Urinary hyaluronidase activity is closely related to vasopressinergic system following an oral water load in men: a potential role in blood pressure regulation and early stages of hypertension development.

Introduction: Blood pressure (BP) regulation is a complex process involving several factors, among which water-sodium balance holds a prominent place. Arginin-vasopressin (AVP), a key player in water metabolism, has been evoked in hypertension development since the 1980s, but, to date, the matter is still controversial. Hyaluronic acid metabolism has been reported to be involved in renal water management, and AVP appears to increase hyaluronidase activity resulting in decreased high-molecular-weight hyaluronan content in the renal interstitium, facilitating water reabsorption in collecting ducts. Hence, our aim was to evaluate urinary hyaluronidase activity in response to an oral water load in hypertensive patients (HT, n=21) compared to normotensive subjects with (NT+, n=36) and without (NT-, n=29) a family history of hypertension, and to study its association with BP and AVP system activation, expressed by serum copeptin levels and urine Aquaporin 2 (AQP2)/creatinine ratio. Methods: Eighty-six Caucasian men were studied. Water load test consisted in oral administration of 15-20 ml of water/kg body weight over 40-45 min. BP, heart rate, serum copeptin, urine hyaluronidase activity and AQP2 were monitored for 4 hours. Results: In response to water drinking, BP raised in all groups with a peak at 20-40 min. Baseline levels of serum copeptin, urinary hyaluronidase activity and AQP2/creatinine ratio were similar among groups and all decreased after water load, reaching their nadir at 120 min and then gradually recovering to baseline values. Significantly, a blunted reduction in serum copeptin, urinary hyaluronidase activity and AQP2/creatinine ratio was observed in NT+ compared to NT- subjects. A strong positive correlation was also found between urinary hyaluronidase activity and AQP2/creatinine ratio, and, although limited to the NT- group, both parameters were positively associated with systolic BP. Discussion: Our results demonstrate for the first time the existence in men of a close association between urinary hyaluronidase activity and vasopressinergic system and suggest that NT+ subjects have a reduced ability to respond to water loading possibly contributing to the blood volume expansion involved in early-stage hypertension. Considering these data, AVP could play a central role in BP regulation by affecting water metabolism through both hyaluronidase activity and AQP2 channel expression.

Low serum ferroxidase I activity is associated with mortality in heart failure and related to both peroxynitrite-induced cysteine oxidation and tyrosine nitration of ceruloplasmin.

RATIONALE: Ceruloplasmin antioxidant function is mainly related to its ferroxidase I (FeOxI) activity, which influences iron-dependent oxidative and nitrosative radical species generation. Peroxynitrite, whose production is increased in heart failure (HF), can affect ceruloplasmin antioxidant function through amino acid modification. OBJECTIVE: We investigated the relationship between FeOxI and ceruloplasmin tyrosine and cysteine modification and explored in a cohort of patients with HF the potential clinical relevance of serum FeOxI. METHODS AND RESULTS: In patients with chronic HF (n=96, 76 ± 9 years; New York Heart Association class, 2.9 ± 0.8) and age-matched controls (n=35), serum FeOxI, FeOxII, ceruloplasmin, nitrotyrosine-bound ceruloplasmin, B-type natriuretic peptide, norepinephrine, and high-sensitivity C-reactive protein were measured, and the patients were followed up for 24 months. Ceruloplasmin, B-type natriuretic peptide, norepinephrine, and high-sensitivity C-reactive protein were increased in HF versus controls. FeOxI was decreased in HF (-20%) and inversely related to nitrotyrosine-bound ceruloplasmin (r, -0.305; P=0.003). In HF, FeOxI lower tertile had a mortality rate doubled compared with middle-higher tertiles. FeOxI emerged as a mortality predictor (hazard ratio, 2.95; 95% confidence intervals [1.29-6.75]; P=0.011) after adjustment for age, sex, hypertension, smoking, sodium level, estimated glomerular filtration rate, and high-sensitivity C-reactive protein. In experimental settings, peroxynitrite incubation of serum samples and isolated purified ceruloplasmin reduced FeOxI activity while increasing ceruloplasmin tyrosine nitration and cysteine thiol oxidation. Reduced glutathione prevented peroxynitrite-induced FeOxI drop, tyrosine nitration, and cysteine oxidation; flavonoid(-)-epicatechin, which prevented ceruloplasmin tyrosine nitration but not cysteine oxidation, partially impeded peroxynitrite-induced FeOxI drop. CONCLUSIONS: Reduced activity of serum FeOxI is associated with ceruloplasmin nitration and reduced survival in patients with HF. Both ceruloplasmin tyrosine nitration and cysteine thiol oxidation may be operant in vivo in peroxynitrite-induced FeOxI activity inhibition.

