In Copd Patients: Role of Differential Cell Counting in Sputum

El tabaquismo es la principal causa de la EPOC, sin embargo, factores como la edad de diagnóstico, la historia previa de asma, exacerbaciones, predisposición genética y otros influirían en el desarrollo de la enfermedad. Esto estaría relacionado con los fenotipos de pacientes con EPOC, los cuales tendrían diferentes respuestas a los corticoides inhalados (CI). Recientemente, ha sido propuesto que los eosinófilos serían potenciales biomarcadores predictores de buena respuesta a los CI. Con la hipótesis de que la presencia de eosinófilos en esputo podría constituir una estrategia para diferenciar fenotipos de pacientes con EPOC, evaluamos los perfiles celulares infamatorios en muestras de esputo inducido en pacientes con EPOC no exacerbados. Para esto, se reclutaron 20 pacientes con EPOC moderado a severo que concurren al gimnasio de rehabilitación respiratoria, los cuales fueron agrupados en eosinofílicos (n: 8, cuando presentaron más de 3% de eosinófilos en la muestra de esputo inducido) o no eosinofílicos (n: 9). Se descartaron 3 muestras por contaminación con células epiteliales. Si bien no se observaron diferencias significativas en los test de función pulmonar o de marcha de 6 minutos, los pacientes con eosinoflia presentaron ligeramente mayor reversibilidad luego del broncodilatador. Además, tuvieron mayor eosinofilia periférica, mayores valores de FeNO y mejor calidad de vida (medida por cuestionarios) que los pacientes no eosinofílicos. El esputo inducido es una técnica no invasiva, económica, que representaría una herramienta útil para conocer los diferentes fenotipos inflamatorios en pacientes con EPOC.

Smoking is the major cause of COPD; however factors such as age, previous history of asthma, exacerbations, and genetic predisposition could infuence the development of the disease. This could be related with the phenotypes of COPD patients, who would have different responses to inhaled corticosteroids (ICs). Recently, it has been suggested that eosinophils are potential biomarkers that contribute to predict good response to ICs. To test the hypothesis that the presence of eosinophils in sputum could be useful to characterize different phenotypes of COPD patients, we assessed the infammatory cell profles in induced sputum samples from not exacerbated COPD patients. 20 patients with moderate to severe COPD, attending a pulmonary rehabilitation gym, were grouped into eosinophilic (8 patients who presented more than 3% eosinophils in the induced sputum sample) or neutrophilic (9 patients who had more than 60% neutrophils). Only 3 patients were excluded due to contamination of the sputum with epithelial cells. Although there were no-signifcant differences in the pulmonary function tests or the 6-minute walk, the patients with eosinophilia showed higher responsiveness to bronchodilator therapy. Besides this group presented an increase of peripheral eosinophils, higher FeNO and better quality of life (measured by questionnaires) compared with the neutrophilic patients. Induced sputum is an economic non-invasive technique and would be a useful tool to know different infammatory phenotypes in COPD patients.

Biomarkers in acute kidney injury: Evidence or paradigm? / Biomarcadores en la lesión renal aguda: ¿ paradigma o evidencia?

Acute kidney injury in the critically ill represents an independent risk factor of morbidity and mortality in the short and long terms, with significant economic impacts in terms of public health costs. Currently its diagnosis is still based on the presence of oliguria and/or a gradual increase in serum creatinine, which make the diagnosis a delayed event and to detriment of the so-called 'therapeutic window'. The appearance of new biomarkers of acute kidney injury could potentially improve this situation, contributing to the detection of 'subclinical acute kidney injury', which could allow the precocious employment of multiple treatment strategies in order to preserve kidney function. However these new biomarkers display sensitive features that may threaten their full capacity of action, which focus specifically on their additional contribution in the early approach of the situation, given the lack of specific validated treatments for acute kidney injury. This review aims to analyze the strengths and weaknesses of these new tools in the early management of acute kidney injury.

Podocyturia is significantly elevated in untreated vs treated Fabry adult patients.

BACKGROUND: Proteinuria suggests kidney involvement in Fabry disease. We assessed podocyturia, an early biomarker, in controls and patients with and without enzyme therapy, correlating podocyturia with proteinuria and renal function. METHODS: Cross-sectional study (n = 67): controls (Group 1, n = 30) vs. Fabry disease (Group 2, n = 37) subdivided into untreated (2A, n = 19) and treated (2B, n = 18). Variables evaluated: age, gender, creatinine, CKD-EPI, proteinuria, podocyte count/10 20× microscopy power fields, podocytes/100 ml urine, podocytes/g creatininuria (results expressed as median and range). RESULTS: Group 1 vs. 2 did not differ concerning age, gender and CKD-EPI, but differed regarding proteinuria and podocyturia. Group 2A vs. 2B: age: 29 (18-74) vs. 43 (18-65) years (p = ns); gender: males n = 3 (16 %) vs. n = 9 (50 %). Proteinuria was significantly higher in Fabry treated patients, while CKD-EPI and podocyturia were significantly elevated in untreated individuals. Significant correlations: group 2A: age-proteinuria, ρ = 0.62 (p = 0.0044); age-CKD-EPI, ρ = -0.84 (p < 0.0001); podocyturia-podocytes/100 ml urine, ρ = 0.99 (p = 0.0001); podocyturia-podocytes/g creatininuria ρ = 0.86 (p = 0.0003), podocytes/100 ml urine-podocytes/g urinary creatinine, ρ = 0.84 (p = 0.0004); proteinuria-CKD-EPI, ρ = -0.68 (p = 0.0013). Group 2B: podocyturia-podocytes/100 ml urine, ρ = 0.88 (p < 0.0001); podocyturia-podocytes/g creatininuria, ρ = 0.84 (p < 0.0001); podocytes/100 ml urine-podocytes/g creatininuria, ρ = 0.94 (p < 0.0001); CKD-EPI-proteinuria, ρ = -0.66 (p = 0.0028). CONCLUSIONS: Patients with Fabry disease display heavy podocyturia; those untreated present significantly higher podocyturia, lower proteinuria and better renal function than those who are treated, suggesting that therapy may be started at advanced stages. Podocyturia may antedate proteinuria, and enzyme therapy may protect against podocyte loss.

[Amoniuria, urinary gap and osmolal in patients with moderate renal insufficiency]. / Amoniuria, gap urinario y osmolal en pacientes con insuficiencia renal moderada.

The chronic metabolic acidosis induces increase in the urinary ammonium production (NH4+u) like equalizer, reflected in major or measured minor, if the process is chronic or acute. The objective of the present work was to study the capacity of urinary acidification in patients with Failure Renal Chronic (FRC), stage II and III measuring NH4+u and to compare results with GAP urinary (GAPu), GAP urinary modified (GAPu mod), GAP Osmolal (GAPosm) and GAP Osmolal modified (GAPosm modif.) like indirect indices of amoniuria. Samples Venous/arterial blood and a draft fresh urine of 34 patients were analyzed. Statistically significant correlation was obtained (p < 0,003) between NH4+u ug/min/1.73m2 versus GAPu mmol/l (r = -0,4979) and GAPu mod mmol/l (- 0.5032), improving when NH4+u normatizó by creatinine (r = - 0.6793 and 0.6087 respectively, p < 0,0001). The GAPosm and GAPosm modif did not show significance at the time of evaluating NH4+u, contrary GAPu and GAPu mod would offer an indirect measurement of excretion of NH4+u, having given this last protein nutritional information. A value of p < 0.05 was considered statistically significant.