Romana Mijovic

Plasma endothelin-1 level, measured glomerular filtration rate and effective renal plasma flow in diabetic nephropathy.

Abstract Background: Endothelin-1 (ET-1) is potent vasoconstrictor peptide which is able to contribute to the functional and structural renal changes. The aim of this study was to investigate the relationship between plasma concentration of ET-1 and indices of renal function in patients with diabetic nephropathy. Methods: We measured plasma ET-1 levels in 99 patients with type 2 diabetes, divided into two groups according to the values of their glomerular filtration rate (GFR): group I (GFR ≥ 60 mL/min/1.73 m2; n = 50), group II (GFR ≥ 60 mL/min/1.73 m2, n = 49), and the control group (n = 30) with clinically healthy subjects who were matched by age and sex. GFR and effective renal plasma flow (ERPF) were measured by the radioisotopic clearance. Other renal function parameters, such as serum concentrations of cystatin C, urea, creatinine, uric acid, 24-h albuminuria and proteinuria were additionally measured. Results: There were significant differences in plasma concentration of ET-1 among groups I, II and the control group (1.45 vs. 2.40 vs. 0.80 pg/mL, p < 0.001). The correlation between ET-1 and mGFR (r = −0.52, p < 0.001), ERPF (r = −0.42, p < 0.001), albuminuria and proteinuria (r = 0.36, p < 0.001; r = 0.48, p < 0.001) and cystatin C (r = 0.42, p < 0.001) was significant. In multiple regression analyses, only plasma concentration of ET-1 (p < 0.001) and duration of hypertension (p < 0.05) were independently and significantly associated with mGFR. Conclusion: A higher plasma concentration of ET-1 is independently associated with a decreased value of GFR in patients with diabetic nephropathy.

Platelet turnover and function in end-stage renal disease

Background/Aim. End-stage renal disease (ESRD) is characterized by significant impairment of platelet functions which may cause bleeding or thrombotic complications. The iam of this study was the aim of this study was the assessement of platelet turnover and function and their correlation with inflammatory and procoagulant markers in ESRD patients as well as platelet indicies comparison between ESRD diabetic and ESRD non-diabetic patients. Methods. The prospective, observational clinical study included 63 ESRD patients and 30 age and sex matched healthy volunteers. Following laboratory parameters of platelet turnover and function (platelet count, reticulated platelets, platelet indices, whole blood impedance platelet aggregation), inflammatory and procoagulant markers (number of neutrophils, neutrophil to lymphocyte ratio, C-reactive protein, plasma fibrinogen, D dimer, von Willebrand factor) were obtained. Results. Platelet turnover (% of reticulated platelets) was significantly higher (3.8 ± 2.3 vs. 2.3 ± 1.3; p < 0.01) and platelet aggregation tests induced by thrombin receptor activiting peptide (TRAP) (p < 0.01), adenosine diphospate (ADP) (p < 0.05), arachidonic acid (ASPI) (p < 0.05) and collagen (p < 0.05) were markedly increased in the ESRD patients compared to the control group. The comparison of chronic inflammation and procoagulant markers revealed higher values in all patients comparing to the group of healthy subjects (p < 0.01 regarding all parameters). There was no difference between the ESRD diabetic and ESRD non-diabetic patients. Conclusion. Results point out increased platelet turnover in ESRD as a consequence of platelet activation and consumption induced by clotting system hyperactivity and chronic inflammation. None of the examined parameters do not predict bleeding occurrence.

Estimation of Glomerular Filtration Rate From Serum Cystatin C and Creatinine in Patients with Thyroid Dysfunction

