Plasma VEGF and soluble VEGF receptor FLT-1 in proliferative retinopathy: relationship to endothelial dysfunction and laser treatment

PURPOSE: To study plasma levels of vascular endothelial growth factor (VEGF, an index of angiogenesis), its soluble receptor (sFlt-1) and von Willebrand factor (vWf, an index of endothelial damage or dysfunction) in patients with proliferative retinopathy and corresponding changes in plasma levels after pan-retinal photocoagulation (PRP). METHODS: Eighteen patients (10 men; age, 57+/-16 years, mean +/- SD) with proliferative retinopathy secondary to diabetes (n = 13) and ischemic retinal vein occlusion (n = 5) with no previous PRP therapy were studied. Blood samples were obtained before and at 4 months after the last PRP session. Baseline (prelaser) plasma levels of VEGF, sFlt-1, and vWf (all by ELISA) were compared with levels in 16 diabetic patients with background retinopathy ("hospital controls"), and 18 healthy, age- and sex-matched "healthy controls." RESULTS: Patients with proliferative retinopathy had significantly raised plasma VEGF when compared with both control groups (P = 0.001). Patients with proliferative retinopathy and hospital controls had significantly raised plasma vWf levels when compared with healthy controls (P = 0.012). There was no difference in sFlt-1 levels between patients and controls (P = 0.162). After PRP, there was a significant reduction in plasma VEGF levels at 4 months' follow-up (P < 0.001), but no significant changes in plasma sFlt-1 or vWf levels. Patients with complete resolution of neovascularization had a trend toward lower median VEGF levels (80 versus 150 pg/ml, P = 0.062), but vWf levels (P = 0.50) and sFlt-1 (P = 0.479) were not statistically different. Baseline VEGF and sFlt-1 levels were significantly correlated (Spearman r = 0.505, P = 0.032) but after PRP at 4 months' follow-up, this was no longer significant (r = -0.269, P = 0.28). CONCLUSIONS: In this pilot study, patients with proliferative retinopathy demonstrate elevated peripheral markers of angiogenesis and endothelial dysfunction, suggesting a role for these processes in the pathogenesis of this condition. A fall in levels of VEGF after successful laser treatment may provide an opportunity for monitoring disease progression or relapse via a blood sample.     

Circulating endothelial cells: realities and promises in vascular disorders

Endothelial contribution to human vascular disorders is difficult to investigate, owing to the paucity of non-invasive methods and of specific endothelial markers .Circulating endothelial cells (CECs) might be used asa surrogate non-invasive marker for the study of vascular alterations. To address this problem, we produced an antibody against the endothelial molecule CD126 (S-Endol) and developed, in the nineties, an original and sensitive immunomagnetic separation assay. Using this approach, we demonstrated elevated number of CECs in clinical diseases linked with vascular injury like heart catheterization, sickle cell anemia,bacterial infection, thrombotic thrombocytopenic purpura or acute coronary syndromes. CECs correspond to very rare cells present in blood since levels in the range of 3 cells/ml are detectable in these pathologies.Several clinical interest of CECs will be discussed including their relevance as marker of disease activity, severity or treatment efficacy, or their use in diagnostic tests. The origin of endothelial cells in peripheral blood is difficult to establish. They could correspond to endothelial cells dislodged from the vessels in response to injury. It was subsequently shown that a subset of CECs comprised a population of bone marrow-derived endothelial progenitors that participate in angiogenesis. Identification of the origin and characteristics of CECs provides fascinating insights into endothelial cell pathophysiology. Moreover, CECs constitute original and promising tools for diagnosis, prognosis and therapy of vascular disorders.     

Use of a multiplex PCR/sequencing strategy to detect both connexin 30 (GJB6) 342 kb deletion and connexin 26 (GJB2) mutations in cases of childhood deafness

Hearing loss is a common congenital disorder that is frequently associated with mutations in the Cx26 gene (GJB2). Three recent reports that found a large deletion in another DFNB1 gene, Cx30 (GJB6), suggest that this defect may cause nonsyndromic recessive hearing loss through either a homozygous deletion of Cx30, or digenic inheritance of a Cx30 deletion and a Cx26 mutation in trans. We designed a simple diagnostic strategy with multiplex PCR followed by direct sequencing to allow for the simultaneous detection of Cx26 mutations and Cx30 deletions, and evaluated its effectiveness as a clinical genetic test by examining 200 DNA samples. In the 108 samples from deaf subjects, two digenic mutations were identified in Cx26 and Cx30 (E47X/342 kb deletion and 167delT/342 kb deletion); 69 had only Cx26 mutations (29 biallelic, 40 singleton), including two novel frameshift mutations 511-512insAACG and 358-360delAG; and 37 had no detectable mutation in either Cx26 or Cx30. Our deletion mapping suggested that the proximal breakpoint of all reported Cx30 large deletions are between the nucleotide 444 and 627 at the Cx30 coding region within a maximal interval of 78 or 184 bp. This simultaneous examination of Cx26 and Cx30 is a practical and efficient diagnostic approach for patients with nonsyndromic congenital deafness.     

