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Substrate reduction augments the efficacy of enzyme therapy in a mouse model of Fabry disease.

Marshall J, Ashe KM, Bangari D, McEachern K, Chuang WL, Pacheco J, Copeland DP, Desnick RJ, Shayman JA, Scheule RK, Cheng SH - PLoS ONE (2010)

Bottom Line: Use of glucosylceramide synthase inhibitors to abate the biosynthesis of glycosphingolipids (substrate reduction therapy, SRT) has been shown to be effective at reducing substrate levels in the related glycosphingolipidosis, Gaucher disease.Relative efficacy of SRT and ERT at reducing GL-3 levels in Fabry mouse tissues differed with SRT being more effective in the kidney, and ERT more efficacious in the heart and liver.Furthermore, treatment normalized urine volume and uromodulin levels and significantly delayed the loss of a nociceptive response.

View Article: PubMed Central - PubMed

Affiliation: Applied Discovery Research, Genzyme Corporation, Framingham, Massachusetts, USA. john.marshall@genzyme.com

ABSTRACT
Fabry disease is an X-linked glycosphingolipid storage disorder caused by a deficiency in the activity of the lysosomal hydrolase α-galactosidase A (α-gal). This deficiency results in accumulation of the glycosphingolipid globotriaosylceramide (GL-3) in lysosomes. Endothelial cell storage of GL-3 frequently leads to kidney dysfunction, cardiac and cerebrovascular disease. The current treatment for Fabry disease is through infusions of recombinant α-gal (enzyme-replacement therapy; ERT). Although ERT can markedly reduce the lysosomal burden of GL-3 in endothelial cells, variability is seen in the clearance from several other cell types. This suggests that alternative and adjuvant therapies may be desirable. Use of glucosylceramide synthase inhibitors to abate the biosynthesis of glycosphingolipids (substrate reduction therapy, SRT) has been shown to be effective at reducing substrate levels in the related glycosphingolipidosis, Gaucher disease. Here, we show that such an inhibitor (eliglustat tartrate, Genz-112638) was effective at lowering GL-3 accumulation in a mouse model of Fabry disease. Relative efficacy of SRT and ERT at reducing GL-3 levels in Fabry mouse tissues differed with SRT being more effective in the kidney, and ERT more efficacious in the heart and liver. Combination therapy with ERT and SRT provided the most complete clearance of GL-3 from all the tissues. Furthermore, treatment normalized urine volume and uromodulin levels and significantly delayed the loss of a nociceptive response. The differential efficacies of SRT and ERT in the different tissues indicate that the combination approach is both additive and complementary suggesting the possibility of an improved therapeutic paradigm in the management of Fabry disease.

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Substrate reduction therapy delays the onset of heat-insensitivity in Fabry mice.Treated Fabry mice received eliglustat tartrate as a component of their food beginning at 5 weeks of age. Mice were placed on a 55°C hot-plate and the time for them to respond (latency) recorded. Latency was measured every two months from 3-months of age for untreated control Fabry (•), eliglustat tartrate treated Fabry (□), and wild-type mice (▴). Statistics compare the treated to the untreated Fabry mice. Data are shown as mean ± SEM (n = 15 mice/time point). Statistics were determined using the Graphpad Prism software t test (* = p<0.05; ** = p<0.01; *** = p<0.001).
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pone-0015033-g003: Substrate reduction therapy delays the onset of heat-insensitivity in Fabry mice.Treated Fabry mice received eliglustat tartrate as a component of their food beginning at 5 weeks of age. Mice were placed on a 55°C hot-plate and the time for them to respond (latency) recorded. Latency was measured every two months from 3-months of age for untreated control Fabry (•), eliglustat tartrate treated Fabry (□), and wild-type mice (▴). Statistics compare the treated to the untreated Fabry mice. Data are shown as mean ± SEM (n = 15 mice/time point). Statistics were determined using the Graphpad Prism software t test (* = p<0.05; ** = p<0.01; *** = p<0.001).

Mentions: Fabry disease is characterized by small fiber dysfunction in both male and female patients that results in increased thresholds for both heat and cold stimuli [28]–[31]. Consistent with this small fiber neuropathy, Fabry mice also develop a demonstrable deficit in their ability to respond to a heat stimulus [22], [23]. Potential therapeutics can be evaluated in this model for their effects on a nociceptive response to a heat stimulus by measuring the time taken by the mouse to react (latency) after being placed on a 55°C hot-plate. Figure 3 shows that there was no difference in latency between treated and untreated Fabry mice at 3 months of age, although both groups reacted more slowly to heat than the wild-type mice at this initial time point. Wild-type mice showed no change in latency throughout the study. However, consistent with our earlier report [23], untreated Fabry mice developed a progressive thermal hypoalgesia beginning at 5 months of age. An equivalent deficit was not observed in the eliglustat tartrate-treated Fabry mice until 7 months of age. This two-month delay in the progression of loss of heat-sensitivity between the treated and untreated Fabry mice was consistent and significant throughout the course of the study. Collectively, these results in the Fabry mouse suggest that SRT with eliglustat tartrate can provide benefit by delaying GL-3 accumulation and its attendant (renal and neurologic) symptoms. Because the Fabry mouse is for α-gal, we reasoned that stabilization or actual reduction of the GL-3 burden would be more likely if recombinant α-gal were included in the treatment regime. To evaluate this possibility, we chose to use the Fabry-Rag model (these mice do not develop mature B or T cells), thereby eliminating any humoral immune response to α-gal epitopes that might complicate interpretation of the experimental results.


