Lysed Erythrocyte Membranes Promote Vascular Calcification.

BACKGROUND: Intraplaque hemorrhage promotes atherosclerosis progression, and erythrocytes may contribute to this process. In this study we examined the effects of red blood cells on smooth muscle cell mineralization and vascular calcification and the possible mechanisms involved. METHODS: Erythrocytes were isolated from human and murine whole blood. Intact and lysed erythrocytes and their membrane fraction or specific erythrocyte components were examined in vitro using diverse calcification assays, ex vivo by using the murine aortic ring calcification model, and in vivo after murine erythrocyte membrane injection into neointimal lesions of hypercholesterolemic apolipoprotein E-deficient mice. Vascular tissues (aortic valves, atherosclerotic carotid artery specimens, abdominal aortic aneurysms) were obtained from patients undergoing surgery. RESULTS: The membrane fraction of lysed, but not intact human erythrocytes promoted mineralization of human arterial smooth muscle cells in culture, as shown by Alizarin red and van Kossa stain and increased alkaline phosphatase activity, and by increased expression of osteoblast-specific transcription factors (eg, runt-related transcription factor 2, osterix) and differentiation markers (eg, osteopontin, osteocalcin, and osterix). Erythrocyte membranes dose-dependently enhanced calcification in murine aortic rings, and extravasated CD235a-positive erythrocytes or Perl iron-positive signals colocalized with calcified areas or osteoblast-like cells in human vascular lesions. Mechanistically, the osteoinductive activity of lysed erythrocytes was localized to their membrane fraction, did not involve membrane lipids, heme, or iron, and was enhanced after removal of the nitric oxide (NO) scavenger hemoglobin. Lysed erythrocyte membranes enhanced calcification to a similar extent as the NO donor diethylenetriamine-NO, and their osteoinductive effects could be further augmented by arginase-1 inhibition (indirectly increasing NO bioavailability). However, the osteoinductive effects of erythrocyte membranes were reduced in human arterial smooth muscle cells treated with the NO scavenger 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide or following inhibition of NO synthase or the NO receptor soluble guanylate cyclase. Erythrocytes isolated from endothelial NO synthase-deficient mice exhibited a reduced potency to promote calcification in the aortic ring assay and after injection into murine vascular lesions. CONCLUSIONS: Our findings in cells, genetically modified mice, and human vascular specimens suggest that intraplaque hemorrhage with erythrocyte extravasation and lysis promotes osteoblastic differentiation of smooth muscle cells and vascular lesion calcification, and also support a role for erythrocyte-derived NO.

A pilot study on plasma levels of micro-RNAs involved in angiogenesis and vascular maturation in patients with breast cancer.

Micro-RNAs (miRNAs) have a complex role in carcinogenesis and tumour progression. Several miRNAs, such as miR-221, miR-27b and miR-132, have been implicated in the regulation of VEGF tumour angiogenic activity. In this pilot study, we assessed angiogenesis and DLL4+ vascular maturation index (VMI) in breast cancer tissues, in parallel with the plasma levels of the above-mentioned miRNAs. Significantly higher than control samples pre-operative levels were recorded in 10/11, 7/11 and 9/11 cases for the miR-221, miR-27b and miR-132, respectively. Seven days after surgery, a significant reduction of these miRNAs was noted in 6/11, 3/11 and 2/11 cases, respectively. High pre-operative levels of miR-27b were linked with node metastasis (p = 0.04). High pre-operative levels of miR-132 were linked with small tumours (p = 0.03) and her2 overexpression (p = 0.003). The DLL4+ VMI ranged from 26 to 69% (median 45%). Patients with poor DLL4+ VMI had significantly high pre-operative and post-operative levels of miR-221 (p = 0.01 and 0.02, respectively) and high post-operative levels of miR-132 (p = 0.02). It is concluded that angiogenesis-related miRs as detected in the plasma of patients may prove of a useful tool in the identification of patients with poor vascular maturation and high risk to develop metastasis. Whether such miRs may identify patients who would benefit from vascular normalization policies is a hypothesis that emerges from the current study.

Differences between perivascular adipose tissue surrounding the heart and the internal mammary artery: possible role for the leptin-inflammation-fibrosis-hypoxia axis.

