Placenta-specific methylation of the vitamin D 24-hydroxylase gene: implications for feedback autoregulation of active vitamin D levels at the fetomaternal interface

Plasma concentrations of biologically active vitamin D (1,25- (OH)2D) are tightly controlled via feedback regulation of renal 1-hydroxylase (CYP27B1; positive) and 24-hydroxylase (CYP24A1; catabolic) enzymes. In pregnancy, this regulation is uncoupled, and 1,25-(OH)2D levels are significantly elevated, suggesting a role in pregnancy progression. Epigenetic regulation of CYP27B1 and CYP24A1 has previously been described in cell and animal models, and despite emerging evidence for a critical role of epigenetics in placentation generally, little is known about the regulation of enzymes modulating vitamin D homeostasis at the fetomaternal interface. In this study, we investigated the methylation status of genes regulating vitamin D bioavailability and activity in the placenta. No methylation of the VDR (vitamin D receptor) and CYP27B1 genes was found in any placental tissues. In contrast, the CYP24A1 gene is methylated in human placenta, purified cytotrophoblasts, and primary and cultured chorionic villus sampling tissue. No methylation was detected in any somatic human tissue tested. Methylation was also evident in marmoset and mouse placental tissue. All three genes were hypermethylated in choriocarcinoma cell lines, highlighting the role of vitaminDderegulation in this cancer. Gene expression analysis confirmed a reduced capacity for CYP24A1 induction with promoter methylation in primary cells and in vitro reporter analysis demonstrated that promoter methylation directly down-regulates basal promoter activity and abolishes vitamin D-mediated feedback activation. This study strongly suggests that epigenetic decoupling of vitamin D feedback catabolism plays an important role in maximizing active vitamin D bioavailability at the fetomaternal interface

Tipo físico ideal e satisfação com a imagem corporal de praticantes de caminhada Tipo físico ideal y satisfaccion con la imagen corporal de los praticantes de caminata Ideal physical type and body image satisfaction of regular walkers

O objetivo do presente estudo foi quantificar o tipo físico ideal e verificar o nível de insatisfação com a imagem corporal de praticantes de caminhada. Participaram do estudo 186 pessoas: 87 mulheres (idade = 28,70 ± 12,6 anos, estatura = 161,6 ± 6,2cm, massa corporal = 58,9 ± 12,0kg e gordura = 25,7 ± 7,8 G%) e 98 homens (idade = 27,9 ± 12,9 anos, estatura = 177,2 ± 6,9cm, massa corporal = 75,0 ± 12,3kg e gordura = 13,3 ± 6,1 G%). Solicitou-se que as pessoas indicassem qual silhueta correspondia ao seu corpo atualmente e qual gostariam de atingir. Apenas 24% das mulheres estão satisfeitas. A silhueta 3 foi apontada como ideal a ser atingido por 55% das mulheres (silhueta 2 = 18%; e 4 = 21%). A silhueta 3, de acordo com os resultados desse estudo, corresponde ao G% 20,5 ± 0,9% (EPM) e ao IMC de 20,0 ± 0,3kg/m² (EPM). Quanto aos homens, apenas 18% estão satisfeitos. A silhueta 4 foi apontada como ideal por 47% dos homens (silhueta 3 = 23%; e 5 = 19%). A silhueta 4 corresponde ao G% 9,8 ± 1,4% (EPM) e ao IMC de 23,1 ± 0,4kg/m² (EPM). Existe um tipo físico ideal para ambos os sexos. Não houve diferença entre o grau de insatisfação com a imagem corporal entre os sexos.<br>El objetivo del presente estudio fué cuantificar el tipo físico ideal y verificar el nivel de insatisfacción con la imagen corporal de praticantes de caminata. Participaron del estudio 186 personas: 87 mujeres (edades = 28,70 ± 12,6 años, estatura = 161,6 ± 6,2 cm, masa corporal = 58,9 ± 12,0 kg y gordura = 25,7 ± 7,8 G%) y 98 hombres (edades = 27.9 ± 12,9 años, estatura = 177,2 ± 6,9 cm, masa corporal = 75,0 ± 12,3 kg y gordura = 13,3 ± 6,1 G%). Se solicitó que las personas indicasen cual era la silueta que correspondía a su cuerpo actualmente e cual guastarian de tener. Apenas 24% de las mujeres están satisfechas. La silueta 3 fué designada como ideal a ser presentada por el 55 % de las mujeres (silueta 2 = 18%; y 4 = 21%). La silueta 3, de acuerdo con los resultados de este estudio, corresponde al G% 20,5 ± 0,9% (EPM) y al IMC de 20,0 ± 0,3 kg/m² (EPM). En cuanto a los hombres, apenas el 18% están satisfechos. La silueta 4 fué apuntada como ideal por el 47% de los hombres (silueta 3 = 23%; y 5 = 19 %). La silueta 4 corresponde al G% 9,8 ± 1,4% (EPM) y al IMC de 23,1 ± 0,4 kg/m² (EPM). Existe un tipo físico ideal para ambos sexos. No hubo diferencia entre el grado de insatisfación con la imagen corporal entre los sexos.<br>The objective of the present study was to quantify the ideal physical type and to verify the body image satisfaction level of regular walkers. One hundred and eighty six individuals participated in this study as follows: 87 women (age = 28.70 ± 12.6 years, stature = 161.6 ± 6.2 cm, body mass = 58.9 ± 12.0 kg and fat = 25.7 ± 7.8 F%) and 98 men (age = 27.9 ± 12.9 years, stature = 177.2 ± 6.9 cm, body mass = 75.0 ± 12.3 kg and fat = 13.3 ± 6.1 F%). The individuals were asked to indicate which profile corresponded to his/her body and which profile they wanted to reach. Only 24% of women are satisfied. Profile 3 was pointed as ideal to be reached by 55% of women (profile 2 = 18%; and profile 4 = 21%). Profile 3, according to results of this study, corresponded to F% of 20.5 ± 0.9% (EPM) and to MBI of 20.0 ± 0.3 kg/m² (EPM). In relation to men, only 18% are satisfied. Profile 4 was pointed as ideal by 46% of men (profile 3 = 23%; and profile 5 = 19%). Profile 4 corresponds to F% of 9.8 ± 1.4% (EPM) and to BMI of 23.1 ± 0.4 kg/m² (EPM). There is an ideal physical type for both genders. No difference with body image satisfaction degree between genders was verified