[Pathogenic mechanisms of SARS-CoV-2 infection and kidney disease: a clinical and molecular perspective].

The SARS-CoV-2 infection has become as a worldwide public health emergency. It exhibits a variety of clinical presentations, ranging from benign to acute respiratory distress syndrome, systemic involvement, and multiorganic failure. The severity of the clinical picture depends on host and virus biological features and the presence of comorbidities such as chronic kidney disease. In addition, the interaction between the virus, angiotensin-converting enzyme 2, and the exacerbated immune response could lead to the development of acute kidney injury. However, the implications of SARS-CoV-2 infection on renal cells, the prognosis of patients with chronic kidney disease, and the long-term behavior of renal function are not entirely understood. This review aims to explore the role of SARS-CoV-2 in acute and chronic kidney disease and the possible pathogenic mechanisms of renal involvement.

[Evolution of kidney function and progression factors in nephrectomised patients]. / Evolución de la función renal y factores de progresión en pacientes nefrectomizados.

Data recorded from external visit in hospitals, reflects high number of nephrectomized patients. Most of these patients were remitted after any surgery or deteriorizated renal function or any other associated pathology. Several studies of nephrectomized patients are reported in literature concerning both healthy patients and comorbidity factors, and renal function and its evolution are evaluated. However, obtained results present a wide variability, which needs to be assessed. In this study we present a retrospective observational study of 92 one-kidney surgical patients, visited in Nephrology surgery of University Clinic Hospital. Patients presented an average age of 67 years old (range 22-89 years old), and a post-surgery monitoring of 21 years. Population was divided in two groups according with their glomerular filtration (FG). Before surgery, group 1 presented FG < 60 ml/min and group 2 > 60 ml/min, respectively. Group 1 patients (a total of 24 patients) presented an FG average of 48 ml/min, 8% had proteinuria and 63% presented high blood pressure. 21% of them needed an average of 20 years (10-30 years) to reach E4 and E5 steps and in general, most of them progressed to insufficient renal chronic disease. Five cases achieved renal therapy replacement. Group 2 patients, composed of a total of 68 patients, had an FG average of 76.5 ml/min, and 10% of patients presented proteinuria and 34% HTA; however, 80% of group 2 patients achieve E3 step with average age of 17 years, and a post-surgery of 47 years (1-48 years). A total of 19.1 % presented an FG higher 60 ml/min with an average development of 22 years along their evolution. According to the results obtained it is suggested that monorrenal surgical patients present a low progression of renal disease and it is also observed a progressive tendency to the chronic renal failure due to emerging of proteinuria.

[Study of diastolic function in peritoneal dialysis patientes. Comparison between pulsed and Tissue Doppler]. / Estudio de la función diastólica en pacientes en diálisis peritoneal. Comparación entre doppler pulsado y tisular.

INTRODUCTION: Left ventricular hypertrophy (LVH) is the main expression of uremic cardiomyopathy. Alteration of the diastolic function is frequently associated with LVH, indicating future cardiovascular events. Recent studies suggest that the Tissue Doppler (TID) of the mitral annulus obtains parameters of diastolic function that are not influenced by other factors, unlike what occurs with the pulsed Doppler (PD), and that the relationship between the velocity of the proto-diastolic waves of both techniques (E/E') would be the most important datum to diagnose a diastolic malfunction. The objective of this study is to verify LVH prevalence in a population of End Stage Renal Disease patients (ESRD) in peritoneal dialysis (CAPD), and to study diastolic function, comparing the results of both techniques (PD/TID), as well as the possible causes that determine the appearance of diastolic malfunction in these patients. PATIENTS AND METHODS: We carried out a cross-section study with 42 patients in peritoneal dialysis. All patients had an ejection fraction of over 50% and had no clinical signs of heart failure, valvular heart disease or arrhytmia. A basic biochemistry, residual renal function, C-reactive protein and an ultrasonic study with M-mode doppler, pulsed doppler and tissue doppler of the mitral annulus, were performed in all patients. RESULTS: 26.2% of the patients had a concentric LVH, 14.3% an asymmetric LVH and 23.8% a concentric growth. The PD showed an E/A ratio under 0.75 in 20 cases (which would indicate an alteration of ventricular relaxation), an E/A between 0.75 and 1.5 in 22 (normal or pseudonormal pattern) and none with an E/A over 1.5. On the other hand, the TID showed: 24 patients with an E/A < 0.75, 16 between 0.75 and 1.5, and 2 with an E/A > 1.5. The E/E' proportion was normal in 13 cases(< 8), intermediate in 12 (8-10), and greater than 10 in 17, expressing a clear diastolic malfunction. Twelve of the 17 with diastolic malfunction had a pseudo-normal pattern with the PD. A relationship was observed between the E/A and age and hs-CRP. A relationship was also found between RRF, ejection fraction and diastolic pressure (p = 0.03, r = 0.32 and p = 0.006, r = 0.29), while, in the multivariant study, the presence of LVH was the only variable with enough significance to influence the diastolic malfunction (odds ratio of 7.6). CONCLUSIONS: Patients in CAPD have a high incidence of diastolic malfunction. LVH, present in a high percentage of patients, is one of the factors that favours its appearance. The non-invasive TID technique and the E/E' ratio have shown to be more sensitive than the PD in diagnosing a diastolic malfunction.