Plasma angiopoietin-1, angiopoietin-2 and Tie-2 in breast and prostate cancer: a comparison with VEGF and Flt-1

BACKGROUND: Angiogenesis is essential for tumour growth and metastasis, and is coordinated by several classes of growth factors mediating their effect through receptors linked, in turn, to tyrosine kinase. These growth factors include angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2) and vascular endothelial growth factor (VEGF), which act through receptors Flt-1 and Tie-2. MATERIALS AND METHODS: In order to further determine abnormalities in levels of Ang-1, Ang-2, Tie-2, sFlt-1 and VEGF in human cancer (and their interrelationships), these molecules were measured in plasma from 30 patients with breast cancer, 30 patients with prostate cancer and 12 healthy controls per cancer group. RESULTS: In breast cancer, levels of Ang-1 (P=0.0005), Ang-2 (P=0.0173), Tie-2 (P=0.0001), and VEGF (P=0.0001) were all significantly raised, and plasma levels of sFlt-1 (P=0.045) were significantly reduced compared with controls. However, in prostate cancer, only levels of VEGF and Tie-2 were significantly higher (both P=0.001). There were no significant differences between levels of any molecule between the two groups of cancer. The only difference between the healthy control groups was lower Ang-1 in the women compared with men. Significant correlations were found between levels of Ang-1 and Tie-2 both in breast (r=0.498, P=0.005) and prostate cancer (r=0.643, P=<0.001). Angiopoietin-1 was also positively correlated with Ang-2 in both breast (r=0.422, P=0.02) and prostate cancer (r=0.543, P=0.002). CONCLUSIONS: Abnormal levels of Ang-1, Ang-2 and their receptor, Tie-2, are present in breast and prostate cancer, and their interrelationships may be important in the pathophysiology of these conditions.     

Admissions with atrial fibrillation in a multiracial population in Kuala Lumpur, Malaysia

BACKGROUND: There are established differences in cardiovascular disease in different racial groups. Worldwide, the literature regarding the clinical epidemiology of atrial fibrillation in non-white populations is scarce. OBJECTIVES: To document the prevalence of atrial fibrillation (AF) in the multiracial population of Malaysia, and to describe the clinical features and management of these patients. SETTING: Busy city centre general hospital in Kuala Lumpur, Malaysia, over a 1-month period. SUBJECTS: One-thousand four hundred and thirty-five acute medical admissions, of whom 40 patients (2.8%) had AF. RESULTS: Of 1435 acute medical admissions to Kuala Lumpur General Hospital over the 4-week study period, 40 had AF (21 male, 19 female; mean age 65 years). Of these, 18 were Malay, 16 Chinese and six Indian. Nineteen patients had previously known AF (seven with paroxysmal AF) and 21 were newly diagnosed cases. The principal associated medical conditions were ischaemic heart disease (42.5%), hypertension (40%) and heart failure (40%). Dyspnoea was the commonest presentation, whilst stroke was the cause of presentation in only two patients. Investigations were under-utilised, with chest X-ray and echocardiography in only 62.5% of patients and thyroid function checked in 15%. Only 16% of those with previously diagnosed AF were on warfarin, with a further three on aspirin. Anticoagulant therapy was started in 13.5% of patients previously not on warfarin, and aspirin in 8%. Records of contraindications to warfarin were unreliable, being identified in only 25%. For those with known AF, 58% were on digoxin. For new onset AF, digoxin was again the most common rate-limiting treatment, initiated in 38%, whilst five patients with new onset AF were commenced on amiodarone. DC cardioversion was not used in any of the patients with new onset AF. CONCLUSION: Amongst acute medical admissions to a single centre in Malaysia the prevalence of AF was 2.8%. Consistent with previous similar surveys in mainly western (caucasian) populations, standard investigations in this Malaysian cohort were also inadequate and there was underuse of anticoagulation, medication for ventricular rate control and cardioversion to sinus rhythm.     

Extracellular matrix biology: a new frontier in linking the pathology and therapy of hypertension?

The extracellular matrix (ECM) is a vital component of connective tissue, and collagen is a major constituent. There is growing evidence that changes in the composition of the cardiac and vascular matrix occurs during hypertension. Clinically, these effects are manifested as left ventricular hypertrophy and a reduction in arterial compliance and luminal diameter, which results in end organ ischaemia. The matrix metalloproteinases and their inhibitors have a central role in the regulation of the composition of the ECM. In this review, we discuss the mediators that affect the structure of the ECM in hypertension using results from animal and human studies.