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ARA 290, a peptide derived from the tertiary structure of erythropoietin, produces long-term relief of neuropathic pain coupled with suppression of the spinal microglia response.

Swartjes M, van Velzen M, Niesters M, Aarts L, Brines M, Dunne A, Cerami A, Dahan A - Mol Pain (2014)

Bottom Line: ARA290 exerted a dose-response effect by significantly reducing mechanical allodynia up to 20 weeks when compared to vehicle.The reduction of cold allodynia was significant up to 20 weeks for the doses 3, 10, 30 and 60 μg/kg when compared to vehicle.In group 1, significant microglia reactivity was observed in the L5 segment of the spinal cord of animals treated with vehicle when compared to sham operated, while animals treated with 10 or 30 μg/kg did not show a increase.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anesthesiology, Leiden University Medical Center, P5-Q, 2300 RC Leiden, The Netherlands. a.dahan@lumc.nl.

ABSTRACT

Background: Neuropathic pain is a difficult to treat disorder arising from central or peripheral nervous system lesions. The etiology of neuropathic pain consists of several overlapping pathways converging into an exaggerated pain state with symptoms such as allodynia and hyperalgesia. One of these pathways involves activation of spinal cord microglia and astrocytes, which drive and maintain the inflammatory response following the lesion. These cells are a potential target for drugs for neuropathic pain relief. In this current study, we investigated the dose-effect relationship of the tissue protective peptide ARA 290, derived from the tertiary structure of erythropoietin, on allodynia and concurrent spinal cord microglia and astrocytes.

Results: Following a spared nerve injury in rats, vehicle or ARA290 (administered in either one of 4 doses: 3, 10, 30 and 60 μg/kg) was administered on days 1, 3, 6, 8 and 10. ARA290 exerted a dose-response effect by significantly reducing mechanical allodynia up to 20 weeks when compared to vehicle. The reduction of cold allodynia was significant up to 20 weeks for the doses 3, 10, 30 and 60 μg/kg when compared to vehicle. The effect 10 and 30 μg/kg ARA290 and vehicle on the microglia response (iba-1-immunoreactivity, iba-1-IR) and astrocyte reaction (GFAP-immunoreactivity, GFAP-IR) was investigated in animals surviving 2 (group 1) or 20 (group 2) weeks following lesion or sham surgery. In group 1, significant microglia reactivity was observed in the L5 segment of the spinal cord of animals treated with vehicle when compared to sham operated, while animals treated with 10 or 30 μg/kg did not show a increase. In group 2, a more widespread and increased microglia reactivity was observed for animals treated with 0 and 10 μg/kg when compared to sham operated animals, indicated by involvement of more spinal cord segments and higher iba-1-IR. Animals treated with 30 μg/kg did not show increased microglia reactivity. No difference in astrocyte reaction was observed.

Conclusions: The erythropoietin-analogue ARA290 dose-dependently reduced allodynia coupled to suppression of the spinal microglia response, suggestive of a mechanistic link between ARA290-induced suppression of central inflammation and relief of neuropathic pain symptoms.

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Effect of ARA 290 on mechanical allodynia. A. Effect of spared nerve injury and treatment with vehicle or different doses of ARA 290 on mechanical allodynia. Animals were sham-operated (grey) or received spared nerve injury and 5 doses of vehicle (red), 3 μg/kg ARA 290 (yellow), 10 μg/kg ARA 290 (green), 30 μg/kg ARA 290 (marine blue), or 60 μg/kg ARA 290 (dark blue) administered on days 1, 3, 6, 8 and 10 post-surgery. B. Correlation of ARA 290 treatment dose and the relief of mechanical allodynia, calculated by the difference in area under the curves (AUC) of the mechanical allodynia response on day 1 vs. day 140. The adjusted R2 is 0.56. C. Survival analysis showing the mechanical allodynia-free proportion of animals in time either sham-operated, or receiving spared nerve injury and treated with vehicle or different doses of ARA 290. Log-Rank p < 0.001.
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Figure 1: Effect of ARA 290 on mechanical allodynia. A. Effect of spared nerve injury and treatment with vehicle or different doses of ARA 290 on mechanical allodynia. Animals were sham-operated (grey) or received spared nerve injury and 5 doses of vehicle (red), 3 μg/kg ARA 290 (yellow), 10 μg/kg ARA 290 (green), 30 μg/kg ARA 290 (marine blue), or 60 μg/kg ARA 290 (dark blue) administered on days 1, 3, 6, 8 and 10 post-surgery. B. Correlation of ARA 290 treatment dose and the relief of mechanical allodynia, calculated by the difference in area under the curves (AUC) of the mechanical allodynia response on day 1 vs. day 140. The adjusted R2 is 0.56. C. Survival analysis showing the mechanical allodynia-free proportion of animals in time either sham-operated, or receiving spared nerve injury and treated with vehicle or different doses of ARA 290. Log-Rank p < 0.001.