Substrate reduction augments the efficacy of enzyme therapy in a mouse model of Fabry disease.

Marshall J, Ashe KM, Bangari D, McEachern K, Chuang WL, Pacheco J, Copeland DP, Desnick RJ, Shayman JA, Scheule RK, Cheng SH - PLoS ONE (2010)

Substrate reduction therapy delays the onset of heat-insensitivity in Fabry mice.Treated Fabry mice received eliglustat tartrate as a component of their food beginning at 5 weeks of age. Mice were placed on a 55°C hot-plate and the time for them to respond (latency) recorded. Latency was measured every two months from 3-months of age for untreated control Fabry (•), eliglustat tartrate treated Fabry (□), and wild-type mice (▴). Statistics compare the treated to the untreated Fabry mice. Data are shown as mean ± SEM (n = 15 mice/time point). Statistics were determined using the Graphpad Prism software t test (* = p<0.05; ** = p<0.01; *** = p<0.001).
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2991350&req=5

pone-0015033-g003: Substrate reduction therapy delays the onset of heat-insensitivity in Fabry mice.Treated Fabry mice received eliglustat tartrate as a component of their food beginning at 5 weeks of age. Mice were placed on a 55°C hot-plate and the time for them to respond (latency) recorded. Latency was measured every two months from 3-months of age for untreated control Fabry (•), eliglustat tartrate treated Fabry (□), and wild-type mice (▴). Statistics compare the treated to the untreated Fabry mice. Data are shown as mean ± SEM (n = 15 mice/time point). Statistics were determined using the Graphpad Prism software t test (* = p<0.05; ** = p<0.01; *** = p<0.001).
Mentions: Fabry disease is characterized by small fiber dysfunction in both male and female patients that results in increased thresholds for both heat and cold stimuli [28]–[31]. Consistent with this small fiber neuropathy, Fabry mice also develop a demonstrable deficit in their ability to respond to a heat stimulus [22], [23]. Potential therapeutics can be evaluated in this model for their effects on a nociceptive response to a heat stimulus by measuring the time taken by the mouse to react (latency) after being placed on a 55°C hot-plate. Figure 3 shows that there was no difference in latency between treated and untreated Fabry mice at 3 months of age, although both groups reacted more slowly to heat than the wild-type mice at this initial time point. Wild-type mice showed no change in latency throughout the study. However, consistent with our earlier report [23], untreated Fabry mice developed a progressive thermal hypoalgesia beginning at 5 months of age. An equivalent deficit was not observed in the eliglustat tartrate-treated Fabry mice until 7 months of age. This two-month delay in the progression of loss of heat-sensitivity between the treated and untreated Fabry mice was consistent and significant throughout the course of the study. Collectively, these results in the Fabry mouse suggest that SRT with eliglustat tartrate can provide benefit by delaying GL-3 accumulation and its attendant (renal and neurologic) symptoms. Because the Fabry mouse is for α-gal, we reasoned that stabilization or actual reduction of the GL-3 burden would be more likely if recombinant α-gal were included in the treatment regime. To evaluate this possibility, we chose to use the Fabry-Rag model (these mice do not develop mature B or T cells), thereby eliminating any humoral immune response to α-gal epitopes that might complicate interpretation of the experimental results.

Bottom Line: Use of glucosylceramide synthase inhibitors to abate the biosynthesis of glycosphingolipids (substrate reduction therapy, SRT) has been shown to be effective at reducing substrate levels in the related glycosphingolipidosis, Gaucher disease.Relative efficacy of SRT and ERT at reducing GL-3 levels in Fabry mouse tissues differed with SRT being more effective in the kidney, and ERT more efficacious in the heart and liver.Furthermore, treatment normalized urine volume and uromodulin levels and significantly delayed the loss of a nociceptive response.

View Article: PubMed Central - PubMed

Affiliation: Applied Discovery Research, Genzyme Corporation, Framingham, Massachusetts, USA. john.marshall@genzyme.com

ABSTRACT
Fabry disease is an X-linked glycosphingolipid storage disorder caused by a deficiency in the activity of the lysosomal hydrolase α-galactosidase A (α-gal). This deficiency results in accumulation of the glycosphingolipid globotriaosylceramide (GL-3) in lysosomes. Endothelial cell storage of GL-3 frequently leads to kidney dysfunction, cardiac and cerebrovascular disease. The current treatment for Fabry disease is through infusions of recombinant α-gal (enzyme-replacement therapy; ERT). Although ERT can markedly reduce the lysosomal burden of GL-3 in endothelial cells, variability is seen in the clearance from several other cell types. This suggests that alternative and adjuvant therapies may be desirable. Use of glucosylceramide synthase inhibitors to abate the biosynthesis of glycosphingolipids (substrate reduction therapy, SRT) has been shown to be effective at reducing substrate levels in the related glycosphingolipidosis, Gaucher disease. Here, we show that such an inhibitor (eliglustat tartrate, Genz-112638) was effective at lowering GL-3 accumulation in a mouse model of Fabry disease. Relative efficacy of SRT and ERT at reducing GL-3 levels in Fabry mouse tissues differed with SRT being more effective in the kidney, and ERT more efficacious in the heart and liver. Combination therapy with ERT and SRT provided the most complete clearance of GL-3 from all the tissues. Furthermore, treatment normalized urine volume and uromodulin levels and significantly delayed the loss of a nociceptive response. The differential efficacies of SRT and ERT in the different tissues indicate that the combination approach is both additive and complementary suggesting the possibility of an improved therapeutic paradigm in the management of Fabry disease.

Show MeSH
Related in: MedlinePlus