RESUMEN
PURPOSE OF REVIEW: Inhibitors of sodium-glucose cotransporter-2 (SGLT2) lower renal glucose reabsorption and, thus, are used to treat patients with type 2 diabetes mellitus. Clinical trials coincidentally showed that SGLT2 inhibitors also benefitted patients with heart failure. This review explores the impact of SGLT2 inhibitors on other aspects of cardiovascular disease and skeletal health. RECENT FINDINGS: In some, but not all, clinical and preclinical studies, SGLT2 inhibitors are found to reduce serum levels of free fatty acids and triglycerides. Their effects on total and low-density lipoprotein cholesterol and cardiac function also vary. However, SGLT2 inhibitors reduce lipid accumulation in the liver, kidney, and heart, and alter expression of lipid metabolism genes. Effects on free fatty acid uptake in abdominal fat depots depend on the location of adipose tissue. In male, but not female, mice, SGLT2 inhibitors reduce the atherosclerotic lesions and aortic calcium deposition. With respect to skeletal health, recent literature has reported conflicting associations with the risks of fracture and amputation. SUMMARY: Studies suggest that SGLT2 inhibitors reduce tissue lipid accumulation, and in a sex-dependent manner, atherosclerosis and vascular calcification. However, their effects on lipid levels and bone health are complex and remain to be established.
RESUMEN
Peripheral serotonin levels are associated with cardiovascular disease risk. We previously found that serum serotonin levels are higher in hyperlipidemic mice than wild-type mice. Evidence also suggests that serotonin regulates biomineralization, in that serotonin treatment augments TNF-a-induced matrix calcification of aortic valve interstitial cells and that a selective inhibitor of peripheral serotonin, LP533401, rescues bone loss induced by ovariectomy in mice. Thus, in the present study, we examined the effects of LP533401 on both skeletal bone mineral density (BMD) and aortic calcification in both young and older hyperlipidemic mice susceptible to calcific atherosclerosis and bone loss. By serial in vivo microCT imaging, we assessed BMD and aortic calcification of Apoe-/- mice fed an atherogenic (high cholesterol) diet alone or mixed with LP533401. Results show that in the young mice, LP533401 blunted skeletal bone loss in lumbar vertebrae but not in femurs. LP533401 also blunted the initial development of aortic calcification but not its progression. Echocardiographic analysis showed that LP533401 blunted both hyperlipidemia-induced cardiac hypertrophy and left ventricular dysfunction. In the older mice, LP533401 increased the BMD of lumbar vertebrae but not of femurs. The aortic calcification progressed in both controls and LP533401-treated mice, but, at post-treatment, LP533401-treated mice had significantly less aortic calcification than the controls. These findings suggest that LP533401 mitigates adverse effects of hyperlipidemia on skeletal and vascular tissues in site- and stage-dependent manners.
Asunto(s)
Aterosclerosis , Calcinosis , Hiperlipidemias , Pirimidinas , Calcificación Vascular , Femenino , Ratones , Animales , Serotonina , Calcificación Fisiológica , Válvula Aórtica/diagnóstico por imagen , Hiperlipidemias/complicaciones , Calcificación Vascular/etiologíaRESUMEN
BACKGROUND: Coronary calcification associates closely with cardiovascular risk, but its progress is accelerated in response to some interventions widely used to reduce risk. This paradox suggests that qualitative, not just quantitative, changes in calcification may affect plaque stability. To determine if the microarchitecture of calcification varies with aging, Western diet, statin therapy, and high intensity, progressive exercise, we assessed changes in a priori selected computed tomography radiomic features (intensity, size, shape, and texture). METHODS: Longitudinal computed tomography scans of mice (Apoe-/-) exposed to each of these conditions were autosegmented by deep learning segmentation, and radiomic features of the largest deposits were analyzed. RESULTS: Over 20 weeks of aging, intensity and most size parameters increased, but surface-area-to-volume ratio (a measure of porosity) decreased, suggesting stabilization. However, texture features (coarseness, cluster tendency, and nonuniformity) increased, suggesting heterogeneity and likely destabilization. Shape parameters showed no significant changes, except sphericity, which showed a decrease. The Western diet had significant effects on radiomic features related to size and texture, but not intensity or shape. In mice undergoing either pravastatin treatment or exercise, the selected radiomic features of their computed tomography scans were not significantly different from those of their respective controls. Interestingly, the total number of calcific deposits increased significantly less in the 2 intervention groups compared with the respective controls, suggesting more coalescence and/or fewer de novo deposits. CONCLUSIONS: Thus, aging and standard interventions alter the microarchitectural features of vascular calcium deposits in ways that may alter plaque biomechanical stability.
