RESUMO
Recent research studies have shown that vitamin C (ascorbic acid) may affect bone mineral density and that a deficiency of ascorbic acid leads to the development of osteoporosis. Patients suffering from an inflammatory bowel disease are at a risk of low bone mineral density. It is vital to notice that patients with Crohn's disease and ulcerative colitis also are at risk of vitamin C deficiency which is due to factors such as reduced consumption of fresh vegetables and fruits, i.e., the main sources of ascorbic acid. Additionally, some patients follow diets which may provide an insufficient amount of vitamin C. Moreover, serum vitamin C level also is dependent on genetic factors, such as SLC23A1 and SLC23A2 genes, encoding sodium-dependent vitamin C transporters and GSTM1, GSTP1 and GSTT1 genes which encode glutathione S-transferases. Furthermore, ascorbic acid may modify the composition of gut microbiota which plays a role in the pathogenesis of an inflammatory bowel disease.
Assuntos
Deficiência de Ácido Ascórbico/sangue , Ácido Ascórbico/sangue , Doenças Inflamatórias Intestinais/sangue , Osteoporose/etiologia , Deficiência de Ácido Ascórbico/etiologia , Deficiência de Ácido Ascórbico/genética , Densidade Óssea , Colite Ulcerativa/sangue , Colite Ulcerativa/complicações , Colite Ulcerativa/genética , Doença de Crohn/sangue , Doença de Crohn/complicações , Doença de Crohn/genética , Dieta/efeitos adversos , Feminino , Microbioma Gastrointestinal/fisiologia , Glutationa S-Transferase pi/sangue , Glutationa Transferase/sangue , Humanos , Doenças Inflamatórias Intestinais/complicações , Doenças Inflamatórias Intestinais/genética , Masculino , Osteoporose/genética , Fatores de Risco , Transportadores de Sódio Acoplados à Vitamina C/sangueRESUMO
Vitamin C is incorporated into the cerebrospinal fluid (CSF) through choroid plexus cells. While the transfer of vitamin C from the blood to the brain has been studied functionally, the vitamin C transporter, SVCT2, has not been detected in the basolateral membrane of choroid plexus cells. Furthermore, it is unknown how its expression is induced in the developing brain and modulated in scurvy conditions. We concluded that SVCT2 is intensely expressed in the second half of embryonic brain development and postnatal stages. In postnatal and adult brain, SVCT2 is highly expressed in all choroidal plexus epithelial cells, shown by colocalization with GLUT1 in the basolateral membranes and without MCT1 colocalization, which is expressed in the apical membrane. We confirmed that choroid plexus explant cells (in vitro) form a sealed epithelial structure, which polarized basolaterally, endogenous or overexpressed SVCT2. These results are reproduced in vivo by injecting hSVCT2wt-EYFP lentivirus into the CSF. Overexpressed SVCT2 incorporates AA (intraperitoneally injected) from the blood to the CSF. Finally, we observed in Guinea pig brain under scorbutic condition, that normal distribution of SVCT2 in choroid plexus may be regulated by peripheral concentrations of vitamin C. Additionally, we observed that SVCT2 polarization also depends on the metabolic stage of the choroid plexus cells.