AIM: The factors mediating the paracrine effects of perivascular adipose tissue (PVAT) in atherosclerosis are largely unknown. The adipokine leptin has been implicated in the increased cardiovascular risk in obesity and may locally promote neointima formation independently of circulating leptin levels. In patients with established coronary artery disease, we examined the expression of leptin as well as of its possible inducers in 'cardiac' PVAT surrounding the aortic root and coronary arteries (C-PVAT), and compared it to the PVAT surrounding the internal mammary artery (IMA-PVAT), a vessel resistant to atherosclerosis. METHODS AND RESULTS: Tissue specimens collected from male patients undergoing coronary artery bypass surgery were processed for real-time PCR, ELISA, in situ hybridization, and immunohistochemistry analysis. Leptin protein expression was elevated in C-PVAT compared to IMA-PVAT, independent of serum leptin levels. Compared to IMA-PVAT, C-PVAT exhibited more pronounced angiogenesis and inflammation, as indicated by significantly higher numbers of PECAM1-positive vessels and CD68-positive macrophages, and was characterized by a greater extent of fibrosis and hypoxia. Increased expression of hypoxia-inducible factor-1α and Fos-like antigen (FOSL)2, factors known to enhance leptin gene transcription, was observed in C-PVAT. As a proof of concept, exposure of human adipocytes to chemical hypoxia resulted in significantly increased FOSL2 and leptin mRNA levels. CONCLUSIONS: A higher degree of local tissue hypoxia and up-regulation of leptin expression in the perivascular adipose tissue, along with increased vascularization, inflammation, and fibrosis, may contribute to the increased atherosclerotic plaque burden in the coronary arteries compared to the IMA.

Genotoxic effect of tocolytic drug ritodrine in combination with smoking during pregnancy.

OBJECTIVE: Tocolytic drugs are used widely in order to prevent preterm birth. Ritodrine, is the only food and drug administration (FDA) approved drug for tocolytic use. We estimated the cytogenetic effect of ritodrine administered as maternal therapy, alone or in combination with smoking, in women and their neonates. METHODS: Lymphocyte and fibroblasts cultures were evaluated and three indices were analyzed; sister chromatid exchanges (SCEs), proliferation rate index (PRI) and mitotic index (MI) as well as average generation time (AGT) and population doubling time (PDT). Campothacin (CPT-11) was used as a positive control. RESULTS: Administration of ritodrine up to a month revealed significant reduction of SCEs/cell in neonates in the presence or absence of the mutagenic agent. A statistical significant increase on SCEs, for mothers and neonates, was noticed in neonate's lymphocytes when tocolytic therapy was over a month. Ritodrine revealed a cytoprotective action against smoking when the two factors were combined, but the synergistic action of ritodrine with smoking increased genotoxicity, cytostaticity and cytotoxicity of neonates after long administration (1-3 months). CONCLUSIONS: The time-depended genotoxic, cytostatic and cytotoxic action of ritodrine alone or in combination with smoking suggests that its administration should not exceed the time period of a month.

Spot urine albumin to creatinine ratio outperforms novel acute kidney injury biomarkers in patients with acute myocardial infarction.

BACKGROUND: Acute kidney injury (AKI) is a frequent complication in patients hospitalized for acute myocardial infarction (AMI), and is associated with in-hospital and long-term morbidity and mortality. We prospectively assessed the diagnostic performance of spot urine albumin to creatinine ratio (uACR) in an adequately sized multicenter cohort of patients admitted to hospital with AMI. We further compared uACR to novel renal injury associated biomarkers regarding their diagnostic ability. METHODS: We enrolled 805 consecutive patients presenting with acute ST-elevation and non-ST elevation AMI. Patients were assessed for presence of AKI at 48h post-admission and at hospital discharge using the Acute Kidney Injury Network (AKIN), the Acute Dialysis Quality Initiative [Risk, Injury and Failure (RIFLE)] criteria and the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Blood and urine sampling for neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), cystatin-C, and uACR assessment was performed during admission. RESULTS: The predictive accuracy of uACR was good (Area Under the Curve (AUC), 0.725; 95% CI 0.676-0.774) and was better compared to urine NGAL (P=0.007), urine (P<0.001) and plasma Cystatin-C (P=0.001). ROC analysis identified concentrations of ≥66.7µg/mg as having the best diagnostic accuracy. The use of uACR exhibited good discriminating ability independent to possible cofounders and additive regarding the use of novel biomarkers. CONCLUSIONS: The use of uACR can easily be applied in the clinical setting, allows for robust risk assessment and offers the potential to improve the management of AMI patients at risk for acute kidney injury.

Effect of maternal smoking during pregnancy on fetus: a cytogenetic perspective.