Mentions: Following SNI, vehicle-treated animals progressively developed mechanical allodynia within 10 days with withdrawal responses to the filament exerting the lowest possible force (0.004 ± 0.0 grams). Sham operated animals showed no decline in response threshold. Regardless of treatment, all SNI groups differed significantly from sham operated animals (p < 0.001 for all groups). The two-week treatment with ARA 290 produced a lasting relief of tactile allodynia (Figure 1A, treatment effect p < 0.001). Post hoc analysis revealed significant effects for the 30 and 60 μg/kg groups (30 μg/kg: p = 0.049 and 60 μg/kg: p < 0.001 versus vehicle). In contrast, the lower doses of ARA 290 did not produce significant relief of allodynia (3 μg/kg: p = 0.825 and 10 μg/kg: p = 0.707 versus vehicle). Comparing efficacy of treatment with ARA 290, a linear dose response relationship was observed with an adjusted R2 of 0.56 (Figure 1B). Higher doses of ARA 290 resulted in higher AUCs corresponding to animals tolerating stimulation with filaments that exert a greater force and hence less mechanical allodynia. Survival analysis indicates that with higher dosages of ARA 290 relief from allodynia persists for longer time periods (Figure 1C, Log-Rank p < 0.001).


ARA 290, a peptide derived from the tertiary structure of erythropoietin, produces long-term relief of neuropathic pain coupled with suppression of the spinal microglia response.

Swartjes M, van Velzen M, Niesters M, Aarts L, Brines M, Dunne A, Cerami A, Dahan A - Mol Pain (2014)

Effect of ARA 290 on mechanical allodynia. A. Effect of spared nerve injury and treatment with vehicle or different doses of ARA 290 on mechanical allodynia. Animals were sham-operated (grey) or received spared nerve injury and 5 doses of vehicle (red), 3 μg/kg ARA 290 (yellow), 10 μg/kg ARA 290 (green), 30 μg/kg ARA 290 (marine blue), or 60 μg/kg ARA 290 (dark blue) administered on days 1, 3, 6, 8 and 10 post-surgery. B. Correlation of ARA 290 treatment dose and the relief of mechanical allodynia, calculated by the difference in area under the curves (AUC) of the mechanical allodynia response on day 1 vs. day 140. The adjusted R2 is 0.56. C. Survival analysis showing the mechanical allodynia-free proportion of animals in time either sham-operated, or receiving spared nerve injury and treated with vehicle or different doses of ARA 290. Log-Rank p < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
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Figure 1: Effect of ARA 290 on mechanical allodynia. A. Effect of spared nerve injury and treatment with vehicle or different doses of ARA 290 on mechanical allodynia. Animals were sham-operated (grey) or received spared nerve injury and 5 doses of vehicle (red), 3 μg/kg ARA 290 (yellow), 10 μg/kg ARA 290 (green), 30 μg/kg ARA 290 (marine blue), or 60 μg/kg ARA 290 (dark blue) administered on days 1, 3, 6, 8 and 10 post-surgery. B. Correlation of ARA 290 treatment dose and the relief of mechanical allodynia, calculated by the difference in area under the curves (AUC) of the mechanical allodynia response on day 1 vs. day 140. The adjusted R2 is 0.56. C. Survival analysis showing the mechanical allodynia-free proportion of animals in time either sham-operated, or receiving spared nerve injury and treated with vehicle or different doses of ARA 290. Log-Rank p < 0.001.
Mentions: Following SNI, vehicle-treated animals progressively developed mechanical allodynia within 10 days with withdrawal responses to the filament exerting the lowest possible force (0.004 ± 0.0 grams). Sham operated animals showed no decline in response threshold. Regardless of treatment, all SNI groups differed significantly from sham operated animals (p < 0.001 for all groups). The two-week treatment with ARA 290 produced a lasting relief of tactile allodynia (Figure 1A, treatment effect p < 0.001). Post hoc analysis revealed significant effects for the 30 and 60 μg/kg groups (30 μg/kg: p = 0.049 and 60 μg/kg: p < 0.001 versus vehicle). In contrast, the lower doses of ARA 290 did not produce significant relief of allodynia (3 μg/kg: p = 0.825 and 10 μg/kg: p = 0.707 versus vehicle). Comparing efficacy of treatment with ARA 290, a linear dose response relationship was observed with an adjusted R2 of 0.56 (Figure 1B). Higher doses of ARA 290 resulted in higher AUCs corresponding to animals tolerating stimulation with filaments that exert a greater force and hence less mechanical allodynia. Survival analysis indicates that with higher dosages of ARA 290 relief from allodynia persists for longer time periods (Figure 1C, Log-Rank p < 0.001).

