Cardiotoxicity of Anti-PD-L1 Antibody and the Effect of Levothyroxine in Attenuating the Related Mortality in Mice

Background and objective Immune checkpoint inhibitors (ICIs) such as antibodies against programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PD-L1), have shown remarkable efficacies in many subtypes of cancers. However, ICIs may also cause severe immune-related adverse events in the recipient patients. Recently, ICI-associated myocarditis have been reported in hundreds of patients worldwide, with a mortality rate of approximately 50% in these cases. This study aims to recapitulate the cardiotoxicity and explore the detoxicifying approaches to attenuate mortality caused by PD-1/PD-L1 inhibitors in healthy mice. Methods Six to eight-week-old C57BL/6 mice were inoculated with anti-PD-1 antibody (12.5 μg/g every 5 days for 6 injections), anti-PD-L1 antibody (10 μg/g once a week for 6 weeks), anti-PD-L1 antibody (with the same dosage described above) in combination with levothyroxine (0.25 μg/g, intraperitoneally injected half an hour before anti-PD-L1 antibody injection), or isotype control immunoglobulin IgG (10 μg/g once a week for 6 weeks). The ejection function of the hearts was detected by echocardiography, body temperature and blood pressure were detected by Mouse MonitorTM and non-invassive blood pressure minotor, and serum free thyroxine concentration was detected by The enzyme linked immunosorbent assay (ELISA). Results PD-L1 was expressed at different levels by the cardiomyocytes of the mice. The isotype control immunoglobulin and anti-PD-1 antibody did not cause death of the mice. The 12 mice receiving 3-6 injections of anti-PD-L1 antibody showed a significant increase in the heart-to-tibial ratio and cardiomyoctye degeneration, hyalinization and extravascular inflammatory cell infiltration. In addition, the serum thyroxine was mardedly decreased to 1/3 of that in the control group mice, and the blood pressure and body temperature were abnormally decreased in mice upon treatment with PD-L1 blockade. Eight of the 12 (66.7%) mice died from multiple intravenous injection of anti-PD-L1 antibody.Intraperitoneal injection of levothyroxine 30 min before the injection of anti-PD-L1 antibody significantly attenuated the mortality rate of the anti-PD-L1 antibody-treated mice. Conclusion The anti-PD-L1 antibody is cardiotoxic and lethal, and levothyroxine is able to rescue the mice from this immune checkpoint inhibitor-caused mortality

miR-193a as a potential mediator of WT-1/synaptopodin in the renoprotective effect of losartan on diabetic kidney

Diabetic nephropathy (DN) is the most common complication of diabetic patients, and has become a global healthcare problem. In this study, we used diabetic mice to evaluate the effect of Losartan on diabetic nephropathy, in which the experimental animals were divided into three groups: non-diabetic mice (db/m group), untreated-diabetic mice (db/db group), and Losartan-treated diabetic mice (db/db-losartan). Next, immunohistochemistry and immunofluorescence were used to detect WT-1 and synaptopodin expression, respectively. Protein levels of WT-1, synaptopodin, claudin1, and Pax-2 were assessed by Western blotting and real-time PCR. The miR-193a mRNA levels were quantitated by real-time PCR. The results showed that albuminuria was increased in diabetic mice compared with control animals and was significantly ameliorated by treatment with Losartan. In addition, Losartan significantly upregulated the immunopositive cell numbers of WT-1, the expression of WT-1 and synaptopodin in renal tissue. By contrast, expression of claudin1 and Pax-2 in renal tissue were decreased in db/db-losartan group. Besides, expression of miR-193a was decreased significantly in db/db-losartan group compared to the untreated diabetic group. Thus, Losartan has renoprotective effects on the control of tissue damage possibly by inhibiting the expression of miR-193a, thereby promoting the repair of podocyte injury in mice with diabetic nephropathy.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author