[Acute severe respiratory distress in chronic haemodialytic patients affected by SARS-CoV-2 pneumonia: prevalence and associated factors. A single-centre experience from Cardarelli Hospital in Naples (Italy)].

Background: SARS­CoV­2-induced severe acute respiratory syndrome is associated with high mortality in the general population; however, the data on chronic haemodialysis (HD) patients are currently scarce. Methods: We performed a retrospective analysis to evaluate the onset of acute respiratory distress syndrome (ARDS) in patients with SARS­CoV­2-induced interstitial pneumonia diagnosed by PCR test and detected by high resolution computed tomography (HRCT). For each patient, we calculated a CT score between 0 and 24, based on the severity of pneumonia. The primary outcome was the onset of ARDS, detected by P/F ratio >200. We included 57/90 HD patients (age: 66.5 ±13.4 years, 61.4 % males, 42.1% diabetics, 52.6% CV disease) treated at the Cardarelli Hospital in Naples (Italy) from 1st September 2020 to 31st March 2021. All patients were treated with intermittent HD. Results: Patients who experienced ARDS had a more severe pneumonia (CT score: 15 [C.I.95%:10-21] in ARDS patients vs 7 [C.I.95%: 1-16] in no ARDS; P=0.015). Logistic regression showed that the CT score was the main factor associated with the onset of ARDS (1.12; 95% c.i.: 1.00-1.25), independently from age, gender, diabetes, chronic obstructive pulmonary disease, and prior CV disease. Thirty-day mortality was much greater in ARDS patients (83,3%) than in no-ARDS (19.3%). Conclusions: This retrospective analysis highlights that HD patients affected by SARS-CoV-2 pneumonia show an increased risk of developing ARDS, dependent on the severity of CT at presentation. This underlines once again the need for prevention strategies, in primis the vaccination campaign, for these frail patients.

Uric acid: a starring role in the intricate scenario of metabolic syndrome with cardio-renal damage?

Elevated uric acid levels are a common finding in patients with metabolic syndrome and in those with cardiovascular and renal disease, but the meaning of this elevation is still unclear. In patients with chronic kidney diseases, it could merely reflect the reduction in glomerular filtration rate: but uric acid levels are known to be elevated in people, also in younger ones, prior to the development of hypertension or renal disease, independently of several risk factors. Multiple potential mechanisms suggest a causative role for uric acid in vascular disease. Uric acid has been shown to be involved in metabolic pathways that lead to oxidative stress, endothelial disfunction, and to a vascular and systemic inflammatory response. Moreover, the elevation in uric acid levels observed after fructose ingestion, with a consequent reduction in nitric oxide, may lead to a reduced glucose uptake in the skeletal muscle, hyperinsulinemia, and insulin resistance. Besides these bench research data, also clinical studies showed the beneficial effects of lowering uric acid therapies on several markers of cardiovascular and renal disease. To date, however, there is no evidence indicating that such therapies, that are not free of risk, may reduce cardiovascular events; so that to manage our prescriptions, we need larger, prospective, interventional data.

[Diverse histological lesions in a patient with antiphospholipid syndrome (APS)]. / Concomitanza di lesioni istologiche multiple in un paziente con sindrome da anticorpi antifosfolipidi (APLS).

Antiphospholipid syndrome (APS) is a rare autoimmune disorder. It can be secondary to systemic lupus erythematosus (SLE) or occur in the absence of autoimmune disease. The hallmark of this so-called primary APS is the presence of circulating antiphospholipid antibodies. Renal involvement in primary APS is caused by thrombosis within the renal vasculature. Recently, nonthrombotic glomerulonephritic renal lesions have been described in primary APS as a new histological entity. We here report a patient with primary APS in whom both lesion types were present. A 58-year-old Caucasian man with no significant past medical history presented to our nephrology unit with diffuse edema. Urinalysis showed proteinuria exceeding 400 mg/dL. The autoantibody panel (p-ANCA, c- ANCA, anti-nucleus, anti-DS-DNA) was negative except for anticardiolipin antibodies, which tested positive in two different samples. The diagnostic workup included a kidney biopsy that revealed thrombotic lesions compatible with primary APS and a typical pattern of focal segmental glomerulosclerosis. The kidney is a major target in APS but the exact mechanism underlying the pathogenesis of APS nephropathy has been poorly recognized. The use of kidney biopsy is a fundamental diagnostic tool in this setting, with possible implications also from a prognostic and therapeutic viewpoint.