[Implementation of a protocol of management of chronic kidney disease between Nephrology and Primary Health Care. Preliminary results]. / Resultados preliminares de la implantación de un protocolo conjunto de manejo de la enfermedad renal crónica entre atención primaria y nefrología.

During the last years there has been an important advance in the knowledge of chronic kidney disease (CKD). In order to adapt our clinical practice to these new data, a protocol of management of CKD between Nephrology and Primary Health Care has been developed. The protocol includes several items like cardiac and renal protection strategies, diagnosis and treatment of complications, use of drugs and clear derivation criteria. Implementation of the protocol has been only partial and has implied, for the Renal Unit, an increase in the number of patients,specially the oldest ones, but a clear improve in the quality of the information too,and a first positive step in the right way to face the challenge of CKD. In view of analysed data we propose some modifications for the protocol.

[Effect of oxidative stress in patients with chronic renal failure]. / Efecto del tratamiento con hemodiálisis sobre el estrés oxidativo en pacientes con insuficiencia renal crónica.

BACKGROUND: Cardiovascular disease remains the single most common cause of excess morbidity and mortality in end-stage renal disease (ESRD) patients and the traditional risk factors can't explain the high incidence of these events. New "non-traditional" risk factors are analysed in uremic patients and the increased oxidative stress is postulated to be an important contributor to uremic cardiovascular risk. METHODS: In order to evaluate the effects of the hemodialysis treatment, a complete oxidative stress study was performed in fifteen uremic patients. Representative antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx), together with oxidized/reduced glutathione ratio (GSSG/GSH) and other oxidation indicators including malondialdehyde (MDA) and 8-oxo-2'-deoxyguanosine (8-oxo-dG), were analysed to assess oxidative stress status in normal control volunteers and in uremic patients treated with hemodialysis (HD). In the latter group blood samples were taken prior and after HD to evaluate the effect of the session of HD over the oxidative markers. RESULTS: Low levels of antioxidant enzyme activities were observed in the uremic patients as compared with normal control subjects. HD treatment results in a significant recovery of these enzyme activities but remain lower as compared with control values. Levels of GSSG and GSH concentrations were increased and reduced respectively in uremic patients. These differences were even higher before the HD and were reduced upon treatment to levels closer to those observed in controls. MDA levels and 8-oxo-dG levels were also increased in uremic patients with the highest values observed in the pre-treated HD group. Even though HD treatment decreases the levels of oxidation products in mononuclear cells of uremic patients the values of the control group are not reached. CONCLUSIONS: Our results suggest that hemodialysis by itself could correct the oxidative status in these patients. The possible mechanisms involved in the oxidative stress changes with the hemodialysis treatment will be discussed below.

[Fungal peritonitis episodes in a peritoneal dialysis centre during a 10-year period: a report of 11 cases]. / Experiencia en peritonitis fúngica en una unidad de diálisis durante diez años.

Fungal peritonitis is a rare cause of peritonitis, but it is associated to poorer prognosis and higher mortality than bacterial peritonitis. Until now, predisposing factors and treatment have not been well established. We retrospectively reviewed all the cases of fungal peritonitis diagnosed for ten years in 218 patients undergoing continuous ambulatory peritoneal dialysis. In all we detected 11 episodes of fungal peritonitis in 11 patients, that means the 4% of continuous ambulatory peritoneal dialysis peritonitis. All the cases of fungal peritonitis were caused by Candida species. As a result of fungal peritonitis 36% of the patients died, 55% had to change to long-term hemodialysis because of failure in peritoneal dialysis technique. Only one case (9%) managed to continue peritoneal dialysis. The factors associated with the development of fungal peritonitis were: the presence of antibiotic use within 1 month before fungal peritonitis, patient older than 70 years old, low levels in albumine plasmatic and long permanence in continuous ambulatory peritoneal dialysis. The treatment consisted in intraperitoneal fluconazol combined with oral 5-flucytosine for 4 to 6 weeks. In the two last cases we associated intravenous caspofungine too. Given that no improvement was seen within 72 hours of treatment, the catheter must be removed in all the cases.

[Monitoring hemodialysis dose with ionic dialisance in on-line hemodiafiltration]. / Valoración de la medición de la dosis de diálisis con dialisancia iónica en hemodiafiltración on-line.

