Zoran Stosic

Changes of serum VEGF concentration after intravitreal injection of Avastin in treatment of diabetic retinopathy

Purpose Avastin (bevacizumab) intravitreal injections are widely used for treatment of diabetic retinopathy. The aim of our study was to analyze effect of 1.25 mg of intravitreal Avastin on serum concentration of vascular endothelial growth factor (VEGF) in diabetic patients. Methods Participants were 10 diabetic patients on insulin therapy, without any other eye or systemic disease, and no kidney disfunction. Both eyes of diabetic patients were injected simultaneously with 1.25 mg of intravitreal Avastin, as a first step in treatment of nonproliferative diabetic retinopathy with clinically significant macular edema (4 patients), and of proliferative diabetic retinopathy (6 patients). Fluorescein angiography was performed prior to and laser therapy followed 1 month after Avastin treatment. VEGF concentration in patients serum was measured by ELISA technique: on the day of the Avastin administration, and 1, 7, and 28 days after intravitreal injection. Results In all analyzed participants, 24 hours after Avastin treatment, serum levels of VEGF were lower then basal (preinjection value). Maximal reduction of serum VEGF was noted on the 7th postoperative day. Twenty-eight days after, VEGF level in serum was raised, without completely reaching basal preoperative concentrations in most patients. Conclusions Intravitreal injections of anti-VEGF drugs have an effect on decreasing systemic VEGF values. Rhythm of changes in serum VEGF concentrations and lowest detected concentration on the seventh postinjection day are according to pharmacokinetics of Avastin in serum and vitreous, reported by similar studies. The small number of patients involved in this pilot study implicates the need for further studies.

Cystatin C in pre-eclampsia.

Objective: To evaluate diagnostic value of cystatin C serum levels as alternative marker of renal function in pre-eclamsia (PE) and compare it with the traditional markers of renal function, creatinine and uric acid. In order to investigate the possible influence of inflammation on biochemical markers of renal function, serum levels of high sensitive CRP were measured (hsCRP). Methods: In this prospective study markers of kidney function were investigated in two groups of pregnant women: one with PE (n = 32) and the other of healthy pregnant women (n = 60). Serum cystatin C levels were measured as well as levels of traditional renal markers creatinin and uric acid and levels of high sensitive C-reactive protein. Results: Serum levels of cystatin C, creatinine and uric acid were significantly higher in the PE group than in the control group. Serum levels of hsCRP were higher in approximately the same number of patients with PE (50%) as in normal pregnancies (40%), without significant differences in CRP values between the two groups of patients. Conclusions: Cystatin C serum level may have significant role as a marker of pre-eclampsia specially when used in combination with uric acid levels.

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.

Determining the Relationship Between Homocysteinemia and Biomarkers of Inflammation, Oxidative Stress and Functional Kidney Status in Patients with Diabetic Nephropathy