Continuous monitoring of left ventricle function by VEST in hemodialyzed patients.

Cardiovascular disease is a major cause of morbidity and mortality in chronic kidney disease. Radionuclide-based methods can be used for analyses on the perfusion of coronary arteries and ventricular function. The present study reports the use of a new procedure for continuous measurements of left ventricle function during a dialytic session with the use of a recently developed portable gamma radiation detector (ventricular function study system). On average, left ventricle ejection fraction and stroke volume progressively and continuously decreased throughout the session (end session versus baseline: -13.8% for ejection fraction, -25.9% for stroke volume, P<.02). A biphasic response was found for heart rate: a transient modest decrease (at session midpoint, -4.2%) followed by an increase up to values higher than baseline (end session, +4.7%). Cardiac output decreased by 10.4% at session midpoint (P=.023 versus baseline) without further reduction in the following hours. Mean changes in systolic pressure paralleled data for cardiac output. Individual changes in indices of left ventricle function were scattered and strongly were correlated with thickness of interventricular septum and telediastolic left ventricular volume measured by standard echocardiogram in the interdialytic period (R>.75, P<.05). Data indicate that the ventricular function study system could be a powerful tool for characterization of the profile of left ventricular function in hemodialyzed patients.

Urinary albumin and cardiovascular profile in the middle-aged population.

The moderate increase in urinary albumin excretion defined as microalbuminuria is not rare and is associated with cardiovascular risk factors. Microalbuminuria prevalence is low in the absence of cardiovascular risk factors and progressively increases with the number cardiovascular risk factors. The main correlate of microalbuminuria is blood pressure, either systolic or diastolic pressure. The relation between blood pressure and microalbuminuria is continuous and graded because the microalbuminuria prevalence increases with the severity of hypertension. Among hypertensive patients on drug treatment, blood pressure control is associated with a low prevalence of microalbuminuria. Thus, blood pressure appears as a determinant of microalbuminuria rather than a mere correlate. For hypercholesterolemia, smoking, and diabetes, data are less strong but point to an independent positive association with microalbuminuria. Altogether, data indicate that microalbuminuria in the population reflects the presence of cardiovascular risk factors. Data on microalbuminuria and coronary heart disease support this idea. There is a continuous and graded relation between urinary albumin excretion and coronary heart disease prevalence. High urinary albumin excretion is likely a sign of vascular damage existing both at the renal and cardiac levels and induced by 1 or more uncontrolled cardiovascular risk factors.

Association of gender and age with erythropoietin resistance in hemodialysis patients: role of menstrual status.

BACKGROUND: Female gender is associated with high erythropoietin (EPO) resistance in end-stage renal disease. The aim of our study was to investigate the roles of age and menstrual status in this relationship. METHODS: Cross-sectional analysis of registry data for 3,224 hemodialysis adults treated with EPO. Data collection included gender, age, weight, height, dialytic age, hemoglobin, EPO dose, and, for women with ages 25-44 only, also information on menstrual status and iron homeostasis. EPO resistance index (ERI) was calculated as EPO dose per kilogram BW/hemoglobin. RESULTS: Men and women had not significantly different hemoglobin and significantly different EPO dose per kilogram weight (women vs. men, +18.2%, p < 0.001). Thus, ERI was higher in women than in men (+19.5%, p < 0.001). The gender-associated difference in ERI linearly decreased along age groups: +30.9% for ages 25-44, +23.2% for ages 45-64, and +14.2% for ages 65-84 (p < 0.05 for interaction between age and gender-associated difference in ERI). Within the subgroup of women with ages 25-44, women with menses in comparison to women without had 44.6% higher ERI (p < 0.01) due to combination of lower hemoglobin (p < 0.05) with higher EPO dose (p < 0.001). Women with menses had also lower serum iron, transferrin saturation, and serum ferritin (p < 0.001). CONCLUSION: The gender-associated difference in ERI is lower with increasing patients' age. The large difference between young men and women is due to women with menses who have iron deficiency more frequently than women without periods.

Cross-sectional and prospective data on urinary calcium and urinary stone disease.

