[Cardiorenal syndromes: historical aspects and current challenges]

The article describes major milestones in acknowledgment of pathophysiological relationship between heart and kidneys since Ancient Egypt till our time and history of term "cardiorenal syndrome" (CRS). First references about kidney and heart functions could be dated to 13 BC when Hippocrates mentioned them. In the XIV century Gentile da Foligno proposed a hypothesis about functional interconnection between heart and kidneys. In the XVIII century Richard Bright described the link between myocardial hypertrophy and kidneys diseases. Frederic Justin Collet was the first one who used the term "cardiorenal" in his article in 1903. In Russia, I.I. Stolnikov conducted his experiments about myocardial hypertrophy and kidneys ischemia in 1880. Famous Russian internist, E.M. Tareev, devoted several paragraphs to cardiorenal interactions in his fundamental manuals "Anemia in Bright's disease" (1929) and "Hypertension" (1948). The research on this topic was continued by Tareev's followers: N.A. Mukhin, V.S. Moiseev, more recent successors - Zh.D. Kobalava, S.V. Moiseev, V.V. Fomin, S.V. Villevalde and others. Their contribution resulted in development of first Russian clinical guidelines on cardio and nephroprotection in CRS in 2014. In 2008 consensus of Acute Disease Quality Initiative summarized current experience on CRS. Today, research on controversial classification questions, biomarkers and other aspects of CRS continues.

[Soy protein as part of a low-protein diet is a new direction in cardio- and nephroprotection in patients with 3B-4 stages of chronic kidney disease: prospective, randomized, controlled clinical study]

BACKGROUND

It has been established that the use of a low-protein diet (LPD) in combination with ketoanalogues (KA) of essential amino acids can contribute to cardio- and nephroprotection in chronic kidney disease (CKD). Moreover, it has been shown that replacing part of the animal protein with soy protein (SP) in the diet contributed to more pronounced nephro- and cardioprotection in CKD, however, the data, available in the literature, are mainly represented by experimental studies.

AIM

To compare the effects of 2 types of diets on the main parameters of nephro- and cardioprotection in patients with CKD.

MATERIALS AND METHODS

We have conducted a prospective, randomized, controlled clinical study which included 85 patients with 3B4 stages of CKD, compliant to LPD (0.6 g of protein/kg body weight) + KA (1 tablet/5 kg body weight). 43 patients (Group 1) received LPD with replacing animal protein with soy (60% soy protein + 40% another vegetable proteins) + KA, and 42 patients (control group, Group 2) received LPD (60% animal protein + 40% vegetable protein) + KA, within 12 months.

RESULTS

The dietary substitution of animal protein with SP to a greater extent delayed the decrease in glomerular filtration rate (-5.9% vs -13.3%; p=0.048), the increase in left ventricular hypertrophy (+4.7% vs +12.3%; p=0.042), as well as the increase in central systolic blood pressure (+2.6% vs +13.0%; p=0.021), augmentation index (+7.6% vs +23.3%; p=0.010), slowed down the decrease in lean body mass in men (+0.9% vs -11.2%; p=0.017) and women (-1.8% vs -10.3%; p=0.024), increase in phosphorus (-10.3% vs +13.0%; p=0.029), cholesterol (-10.7% vs -3.4%; p=0.047) and urea (+6.3% vs +19.6%; p=0.035) serum levels.

CONCLUSION

The use of LPD with substitution of animal protein with soy protein + KA provides a more pronounced effect on nephro- and cardioprotection as well as maintenance of nutritional status, than conventional LPD + KA in patients with 3B4 stages of CKD.

[Low serum Klotho level as a predictor of calcification of the heart and blood vessels in patients with CKD stages 2-5D]

Cardiovascular calcification (CVC) makes a significant contribution to the manifestation of cardiovascular complications in patients with chronic kidney disease. Early CVC markers are currently being actively studied to optimize cardio-renoprotective strategies. We performed a prospective comparative analysis of the following factors: FGF-23, a-Klotho, sclecrostin, phosphate, parathyroid hormone, the estimated glomerular filtration rate (eGFR), central systolic pressure as an independent determinant of CVC.

MATERIALS AND METHODS

The study included 131 patients with chronic kidney disease 25D st. Serum levels of FGF-23, Klotho, and sclerostin were evaluated using the ELISA method. Vascular augmentation (stiffness) indices, central arterial pressure (using the SphygmoCor device), calcification of heart valves and the degree of aortic calcification (aortic radiography) were also investigated. The observation period was 2 years.