Summary Background: One of the leading causes of terminal renal failure is diabetic nephropathy. The aim of this study was to determine the relationship between homocysteine levels and the biomarkers of renal function, inflammation and oxidative stress, as well as the incidence of macrovascular complications in patients with diabetic nephropathy. Methods: Sixty-four patients with diabetic nephropathy were included in this study. They were divided according to their homocysteine levels into two groups: hyperhomocysteinemic (HHcy, n=47) and normohomocysteinemic patients (NHCy, n=17). The re sults were compared to a control group (n=20) with normal renal function and without diabetes. Besides homocysteine, cystatine C, creatinine, urea, albuminuria, creatinine clearance, lipid status parameters, apolipoprotein A-I and B, lipo protein (a), CRP, fibrinogen, oxidative LDL were determined using appropriate methods. The incidence of macro vascular diabetic complications was also determined. Results: The results indicate that the level of renal dysfunction is greater in HHcy than in NHcy patients (p<0.05). In HHcy patients levels of oxLDL were also higher compared to NHcy patients (119.3±140.4 vs. 71.4±50.8 ng/mL, disp< 0.05) as well as fibrinogen levels (4.3±1.3 vs. 3.7±0.8 g/L, p<0.05). The in cidence of macrovascular complications is more frequent in HHcy than in NHcy patients (55.3. vs. 35.3 %, p>0.05), and in patients with macroalbuminuria compared to patients with microalbuminuria (65% vs. 39%, p<0.05). Conclusions: It can be concluded that HHcy is significantly present in patients with diabetic nephropathy, especially if there is greater reduction of renal function. Besides that, significantly higher concentrations of inflammatory (fibrinogen) and oxidative stress (oxLDL) markers were present in HHcy patients with diabetic nephropathy compared to NHcy patients.Therefore in diabetic nephropathy patients it is useful to regularly monitor the levels of homocysteine, as well as inflammatory and markers of oxidative stress. Kratak sadržaj Uvod: Dijabetesna nefropatija jedan je od vodećih uzroka terminalne bubrežne insuficijencije. Cilj ove studije bio je ispitivanje odnosa homocisteinemije i biomarkera bu bre`ne funkcije, inflamacije i oksidativnog stresa, kao i u~e stalosti makrovaskularnih komplikacija kod bolesnika sa dijabetesnom nefropatijom. Metode: U studiju je uklju~eno 64 ispitanika sa dijabetesnom nefropatijom koji su podeljeni u dve grupe u odnosu na homocisteinemiju: hi per homociste i nemi~ni (HHcy, n=47) i normohomo cistei ne mi~ni (NHcy, n=17). Odgovaraju}im metodama su pored nivoa homocisteina u krvi odre|ivani i nivoi cistatina C, kreatinina, uree, albuminurije, klirensa kreatinina, parametara lipidskog statusa, apolipoproteina A i B, lipoproteina(a), CRP, fibrinogena, oksidisanog LDL, kao i u~estalost makrovaskularnih komplikacija dijabetesne bo - lesti. Rezultati: Dobijeni rezultati upore|ivani su sa rezultatima kontrolne grupe ispitanika (n=20) sa urednom bubre`nom funkcijom, bez prisutne dijabetesne bolesti. Rezultati ukazuju da je stepen bubre`ne disfunkcije ve}i kod HHcy nego kod NHcy pacijenata (p<0,05). Tako|e, kod HHcy pacijenata nivo oxLDL je zna~ajno vi{i u odnosu na NHcy pacijente (119,3±140,4 vs. 71,4±50,8 ng/mL, p<0,05), kao i nivofibrinogena (4,3±1,3 vs. 3,7±0,8 g/L, p<0,05). Pojava makrovaskularnih komplikacija je u~estalija kod HHcy nego NHcy pacijenata (55,3% vs. 35,3%, p> 0,05), kao i kod pacijenata sa makroalbuminurijom u od nosu na pacijente sa mikroalbuminurijom (65% vs. 39%, p<0,05). Zakljućak: Na osnovu dobijenih rezultata mo`e se zaklju~iti da je HHcy u zna~ajnom stepenu prisutna kod bolesnika sa dijabetesnom nefropatijom, naro~ito ukoliko postoji izra `enija redukcija funk cio nalne rezerve bubrega. Osim toga, u odnosu na NHcy bo lesnike, kod HHcy bolesnika sa dijabetesnom nefropatijom zna~ajno su vi{e koncentracije inflamatornih (fibrinogena) i markera oksidativnog stresa u krvi (oxLDL). Stoga je kod bolesnika sa dijabetesnom nefropatijom po`eljno redovno pra}enje homocisteina u krvi, ali i inflamatornih markera, kao i markera oksidativnog stresa.

Ceruloplasmin and antioxidative enzymes in pre-eclampsia

Abstract Objective: To evaluate diagnostic value of ceruloplasmin together with other enzymatic and nonenzymatic antioxidants (superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and uric acid) and to evaluate the level of oxidative stress in patients with pre-eclampsia (PE) and compare it with normal pregnancy. Methods: In this prospective study, antioxidative markers were investigated in two groups of pregnant women: patients with pre-eclampsia (n = 32) and the healthy pregnant women (n = 60). The following antioxidative markers and enzymes were evaluated: serum ceruloplasmin levels, uric acid, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Results: Serum levels of ceruloplasmin, uric acid and SOD were significantly higher in the PE group compared to the control group. Serum levels of GSH-Px were not significantly higher in the PE group compared to the control group. Serum ceruloplasmin and serum uric acid have the best diagnostic accuracy for oxidative stress in PE and are more accurate compared to antioxidative enzymes -SOD and specially more accurate than GSH-Px. Conclusions: Serum ceruloplasmin level may have significant role as the markers of oxidative stress in pre-eclampsia especially when used in combination with uric acid levels.