Asunto(s)
Aprendizaje Profundo , Placa Aterosclerótica , Animales , Ratones , Tomografía Computarizada por Rayos X/métodosRESUMEN
PURPOSE OF REVIEW: Lipids and lipoproteins have long been known to contribute to atherosclerosis and cardiovascular calcification. One theme of recent work is the study of lipoprotein (a) [Lp(a)], a lipoprotein particle similar to LDL-cholesterol that carries a long apoprotein tail and most of the circulating oxidized phospholipids. RECENT FINDINGS: In-vitro studies show that Lp(a) stimulates osteoblastic differentiation and mineralization of vascular smooth muscle cells, while the association of Lp(a) with coronary artery calcification continues to have varying results, possibly because of the widely varying threshold levels of Lp(a) chosen for association analyses. Another emerging area in the field of cardiovascular calcification is pathological endothelial-to-mesenchymal transition (EndMT), the process whereby endothelial cell transition into multipotent mesenchymal cells, some of which differentiate into osteochondrogenic cells and mineralize. The effects of lipids and lipoproteins on EndMT suggest that they modulate cardiovascular calcification through multiple mechanisms. There are also emerging trends in imaging of calcific vasculopathy, including: intravascular optical coherence tomography for quantifying plaque characteristics, PET with a radiolabeled NaF tracer, with either CT or MRI to detect coronary plaque vulnerability. SUMMARY: Recent work in this field includes studies of Lp(a), EndMT, and new imaging techniques.
Asunto(s)
Aterosclerosis , Calcinosis , Enfermedad de la Arteria Coronaria , Placa Aterosclerótica , Humanos , Lipoproteína(a) , Lipoproteínas LDLRESUMEN
[Figure: see text].
Asunto(s)
Aorta/efectos de los fármacos , Enfermedades de la Aorta/tratamiento farmacológico , Aterosclerosis/tratamiento farmacológico , Calcio/metabolismo , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacología , Hiperlipidemias/tratamiento farmacológico , Pravastatina/farmacología , Calcificación Vascular/tratamiento farmacológico , Factores de Edad , Animales , Aorta/diagnóstico por imagen , Aorta/metabolismo , Aorta/patología , Enfermedades de la Aorta/diagnóstico por imagen , Enfermedades de la Aorta/metabolismo , Enfermedades de la Aorta/patología , Aterosclerosis/diagnóstico por imagen , Aterosclerosis/metabolismo , Aterosclerosis/patología , Modelos Animales de Enfermedad , Femenino , Hiperlipidemias/sangre , Lípidos/sangre , Ratones Endogámicos C57BL , Ratones Noqueados para ApoE , Placa Aterosclerótica , Rotura Espontánea , Factores de Tiempo , Calcificación Vascular/diagnóstico por imagen , Calcificación Vascular/metabolismo , Calcificación Vascular/patologíaRESUMEN
PURPOSE OF REVIEW: Cardiovascular calcification, a common feature of atherosclerotic lesions, has long been known to associate with cardiovascular risk. The roles of lipoproteins in atherosclerosis are also established, and lipid-modifying therapies have shown capacity for plaque regression. However, the association of lipid-modifying therapies with calcification is more complex, and currently no medical therapies have been found to reverse or attenuate calcification in patients. In this review, we summarize recent developments in our understanding of the interplay between lipids and cardiovascular calcification, as well as new imaging modalities for assessing calcified atherosclerotic plaque vulnerability. RECENT FINDINGS: Recent clinical studies have highlighted the associations of lipoprotein subtypes, such as low-density and high-density lipoprotein particles, as well as lipoprotein (a) [Lp(a)], with coronary calcification and calcific aortic valve disease. Further, evidence continues to emerge for the utility of fused 18F-sodium fluoride positron-emission tomographic and computed tomographic (18F-NaF PET/CT) imaging in characterizing the microarchitecture and vulnerability of atherosclerotic plaque, in both humans and animal models. SUMMARY: The relationship between lipids and cardiovascular calcification is complex, and new imaging techniques, such as 18F-NaF PET/CT imaging, may allow for better identification of disease-modifying therapies and prediction of calcified plaque progression and stability to help guide clinical management.
