Inflammatory and Biomechanical Drivers of Endothelial-Interstitial Interactions in Calcific Aortic Valve Disease.

Calcific aortic valve disease is dramatically increasing in global burden, yet no therapy exists outside of prosthetic replacement. The increasing proportion of younger and more active patients mandates alternative therapies. Studies suggest a window of opportunity for biologically based diagnostics and therapeutics to alleviate or delay calcific aortic valve disease progression. Advancement, however, has been hampered by limited understanding of the complex mechanisms driving calcific aortic valve disease initiation and progression towards clinically relevant interventions.

Simvastatin reduces the TLR4-induced inflammatory response in human aortic valve interstitial cells.

BACKGROUND: Calcific aortic stenosis is a chronic inflammatory disease. Proinflammatory stimulation via toll-like receptor 4 (TLR4) causes the aortic valve interstitial cell (AVIC) to undergo phenotypic change. The AVIC first assumes an inflammatory phenotype characterized by the production of inflammatory mediators such as intercellular adhesion molecule-1 (ICAM-1), interleukin-8 (IL-8), and monocyte chemoattractant protein-1 (MCP-1). This change has been linked with an osteogenic phenotypic response. Statins have recently been shown to have anti-inflammatory properties. We therefore hypothesized that statins may have an anti-inflammatory effect on human AVICs by downregulation of TLR4-stimulated inflammatory responses. Our purposes were (1) to determine the effect of simvastatin on TLR4-induced expression of inflammatory mediators in human AVICs and (2) to determine the mechanism(s) through which simvastatin exert this effect. MATERIALS AND METHODS: Human AVICs were isolated from the explanted hearts of four patients undergoing cardiac transplantation. Cells were treated with simvastatin (50 µM) for 1 h before stimulation with TLR4 agonist lipopolysaccharide (LPS, 0.2 µg/mL). Immunoblotting (IB) was used to analyze cell lysates for ICAM-1 expression, and enzyme-linked immunosorbent assay was used to detect IL-8 and MCP-1 in cell culture media. Likewise, lysates were analyzed for TLR4 and nuclear factor-kappa B activation (IB). After simvastatin treatment, lysates were analyzed for TLR4 levels (IB). Statistics were by analysis of variance (P < 0.05). RESULTS: Simvastatin reduced TLR4-induced ICAM-1, IL-8, and MCP-1 expression in AVICs. Simvastatin down-regulated TLR4 levels and suppressed TLR4-induced phosphorylation of nuclear factor-kappa B. CONCLUSIONS: These data demonstrate the potential of a medical therapy (simvastatin) to impact the pathogenesis of aortic stenosis.

[In vitro effect of the S3Pvac vaccine against cysticercosis in human mononucleate cells]. / Efecto in vitro de la vacuna S3Pvac contra cisticercosis en celulas mononucleares humanas.

INTRODUCTION: Neurocysticercosis (NCC) is a parasitic infection caused by the establishment of Taenia solium cysticerci in the central nervous system. The larval stage of the parasite also affects the pig, which is the essential intermediate host for transmission. For this reason, many researchers have focused on identifying protective antigens to prevent swine cysticercosis and interrupt the transmission. These include S3Pvac vaccine antigens. Vaccine is constituted by three protective synthetic peptides: KETc1, KETc12 and GK1. AIM. To evaluate the effect of the vaccine peptides KETc1, KETc12 and GK1 in mononuclear cells of patients with neuro-cysticercosis and healthy individuals. SUBJECTS AND METHODS: Comparative, prospective, transverse study. We studied the proliferation and cytokine profile induced by the three peptides in mononuclear cells from three patients with active NCC, 16 patients by calcified NCC and 16 healthy subjects. RESULTS: KETc1 induces low levels of proliferation in cells from patients with active and controlled NCC, both in lymphocytes and in monocytes. KETc12 and GK-1 induce positive proliferation levels of monocytes in healthy subjects. CONCLUSIONS: KETc1 peptide could be used as an adjuvant in the treatment of patients with active NCC, as induced a Th2 response also GK1 peptide as stimulator of monocyte/macrophage in immunizations with other proteins.