Vitamin D status and circulating biomarkers of endothelial dysfunction and inflammation in non-diabetic obese individuals: a pilot study

Introduction Obesity and inadequate vitamin D status are associated with endothelial dysfunction and cardiovascular disease. We evaluated the associations between vitamin D status (i.e. serum levels of 25-hydroxyvitamin D (25(OH)D)), biomarkers of endothelial dysfunction (i.e. serum concentrations of soluble intercellular adhesion molecule 1 (sICAM-1) and soluble E-selectin (sE-selectin)), inflammatory markers (i.e. high-sensitivity C-reactive protein (hsCRP) and fibrinogen) and cardiometabolic risk factors. Material and methods Fifty obese (body mass index (BMI) ≥ 30 kg/m2) non-diabetic adults (mean age: 36.2 ±5.4 years) without pre-existing cardiovascular abnormalities and 25 clinically healthy, normal weight and age-matched individuals were included. Anthropometric parameters, markers of glucose and lipid metabolism, and serum levels of inflammatory and endothelial dysfunction biomarkers were assessed in all subjects. Results The mean serum 25(OH)D level was significantly lower in the obese group than in controls (33.5 ±15.2 vs. 60.1 ±23.1 nmol/l; p < 0.001). In the obese group, sE-selectin (36.4 (32.1–47.2) vs. 32.4 (24.6–35.5) ng/ml, p < 0.05) and hsCRP (6.0 ±3.4 vs. 3.5 ±1.0 mg/l, p < 0.05) were significantly higher in individuals with lower than median vitamin D levels (i.e. 31 nmol/l) compared with those with higher vitamin D levels. In multivariable linear regression analysis, hsCRP (β = –0.43; p < 0.001) and sE-selectin (β = –0.30; p = 0.03) were independently and significantly associated with serum 25(OH)D levels in the obese group. Conclusions Vitamin D levels may be related to increased levels of biomarkers of endothelial dysfunction and inflammation in obese non-diabetic individuals.

Serum Cystatin C in Estimating Glomerular Filtration Rate

Serum Cystatin C in Estimating Glomerular Filtration Rate Using serum cystatin C in estimating glomerular filtration rate (GFR) has in recent times been recommended. A number of simple formulas for calculating GFR have been derived specifically from serum cystatin C concentrations. The purpose of this study was to assess the significance of cystatin C and of the two most frequently applied of these formulas in estimating glomerular filtration rate compared to serum creatinine and its derived formulas for estimating glomerular filtration rate from creatinine concentrations. The study included 74 patients: 59 were in various stages of chronic renal insufficiency (divided into two subgroups: I with GFR ≥ 60 mL/min/1.73m2 and II with GFR<60 mL/min/1.73m2) and 15 on hemodialysis. A control group of 30 healthy participants was also included in the study. Serum values of cystatin C ranged from: 0.86 ± 0.16 mg/L in subgroup I, and 1.77 ± 0.79 mg/L in subgroup II, to 6.9 ± 1.83 mg/L in patients on hemodialysis. The correlation between the two formulas derived from cystatin C and the clearance of creatinine, as well as the Cockcroft and Gaults formula, was significant, while one of the formulas derived from cystatin C did not show a significant correlation with MDRD. It was concluded that serum cystatin C is a significant marker in estimating glomerular filtration rate, especially in the advanced stages of chronic renal insufficiency. Serumski Cistatin C U Proceni Jačine Glomerulske Filtracije U novije vreme preporučena je upotreba serumskog cistatina C u proceni jačine glomerulske filtracije (GFR). Upravo iz serumske koncentracije cistatina C je izvedeno nekoliko jednostavnih formula za izračunavanje GFR. Cilj ove studije je bio da proceni značaj cistatina C i dve najčešće primenjivane od tih formula u proceni jačine glomerulske filtracije u poređenju sa serumskim kreatininom i izvedenim formulama za procenu jačine glomerulske filtracije iz koncentracija kreatinina. U studiju je uključeno 74 ispitanika: 59 u različitim stadijumima hronične bubrežne insuficijencije (podeljenih u dve podgrupe: I sa GFR ≥ 60 mL/min/1,73m2 i II sa GFR< 60 mL/min/1,73m2) i 15 na hemodijalizi. U studiju je bila uključena i kontrolna grupa od 30 zdravih ispitanika. Serumske vrednosti cistatina C su se kretale: u podgrupi I 0,86 ± 0,16 mg/L, u podgrupi II 1,77 ± 0,79 mg/L i kod ispitanika na hemodijalizi 6,9 ± 1,83 mg/L. Korelacija između obe formule izvedene iz cistatina C i klirensa kreatinina kao i Kokroft-Gaultove formule bila je značajna, dok jedna od ovih formuli izvedenih iz cistatina C nije pokazala značajnu korelaciju sa MDRD. Može se zaključiti da je serumski cistatin C značajan parametar u proceni jačine glomerulske filtracije, naročito u odmaklim stadijumima hronične bubrežne insuficijencije.

