The expression mechanism of programmed cell death 1 ligand 1 and its role in immunomodulatory ability of mesenchymal stem cells.

Programmed cell death 1 ligand 1 (PD-L1) is an important immunosuppressive molecule, which inhibits the function of T cells and other immune cells by binding to the receptor programmed cell death-1. The PD-L1 expression disorder plays an important role in the occurrence, development, and treatment of sepsis or other inflammatory diseases, and has become an important target for the treatment of these diseases. Mesenchymal stem cells (MSCs) are a kind of pluripotent stem cells with multiple differentiation potential. In recent years, MSCs have been found to have a strong immunosuppressive ability and are used to treat various inflammatory insults caused by hyperimmune diseases. Moreover, PD-L1 is deeply involved in the immunosuppressive events of MSCs and plays an important role in the treatment of various diseases. In this review, we will summarize the main regulatory mechanism of PD-L1 expression, and discuss various biological functions of PD-L1 in the immune regulation of MSCs.

Semiquantitative assessment of 99mTc-MIBI uptake in parathyroids of secondary hyperparathyroidism patients with chronic renal failure.

Objective: To explore the valuably influential factors and improve the diagnostic accuracy and efficiency of 99mTc-methoxyisobutylisonitrile (MIBI) uptake in parathyroids of secondary hyperparathyroidism (SHPT) patients with chronic renal failure (CRF). Methods: The correlation analysis was performed between clinical indices related to CRF and 99mTc-MIBI uptake intensity TBR (the gray value mean ratio between the parathyroid target and the bilateral neck background, semiquantitatively calculated with ImageJ software). All clinical indices and TBRs were compared by a three- or two-level grouping method of MIBI uptake, which was visually qualitatively assessed. The three-level grouping method comprised slight, medium, and high groups with little, faint, and distinct MIBI concentration in parathyroids, respectively. The two-level grouping method comprised insignificant and significant groups with TBR greater than or less than 0.49-0.71, respectively. Results: MIBI uptake was significantly positively related to patient age, CRF course, hemodialysis vintage, serum parathyroid hormone (PTH), and alkaline phosphatase (AKP) but was significantly negatively related to serum uric acid (UA). MIBI washout was significantly positively related to patient age but was significantly negatively related to serum phosphorus (P) and calcium (Ca) × P. Oral administration of calcitriol and calcium could significantly reduce the MIBI uptake. MIBI uptake tendency might alter. Such seven indices, namely the MIBI uptake, CRF course, hemodialysis vintage, serum AKP, calcium, cysteine proteinase inhibitor C, and PTH, were comparable between the slight and medium groups but were significantly different between the slight and high groups or between the medium and high groups. The above seven indices plus blood urea nitrogen/creatinine were all significantly different between the insignificant and significant groups. All above significances were with P < 0.05. Conclusions: Patient age, CRF course, hemodialysis vintage, serum PTH, AKP, UA, phosphorus, Ca × P, oral administration of calcitriol and calcium, and parathyroids themselves can significantly influence MIBI uptake in parathyroids of SHPT patients with CRF. The two-level grouping method of MIBI intensity should be adopted to qualitatively diagnose the MIBI uptake.