Asunto(s)
Placa Aterosclerótica , Animales , Humanos , Lípidos , Placa Aterosclerótica/complicaciones , Placa Aterosclerótica/diagnóstico por imagen , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Radiofármacos , Fluoruro de SodioRESUMEN
Calcification, fibrosis, and chronic inflammation are the predominant features of calcific aortic valve disease, a life-threatening condition. Drugs that induce serotonin (5-hydroxytryptamine [5-HT]) are known to damage valves, and activated platelets, which carry peripheral serotonin, are known to promote calcific aortic valve stenosis. However, the role of 5-HT in valve leaflet pathology is not known. We tested whether serotonin mediates inflammation-induced matrix mineralization in valve cells. Real-time reverse transcription-polymerase chain reaction analysis showed that murine aortic valve interstitial cells (VICs) expressed both serotonin receptor types 2A and 2B (Htr2a and Htr2b). Although Htr2a expression was greater at baseline, Htr2b expression was induced several-fold more than Htr2a in response to the pro-calcific tumor necrosis factor-α (TNF-α) treatment. 5-HT also augmented TNF-α-induced osteoblastic differentiation and matrix mineralization of VIC, but 5-HT alone had no effects. Inhibition of serotonin receptor type 2B, using specific inhibitors or lentiviral knockdown in VIC, attenuated 5-HT effects on TNF-α-induced osteoblastic differentiation and mineralization. 5-HT treatment also augmented TNF-α-induced matrix metalloproteinase-3 expression, which was also attenuated by Htr2b knockdown. Htr2b expression in aortic roots and serum levels of peripheral 5-HT were also greater in the hyperlipidemic Apoe-/- mice than in control normolipemic mice. These findings suggest a new role for serotonin signaling in inflammation-induced calcific valvulopathy.
Asunto(s)
Receptor de Serotonina 5-HT2B/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Apolipoproteínas E/metabolismo , Células Cultivadas , Inflamación/metabolismo , Metaloproteinasa 3 de la Matriz/metabolismo , Ratones , Receptor de Serotonina 5-HT2B/genética , Serotonina/farmacología , Transducción de Señal/efectos de los fármacos , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
The role of vitamin D in the cardiovascular system is complex because it regulates expression of genes involved in diverse metabolic processes. Although referred to as a vitamin, it is more accurately considered a steroid hormone, because it is produced endogenously in the presence of ultraviolet light. It occurs as a series of sequentially activated forms, here referred to as vitamin D-hormones. A little-known phenomenon, based on pre-clinical data, is that its biodistribution and potential effects on vascular disease likely depend on whether it is derived from diet or sunlight. Diet-derived vitamin D-hormones are carried in the blood, at least in part, in chylomicrons and lipoprotein particles, including low-density lipoprotein. Since low-density lipoprotein is known to accumulate in the artery wall and atherosclerotic plaque, diet-derived vitamin D-hormones may also collect there, and possibly promote the osteochondrogenic mineralization associated with plaque. Also, little known is the fact that the body stores vitamin D-hormones in adipose tissue with a half-life on the order of months, raising doubts about whether the use of the term "daily requirement" is appropriate. Cardiovascular effects of vitamin D-hormones are controversial, and risk appears to increase with both low and high blood levels. Since low serum vitamin D-hormone concentration is reportedly associated with increased cardiovascular and orthopedic risk, oral supplementation is widely used, often together with calcium supplements. However, meta-analyses show that oral vitamin D-hormone supplementation does not protect against cardiovascular events, findings that are also supported by a randomized controlled trial. These considerations suggest that prevalent recommendations for vitamin D-hormone supplementation for the purpose of cardiovascular protection should be carefully reconsidered.
Asunto(s)
Sistema Cardiovascular/metabolismo , Vitamina D , Enfermedades Cardiovasculares/prevención & control , Suplementos Dietéticos , Humanos , Resultado del Tratamiento , Vitamina D/sangre , Vitamina D/metabolismo , Vitamina D/farmacologíaRESUMEN
BACKGROUND: Despite the association of physical activity with improved cardiovascular outcomes and the association of high coronary artery calcification (CAC) scores with poor prognosis, elite endurance athletes have increased CAC. Yet, they nevertheless have better cardiovascular survival. We hypothesized that exercise may transform vascular calcium deposits to a more stable morphology. METHODS: To test this, hyperlipidemic mice (Apoe-/-) with baseline aortic calcification were separated into 2 groups (n = 9/group) with control mice allowed to move ad-lib while the exercise group underwent a progressive treadmill regimen for 9 weeks. All mice underwent blood collections and in vivo 18F-NaF µPET/µCT imaging both at the start and end of the exercise regimen. At euthanasia, aortic root specimens were obtained for histomorphometry. RESULTS: Results showed that, while aortic calcification progressed similarly in both groups based on µCT, the fold change in 18F-NaF density was significantly less in the exercise group. Histomorphometric analysis of the aortic root calcium deposits showed that the exercised mice had a lower mineral surface area index than the control group. The exercise regimen also raised serum PTH levels twofold. CONCLUSION: These findings suggest that weeks-long progressive exercise alters the microarchitecture of atherosclerotic calcium deposits by reducing mineral surface growth, potentially favoring plaque stability.
