High cerebrospinal fluid levels of interleukin-10 attained by AAV in dogs

Abstract

Intrathecal (IT) gene transfer using adeno-associated virus (AAV) may be clinically promising as a treatment for chronic pain if it can produce sufficiently high levels of a transgene product in the cerebrospinal fluid (CSF). While this strategy was developed in rodents, no studies investigating CSF levels of an analgesic or anti-allodynic protein delivered by IT AAV have been performed in large animals. Interleukin-10 (IL-10) is an anti-allodynic cytokine, for which target therapeutic levels have been established in rats. The present study tested IT AAV8 encoding either human IL-10 (hIL-10) or enhanced green fluorescent protein (EGFP) in a dog model of IT drug delivery. AAV8/hIL-10 at a dose of 3.5×1012 genome copies induced high hIL-10 levels in the CSF, exceeding the target concentration previously found to be anti-allodynic in rodents by >1000-fold. AAV8/EGFP targeted the primary sensory and motor neurons and the meninges. hIL-10, a xenogeneic protein in dogs, induced anti-hIL-10 antibodies detectable in the dogs’ CSF and serum. The high hIL-10 levels demonstrate the efficacy of AAV for delivery of secreted transgenes into the IT space of large animals suggesting a strong case for further development towards clinical testing.

Human interleukin‐10 delivered intrathecally by self‐complementary adeno‐associated virus 8 induces xenogeneic transgene immunity without clinical neurotoxicity in swine

“…Analysis revealed minimal spread with less than 0.01 transgene copies/diploid host genome in all samples, including the liver (Figure 4). For comparison, the dog study of IT scAAV8-hIL-10 resulted in over 50-fold greater viral spread to the liver 10 than detected here. It appears that the diminished systemic spread of vector genomes to peripheral organs may be due to the different means of vector delivery.…”

“…The model allowed for frequent CSF sampling using an approach similar to bedside methods and provided a longer time series with higher resolution of IT IL-10 secretion kinetics compared to similar studies in swine and dogs. 9,10 …”

“…Alternatively, the immunological compatibility between transgenic IL-10 and its host influenced the observed outcomes. In dogs the human ortholog was used, 10 i.e., a xenogeneic form was tested, while in swine the porcine form was used, i.e., a syngeneic model. 9 To improve interpretation of available large animal data regarding safety of IT IL-10, we sought to study xenogeneic IL-10 in a second large animal species.…”

Targeting dorsal root ganglia and primary sensory neurons for the treatment of chronic pain

“…Lumbar intrathecal injection of AAV6 resulted not only in transfection of lumbar DRG neurons, but also cervical DRG neurons [55]. Similar observations were reported after intrathecal injection of AVV8 in dogs, with an additional spread of the virus to the spinal cord, the liver, and the spleen[56]. …”

Current and Future Issues in the development of spinal agents for the management of pain

“…iii) The use of intrathecal viral vectors or plasmid delivery to increase appropriate antihyperalgesic targets has been shown to have utility. Thus, increased spinal expression of IL-10 (anti-inflammatory cytokine)or plasmid delivery was anti-hyperalgesic [424,[429][430][431]. Increasing MAPK (Mitogen activated protein kinase) phosphatase-1 reduces activation of P38 MAPKs and this resulted in reduced nerve injury-evoked increases in inflammatory cytokines and chemokines and hyperalgesia [432].…”