title: Can L-Cysteine and Vitamin D Rescue Vitamin D and Vitamin D Binding Protein Levels in Blood Plasma of African American Type 2 Diabetic Patients?
abstract: OBJECTIVE
  Vitamin D (VD) deficiency has become a worldwide epidemic, particularly affecting African Americans (AA). VD deficiency has been implicated in the excessive rate of complications associated with diabetes in AA. Blood levels of VD binding protein (VDBP) and glutathione (GSH) are lower in AA compared with those in Caucasians. This study tested the hypothesis that lower GSH levels are linked to VDBP and VD deficiency in AA-type 2 diabetic (AA-T2D) patients. Blood was analyzed from T2D and nondiabetic subjects (N). Experiments examining GSH deficiency and l-cysteine (LC) supplementation were performed using THP-1 monocytes.
  
  
  RESULTS
  Plasma levels of LC, GSH, VDBP, and VD were significantly lower in AA-T2D compared with age-matched AA-N or Caucasian-T2D. Lower levels of LC and GSH showed a significant positive correlation with lower VDBP and VD levels in AA-T2D. GSH deficiency investigated using an antisense approach depleted VDBP/vitamin D receptor (VDR); LC supplementation caused significant upregulation of GSH and of VDBP/VDR, while supplementation with VD+LC caused a significantly greater GSH and VDBP/VDR upregulation compared with that of VD alone in monocytes.
  
  
  CONCLUSIONS
  The reported observations suggest that VD deficiency may be linked to GSH and LC status and lead to a novel hypothesis that supplementation with LC in combination with VD will be effective in increasing VD levels and reducing health disparities in AA.
authors: Departments of Pediatrics and Medicine, Louisiana State University Health Sciences Center , Shreveport, Louisiana.
authors: Sushil K
authors: SK
authors: Jain
authors: Departments of Pediatrics and Medicine, Louisiana State University Health Sciences Center , Shreveport, Louisiana.
authors: Gunjan
authors: G
authors: Kahlon
authors: Departments of Pediatrics and Medicine, Louisiana State University Health Sciences Center , Shreveport, Louisiana.
authors: Pat
authors: P
authors: Bass
authors: Departments of Pediatrics and Medicine, Louisiana State University Health Sciences Center , Shreveport, Louisiana.
authors: Steven N
authors: SN
authors: Levine
authors: Departments of Pediatrics and Medicine, Louisiana State University Health Sciences Center , Shreveport, Louisiana.
authors: Cassandra
authors: C
authors: Warden
mesh_terms: D000328:Adult; D001741:Black or African American; D003545:Cysteine / Q000627:therapeutic use*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy* / Q000453:epidemiology / Q000503:physiopathology; D005978:Glutathione / Q000172:deficiency; D006801:Humans; D008875:Middle Aged; D014807:Vitamin D / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000188:drug therapy; D014809:Vitamin D-Binding Protein / Q000097:blood*
chemical_list: D014809:Vitamin D-Binding Protein; D014807:Vitamin D; D005978:Glutathione; D003545:Cysteine