1
|
Balakrishnan B, Yan X, McCue MD, Bellagamba O, Guo A, Winkler F, Thall J, Crawford L, Dimen R, Chen S, McEnaney S, Wu Y, Zimmer M, Sarkis J, Martini PG, Finn PF, Lai K. Whole-body galactose oxidation as a robust functional assay to assess the efficacy of gene-based therapies in a mouse model of Galactosemia. Mol Ther Methods Clin Dev 2024; 32:101191. [PMID: 38352271 PMCID: PMC10863324 DOI: 10.1016/j.omtm.2024.101191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 01/12/2024] [Indexed: 02/16/2024]
Abstract
Despite the implementation of lifesaving newborn screening programs and a galactose-restricted diet, many patients with classic galactosemia develop long-term debilitating neurological deficits and primary ovarian insufficiency. Previously, we showed that the administration of human GALT mRNA predominantly expressed in the GalT gene-trapped mouse liver augmented the expression of hepatic GALT activity, which decreased not only galactose-1 phosphate (gal-1P) in the liver but also peripheral tissues. Since each peripheral tissue requires distinct methods to examine the biomarker and/or GALT effect, this highlights the necessity for alternative strategies to evaluate the overall impact of therapies. In this study, we established that whole-body galactose oxidation (WBGO) as a robust, noninvasive, and specific method to assess the in vivo pharmacokinetic and pharmacodynamic parameters of two experimental gene-based therapies that aimed to restore GALT activity in a mouse model of galactosemia. Although our results illustrated the long-lasting efficacy of AAVrh10-mediated GALT gene transfer, we found that GALT mRNA therapy that targets the liver predominantly is sufficient to sustain WBGO. The latter could have important implications in the design of novel targeted therapy to ensure optimal efficacy and safety.
Collapse
Affiliation(s)
- Bijina Balakrishnan
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
| | | | | | - Olivia Bellagamba
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
| | - Aaron Guo
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
| | | | | | | | | | | | | | - Yiman Wu
- Moderna, Cambridge, MA 02139, USA
| | | | | | | | | | - Kent Lai
- Division of Medical Genetics, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
| |
Collapse
|
2
|
Asano T, Saito Y, Kawakami M, Yamada N. Fidarestat (SNK-860), a potent aldose reductase inhibitor, normalizes the elevated sorbitol accumulation in erythrocytes of diabetic patients. J Diabetes Complications 2002; 16:133-8. [PMID: 12039395 DOI: 10.1016/s1056-8727(01)00175-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Sorbitol accumulation in nerves has been regarded as one of the major causes of diabetic neuropathy. In this study, fidarestat (SNK-860; 1 mg daily), a potent new aldose reductase inhibitor (ARI), or the commercially available ARI epalrestat (150 mg daily), was administered for 4 weeks to 58 Type 2 diabetic patients. Treatment with these drugs had no effect on glycemic control, judging from plasma glucose and HbA(1c) levels. However, fidarestat treatment normalized the elevated sorbitol content of erythrocytes under fasting as well as postprandial conditions. In contrast, the effect of epalrestat was minimal. There were no major side effects with fidarestat. Thus, fidarestat is considered to be a potent and promising ARI, possibly useful for both preventing and treating diabetic neuropathy. Further studies are needed to clarify how much the occurrence and progression of diabetic neuropathy are inhibited by normalizing sorbitol elevation with fidarestat treatment.