Estimation of Glomerular Filtration Rate From Serum Cystatin C and Creatinine in Patients with Thyroid Dysfunction Given that thyroid function influences serum cystatin C and creatinine levels, the question arises as to whether it is possible to accurately estimate glomerular filtration rate (GFR) in patients with thyroid dysfunction. The objective of the study was to determine serum cystatin C and creatinine levels and estimate GFR in patients with thyroid dysfunction. The study included 32 cases with newly diagnosed hyperthyroidism and 27 cases with newly diagnosed hypothyroidism, as well as 20 healthy controls matched for sex and age with the cases. Serum concentrations of thyroid stimulating hormone (TSH), free triiodothyronine (fT3) and free thyroxine (fT4), creatinine and cystatin C were measured in all study subjects. GFR was estimated using the Modification of Diet in Renal Disease (MDRD), the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and cystatin C-based equations. Serum cystatin C levels were significantly higher in hyperthyroid subjects compared to controls (1.32±0.31 vs. 0.89±0.15; p<0.01). Serum creatinine levels were significantly lower in hyperthyroid subjects compared to controls (60.6±10.2 vs. 76.4±8.6; p<0.01), and significantly higher in hypothyroid subjects compared to controls (94.5±13.2 vs. 76.4±8.6; p<0.01). GFR estimated with the MDRD equations was significantly higher in hyperthyroid subjects compared to hypothyroid subjects (101.6±20.7 vs. 64.1±11.6 mL/min/1.73m2; p<0.01). GFR estimated with the equation based on serum cystatin C was significantly lower in hyperthyroid subjects compared to hypothyroid subjects (59.2±22.1 vs. 92.1±16.0 mL/min/1.73m2; p<0.01). Although serum cystatin C is regarded a reliable marker of GFR and more sensitive than serum creatinine, it has limitations in patients with thyroid dysfunction, due to significant changes in its serum concentrations regardless of renal function. In patients with thyroid dysfunction GFR should therefore be estimated using the equations based on serum creatinine. Određivanje Jačine Glomerulske Filtracije na Osnovu Serumske Koncentracije Cistatina C i Kreatinina Kod Bolesnika sa Poremećajem Funkcije Štitaste Žlezde S obzirom na uticaj tireoidne funkcije na nivo cistatina C i kreatinina, postavlja se pitanje mogućnosti pravilne procene (GFR) brzine glomerularne filtracije kod bolesnika sa tireoidnom disfunkcijom. Cilj ove studije je evaluacija vrednosti cistatina C i kreatinina uz procenu (GFR) kod bolesnika sa poremećajem funkcije štitaste žlezde. U ispitivanje je uključeno 32 bolesnika sa novodijagnostikovanom hipertireozom i 27 bolesnika sa novodijagnostikovanom hipotireozom. Kontrolnu grupu sačinjava 20 zdravih ispitanika koji odgovaraju ispitivanoj grupi prema starosti i polu. Svim ispitanicima je određena koncentracija fT3, fT4, TSH, kreatinina i cistatina C. Procenjena je vrednost GFR jednačinama na osnovu serumske koncentracije kreatinina, kao i jednačinom baziranom na vrednosti cistatina C. Značajno su više vrednosti cistatina C u grupi hipertireoidnih bolesnika u odnosu na kontrolnu grupu (1,32±0,31 vs. 0,89±0,15; p<0,01). Vrednosti kreatinina statistički su značajno niže u grupi hipertireoidnih bolesnika u odnosu na kontrolnu grupu (60,6± 10,2 vs. 76,4±8,6; p<0,01), za razliku od značajno viših vrednosti kreatinina u grupi hipotireoidnih bolesnika u odnosu na kontrolnu grupu (94,5± 13,2 vs. 76,4±8,6; p<0,01). GFR procenjena MDRD i CKD-EPI jednačinama u grupi hipertireoidnih bolesnika značajno je viša u odnosu na GFR u grupi hipotireoidnih bolesnika (101,6±20,7 vs. 64,1±11,6 mL/min/1,73m2; p<0,01). GFR procenjena jednačinom baziranom na serumskoj koncentraciji cistatina C u grupi hipertireoidnih ispitanika statistički je značajno niža u odnosu na iste vrednosti u grupi hipotireoidnih subjekata (59,2± 22,1 vs. 92,1±16,0 mL/min/1,73m2; p<0,01). Iako se smatra da je cistatin C pouzdan parametar u proceni GFR, senzitivniji od serumske koncentracije kreatinina, njegova upotreba je ograničena kod bolesnika sa tireoidnom disfunkcijom usled značajnih promena njegove serumske koncentracije nezavisno od bubrežne funkcije, odnosno, kod bolesnika sa tireoidnom disfunkcijom za procenu GFR treba koristiti jednačinu baziranu na serumskoj koncentraciji kreatinina.