Alzheimer’s disease (AD) is characterized by amyloid-beta (Aβ) accumulation and cognitive mental decline. Epidemiological studies have suggested an association between low serum vitamin D levels and an increased risk of AD. Vitamin D regulates gene expression via the vitamin D receptor, a nuclear ligand-dependent transcription factor. However, the molecular mechanism underlying the pathogenic and therapeutic effects of vitamin D on AD is not fully understood yet. To better understand how vitamin D regulates the expression of genes related to AD pathology, first, we induced vitamin D deficiency in 5xFAD mice by providing a vitamin-D-deficient diet and observed the changes in the mRNA level of genes related to Aβ processing, which resulted in an increase in the Aβ load in the brain. The vitamin D-deficient diet also suppressed the expression of genes for microglial Aβ phagocytosis. Interestingly, vitamin D deficiency in the early stage of AD resulted in earlier memory impairment. In addition, we administered vitamin D intraperitoneally to 5xFAD mice with a normal diet and found lower Aβ levels with the suppressed expression of genes for Aβ generation and observed improved memory function, which may be potentially associated with reduced MAO-B expression. These findings strongly suggest the role of vitamin D as a crucial disease-modifying factor that may modulate the amyloid pathology with regard to reducing AD symptoms.

Objective: This study identified the effects of Korean medicine treatment on a patient with metabolic dysfunction-associated fatty liver disease (MAFLD).Methods: A 43-year-old man with MAFLD was treated with <i>Saenggangunbi-tang</i> with regular exercise from August 13, 2022, to December 24, 2022, to reduce fatigue and dyspepsia and to improve laboratory findings, such as liver enzymes and lipid profiles. We observed changes in symptoms and laboratory findings during the approximately four-month treatment.Results: Treatment with <i>Saenggangunbi-tang</i> resulted in decreased serum levels of liver enzymes, triglycerides, hepatic steatosis index scores, and clinical symptoms. During the treatment, the patient performed regular exercise; however, there was no significant change in body weight until the end of the study.Conclusion: This study suggests the availability of <i>Saenggangunbi-tang</i> as a therapeutic option for managing MAFLD patients.