Relation between osteocalcin and the energy metabolism in obesity

Background/aims:Numerous findings have indicated the potential relation between the osteocalcin, the traditional parameter of bone turnover and the regulation of energy metabolism. The aim of this study was to identify the relationship between osteocalcin and calculated indexes, which evaluate insulin sensitivity, insulin resistance and/or secretory capacity of the pancreas, in non-diabetic, obese subjects. Methods:The study included 57 (11 men and 46 women) euglycemic, obese patients (BMI:41,03 ± 6,61kg/m2) and 48 healthy individuals, age and sex matched (BMI:23,15±2,04kg/m2). Plasma glucose and insulin levels during two hour oral glucose tolerance test (OGTT) were determined in order to calculate HOMA indexes (HOMA-IR, HOMA-B%), EISI (estimated insulin sensitivity index), EFP (estimated first phase) and ESP (estimated second phase). Osteocalcin was measured using Electrochemiluminescence (ECLIA) methodology. Results: Statistically lower osteocalcin was found in obese subjects (24.72±9.80 vs 33.31±10.89 ng/mL;p<0.01). Тhere was a statistically significant positive correlation between osteocalcin and EISI (r=0.340;p<0.01). The inverse correlations were found between the osteocalcin and HOMA-IR (r=-0.276;p<0.01), HOMA-B% (r=-0.337;p<0.01), EFP (r=-0.332;p<0.01) and ESP (r=-0.266;p<0.01). Multiple regression showed that, BMI and osteocalcin have a significant inverse prediction with EISI and HOMA-IR, but the level of prediction of BMI was is substantially higher. Conclusion: The effect of osteocalcin in the glyco-regulation is evident, but its contribution is significantly smaller in relation to primarily, obesity associated factors. Therefore, when assessing the position and the role in glycemic control, aways must bear in mind that osteocalcin represents only one of the many contributing factors, some of which exhibit dominant influence then osteocalcin itself.

Chronic Latent Magnesium Deficiency in Obesity Decreases Positive Effects of Vitamin D on Cardiometabolic Risk Indicators

BACKGROUND Obesity and micronutrient deficiencies contribute to the risk of cardiometabolic diseases such are type 2 diabetes mellitus and Cardiovascular Disease (CVD). OBJECTIVE We examined the frequency of concomitant deficit of Magnesium (Mg) and vitamin D in obese patients and evaluated the connection of these combined deficiencies with indicators of cardiometabolic risk in non-diabetic subjects. METHODS Non-diabetic middle aged adults (n = 80; mean age 36 ± 4 years, 52% women) were recruited based on weight/adiposity parameters [i.e. Body Mass Index (BMI) and body fat percentage (FAT%)]. Cardiometabolic risk indicators [insulin resistance (Homeostatic Model Assessment for Insulin Resistance (HOMA-IR)) and CVD risk (Framingham risk score for predicting 10-year CVD)], Mg status (i.e. total serum Mg concentration (TMg), Chronic Latent Mg Deficiency (CLMD) - 0.75-0.85 mmol/L), vitamin D status (i.e. serum concentration of 25-hydroxyvitamin D (25(OH)D), vitamin D deficiency <50 nmol/l) were assessed. RESULTS Among obese subjects 36% presented a combination of vitamin D deficiency and CLMD. In all studied patients, 25(OH)D and TMg levels both, individually and combined, showed a negative linear correlation with HOMA-IR and CVD risk. In subjects with CLMD (TMg <0.85 mmol/L), a negative linear coefficient was found between 25(OH)D and, HOMA-IR and CVD risk, compared with subjects with normal TMg status (TMg ≥0.85 mmol/L). CONCLUSION CLMD and vitamin D deficiency may commonly be present in obese non-diabetic subjects. Individually and combined, both deficiencies predispose non-diabetic patients to increased risk of cardiometabolic diseases. Maintaining normal Mg status may improve the beneficial effects of vitamin D on cardiometabolic risk indicators.

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.