ABSTRACT
Patients with chronic kidney disease (CKD) sometimes experience gastrointestinal symptoms, such as nausea and vomiting. In addition, hypertension and CKD are closely linked, and sustained hypertension in children is associated with the progression of CKD, leading to early cardiomyopathy and premature atherosclerosis. These symptoms substantially affect the quality of daily life of CKD patients, and particularly in children with CKD, they may cause growth retardation. Therefore, establishing effective management methods to alleviate these symptoms is very important. Here, we report a case of a male patient who was born at 34 weeks of gestation weighing 1400 g. At birth, abdominal ultrasonography displayed left multicystic dysplastic kidney. From 6 months after birth, he was frequently hospitalized owing to refractory periodic vomiting. At 9 months old, he was diagnosed as having stage 3a CKD, and at 20 months old, he presented with stage 2 high blood pressure. In Japan, the uremic toxin adsorbent AST-120 and angiotensin-converting enzyme inhibitor-I (ACE-I) are not strongly recommended for CKD patients. However, after the patient underwent combination therapy of AST-120 and ACE-I, his frequent hospitalizations for refractory periodic vomiting ceased, and his blood pressure decreased. These results indicate that AST-120 and ACE-I are effective for refractory periodic vomiting and hypertension associated with CKD. The patient's height, weight, and mental development are catching up smoothly. The cause of the patient's refractory periodic vomiting remains unclear. However, his impaired kidney function owing to congenital anomalies of the kidney and urinary tract may have caused the refractory periodic vomiting and dehydration. The production of uremic toxins in CKD patients is thought to lead to the secretion of proinflammatory cytokines into the circulation. However, our patient had low serum levels of proinflammatory cytokines, and his serum levels of the chemokines CX3CL1 and CCL2 decreased with age, together with improvement in his clinical course. Therefore, some specific chemokines might be diagnostic and/or prognostic biomarkers of CKD.
ABSTRACT
OBJECTIVES: Some studies have reported that tacrolimus (FK506), an immunosuppressant, may have positive effects on bone formation. However, the precise effects of FK506 on bone repair or osteoblasts remain inadequately elucidated, and limited research has explored the outcomes of its use in an in vivo mouse model. This study aims to examine the effects of FK506 on bone repair and osteoblast functions using bone defect and BMP-2-induced ectopic ossification mouse models, as well as cultured primary mouse osteoblasts treated with FK506. METHODS: We established mouse models of femur bone defect and BMP-2-induced ectopic ossification to evaluate the effect of FK506 on new bone formation, respectively. Additionally, primary mouse osteoblasts were cultured with FK506 and examined for gene expressions related to osteoblast differentiation. RESULTS: While FK506 promoted the repair of bone defect areas in the femur of the bone defect mouse model, it also led to widespread abnormal bone formation outside the intended area. Additionally, following the implantation of a collagen sponge containing BMP-2 into mouse muscle tissue, FK506 was found to promote ectopic ossification and enhance BMP-2-induced osteoblast differentiation in vitro. Our findings also revealed that FK506 increased the number of immature osteoblasts in the absence of BMP-2 without affecting osteoblast differentiation. Furthermore, direct effects were observed, reducing the ability of osteoblasts to support osteoclastogenesis. CONCLUSIONS: These results indicate that FK506 increases new bone formation during bone repair and influences the proliferation of immature osteoblasts, as well as osteoblast-supported osteoclastogenesis.
Subject(s)
Bone Morphogenetic Protein 2 , Cell Differentiation , Disease Models, Animal , Femur , Osteoblasts , Osteogenesis , Tacrolimus , Animals , Tacrolimus/pharmacology , Mice , Osteogenesis/drug effects , Osteoblasts/drug effects , Osteoblasts/metabolism , Bone Morphogenetic Protein 2/metabolism , Bone Morphogenetic Protein 2/genetics , Cell Differentiation/drug effects , Femur/drug effects , Femur/pathology , Immunosuppressive Agents/pharmacology , Ossification, Heterotopic/pathology , Cells, CulturedABSTRACT
OBJECTIVES: Bone tissue in bony fish demonstrates a remarkable ability to regenerate, particularly evident following induction of extensive bone defects, such as fin amputation. This regenerative capacity has been reported to be promoted by the immunosuppressant FK506, yet its precise effects on bone cells during fin regeneration remains insufficiently elucidated. This study aims to investigate the effects of FK506 treatment on bone morphology, osteoblasts, and osteoclasts in the bony fin rays of osterix promoter-DsRed/TRAP promoter-EGFP double transgenic (Tg) medaka. METHODS: The caudal fin of double Tg medaka was amputated, followed by a 20-day treatment with FK506 (1.0 µg/ml) to observe its effects on fin regeneration. Additionally, the regenerated caudal fin area underwent evaluation using genetic analysis and cell proliferation assays. RESULTS: FK506 treatment significantly increased osterix-positive osteoblast formation, resulting in both a significantly longer fin length and fewer joints in the bony fin rays formed during fin regeneration. Notably, TRAP-positive osteoclast formation and bone resorption were observed to occur primarily during the latter stages of fin regeneration. Furthermore, while the expression levels of osteoblast-related genes in the regenerated area remained unchanged following FK506 treatment, a heightened cell proliferation was observed at the tip of the fin. CONCLUSIONS: Our findings suggest that treatment with FK506 promotes bone regeneration by increasing the number of osteoblasts in the amputated area of the fin. However, long-term treatment disrupts regular bone metabolism by inducing abnormal osteoclast formation.