Until now, with the ionic dialysance measurement, it has been possible to determine hemodialysis dose in each session of hemodialysis (HD) and in the conventional hemofiltration (HDF) but not in the modality of on-line HDF. Recently it is possible with a new biosensor that allows to measure the dose in on-line HDF. The aim of this study was to evaluate the value of this biosensor in different dialysis situations comparing the dialysis dose measured in blood in comparison with the values obtained from the sensor. We have analysed 192 hemodialysis sessions performed in 24 patients, 15 male and 9 female, mean age of 70.2 +/- 12 years, included in on-line HDF. All treatments were done using 4008H (Fresenius) monitor equipped with on-line clearance monitoring (OCM), that measure, with non invasive monitoring, the effective ionic dialysance equivalent to urea clearance. Every patient received eight dialysis sessions: one with dialysate flow (Qd) 500 ml/min, two with HD and Qd 800 ml/min and five with on-line HDF. Other habitual haemodialysis parameters were no changed, dialysis time 200 +/- 63 min (135-300) and blood flow 421 +/- 29 ml/min (350-450). Initial and final ionic dialysance values (K), final Kt, Kt/V measured with OCM using V of Watson, and Kt/V determined in blood pre and postdialysis concentrations of urea (Daugirdas second generation), were measured. The mean of initial K was 251 +/- 21 ml/min and the final K was 234 +/- 24 ml/min. The Kt measured with OCM was 50.6 +/- 17 L, 51.2 +/- 17 in men and 49.7 +/- 16 in women. The V (Watson) was 34.5 +/- 6 L. The Kt/V measured with the Kt of OCM and V was 1,499 +/- 0.54 and Kt/V measured in blood samples was 1,742 +/- 0.58. The correlation between both values was 0.956. The Kt was different according to dialysis modality used: in HD and Qd 500 was 44.7 +/- 15 L, in HD and Qd 800 was 50.7 +/- 17 and in on-line HDF (22.1 +/- 7 L of reposition volume), was 51.8 +/- 17 L. The Kt/V from blood samples also shows variation: in HD and QD 500 was 1.60 +/- 0.55, in HD and Qd 800 was 1,726 +/- 0.56 and in on-line HDF was 1,776 +/- 0.59. In this study has been observed a close correlation between the new biosensor OCM with the measures obtained from the blood samples. For this reason this sensor it is useful in all modalities of dialysis treatment, included on-line HDF. The sensor was able to discriminate the efficacy of different dialysis modalities used in this study.

Clinical value of increased serum creatinine concentration as predictor of short-term outcome in decompensated cirrhosis.

BACKGROUND: The purpose of this study was to assess whether serum creatinine concentration alone or associated with other biological parameters was an independent predictor of short-term mortality in patients with decompensated cirrhosis. METHODS: A total of 212 consecutive episodes of decompensated cirrhosis in patients admitted to the hospital between January 1999 and December 2001 were reviewed retrospectively. Depending on a serum creatinine concentration equal to or greater than 1.5 mg/dL at the time of admission, patients were divided into decompensated cirrhosis with renal failure (101 episodes in 59 patients, aged 69.8 +/- 10 years) and without renal failure (111 episodes in 61 patients, aged 64.5 +/- 13 years). Outcome (alive, death) during the episode of decompensation of liver disease and outcome at 90 days after admission were assessed. RESULTS: Differences in the frequency of variables according to outcome in the overall episodes of decompensated cirrhosis with and without renal failure showed significant differences between patients who died and those who were alive both at hospital discharge and at 90 days in serum bilirubin, Child-Pugh score, MELD (model for end-stage liver disease) score, and serum creatinine levels. In the multivariate analysis, serum creatinine was not an independent predictor of outcome. The prediction accuracy according to the area under the ROC (receiver operating characteristic) curve was greater for the MELD scale than for serum creatinine. CONCLUSIONS: Serum creatinine concentration is a parameter that should be included in the prognostic assessment of patients with decompensated cirrhosis, but should be combined with other specific parameters of liver function, such as bilirubin, albumin, and the international normalized ratio (INR) for prothrombin time.

[Hypokalemic metabolic alkalosis: apropos of a case of Gitelman's syndrome]. / Alcalosis metabólica hipopotasémica: a propósito de un síndrome de Gitelman.

We present a case of Gitelman's Syndrome in a 20 year-old woman who came to our service with weakness, asthenia, leg cramps and tetany. Laboratory studies revealed metabolic alkalosis with hypokalemia, hypomagnesemia and low calcium in a 24-hour urine test. The diagnosis of this syndrome is made in some cases during adult life because this syndrome is asymptomatic over several years. Gitelman's Syndrome is autosomal recessive as is Bartter's Syndrome. The gene is located in chromosome 16q, which encodes the cotransporter Na/Cl sensitive to thiazide in the distal convoluted tubule. The defect of cotransporter produces an alteration of sodium reabsorption that causes electrolytic disorders typical of this Syndrome and different from Bartter's Syndrome. The typical electrolytic alterations are hypocalciuria and hypomagnesemia secondary to high urinary magnesium excretion. The prognosis of this syndrome is excellent and treatment consists in correction of serum electrolytes with oral administration of magnesium and potassium. In spite of this treatment, in some cases it is very difficult to reach normal serum levels of magnesium because of the high doses of oral magnesium, which produce common crises of diarrhea that increase magnesium gastrointestinal losses.