Bottom Line: ARA290 exerted a dose-response effect by significantly reducing mechanical allodynia up to 20 weeks when compared to vehicle.The reduction of cold allodynia was significant up to 20 weeks for the doses 3, 10, 30 and 60 μg/kg when compared to vehicle.In group 1, significant microglia reactivity was observed in the L5 segment of the spinal cord of animals treated with vehicle when compared to sham operated, while animals treated with 10 or 30 μg/kg did not show a increase.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anesthesiology, Leiden University Medical Center, P5-Q, 2300 RC Leiden, The Netherlands. a.dahan@lumc.nl.

ABSTRACT

Background: Neuropathic pain is a difficult to treat disorder arising from central or peripheral nervous system lesions. The etiology of neuropathic pain consists of several overlapping pathways converging into an exaggerated pain state with symptoms such as allodynia and hyperalgesia. One of these pathways involves activation of spinal cord microglia and astrocytes, which drive and maintain the inflammatory response following the lesion. These cells are a potential target for drugs for neuropathic pain relief. In this current study, we investigated the dose-effect relationship of the tissue protective peptide ARA 290, derived from the tertiary structure of erythropoietin, on allodynia and concurrent spinal cord microglia and astrocytes.

Results: Following a spared nerve injury in rats, vehicle or ARA290 (administered in either one of 4 doses: 3, 10, 30 and 60 μg/kg) was administered on days 1, 3, 6, 8 and 10. ARA290 exerted a dose-response effect by significantly reducing mechanical allodynia up to 20 weeks when compared to vehicle. The reduction of cold allodynia was significant up to 20 weeks for the doses 3, 10, 30 and 60 μg/kg when compared to vehicle. The effect 10 and 30 μg/kg ARA290 and vehicle on the microglia response (iba-1-immunoreactivity, iba-1-IR) and astrocyte reaction (GFAP-immunoreactivity, GFAP-IR) was investigated in animals surviving 2 (group 1) or 20 (group 2) weeks following lesion or sham surgery. In group 1, significant microglia reactivity was observed in the L5 segment of the spinal cord of animals treated with vehicle when compared to sham operated, while animals treated with 10 or 30 μg/kg did not show a increase. In group 2, a more widespread and increased microglia reactivity was observed for animals treated with 0 and 10 μg/kg when compared to sham operated animals, indicated by involvement of more spinal cord segments and higher iba-1-IR. Animals treated with 30 μg/kg did not show increased microglia reactivity. No difference in astrocyte reaction was observed.

Conclusions: The erythropoietin-analogue ARA290 dose-dependently reduced allodynia coupled to suppression of the spinal microglia response, suggestive of a mechanistic link between ARA290-induced suppression of central inflammation and relief of neuropathic pain symptoms.

Show MeSH
Related in: MedlinePlus