Asunto(s)
Calcificación Fisiológica/fisiología , Hiperlipidemias/complicaciones , Condicionamiento Físico Animal/normas , Placa Aterosclerótica/diagnóstico por imagen , Animales , Modelos Animales de Enfermedad , Fluorodesoxiglucosa F18/administración & dosificación , Fluorodesoxiglucosa F18/uso terapéutico , Hiperlipidemias/diagnóstico por imagen , Ratones , Condicionamiento Físico Animal/métodos , Condicionamiento Físico Animal/estadística & datos numéricos , Placa Aterosclerótica/fisiopatología , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Tomografía Computarizada por Tomografía de Emisión de Positrones/estadística & datos numéricos , Radiofármacos/administración & dosificación , Radiofármacos/uso terapéuticoRESUMEN
Understanding of vitamin D physiology is important because about half of the population is being diagnosed with deficiency and treated with supplements. Clinical guidelines were developed based on observational studies showing an association between low serum levels and increased cardiovascular risk. However, new randomized controlled trials have failed to confirm any cardiovascular benefit from supplementation in the general population. A major concern is that excess vitamin D is known to cause calcific vasculopathy and valvulopathy in animal models. For decades, administration of vitamin D has been used in rodents as a reliable experimental model of vascular calcification. Technically, vitamin D is a misnomer. It is not a true vitamin because it can be synthesized endogenously through ultraviolet exposure of the skin. It is a steroid hormone that comes in 3 forms that are sequential metabolites produced by hydroxylases. As a fat-soluble hormone, the vitamin D-hormone metabolites must have special mechanisms for delivery in the aqueous bloodstream. Importantly, endogenously synthesized forms are carried by a binding protein, whereas dietary forms are carried within lipoprotein particles. This may result in distinct biodistributions for sunlight-derived versus supplement-derived vitamin D hormones. Because the cardiovascular effects of vitamin D hormones are not straightforward, both toxic and beneficial effects may result from current recommendations.
Asunto(s)
Enfermedades Cardiovasculares/etiología , Vitamina D/administración & dosificación , Vitamina D/metabolismo , Vitaminas/administración & dosificación , Vitaminas/metabolismo , Factores de Edad , Aterosclerosis/etiología , Calcio de la Dieta/administración & dosificación , Calcio de la Dieta/metabolismo , Enfermedades Cardiovasculares/sangre , Enfermedades Cardiovasculares/diagnóstico , Colecalciferol/biosíntesis , Colecalciferol/metabolismo , Factores de Confusión Epidemiológicos , Suplementos Dietéticos/efectos adversos , Esquema de Medicación , Alimentos , Guías como Asunto , Humanos , Hidroxilación , Estudios Observacionales como Asunto , Medicina de Precisión , Receptores de LDL/metabolismo , Luz Solar , Calcificación Vascular/etiología , Vitamina D/efectos adversos , Vitamina D/biosíntesis , Deficiencia de Vitamina D/sangre , Deficiencia de Vitamina D/diagnóstico , Vitaminas/efectos adversosRESUMEN
PURPOSE OF REVIEW: This review addresses recent developments in studies of lipid regulation of calcific disease of arteries and cardiac valves, including the role of nuclear receptors. The role of lipid-soluble signals and their receptors is timely given the recent evidence and concerns that lipid-lowering treatment may increase the rate of progression of coronary artery calcification, which has been long associated with increased cardiovascular risk. Understanding the mechanisms will be important for interpreting such clinical information. RECENT FINDINGS: New findings support regulation of calcific vascular and valvular disease by nuclear receptors, including the vitamin D receptor, glucocorticoid receptor, nutrient-sensing nuclear receptors (liver X receptor, farnesoid X receptor, and peroxisome proliferator-activated receptors), and sex hormone (estrogen and androgen) receptors. There were two major unexpected findings: first, vitamin D supplementation, which was previously believed to prevent or reduce vascular calcification, showed no cardiovascular benefit in large randomized, controlled trials. Second, both epidemiological studies and coronary intravascular ultrasound studies suggest that treatment with HMG-CoA reductase inhibitors increases progression of coronary artery calcification, raising a question of whether there are mechanically stable and unstable forms of coronary calcification. SUMMARY: For clinical practice and research, these new findings offer new fundamental mechanisms for vascular calcification and provide new cautionary insights for therapeutic avenues.
