Production and Characterization of Monoclonal Antibodies against the Vasoconstrictive Peptide Human Urotensin-II

Urotensin II: an inflammatory cytokine

Urotensin II (UII) is a polypeptide molecule with neurohormone-like activity. It has been confirmed that UII is widely distributed in numerous organs of different animal species from fish to mammals, including humans. The UII receptor is orphan G-protein coupled receptor 14, also known as UT. The tissue distribution of UII and UT is highly consistent, and their expression may be regulated by autocrine and paracrine mechanisms. In the body, UII has many physiological and pathophysiological activities, such as vasoconstrictor and vasodilatory actions, cell proliferation, pro-fibrosis, neuroendocrine activity, insulin resistance, and carcinogenic and inflammatory effects, which have been recognized only in recent years. In fact, UII is involved in the process of inflammatory injury and plays a key role in the onset and development of inflammatory diseases. In this paper, we will review the roles UII plays in inflammatory diseases.

Renal impairment, hypertension and plasma urotensin II

BACKGROUND

Human urotensin II (UII) is a potent mammalian vasoconstrictor thought to be produced and cleared by the kidneys. Conflicting data exist regarding the relationship between UII concentrations, kidney function and blood pressure (BP). We measured the associations between kidney function [including end-stage renal disease (ESRD)] and levels of BP with plasma concentrations of UII.

METHODS

Ninety-one subjects were enrolled. Thirty-one subjects had ESRD (undergoing haemodialysis), 30 subjects had chronic kidney disease (CKD) and 30 control subjects had no kidney disease. Plasma UII concentrations were measured by radioimmunoassay.

RESULTS

Mean plasma UII concentrations were highest in controls, lower in subjects with ESRD and lowest in subjects with non-ESRD CKD (P<0.0001). UII concentrations correlated negatively with serum creatinine (P=0.0012) and CKD stage, and positively with creatinine clearance (P=0.013). In ESRD subjects, plasma UII (P=0.008) increased after dialysis, while SBP (P=0.007), DBP (P=0.009), serum creatinine (P<0.0001) and serum urea nitrogen (P<0.0001) decreased. UII concentrations were lower in patients with a history of hypertension (HTN) (P=0.016). Age, race and gender did not appear to be associated with UII concentration. However, the distribution of African American race and male gender appear to be associated with increasing stages of chronic kidney disease.

CONCLUSIONS

These data suggest a potential vasodilatory role of UII in humans with kidney disease or hypertension. The reduction in UII levels in CKD also suggests either reduced production or greater clearance, or both, of UII.

Urotensin-II levels in acute coronary syndromes

BACKGROUND

Urotensin-II (U-II) is a vasoactive peptide with diffuse expression in human cardiomyocyte and vascular smooth muscle cells. Recent studies have reported increased plasma levels of U-II in patients with congestive heart failure.

OBJECTIVE

We sought to determine the plasma levels of U-II in patients with acute coronary syndromes (ACS), stable coronary artery disease (CAD) and healthy controls.

METHODS

We prospectively measured plasma U-II levels in 54 patients with ACS, 51 patients with stable coronary disease and 29 healthy volunteers. Monoclonal antibodies against U-II were generated and plasma U-II levels were determined by radioimmunoassay from extracted venous samples.

RESULTS

ACS patients had significantly lower levels than patients with stable CAD and healthy controls (2.53+/-1.62 vs. 3.45+/-2.53 vs. 3.3+/-3.9 ng/ml, p=0.008, respectively). In both ACS and stable CAD patients, we found a negative relationship between plasma U-II levels and systemic arterial pressures. The correlation coefficients for systolic and mean arterial pressure were -0.272, p=0.006 and -0.209, p=0.04, respectively.

CONCLUSIONS

Plasma U-II levels were significantly decreased in patients with acute coronary syndromes and related negatively to systemic arterial pressures. This finding suggests a down-regulation of U-II expression in patients with acute coronary syndromes.

CONDENSED ABSTRACT

Urotensin-II (U-II) is a vasoactive peptide with diffuse staining in human cardiomyocytes and vascular smooth muscle cells. We measured plasma U-II levels in patients with acute coronary syndromes (ACS), stable coronary artery disease (CAD) and healthy controls. We observed lower U-II levels in ACS patients and a negative correlation between U-II levels and systemic arterial pressure. This finding suggests a down-regulation of U-II expression in patients with ACS.

Survey of the year 2003 commercial optical biosensor literature

In the year 2003 there was a 17% increase in the number of publications citing work performed using optical biosensor technology compared with the previous year. We collated the 962 total papers for 2003, identified the geographical regions where the work was performed, highlighted the instrument types on which it was carried out, and segregated the papers by biological system. In this overview, we spotlight 13 papers that should be on everyone's 'must read' list for 2003 and provide examples of how to identify and interpret high-quality biosensor data. Although we still find that the literature is replete with poorly performed experiments, over-interpreted results and a general lack of understanding of data analysis, we are optimistic that these shortcomings will be addressed as biosensor technology continues to mature.

Differential levels of "urotensin-II-like" activity determined by radio-receptor and radioimmuno-assays

Plasma and urinary levels of "urotensin(U)-II-like" substances determined in healthy human volunteers were 12.4 +/- 0.6 ng/ml and 2.2 +/- 0.3 ng/ml by RIA, an order of magnitude lower than that seen by RRA, 167.5 +/- 9.5 ng/ml and 65.2 +/- 4.3 ng/ml. HPLC demonstrated the existence of at least three prominent activity peaks in plasma and urine, the more hydrophobic of which did not co-elute with U-II, degradation products or URP. RRA and RIA recognized these peaks with contrasting efficacy. As such, published levels of "U-II-like" activity should be interpreted with caution until a better understanding is obtained regarding what species specific RIA and RRA assay reagents interact with.