Renal Tubular CD24 Upregulation Aggravates Folic Acid Induced Acute Kidney Injury: A Possible Role for T Regulatory Cells Inhibition in Mice.

Acute kidney injury (AKI) is characterized by cell death and inflammation. CD24 is a protein induced during tissue damage and is not expressed in mature renal tissue. We explored the role of CD24 in the pathogenesis of folic acid-induced AKI (FA-AKI) in mice. A single Intraperitoneal (IP) injection of folic acid induced AKI in WT and CD24-/- mice. Renal function tests, histological analysis, immunohistochemistry, Western blot analysis, and ELISA were performed to assess the severity of renal damage and the intensity of the inflammatory response. FA-AKI induced CD24 in the distal tubular epithelial cells. Compared to WT mice, FA-AKI CD24-/- mice exhibited an attenuated reduction in renal function and histological injury, lower serum IL-10 and interferon γ, and decreased expression of renal TNFα. In contrast, renal and systemic IL-33 upregulation were augmented. CD24-/- FA-AKI animals exhibited increased splenic margination and renal infiltration of regulatory T cells (Tregs). At day 7, FA-AKI CD24-/- mice exhibited increased expression of tubular pro-apoptotic and decreased anti-apoptotic proteins compared to WT animals. Anti-CD24 antibody administration to FA-AKI mice attenuated the decrease in renal function as well as the histological injury. Renal biopsies from patients with ATN stained strongly for CD24 in the distal tubules. In conclusion, during AKI, upregulation of CD24 promotes renal inflammation through inhibition of Treg infiltration and diversion of cell death towards necrosis rather than apoptosis. Neutralization of CD24 may prove a target for future therapies in AKI.

Topical tretinoin treatment for burning mouth syndrome: a pilot study.

OBJECTIVES: Burning mouth syndrome is an intraoral chronic pain condition characterized by a moderate to severe sensation of burning from the oral mucosa. No clinical signs are found and there is no efficient treatment. METHOD AND MATERIALS: This pilot study included 10 women that were resistant to other previous treatments or noncompliant to systemic medications. Patients were asked to apply tretinoin gel 0.05% on their tongues twice daily for 14 days. Treatment effectiveness was assessed by completing a pre-study psychologic questionnaire and recording a daily wellbeing and pain log. RESULTS: Significant pain-score decrease in 50% of the patients (delta numerical rating score -3.15 ± 3.02, P value = .005) was recorded. This finding was in concordance with the verbal statements including major quality-of-life improvement (P value = .05), without any treatment positive or negative predictive factors. CONCLUSIONS: Topical tretinoin exhibits potential efficacy in patients with treatment resistant burning mouth syndrome and may also be used as a primary treatment modality.