Albuminuria, Forgotten No More: Underlining the Emerging Role in CardioRenal Crosstalk.

Kidneys have an amazing ability to adapt to adverse situations, both acute and chronic. In the presence of injury, the kidney is able to activate mechanisms such as autoregulation or glomerular hyperfiltration to maintain the glomerular filtration rate (GFR). While these adaptive mechanisms can occur in physiological situations such as pregnancy or high protein intake, they can also occur as an early manifestation of diseases such as diabetes mellitus or as an adaptive response to nephron loss. Although over-activation of these mechanisms can lead to intraglomerular hypertension and albuminuria, other associated mechanisms related to the activation of inflammasome pathways, including endothelial and tubular damage, and the hemodynamic effects of increased activity of the renin-angiotensin-aldosterone system, among others, are recognized pathways for the development of albuminuria. While the role of albuminuria in the progression of chronic kidney disease (CKD) is well known, there is increasing evidence of its negative association with cardiovascular events. For example, the presence of albuminuria is associated with an increased likelihood of developing heart failure (HF), even in patients with normal GFR, and the role of albuminuria in atherosclerosis has recently been described. Albuminuria is associated with adverse outcomes such as mortality and HF hospitalization. On the other hand, it is increasingly known that the systemic effects of congestion are mainly preceded by increased central venous pressure and transmitted retrogradely to organs such as the liver or kidney. With regard to the latter, a new entity called congestive nephropathy is emerging, in which increased renal venous pressure can lead to albuminuria. Fortunately, the presence of albuminuria is modifiable and new treatments are now available to reverse this common risk factor in the cardiorenal interaction.

Evolving Concepts on Inflammatory Biomarkers and Malnutrition in Chronic Kidney Disease.

While patient care, kidney replacement therapy, and transplantation techniques for chronic kidney disease (CKD) have continued to progress, the incidence of malnutrition disorders in CKD appears to have remained unchanged over time. However, there is now a better understanding of the underlying pathophysiology according to the disease background, disease stage, and the treatment received. In CKD patients, the increased production of proinflammatory cytokines and oxidative stress lead to a proinflammatory milieu that is at least partially responsible for the increased morbidity and mortality in this patient population. New insights into the pathogenic role of innate immunity and the proinflammatory cytokine profile, characterized, for instance, by higher levels of IL-6 and TNF-α, explain some of the clinical and laboratory abnormalities observed in these patients. In this article, we will explore currently available nutritional-inflammatory biomarkers in distinct CKD populations (hemodialysis, peritoneal dialysis, transplantation) with a view to evaluating their efficacy as predictors of malnutrition and their involvement in the common proinflammatory process. Although there is a direct relationship between inflammatory-nutritional status, signs and symptoms [e.g., protein-energy wasting (PEW), anorexia], and comorbidities (e.g., atheromatosis, atherosclerosis), we are in need of clearly standardized markers for nutritional-inflammatory assessment to improve their performance and design appropriate bidirectional interventions.

The "FIFTY SHADOWS" of the RALES Trial: Lessons about the Potential Risk of Dietary Potassium Supplementation in Patients with Chronic Kidney Disease.

Hyperkalaemia (HK) is one of the most common electrolyte disorders and a frequent reason for nephrological consultations. High serum potassium (K+) levels are associated with elevated morbidity and mortality, mainly due to life-threatening arrhythmias. In the majority of cases, HK is associated with chronic kidney disease (CKD), or with the use of renin-angiotensin-aldosterone system inhibitors (RAASis) and/or mineral corticoid antagonists (MRAs). These drugs represent the mainstays of treatment in CKD, HF, diabetes, hypertension, and even glomerular diseases, in consideration of their beneficial effect on hard outcomes related to cardiovascular events and CKD progression. However, experiences in relation to the Randomised Aldactone Evaluation Study (RALES) cast a long shadow that extends to the present day, since the increased risk for HK remains a major concern. In this article, we summarise the physiology of K+ homeostasis, and we review the effects of dietary K+ on blood pressure and cardiovascular risk in the general population and in patients with early CKD, who are often not aware of this disease. We conclude with a note of caution regarding the recent publication of the SSaSS trial and the use of salt substitutes, particularly in patients with a limited capacity to increase K+ secretion in response to an exogenous load, particularly in the context of "occult" CKD, HF, and in patients taking RAASis and/or MRAs.

Routine Biomarkers for the Severity of COVID-19 Pneumonia May Present Differently in Kidney Transplant Recipients.

BACKGROUND: The treatment of coronavirus disease 2019 (COVID-19) is based on the patient's clinical status and levels of inflammatory biomarkers. The comparative activity of these biomarkers in kidney transplant (KT) patients with COVID-19 pneumonia from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and non-SARS-CoV-2 etiologies is unknown. The aim of this study was to compare the clinical presentation and inflammatory parameters at admission of KT patients with COVID-19 pneumonia and those with non-COVID-19 pneumonia over the same period. METHODS: Biomarkers were measured and compared between KT patients with COVID-19 pneumonia (n = 57) and non-COVID-19 pneumonia (n = 20) from March 2020 to March 2021. RESULTS: Both groups showed comparable demographics. The KT patients with COVID-19 had fewer neutrophils (6824 ± 5000 vs 8969 ± 4206; P = .09) than the non-COVID group, although there was no significant difference in the lymphocyte count. Non-COVID-19 pneumonia was associated with higher d-dimer (median, 921 [interquartile range (IQR), 495-1680] vs median, 2215 [IQR, 879-3934]; P = 0.09) and interleukin-6 (median, 35 [IQR, 20-128] vs median, 222 [IQR, 38-500]; P = 0.006) levels. The ferritin level was higher in the COVID-19 group (median, 809 [IQR, 442-1,330] vs median, 377 [IQR, 276-885]; P = 0.008). In multivariable analysis, only d-dimer (hazard ratio [HR], 1; 95% confidence interval [CI],1-1.002; P = .02) and ferritin (HR, 1; 95% CI, 0.9-0.9; P = .02) increase the statistic signification. CONCLUSION: COVID-19 pneumonia in KT patients shows a different presentation of inflammatory biomarkers than other non-COVID pneumonias. It could be useful to identify KT patients with COVID-19. More detailed studies are necessary to understand the presentation of biomarkers in KT with COVID-19.