BACKGROUND: Urinary calcium is considered a risk factor for urinary stone disease (USD), although prospective data are missing. This epidemiologic study investigates cross-sectionally and longitudinally the relation of urinary calcium excretion to USD. METHODS: In the Gubbio Population Study, data on USD were collected by questionnaire during medical examinations from 1989 to 1992 (baseline) and telephone interviews in 1997 to 1998 (follow-up). Baseline data collection included overnight urinary calcium excretion and use of medications. Study cohort was made of 1458 men and 1799 women, age 25 to 74 years, and not on treatment with diuretics at baseline. USD was diagnosed by: excretion of stone(s), and/or radiographic or ultrasonic evidence, and/or surgical or endoscopic removal of stone(s). RESULTS: At baseline, urinary calcium excretion was higher in persons with than without USD (215 and 182 micromol/hour, P < 0.001) and related to USD prevalence independent of gender, age, and other variables (P < 0.001). Among persons without USD at baseline, baseline urinary calcium excretion was higher in persons with than without incident USD at follow-up (202 and 181 micromol/hour, P = 0.034) and related to incident USD independent of gender, age, and other variables. A difference of 100 micromol/hour (about 1 SD) in urinary calcium excretion related to a difference in USD risk of 1.32 for prevalence and 1.21 for incidence (95% CI = 1.15/1.52 and 1.01/1.45, respectively) in multivariate analyses controlled for gender, age, body mass index, parental history of USD, urinary excretion of urea, sodium, and potassium. CONCLUSION: Cross-sectional and prospective data show that urinary calcium excretion is a risk factor for USD.

Low urinary albumin excretion in astronauts during space missions.

BACKGROUND: Physiological changes occur in man during space missions also at the renal level. Proteinuria was hypothesized for space missions but research data are missing. METHODS: Urinary albumin, as an index of proteinuria, and other variables were analyzed in 4 astronauts during space missions onboard the MIR station and on the ground (control). Mission duration before first urine collection in the four astronauts was 4, 26, 26, and 106 days, respectively. On the ground, data were collected 2 months before mission in two astronauts, 6 months after in the other astronauts. A total of twenty-two 24-hour urine collections were obtained in space (n per astronaut = 1-14) and on the ground (n per astronaut = 2-12). Urinary albumin was measured by radioimmunoassay. For each astronaut, mean of data in space and on the ground was defined as individual average. RESULTS: The individual averages of 24 h urinary albumin were lower in space than on the ground in all astronauts; the difference was significant (mean +/- SD, space and on the ground = 3.41 +/- 0.56 and 4.70 +/- 1.20 mg/24 h, p = 0.017). Dietary protein intake and 24-hour urinary urea were not significantly different between space and on the ground. CONCLUSIONS: Urinary albumin excretion is low during space mission compared to data on the ground before or after mission. Low urinary albumin excretion could be another effect of exposure to weightlessness (microgravity).

Urinary albumin in space missions.

Proteinuria was hypothesized for space mission but research data are missing. Urinary albumin, as index of proteinuria, was analyzed in frozen urine samples collected by astronauts during space missions onboard MIR station and on ground (control). Urinary albumin was measured by a double antibody radioimmunoassay. On average, 24h urinary albumin was 27.4% lower in space than on ground; the difference was statistically significant. Low urinary albumin excretion could be another effect of exposure to weightlessness (microgravity).

Urinary albumin in head-down bed rest.

Previous studies reported low urinary albumin excretion in astronauts during space missions, suggesting an effect of microgravity on renal albumin handling. To test this hypothesis, urinary albumin excretion was investigated with use of head-down bed rest at -6 degrees (HDBR), an experimental model of microgravity. Eight healthy young men underwent two phases. Each phase included 2 days of dietary adaptation (run-in), 4 days of baseline (light activities and bed rest), and 6 days of experiment: HDBR 24h every day for intervention light activities and bed rest for control. The study was done in metabolic ward (DLR, Cologne, Germany). Urine were collected in days 3-4 of baseline and days 4-6 of experiment. Urinary albumin was measured by a double antibody radioimmunoassay, creatininuria by automated colourimetry. Data are expressed as albumin/creatinine ratio to control for timing and completeness of urine collection. Compared to baseline, albumin/creatinine ratio decreased by 9.3% during HDBR and increased by 14.9% during control. The difference in changes over baseline was significant between HDBR and control (p < 0.01 by paired comparison). The data support the hypothesis that low gravity reduces renal albumin excretion.