Asunto(s)
Calcinosis/genética , Enfermedades de las Válvulas Cardíacas/genética , Receptores Citoplasmáticos y Nucleares/genética , Calcificación Vascular/genética , Arterias/efectos de los fármacos , Arterias/patología , Calcinosis/patología , Enfermedades de las Válvulas Cardíacas/tratamiento farmacológico , Enfermedades de las Válvulas Cardíacas/patología , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Metabolismo de los Lípidos/genética , Receptores X del Hígado/genética , Receptores Activados del Proliferador del Peroxisoma/genética , Calcificación Vascular/tratamiento farmacológico , Calcificación Vascular/patologíaRESUMEN
Calcific aortic vasculopathy correlates with bone loss in osteoporosis in an age-independent manner. Prior work suggests that teriparatide, the bone anabolic treatment for postmenopausal osteoporosis, may inhibit the onset of aortic calcification. Whether teriparatide affects the progression of preexisting aortic calcification, widespread among this patient population, is unknown. Female apolipoprotein E-deficient mice were aged for over 1 yr to induce aortic calcification, treated for 4.5 wk with daily injections of control vehicle (PBS), 40 µg/kg teriparatide (PTH40), or 400 µg/kg teriparatide (PTH400), and assayed for aortic calcification by microcomputed tomography (microCT) before and after treatment. In a followup cohort, aged female apolipoprotein E-deficient mice were treated with PBS or PTH400 and assayed for aortic calcification by serial microCT and micropositron emission tomography. In both cohorts, aortic calcification detected by microCT progressed similarly in all groups. Mean aortic 18F-NaF incorporation, detected by serial micropositron emission tomography, increased in the PBS-treated group (+14 ± 5%). In contrast, 18F-NaF incorporation decreased in the PTH400-treated group (-33 ± 20%, P = 0.03). Quantitative histochemical analysis by Alizarin red staining revealed a lower mineral surface area index in the PTH400-treated group compared with the PBS-treated group ( P = 0.04). Furthermore, Masson trichrome staining showed a significant increase in collagen deposition in the left ventricular myocardium of mice that received PTH400 [2.1 ± 0.6% vs. control mice (0.5 ± 0.1%), P = 0.02]. In summary, although teriparatide may not affect the calcium mineral content of aortic calcification, it reduces 18F-NaF uptake in calcified lesions, suggesting the possibility that it may reduce mineral surface area with potential impact on plaque stability. NEW & NOTEWORTHY Parathyroid hormone regulates bone mineralization and may also affect vascular calcification, which is an important issue, given that its active fragment, teriparatide, is widely used for the treatment of osteoporosis. To determine whether teriparatide alters vascular calcification, we imaged aortic calcification in mice treated with teriparatide and control mice. Although teriparatide did not affect the calcium content of cardiovascular deposits, it reduced their fluoride tracer uptake.
Asunto(s)
Aorta/efectos de los fármacos , Enfermedades de la Aorta/tratamiento farmacológico , Aterosclerosis/tratamiento farmacológico , Conservadores de la Densidad Ósea/farmacología , Hiperlipidemias/complicaciones , Teriparatido/farmacología , Calcificación Vascular/tratamiento farmacológico , Factores de Edad , Envejecimiento , Animales , Aorta/diagnóstico por imagen , Aorta/patología , Enfermedades de la Aorta/diagnóstico por imagen , Enfermedades de la Aorta/patología , Aortografía/métodos , Aterosclerosis/diagnóstico por imagen , Aterosclerosis/etiología , Aterosclerosis/patología , Conservadores de la Densidad Ósea/toxicidad , Angiografía por Tomografía Computarizada , Modelos Animales de Enfermedad , Femenino , Fibrosis , Ventrículos Cardíacos/diagnóstico por imagen , Ventrículos Cardíacos/efectos de los fármacos , Ventrículos Cardíacos/patología , Ratones Noqueados para ApoE , Placa Aterosclerótica , Tomografía de Emisión de Positrones , Teriparatido/toxicidad , Calcificación Vascular/diagnóstico por imagen , Calcificación Vascular/etiología , Calcificación Vascular/patología , Microtomografía por Rayos XAsunto(s)
