Safety of intracerebroventricular copper histidine in adult rats.
Classical Menkes disease is an X-linked recessive neurodegenerative disorder caused by mutations in a P-type ATPase (ATP7A) that normally delivers copper to the developing central nervous system. Infants with large deletions, or other mutations in ATP7A that incapacitate copper transport to the brain, show poor clinical outcomes and subnormal brain copper despite early subcutaneous copper histidine (CuHis) injections. These findings suggest a need for direct central nervous system approaches in such patients. To begin to evaluate an aggressive but potentially useful new strategy for metabolic improvement of this disorder, we studied the acute and chronic effects of CuHis administered by intracerebroventricular (ICV) injection in healthy adult rats. Magnetic resonance imaging (MRI) after ICV CuHis showed diffuse T(1)-signal enhancement, indicating wide brain distribution of copper after ICV administration, and implying the utility of this paramagnetic metal as a MRI contrast agent. The maximum tolerated dose (MTD) of CuHis, defined as the highest dose that did not induce overt toxicity, growth retardation, or reduce lifespan, was 0.5mcg. Animals receiving multiple infusions of this MTD showed increased brain copper concentrations, but no significant differences in activity, behavior, and somatic growth, or brain histology compared to saline-injected controls. Based on estimates of the brain copper deficit in Menkes disease patients, CuHis doses 10-fold lower than the MTD found in this study may restore proper brain copper concentration. Our results suggest that ICV CuHis administration have potential as a novel treatment approach in Menkes disease infants with severe mutations. Future trials of direct CNS copper administration in mouse models of Menkes disease will be informative.
Lem
Kristen E
KE
Unit on Pediatric Genetics, Laboratory of Clinical Genomics, National Institute of Child Health and Human Development, Bethesda, MD, USA.
Brinster
Lauren R
LR
Tjurmina
Olga
O
Lizak
Martin
M
Lal
Simina
S
Centeno
Jose A
JA
Liu
Po-Ching
PC
Godwin
Sarah C
SC
Kaler
Stephen G
SG
D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000473:pathology; D001929:Brain Edema / Q000139:chemically induced / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D006639:Histidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000633:toxicity; D007276:Injections, Intraventricular; D008279:Magnetic Resonance Imaging; D008297:Male; D020714:Maximum Tolerated Dose; D007706:Menkes Kinky Hair Syndrome / Q000188:drug therapy; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000633:toxicity*; D011859:Radiography; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D009942:Organometallic Compounds; D006639:Histidine; C098468:copper histidine