RESULTS

According to the Spearman correlation analysis, the percent of calcification increase and the change in Klotho level are most related. According to ROC analysis, a decrease in serum levels of Klotho by 50 units or more is a significant predictor of an increase in aortic calcification of 50% or more with a sensitivity of 86% and a specificity of 77%. Using logistic regression analysis, it was found that a serum Klotho level 632 pg/L predicts an eGFR below a median level of 48 ml/min/1.73 m2 with a sensitivity of 85.5% and a specificity of 78.5%. Wherein OR 17.477 (CI 95% 8.04637.962; p0.001).

CONCLUSION

The factor most associated with CVC is Klotho. Decreased serum level of Klotho is a predictor of aortic calcification. In addition, the initial serum level of Klotho is a predictor of eGFR after 2 years.

[Clinicopatological variants and risk factors for chronic kidney disease in rheumatoid arthritis]

Recent studies have shown a high risk of chronic kidney disease and associated cardiovascular complications in patients with rheumatoid arthritis (RA), which determines the prognosis. However, the prevalence of chronic kidney disease (CKD) in RA has not been established in the Russians.

AIM

Study was to examine the prevalence, risk factors and histological variants of CKD in RA.

MATERIALS AND METHODS

180 patients with rheumatoid arthritis were observed in the Tareev clinic of nephrology, for the period from 2014 to 2019 years. Age, gender, duration of RA, drug therapy, ESR, CRP, DAS28, renal function, proteinuria, histological variants were analyzed. Of the common population risk factors for CKD arterial hypertension, weight index, serum lipids and glucose levels were also assessed.

RESULTS

The prevalence of CKD in RA was 19.7%. Age, presence and stage of arterial hypertension, an increase in body mass index, as well as high rates of disease activity ESR, CRP, DAS28 score and duration of RA were risk factors of CKD in RA. Age, duration of the disease, stage of AH and hypercholesterolemia were risk factors in multifactorial regression analysis. Amyloidosis was the most common histologic pattern (50.0%), followed by chronic glomerulonephritis (30.4%) and tubulo-interstitial nephritis (19.6%). Among chronic glomerulonephritis mesangial glomerulonephritis was the most frequent. Renal amyloidosis was associated with a duration of RA, presence of systemic symptoms and CRP level. An isolated decrease in GFR of less than 60 ml/min was detected in 31 (36.0%) out of 86 patients. Сonclusion. The risk factors for CKD in patients with RA are activity and duration of the disease In addition to common population factors. Amyloidosis was the most common histologic pattern associated with duration of RA and inflammatory proteins levels.

Decreased Serum Levels of Klotho Protein in Chronic Kidney Disease Patients: Clinical Imortance

Objective: to determine the role of serum Klotho (s-Klotho) protein levels changes in patients with different stages of chronic kidney disease (CKD).Methods: The study involved 130 patients with CKD stages 1–5D (mean age ― 41±6.7 years). Serum levels of parathyroid hormone (PTH), calcium, phosphorus and s-Klotho protein (ELISA method) at baseline and after 1 year of follow-up were examined in all the patients so as the blood pressure (BP), including central (aortic), pulse wave velocity ― with the help of «Sphygmоcor» (Australia), echocardiography, radiography of the abdominal aorta in a lateral projection were also performed.Results: when comparing the s-Klotho levels in patients with different CKD stages, it was found that the level change associated with the reduction of glomerular filtration rate (GFR) ahead of phosphorus and PTH increase in serum, stared at 3A CKD, whereas hyperphosphatemia and PTH increase started at 4–5 CKD stages. According to ROC analysis, decreasing of s-Klotho levels below 387 pg/ml was indicated a calcification risk of abdominal aorta increased with an 80% sensitivity and 75% specificity. In addition, a strong negative relationship of low s-Klotho levels and heart remodeling was found. When comparing the patients with hypertension who were receiving antihypertensive monotherapy, the highest serum levels of Klotho protein were observed in those of them whose target blood pressure level was achieved primarily through Angiotensin II Receptors Blockers (ARB), compared to those who was administered another drug group (p0.01) or has not reached the target blood pressure level (p=0,008).Conclusion: The change of serum Klotho levels (decrease) in CKD progression is associated with the degree (increase) of cardiovascular calcification and remodeling (the development of left ventricular hypertrophy, and cardiomyopathy) and it can be seen as an early independent marker of the cardiovascular system lesions in CKD. Our preliminary data of the effect of blood pressure correction on s-Klotho levels may indicate the possibility of drug maintaining serum Klotho levels and it requires further research.