Ustekinumab Use in Pediatric Inflammatory Bowel Disease: A French Multicenter Study From the Pediatric GETAID.

OBJECTIVES: Ustekinumab is known to be efficient in adult patients suffering from moderate to severe Crohn disease (CD) and ulcerative colitis (UC) resistant to anti-tumor necrosis factor-alpha (TNF-α). Here, we described the clinical course of treatment with ustekinumab in French pediatric inflammatory bowel disease (IBD) patients treated with ustekinumab. METHODS: This study includes all pediatric patients treated by ustekinumab injection for IBD (CD and UC), between January 2016 and December 2019. RESULTS: Fifty-three patients were enrolled, 15 males and 38 females. Forty-eight patients (90%) had a diagnosis of CD and 5 (9.4%) had UC. Sixty-five percent of CD patients presented an ileocolitis. Perineal disease was observed in 20 out of 48 CD patients (41.7%), among them 9 were treated surgically. All patients included were resistant to anti-TNF-α treatment. Fifty-one percent had presented side effects linked to anti-TNF-α, including psoriasis and anaphylactic reaction. The average Pediatric Crohn Disease Activity Index (PCDAI) at induction was 28.7 (5-85), 18.7 (0-75) at 3 months of treatment and 10 (0-35) at the last follow-up. The average Pediatric Ulcerative Colitis Activity Index at induction was 47 (25-65), 25 (15-40) at 3 months of treatment and 18.3 (0-35) at the last follow-up. No severe side effects were observed. CONCLUSION: In this retrospective, multicentral study, ustekinumab proved to be efficient in pediatric patients resistant to anti-TNF-α. PCDAI has been significantly improved in patients with severe disease, treated with ustekinumab.

Plasmalogens Regulate Retinal Connexin 43 Expression and Müller Glial Cells Gap Junction Intercellular Communication and Migration.

Plasmalogens are a specific glycerophospholipid subtype characterized by a vinyl-ether bound at their sn-1 moiety. Their biosynthesis is initiated in the peroxisome by dihydroxyacetone phosphate-acyltransferase (DHAPAT), which is encoded by the DAPAT gene. Previous studies have shown that plasmalogen-deficient mice exhibit major physiological dysfunctions including several eye defects, among which abnormal vascular development of the retina and a reactive activation of macroglial Müller cells. Interestingly, plasmalogen deficiency in mice is also associated with a reduced expression of brain connexin 43 (Cx43). Cx43 is the main connexin subtype of retinal glial cells and is involved in several cellular mechanisms such as calcium-based gap junction intercellular communication (GJIC) or cell migration. Thus, the aim of our work was 1) to confirm the alteration of Cx43 expression in the retina of plasmalogen-deficient DAPAT-/- mice and 2) to investigate whether plasmalogens are involved in crucial functions of Müller cells such as GJIC and cell migration. First, we found that plasmalogen deficiency was associated with a significant reduction of Cx43 expression in the retina of DAPAT-/- mice in vivo. Secondly, using a siRNA targeting DHAPAT in vitro, we found that a 50%-reduction of Müller cells content in plasmalogens was sufficient to significantly downregulate Cx43 expression, while increasing its phosphorylation. Furthermore, plasmalogen-depleted Müller cells exhibited several alterations in ATP-induced GJIC, such as calcium waves of higher amplitude that propagated slower to neighboring cells, including astrocytes. Finally, in vitro plasmalogen depletion was also associated with a significant downregulation of Müller cells migration. Taken together, these data confirm that plasmalogens are critical for the regulation of Cx43 expression and for characteristics of retinal Müller glial cells such as GJIC and cell migration.