Collapse
Affiliation(s)
- Tomoichiro Asano
- Department of Internal Medicine, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113, Tokyo, Japan.
| | | | | | | |
Collapse
|
3
|
Berry GT, Wehrli S, Reynolds R, Palmieri M, Frangos M, Williamson JR, Segal S. Elevation of erythrocyte redox potential linked to galactonate biosynthesis: elimination by Tolrestat. Metabolism 1998; 47:1423-8. [PMID: 9826225 DOI: 10.1016/s0026-0495(98)90317-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Alternate pathways of galactose metabolism were explored in erythrocytes from normal subjects and patients with galactose-1-phosphate uridylyltransferase (GALT) deficiency incubated with galactose. Micromolar quantities of galactonate accumulated in both normal and mutant cells linearly with time up to 5 hours and with concentrations of galactose up to 25 mmol/L. Galactitol also was found at levels less than one third of the galactonate level, while galactose-1-phosphate concentrations comparable to those of galactonate were found in galactosemic cells. Concomitant with the formation of these galactose metabolites, the erythrocyte redox potential based on measurement of lactate and pyruvate increased fourfold in both cell types. This was due to a 60% to 72% decrease in pyruvate and a 24% to 26% increase in lactate. The oxidation of galactose to galactonate, which is known to generate NADH, is the most likely explanation for the increase in the redox state. The aldose reductase inhibitor (ARI), Tolrestat (Wyeth Ayerst Research, Princeton, NJ), at 70 micromol/L inhibited the formation of both galactonate and galactitol in both cell types without affecting galactose-1-phosphate, and eliminated the increase in the redox potential as indicated by restoration of pyruvate and lactate levels to the levels obtained before exposure of the cells to galactose. A functioning galactonate pathway is a route of galactose disposal in patients with GALT deficiency, but by altering the cellular redox potential, it may also contribute to galactose toxicity.
Collapse
Affiliation(s)
- G T Berry
- Department of Pediatrics, University of Pennsylvania School of Medicine, The Children's Hospital of Philadelphia, 19104, USA
| | | | | | | | | | | | | |
Collapse
|
4
|
Abstract
The clinical efficacy of an aldose reductase (AR) inhibitor in diabetic polyneuropathy depends on its bioavailability at the site(s) of AR in peripheral nerves. Accordingly, the link between the concentration of the AR inhibitor, tolrestat, and the extent of its inhibition of the AR-catalyzed polyol production was investigated in sciatic nerves of galactosemic rats. Tolrestat was administered by gavage (1 x 150 mg/kg, or 5, and 15 mg/kg/day for 15 days to attain steady state as estimated from the 53-h half-life of tolrestat determined in rat nerve); subsequently, at six time intervals, ranging from 4 to 59 days, rats were given access for 4 days to a 20% galactose diet, and killed. At every time point, the composite tolrestat concentration in the nerve correlated with the percentage decrease in nerve galactitol (r = 0.857, p = 0.0015). Because the latter should reflect the extent of nerve AR inhibition by tolrestat, the concentration of "free" tolrestat available at the site(s) of AR in the nerve was estimated from the tolrestat concentration/percent AR inhibition plot obtained in vitro. The estimated amount of tolrestat present at the site(s) of nerve AR represented 0.4% of the composite tolrestat concentration measured in the nerve. The results support the view that the effectiveness of an AR inhibitor in peripheral nerve depends on its pharmacokinetics in the nerve, i.e., on its uptake, nonspecific binding to cellular constituents, and elimination.
Collapse
Affiliation(s)
- D Dvornik
- Wyeth-Ayerst Research, Princeton, NJ 08543-8000
| | | | | | | |
Collapse
|
5
|
Abstract
Aldose reductase inhibitors impede flux of glucose through the sorbitol pathway in diabetes mellitus. They therefore reduce the accumulation of the pathway metabolites, sorbitol and fructose, reduce the impact of the flux on the cofactors used by the pathway and reduce other derived phenomena, such as osmotic stress and myo-inositol depletion. As drugs, their targets are the chronic complications of diabetes--neuropathy, retinopathy, nephropathy and vasculopathy. In experimental models there is proof of activity against biochemical, functional and structural defects in all of the involved tissues, but we await full clinical verification of this potential.
Collapse
Affiliation(s)
- D R Tomlinson
- Department of Pharmacology, Queen Mary and Westfield College, London, U.K
| | | | | |
Collapse
|