Estenosis de la Válvula Aórtica , Conservadores de la Densidad Ósea , Calcinosis , Osteoporosis , Válvula Aórtica , Estenosis de la Válvula Aórtica/diagnóstico por imagen , Estenosis de la Válvula Aórtica/tratamiento farmacológico , Conservadores de la Densidad Ósea/uso terapéutico , Calcinosis/diagnóstico por imagen , Calcinosis/tratamiento farmacológico , Humanos , Osteoporosis/tratamiento farmacológicoRESUMEN
In calcific aortic valve disease, the valve cusps undergo retraction, stiffening, and nodular calcification. The inflammatory cytokine, tumor necrosis factor (TNF)-α, contributes to valve disease progression; however, the mechanisms of its actions on cusp retraction and stiffening are unclear. We investigated effects of TNF-α on murine aortic valvular interstitial cells (VICs) within three-dimensional, free-floating, compliant, collagen hydrogels, simulating their natural substrate and biomechanics. TNF-α increased retraction (percentage of diameter), stiffness, and formation of macroscopic, nodular structures with calcification in the VIC-laden hydrogels. The effects of TNF-α were attenuated by blebbistatin inhibition of myosin II-mediated cytoskeletal contraction. Inhibition of actin polymerization with cytochalasin-D, but not inhibition of Rho kinase with Y27632, blocked TNF-α-induced retraction in three-dimensional VIC hydrogels, suggesting that actin stress fibers mediate TNF-α-induced effects. In the hydrogels, inhibitors of NF-κB blocked TNF-α-induced retraction, whereas simultaneous inhibition of c-Jun N-terminal kinase was required to block TNF-α-induced stiffness. TNF-α also significantly increased collagen deposition, as visualized by Masson's trichrome staining, and up-regulated mRNA expression of discoidin domain receptor tyrosine kinase 2, fibronectin, and α-smooth muscle actin. In human aortic valves, calcified cusps were stiffer and had more collagen deposition than noncalcified cusps. These findings suggest that inflammation, through stimulation of cytoskeletal contractile activity, may be responsible for valvular cusp retraction, stiffening, and formation of calcified nodules.
Asunto(s)
Estenosis de la Válvula Aórtica/patología , Válvula Aórtica/patología , Calcinosis/patología , Citoesqueleto/patología , Inflamación/patología , Animales , Western Blotting , Técnicas de Cultivo de Célula , Células Cultivadas , Modelos Animales de Enfermedad , Técnica del Anticuerpo Fluorescente , Humanos , Hidrogel de Polietilenoglicol-Dimetacrilato , Ratones , Ratones Endogámicos C57BL , Reacción en Cadena en Tiempo Real de la Polimerasa , Factor de Necrosis Tumoral alfa/metabolismo , Factor de Necrosis Tumoral alfa/farmacologíaRESUMEN
Calcific aortic vascular and valvular disease (CAVD) is associated with hyperlipidemia, the effects of which occur through chronic inflammation. Evidence suggests that inhibitory small mothers against decapentaplegic (I-Smads; Smad6 and 7) regulate valve embryogenesis and may serve as a mitigating factor in CAVD. However, whether I-Smads regulate inflammation-induced calcific vasculopathy is not clear. Therefore, we investigated the role of I-Smads in atherosclerotic calcification. Results showed that expression of Smad6, but not Smad7, was reduced in aortic and valve tissues of hyperlipidemic compared with normolipemic mice, while expression of tumor necrosis factor alpha (TNF-α) was upregulated. To test whether the effects are in response to inflammatory cytokines, we isolated murine aortic valve leaflets and cultured valvular interstitial cells (mVIC) from the normolipemic mice. By immunochemistry, mVICs were strongly positive for vimentin, weakly positive for smooth muscle α actin, and negative for an endothelial cell marker. TNF-α upregulated alkaline phosphatase (ALP) activity and matrix mineralization in mVICs. By gene expression analysis, TNF-α significantly upregulated bone morphogenetic protein 2 (BMP-2) expression while downregulating Smad6 expression. Smad7 expression was not significantly affected. To further test the role of Smad6 on TNF-α-induced valvular cell calcification, we knocked down Smad6 expression using lentiviral transfection. In cells transfected with Smad6 shRNA, TNF-α further augmented ALP activity, expression of BMP-2, Wnt- and redox-regulated genes, and matrix mineralization compared with the control cells. These findings suggest that TNF-α induces valvular and vascular cell calcification, in part, by specifically reducing the expression of a BMP-2 signaling inhibitor, Smad6.
