Clinical observation and preliminary study of mechanism of daphnetin in improving therapeutic effects for colitis

BACKGROUND

Daphnein is the first new drug in China. In addition to the treatment of cardiovascular diseases and coronary heart disease, daphnein also has anti-inflammatory, anti-apoptosis, analgesia, and immunity-enhancing activities. Some studies have reported that daphnetin may inhibit the activities of cyclooxygenase and 5-ester oxidase and produce anti-inflammatory and anti-allergic reactions by inhibiting the synthesis of prostaglandin and leukotriene.

AIM

To explore the efficacy of daphnetin in the treatment of colitis, and observe its effect on the composition of microbiota and the balance of regulatory T cells (Treg)/helper Th17 cells (Th17).

METHODS

One hundred and eight patients with ulcerative colitis (UC) admitted to our hospital from June 2017 to November 2019 were selected and randomly divided into either a control group or an observation group, with 54 cases in each group. Both groups were given conventional Western medicine treatment, and the observation group was additionally given daphnetin. The total effective rate, Baron endoscopic score, Geboes mucosal histology score, modified Mayo activity index, intestinal flora distribution, Treg/Th17 balance changes [CD4⁺CD25⁺Foxp3⁺ Treg, interleukin-10 (IL-10), transforming growth factor β (TGF-β), CD3⁺CD4⁺IL-17A⁺ Th17, interleukin-17 (IL-17), and interleukin-21 (IL-21)], the simplified Chinese version of the Inflammatory Bowel Disease Quality of Life Scale (IBDQ) score, and adverse reactions of the two groups were compared.

RESULTS

The total effective rate of the observation group was 90.74%, which was higher than that of the control group (70.37%; P < 0.05). Baron endoscopy score, Geboes mucosal histology score, and modified Mayo activity index of the observation group after treatment were significantly lower than those of the control group (P < 0.05). The numbers of E. coli, Bacteroides, and Enterococcus in the observation group were significantly lower and those of Lactobacillus and Bifidobacterium were significantly higher in the observation group than in the control group (P < 0.05). CD4⁺CD25⁺Foxp3⁺ Treg, IL-10, and TGF-β were significantly higher and CD3⁺CD4⁺IL-17A⁺ Th17, IL-17, and IL-21 were significantly lower in the observation group than in the control group (P < 0.05). The scores of emotional ability, intestinal symptoms, social ability, and systemic symptoms on the IBDQ scale were significantly higher in the observation group than in the control group (P < 0.05).

CONCLUSION

Daphnetin can promote the healing of the intestinal mucosa of UC patients by modulating the microbiome composition and Treg/Th17 balance and effectively improve the patient's condition and quality of life, which is safe and reliable.

Autocrine/paracrine action of vitamin D on FGF23 expression in cultured rat osteoblasts

To explore the local mechanisms of fibroblast growth factor (FGF) 23 regulations, we examined the FGF23 expression patterns in an osteoblast culture model. The characteristics of cultured rat calvaria osteoblasts in half-confluence, confluence, osteoid deposition, and osteoid mineralization stages might reflect the proliferation, differentiation, maturation, and matrix mineralization stages, respectively. Compared with proliferating cells in half-confluence, FGF23 expression was upregulated by 7.5-fold at the mRNA level and 126% at the protein level in confluent differentiated cells as determined by real-time RT-PCR and Western blot analysis. Interestingly, mRNA levels of CYP27B1 (the gene coding for 1alpha-hydroxylase enzyme which catalyses the conversion of 1alpha,25-dihydroxyvitamin D, 1alpha,25[OH]2D, from its inactive form, 25-hydroxycholecalciferol, 25[OH]D) and CYP24A (the gene coding for 24-hydroxylase, a target gene of 1alpha,25[OH]2D) were significantly increased by twofold and 34-fold, respectively, in differentiated osteoblasts compared with proliferating cells. We next examined if the local production of 1alpha,25(OH)2D might contribute to the FGF23 upregulation. We cultured osteoblasts in serum-free medium with or without 25-(OH)D (the substrate of 1alpha-hydroxylase). FGF23 mRNA levels were increased in proliferating cells (16-fold) and in differentiated cells (28-fold) by the physiological dose of 25-(OH)D3 treatment. CYP27B1 was slightly but significantly upregulated and CYP24A was increased by 1,700-fold and 800-fold, respectively, in transcriptional levels. Because FGF23 was upregulated in confluent osteoblasts regardless of the presence or absence of 25-(OH)D in serum-free medium, we further examined the possible impact of cell communication on FGF23 expression. We treated osteoblasts with carbenoxolone, a gap junction Cx43 blocker in serum-free medium. The FGF23 mRNA level was reduced by 50% in confluent differentiated cells and slightly but not significantly reduced in half-confluent cells by carbenoxolone treatments. The results suggested that upregulation of FGF23 in differentiated osteoblast appeared to be due to increased autocrine/paracrine action of osteoblast-derived 1alpha,25(OH)2D and increased cell communication, which were identified in cultured rat calvaria osteoblasts. These results indicate that FGF23 expression was stimulated not only by circulating calcitriol but also by locally produced 1alpha,25(OH)2D. The local mechanisms of FGF23 expression remain to be characterized.

Modulation of isoflavones on bone-nodule formation in rat calvaria osteoblasts in vitro

OBJECTIVE

To observe the effects of two main isoflavones, daidzein and genistein on the bone-nodule formation in rat calvaria osteoblasts in vitro.

METHODS

Osteoblasts obtained from newborn Sprague-dawley rat calvaria were cultured for several generations. The second generation cells were cultured in Minimum Essential Medium supplemented with ascorbic acid and Na-beta-glycerophosphate for several days, in the presence of daidzein and genistein, with or without the estrogen receptor antagonist ICI 182780. Number of nodules was counted at the end of the incubation period (day 20) by staining with Alizarin Red S calcium stain. The release of osteocalcin, as a marker of osteoblast activity, was also determined on day 7 and day 12 during the incubation period.

RESULTS

Compared with the control, the numbers of nodules were both increased by incubation with daidzein and genistein. 17 beta-estradiol was used as a positive control and proved to be a more effective inducer of the increase in bone-nodules formation that daidzein and genistein. The release of osteocalcin into culture media was also increased in the presence of daidzein and genistein, as well as 17 beta-estradiol on day 7 and day 12 (day 12 were higher). The estrogen receptor antagonist ICI 182780 completely blocked the genistein- and 17 beta-estradiol-induced increase of nodule numbers and osteocalcin release in osteoblasts. However, the effects induced by daidzein could not be inhibited by ICI 182780.

CONCLUSION

These findings suggest that geinistein can stimulate bone-nodule formation and increase the release of osteocalcin in rat osteoblasts. The effects, like those induced by 17 beta-estradiol, are mediated by the estrogen receptor dependent pathway. Daidzein also can stimulate bone-nodule formation and increase the release of osteocalcin in rat osteoblasts, but it is not, at least not merely, mediated by the estrogen receptor dependent pathway.