OBJECTIVE: The examination of the genotoxic, cytostatic and cytotoxic effects of smoking during pregnancy. METHOD: Lymphocyte cultures of peripheral blood were received from 20 women who smoked during pregnancy as well as umbilical cord blood of their newborns. Fluorescence Plus Giemsa staining technique was used in order to perform cytogenetic analyses for three indices, Sister Chromatid Exchanges (SCEs), Proliferation Rate Index (PRI) and Mitotic Index (MI). To reveal any underlying chromosome instability, CPT-11 was used as a positive control. RESULTS: Newborns whose mothers smoke during pregnancy had increased SCEs levels on their lymphocytes when they were exposed to the mutagenic agent CPT-11 (p < 0.01) compared with newborns lymphocytes exposed to the same agent with non-smoking mothers. Also, mothers smoking during pregnancy had increased SCE levels when their lymphocytes were exposed to CPT-11 (p < 0.01) compared with non smoking mothers whose lymphocytes were exposed to the same agent. In both groups newborns appeared as having decreased (p < 0.01) spontaneous SCEs levels compared with the corresponding SCE rates of their mothers. Decreases of PRIs and MIs are observed in mothers compared to their newborns. CONCLUSION: Smoking during pregnancy can promote cytogenetic damage in newborn's DNA, causing chromosome instability. The clinical importance of this indirect damage lies in the fact that this type of damage can act synergistically with other environmental and/or chemical mutagenic substances possibly leading to carcinogenicity.

Cytogenetic evaluation of pre-pregnancy smoking in maternal and newborn lymphocytes.

OBJECTIVE: To study cytogenetic damage in order to estimate the effect of pre-pregnancy smoking on pregnant women and their foetuses. STUDY DESIGN: Lymphocyte cultures were obtained from peripheral blood of 20 women who quit smoking during pregnancy, and umbilical cord blood of their newborns at delivery. Cytogenetic analyses were performed for sister chromatid exchanges (SCEs), proliferation rate index (PRI) and mitotic index (MI) using the Fluorescence Plus Giemsa staining technique. Twenty non-smoking women and their newborns were evaluated as controls. CPT-11, a known antineoplastic, was used as a positive genotoxic agent in order to correlate non-smoking women with smoking women and reveal any underlying chromosome instability. Statistical evaluation of SCE frequencies, PRI and MI was based on independent samples t-test in order to estimate the effect of pre-pregnancy smoking on mothers and their newborns. RESULTS: SCEs were induced in the cord blood lymphocytes of newborns whose mothers smoked before pregnancy when they were exposed to the mutagenic agent CPT-11 (p<0.01). A similar increase in SCEs was observed in both non-smoking and smoking mothers exposed to CPT-11. Newborns in both groups had significantly lower SCE levels than their mothers (p<0.01). CONCLUSION: Pre-pregnancy smoking results in cytogenetic damage for both mothers and newborns, and is an important risk factor for cancer and/or other genetic-related diseases. Smoking cessation needs to occur well before conception in order to avoid the strong cytogenetic association between pre-pregnancy smoking by mothers and their newborns.

Synergistic cytogenetic and antineoplastic effects by the combined action of esteric steroidal derivatives of nitrogen mustards.

We studied the effect of five newly synthesized steroidal derivatives of nitrogen mustards. These derivatives have as alkylators either P-N, N-bis(2-chloroethyl)aminophenyl-butyrate (CHL) or P-N, N-bis(2-chloroethyl)aminophenyl-acetate (PHE) groups esterified with different modified steroidal nuclei. We examined them alone or in combination, on sister chromatid exchange rates and on human lymphocyte proliferation kinetics. The antitumor activity of these compounds, alone or in combination, was also tested on Leukemia P388-bearing mice. A pronounced cytogenetic and antineoplastic action was demonstrated by the compounds that contain either PHE or CHL as alkylators and are esterified with a steroidal nucleus having added a cholestene group in the 17 position of the D-ring. The exocyclical insertion of an -NHCO- group in the D-ring of the steroidal nucleus esterified with PHE (amide ester of PHE) yielded a compound demonstrating a distinct cytogenetic and antineoplastic effect. In contrast, the ketone group in the D-ring being inserted endocyclically in the steroidal nucleus (androstene) esterified with either CHL or with PHE gave negative cytogenetic and antineoplastic effects. However, the combined action of cholestene esterified with either CHL or with PHE in combination with either the androstene ester of PHE or with the androstene ester of CHL, respectively, gave synergistic cytogenetic and antineoplastic effects. Also the amide ester of PHE in combination with the androstene ester of CHL gave distinct cytogenetic and antineoplastic effects in a synergistic manner.