Asunto(s)
Estenosis de la Válvula Aórtica/genética , Válvula Aórtica/patología , Proteína Morfogenética Ósea 2/biosíntesis , Calcinosis/genética , Inflamación/genética , Proteína smad6/metabolismo , Factor de Necrosis Tumoral alfa/biosíntesis , Fosfatasa Alcalina/biosíntesis , Animales , Aorta/metabolismo , Aorta/patología , Válvula Aórtica/metabolismo , Regulación de la Expresión Génica , Humanos , Inflamación/metabolismo , Inflamación/patología , Lentivirus/genética , Ratones , Osteoblastos/metabolismo , Osteoblastos/patología , Transducción de Señal/genética , Proteína smad6/genética , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
This review centers on updating the active research area of vascular calcification. This pathology underlies substantial cardiovascular morbidity and mortality, through adverse mechanical effects on vascular compliance, vasomotion, and, most likely, plaque stability. Biomineralization is a complex, regulated process occurring widely throughout nature. Decades ago, its presence in the vasculature was considered a mere curiosity and an unregulated, dystrophic process that does not involve biological mechanisms. Although it remains controversial whether the process has any adaptive value or past evolutionary advantage, substantial advances have been made in understanding the biological mechanisms driving the process. Different types of calcific vasculopathy, such as inflammatory versus metabolic, have parallel mechanisms in skeletal bone calcification, such as intramembranous and endochondral ossification. Recent work has identified important regulatory roles for inflammation, oxidized lipids, elastin, alkaline phosphatase, osteoprogenitor cells, matrix γ-carboxyglutamic acid protein, transglutaminase, osteoclastic regulatory factors, phosphate regulatory hormones and receptors, apoptosis, prelamin A, autophagy, and microvesicles or microparticles similar to the matrix vesicles of skeletal bone. Recent work has uncovered fascinating interactions between matrix γ-carboxyglutamic acid protein, vitamin K, warfarin, and transport proteins. And, lastly, recent breakthroughs in inherited forms of calcific vasculopathy have identified the genes responsible as well as an unexpected overlap of phenotypes. Until recently, vascular calcification was considered a purely degenerative, unregulated process. Since then, investigative groups around the world have identified a wide range of causative mechanisms and regulatory pathways, and some of the recent developments are highlighted in this review.
Asunto(s)
Vasos Sanguíneos/metabolismo , Inflamación/complicaciones , Calcificación Vascular/etiología , Animales , Vasos Sanguíneos/inmunología , Vasos Sanguíneos/patología , Calcificación Fisiológica , Predisposición Genética a la Enfermedad , Humanos , Inflamación/inmunología , Inflamación/metabolismo , Mediadores de Inflamación/metabolismo , Fenotipo , Factores de Riesgo , Calcificación Vascular/genética , Calcificación Vascular/inmunología , Calcificación Vascular/metabolismo , Calcificación Vascular/patologíaRESUMEN
Bioactive lipids initiate inflammatory reactions leading to pathogenesis of atherosclerosis. Evidence shows that they also contribute to bone loss by inhibiting parathyroid hormone receptor (PTH1R) expression and differentiation of osteoblasts. We previously demonstrated that bone anabolic effects of PTH(1-34) are blunted in hyperlipidemic mice and that these PTH effects are restored by antioxidants. However, it is not clear which osteoblastic cell developmental stage is targeted by bioactive lipids. To investigate the effects of hyperlipidemia at the cellular level, hyperlipidemic Ldlr(-/-) mice were bred with Col3.6GFPtpz mice, in which preosteoblasts/osteoblasts carry a topaz fluorescent label, and with Col2.3GFPcyan mice, in which more mature osteoblasts/osteocytes carry a cyan fluorescent label. Histological analyses of trabecular bone surfaces in femoral as well as calvarial bones showed that intermittent PTH(1-34) increased fluorescence intensity in WT-Tpz mice, but not in Tpz-Ldlr(-/-) mice. In contrast, PTH(1-34) did not alter fluorescence intensity in femoral cortical envelopes of either WT-Cyan or Ldlr(-/-)-Cyan mice. To test the mechanism of PTH1R downregulation, preosteoblastic MC3T3-E1 cells were treated with bioactive lipids and the antioxidant Trolox. Results showed that inhibitory effects of PTH1R levels by bioactive lipids were rescued by pretreatment with Trolox. The inhibitory effects on expression of PTH1R as well as on PTH-induced osteoblastic genes were mimicked by xanthine/xanthine oxidase, a known generator of reactive oxygen species. These findings suggest an important role of the preosteoblastic development stage as the target and downregulation of PTH receptor expression mediated by intracellular oxidant stress as a mechanism in hyperlipidemia-induced PTH resistance.