TITLE: Efecto in vitro de la vacuna S3Pvac contra cisticercosis en celulas mononucleares humanas.Introduccion. La neurocisticercosis (NCC) es una infeccion parasitaria generada por el establecimiento de cisticercos de Taenia solium en el sistema nervioso central. La fase larvaria del parasito tambien afecta al cerdo, que es el huesped intermediario indispensable para la transmision. Por tal motivo, muchos investigadores se han enfocado en identificar antigenos protectores para prevenir la cisticercosis porcina e interrumpir la transmision. Entre ellos figuran los antigenos de la vacuna S3Pvac, constituida por tres peptidos protectores: KETc1, KETc12 y GK1. Objetivo. Evaluar el efecto de los peptidos vacunales KETc1, KETc12 y GK1 en celulas mononucleares de pacientes con NCC e individuos sanos. Sujetos y metodos. Estudio comparativo, prospectivo y transversal. Se analizo la proliferacion y el perfil de citocinas inducidos por los tres peptidos en celulas mononucleares de tres pacientes con NCC activa, 16 pacientes con NCC calcificada y 16 sujetos sanos. Resultados. KETc1 induce bajos niveles de proliferacion en las celulas de los pacientes con NCC activa y controlada, tanto en linfocitos como en monocitos. KETc12 y GK-1 inducen niveles positivos de proliferacion de monocitos en sujetos sanos. Conclusiones. El peptido KETc1 podria usarse como coadyuvante en el tratamiento de los pacientes con NCC activa, ya que indujo una respuesta Th2; y el peptido GK1, como estimulador del monocito/macrofago en inmunizaciones con otras proteinas.

Pioglitazone attenuates progression of aortic valve calcification via down-regulating receptor for advanced glycation end products.

Receptor for advanced glycation end products (RAGE) is associated with inflammation and the progression of cardiovascular diseases. The current study tested the hypothesis that RAGE is involved in the pathogenesis of aortic valve (AV) calcification. Pioglitazone attenuated AV calcification in experimental hypercholesterolemic rabbits via down-regulation of RAGE. Male New Zealand rabbits weighing 2.5-3.0 kg were randomly divided into three groups: control group, high cholesterol + vitamin D(2) (HC + vitD(2)) group and HC + vitD(2) supplemented with pioglitazone group. Compared with HC + vitD(2) group, pioglitazone significantly inhibited the progression of AV calcification assessed by echocardiography. HC + vitD(2) diet markedly increased RAGE expression, oxidative stress, inflammatory cells infiltration and osteopontin expression. These changes were also significantly attenuated by administration of pioglitazone. Cultured porcine aortic valve interstitial cells (VICs) were used as in vitro model. We found that advanced glycation end products of bovine serum albumin markedly increased the expression of RAGE, induced high levels of production of pro-inflammatory cytokines and promoted osteoblastic differentiation of VICs. However, these effects were found to be remarkably suppressed by siRNA silencing of RAGE and pioglitazone as well. Our data provide evidence that RAGE activation-induced inflammation promotes AV calcification in hypercholesterolemic rabbits, which can be attenuated by pioglitazone treatment. This beneficial effect is associated with remarkable down-regulation of RAGE expression.

Putting cardiovascular disease and vitamin D insufficiency into perspective.

The aetiology of CVD is still not completely understood. The present review article summarises data supporting the hypothesis that an insufficient vitamin D status may contribute to the worldwide high prevalence of CVD. Human vitamin D status primarily depends on skin exposure to the UVB spectrum of the sunlight. Epidemiological data indicate that geographic latitude, altitude, season, and the place of residence (urban or rural) are associated with CVD mortality. Interestingly, all these factors also have an influence on human UVB exposure and thus on vitamin D status. Several mechanisms might be responsible for a protective role of vitamin D in CVD. These mechanisms include the inhibition of vascular smooth muscle proliferation, the suppression of vascular calcification, the down regulation of pro-inflammatory cytokines, the up regulation of anti-inflammatory cytokines, and the action of vitamin D as a negative endocrine regulator of the renin-angiotensin system. The first intervention trials indicate that vitamin D may suppress cardiovascular risk markers. However, more controlled clinical trials are needed to investigate whether optimal oral vitamin D supplementation is able to reduce CVD morbidity and mortality.

