Under physiological conditions insulin controls the metabolism of carbohydrates, lipids and proteins. Diabetes mellitus is a metabolic disease characterized by a disturbance in the intermediary metabolism of glucose and glucose-induced insulin release. Arginase (L-arginine amidinohydrolase, EC 3.5.3.1) modulates nitric oxide synthase activity by regulating intracellular L-arginine availability. In diabetes mellitus, a decrease in nitric oxide bioavailability is a central mechanism for endothelial dysfunction. The aim of our study was to assess arginase activity in the blood of children with diabetes mellitus. Blood arginase activity, serum glucose (14.155 +/- 4.197 mmol/L; p < .001) and blood HbA1c (11.222 +/- 3.186 %; p < .001), were significantly higher in diabetic children than in healthy controls, whereas the magnesium (Mg2+) level, a cofactor of many enzymes, was significantly lower (0.681 +/- 0.104 micromol; p < .001). In diabetic children, arginase activity, hyperglycemia (r = 0.143), and the HbA1, level (r = 0.381) showed a positive correlation between but a negative correlation between Mg2+ and arginase activity (r= -0.206). The higher arginase activity and the lower Mg2+' levels in diabetic children could be a consequence of reduced insulin action and increased protein catabolic processes in these pathophysiological conditions. The inverse directions of arginase activity and serum Mg2+ levels are in agreement with this concept.

Soluble suppressor of tumorigenicity 2 (sST2), galectin-3, growth differentiation factor (GDF)-15 and syndecan-1 represent biomarkers of cardiac remodeling, involved in heart failure (HF) progression. We hypothesize that their plasma concentrations, together with brain natriuretic peptide (BNP), are different in HF stratified by ejection fraction (EF), demonstrating correlations with echocardiographic parameters that indicate left ventricular (LV) hypertrophy; LV mass index (LVMI) and posterior wall and septum diameters. HF patients (n = 77) were classified according to EF: reduced EF < 40% (HFrEF), mid-range EF = 40-49% (HFmrEF), preserved EF > 50% (HFpEF). We found that plasma concentrations of four cardiac remodeling biomarkers were highest in HFrEF and lowest in HFpEF, p < 0.001. In HFpEF, remodeling biomarkers independently correlated with LVMI: sST2 (p = 0. 002), galectin-3 (p < 0.001), GDF-15 (p = 0.011), and syndecan-1 (p = 0.006), whereas galectin-3 correlated after multivariable adjustments (p = 0.001). Independent correlates of septum and posterior wall diameters, in HFpEF, were sST2 (p = 0.019; p = 0.026), galectin-3 (p = 0.011; p = 0.009), GDF-15 (p = 0.007; p = 0.001), and syndecan-1 (p = 0.005; p = 0.002). In HFrEF, only sST2, adjusted, correlated with LVMI (p = 0.010), whereas BNP correlated with LVMI (p = 0.002) and EF (p = 0.001). GDF-15 correlated with diastolic dysfunction in HFpEF (p = 0.046) and HFrEF (p = 0.024). Cardiac remodeling biomarkers are potential circulating indicators of LV hypertrophy in HFpEF, which may ensure timely recognition of disease progression among high-risk patients.

Arginase activity is important in polyamines and nitric oxide production which are required for the normal growth of placenta and embryo. A considerable arginase activity is observed in amniotic fluid in women at the end of pregnancy. Lecithin to sphingomyelin (L/S) ratio is widely used in order to assess fetal lung immaturity and prevention of neonatal respiratory distress syndrome, the major cause of neonatal morbidity and mortality. The purpose of our study was to determine if there is a relationship between arginase activity and L/S ratio in amniotic fluid. The study included 170 pregnant women, 18-43 years old, with normal and pathological pregnancy. The arginase activity was measured on the basis of the determination of the amount of liberated ornithine from arginine as substrate. The L/S ratio was done by using a thin layer chromatography. Increased level of arginase activity correlates with the fetal lung maturity. Arginase activity and L/S values may be useful biochemical data, for intrauterine baby maturity.

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