Asunto(s)
Hiperlipidemias/metabolismo , Osteoblastos/metabolismo , Hormona Paratiroidea/farmacología , Especies Reactivas de Oxígeno/metabolismo , Receptor de Hormona Paratiroídea Tipo 1/fisiología , Animales , Células Cultivadas , Cromanos/farmacología , Femenino , Proteínas Fluorescentes Verdes/genética , Hiperlipidemias/fisiopatología , Inflamación/metabolismo , Ratones , Ratones Mutantes , Ratones Transgénicos , Osteoblastos/efectos de los fármacos , Osteocitos/efectos de los fármacos , Receptores de LDL/genéticaRESUMEN
RATIONALE: Left-right (LR) asymmetry is ubiquitous in animal development. Cytoskeletal chirality was recently reported to specify LR asymmetry in embryogenesis, suggesting that LR asymmetry in tissue morphogenesis is coordinated by single- or multi-cell organizers. Thus, to organize LR asymmetry at multiscale levels of morphogenesis, cells with chirality must also be present in adequate numbers. However, observation of LR asymmetry is rarely reported in cultured cells. OBJECTIVES: Using cultured vascular mesenchymal cells, we tested whether LR asymmetry occurs at the single cell level and in self-organized multicellular structures. METHODS AND RESULTS: Using micropatterning, immunofluorescence revealed that adult vascular cells polarized rightward and accumulated stress fibers at an unbiased mechanical interface between adhesive and nonadhesive substrates. Green fluorescent protein transfection revealed that the cells each turned rightward at the interface, aligning into a coherent orientation at 20° relative to the interface axis at confluence. During the subsequent aggregation stage, time-lapse videomicroscopy showed that cells migrated along the same 20° angle into neighboring aggregates, resulting in a macroscale structure with LR asymmetry as parallel, diagonal stripes evenly spaced throughout the culture. Removal of substrate interface by shadow mask-plating, or inhibition of Rho kinase or nonmuscle myosin attenuated stress fiber accumulation and abrogated LR asymmetry of both single-cell polarity and multicellular coherence, suggesting that the interface triggers asymmetry via cytoskeletal mechanics. Examination of other cell types suggests that LR asymmetry is cell-type specific. CONCLUSIONS: Our results show that adult stem cells retain inherent LR asymmetry that elicits de novo macroscale tissue morphogenesis, indicating that mechanical induction is required for cellular LR specification.
Asunto(s)
Células Madre Adultas/fisiología , Vasos Sanguíneos/embriología , Polaridad Celular , Citoesqueleto/fisiología , Mesodermo/fisiología , Animales , Vasos Sanguíneos/citología , Adhesión Celular , Técnicas de Cultivo de Célula , Movimiento Celular , Simulación por Computador , Vidrio , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Mesodermo/citología , Ratones , Microscopía Fluorescente , Microscopía por Video , Modelos Biológicos , Morfogénesis , Células 3T3 NIH , Análisis Numérico Asistido por Computador , Fibras de Estrés/fisiología , Propiedades de Superficie , Factores de Tiempo , Imagen de Lapso de Tiempo , TransfecciónRESUMEN
BACKGROUND: Fibroblast growth factor 23 (FGF23) levels are elevated in chronic kidney disease (CKD) and elevated values have been associated with both heart disease and mortality. Recent studies show that FGF23, a protein synthesized by osteocytes, is also present in calcified atherosclerotic plaques and may be induced by heart disease. Whether vascular expression of FGF23 is associated with progressive CKD, however, remains unknown. Therefore, the relationship between kidney function, vascular calcification and FGF23 expression was evaluated in patients with heart disease. METHODS: Immunohistochemistry for FGF23 was performed in coronary arteries of all patients undergoing heart transplantation at UCLA between February 2008 and 2010. Immunohistochemical staining for Klotho, DMP1, FGFR1, and FGFR3; calcium deposition; and RNA expression of Klotho and DMP1 were assessed in a subset of eight samples. RESULTS: FGF23 was detected by immunohistochemistry in 56% of the coronary artery specimens. Vascular FGF23 expression correlated with declining kidney function, as evidenced by reduced creatinine clearance. FGFR1 and FGFR3 were detected throughout the vascular tissue and in calcified plaques. Calcium deposition, Klotho expression and DMP1 expression correlated with FGF23 immunoreactivity. CONCLUSIONS: The findings suggest that the Klotho-FGF23-FGFR system is active in coronary arteries and its upregulation correlates with impaired renal function and matrix calcium deposition.