Characterization of the immune response to valve bioprostheses and its role in primary tissue failure.

BACKGROUND: The role of an immune response in the failure of bioprosthetic heart valves is poorly understood and disregarded by many. To elucidate the nature of the immune response to glutaraldehyde-treated tissue and the possible role of graft-specific antibody in graft mineralization, we performed immune-calcification studies in the rabbit and correlated those results with the analysis of specific antibodies. METHODS: Aortic wall buttons (6 mm) were punched from porcine aortic wall tissue fixed with 0.2% glutaraldehyde and detoxified with urazole and then subsequently perforated under sterile conditions. The perforated buttons were then incubated with either immune serum prepared by immunization of New Zealand White rabbits (n = 5) with Freund's incomplete adjuvant emulsions of tissue homogenates of similarly treated aortic wall tissue, or incubated with the corresponding control preimmune sera obtained before immunization of the same animals. The tissue was then implanted subdermally on the back of unrelated New Zealand White rabbits (n = 8) for a period of 3 weeks. After the buttons were explanted, tissue calcium levels were determined by atomic absorption spectroscopy. RESULTS: Tissue calcium was increased in all five immune serum-treated replicates (range, 61.8% to 431.2%; mean, 225.9%+/-73.2%) when compared with control samples treated with preimmune sera. Overall, the mean calcium level was significantly increased (p < 0.0001) when tissue was treated with immune sera (66.0+/-10.0 microg/mg versus 22.6+/-4.8 microg/mg in control tissue). Graft specificity of immune sera was confirmed by Western blot analysis. CONCLUSIONS: These results strongly suggest a role of circulating graft-specific antibody in the disease of bioprosthetic graft calcification.

Phlebosclerosis of the colon with positive anti-centromere antibody.

A 56-year-old woman with symptoms of chronic bowel disease presented a peculiar calcification of the mesenteric vein of the ascending to transverse colon on barium enema study. The resected colon was hard and black. Histo-pathologic examinations demonstrated fibrous change of the colon with a calcified and hyaline-deposited mesenteric vein. No cell infiltration was observed. These findings were compatible with phlebosclerosis and also with systemic sclerosis. Positive anti-centromere antibody and Raynaud's phenomenon, hallmarks of a variant systemic sclerosis, the CREST syndrome were observed. We therefore speculated that the pathogenesis of the phlebosclerosis of the colon is related to the CREST syndrome.

[Hydroxyapatite rheumatism (multiple tendon calcification disease). II. - Microscopic study - HL-A antigen - Experimental arthritis - Pathogeny]. / Le rhumatisme à hydroxyapatite (la maladie des calcifications tendineuses multiples). II - Etude microscopique - Antigène HLA - Arthrite expérimentale - Pathogénie.

Optical and electron microscopic studies of the articular fluid in multiple calcification disease reveals the existence of rounded intra- and extracellular crystalline formations. These crystalline formations of calcium and phosphorus are made up of accumulations of tiny crystals shaped like fine needles 200 nm X 15-20 nm and are highly suggestive of hydroxyapatite. Crystals injected into the plantar pads of rats or the knees of rabbits induce an acute inflammatory reaction maximal at 5 hours and recovering in 24 72 hours. Hydroxyapatite crystals are swiftly dissolved in serum and more rapidly still when cells are present. Their dissolution releases calcium into the surrounding area. HLA typing of patients with multiple tendinous calcification (28 cases) or single tendinous calcification (10 cases) shows an increased frequency of HLA A2 and BW 35 in comparison with controls.