Prealbumin improves death risk prediction of BNP-added Seattle Heart Failure Model: results from a pilot study in elderly chronic heart failure patients.

BACKGROUND: An accurate prognosis prediction represents a key element in chronic heart failure (CHF) management. Seattle Heart Failure Model (SHFM) prognostic power, a validated risk score for predicting mortality in CHF, is improved by adding B-type natriuretic peptide (BNP). We evaluated in a prospective study the incremental value of several biomarkers, linked to different biological domains, on death risk prediction of BNP-added SHFM. METHODS: Troponin I (cTnI), norepinephrine, plasma renin activity, aldosterone, high sensitivity-C reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), interleukin 2 soluble receptor, leptin, prealbumin, free malondialdehyde, and 15-F2t-isoprostane were measured in plasma from 142 consecutive ambulatory, non-diabetic stable CHF (mean NYHA-class 2.6) patients (mean age 75±8years). Calibration, discrimination, and risk reclassification of BNP-added SHFM were evaluated after individual biomarker addition. RESULTS: Individual addition of biomarkers to BNP-added SHFM did not improve death prediction, except for prealbumin (HR 0.49 CI: (0.31-0.76) p=0.002) and cTnI (HR 2.03 CI: (1.20-3.45) p=0.009). In fact, with respect to BNP-added SHFM (Harrell's C-statistic 0.702), prealbumin emerged as a stronger predictor of death showing the highest improvement in model discrimination (+0.021, p=0.033) and only a trend was observed for cTn I (+0.023, p=0.063). These biomarkers showed also the best reclassification statistic (Integrated Discrimination Improvement-IDI) at 1-year (IDI: cTnI, p=0.002; prealbumin, p=0.020), 2-years (IDI: cTnI, p=0.018; prealbumin: p=0.006) and 3-years of follow-up (IDI: cTnI p=0.024; prealbumin: p=0.012). CONCLUSIONS: Individual addition of prealbumin allows a more accurate prediction of mortality of BNP enriched SHFM in ambulatory elderly CHF suggesting its potential use in identifying those at high-risk that need nutritional surveillance.

Serum adipokine zinc α2-glycoprotein and lipolysis in cachectic and noncachectic heart failure patients: relationship with neurohormonal and inflammatory biomarkers.

Chronic heart failure is often complicated by the development of cachexia with the loss of fat mass. Zinc α2-glycoprotein (ZAG) is a serum adipokine with lipolytic effects in cancer cachexia. We evaluated in patients with advanced heart failure with (CxHF) or without cachexia (nCxHF) the relationship of ZAG with circulating free fatty acid (FFA), as an index of lipolysis, and with other neurohormonal and inflammatory biomarkers. Two groups, nCxHF (n = 46) and CxHF (n = 18), the latter having a documented, involuntary, edema-free loss of body weight of at least 7.5% in the previous 6 months, underwent plasma determination of FFA, ZAG, norepinephrine (NE), tumor necrosis factor-α, and natriuretic peptide levels (atrial natriuretic, B-type natriuretic peptide). The patients were compared with age-matched healthy controls (CTR) (n = 21). Zinc α2-glycoprotein, atrial natriuretic peptide, B-type natriuretic peptide, and tumor necrosis factor-α circulating levels were similarly greater in CxHF and nCxHF than in CTR. Free fatty acid and NE were higher in CxHF than in nCxHF. A positive correlation between FFA and NE was found in both CxHF (r = 0.73, P < .01) and nCxHF (r = 0.48, P < .01) but only in CxHF between ZAG and FFA (r = 0.54, P = .02) and between ZAG and NE (r = 0.70, P < .01). No correlations between natriuretic peptides and ZAG were found. Serum ZAG levels are increased in advanced heart failure patients compared with CTR, without differences between CxHF and nCxHF. Only in CxHF, ZAG levels are directly correlated to circulating levels of FFA and NE, suggesting a close interaction of ZAG with sympathetic-mediated lipolysis.