Selective Loss of Calcitonin Gene-Related Peptide-Expressing Primary Sensory Neurons in Early Experimental Diabetes

Strategic Insights -

Recent research from Denmark has shed light on the effects of experimental diabetes on calcitonin gene-related peptide-expressing primary sensory neurons. According to a study published in Diabetes, the absolute numbers of immunoreactive substance P and calcitonin gene-related peptide (CGRP) dorsal root ganglion (DRG) cell bodies were estimated in diabetic and nondiabetic mice. The findings suggest that experimental diabetes is associated with the selective loss of CGRP-expressing primary sensory neurons of the A-cell phenotype, which could play a role in the development of nociceptive dysfunction in diabetes.

Key Takeaways:

  • The number of immunoreactive CGRP A-cells was reduced from 692[+ or -]122 to 489[+ or -]125 (p=0.004) in p75[superscript]+/+ mice on the noncrushed side after 4 weeks of streptozotocin-induced diabetes.
  • In p75[superscript]-/- mice, there was no effect of diabetes on the immunoreactive CGRP A-cell number.
  • Sciatic nerve crush was associated with a substantial loss of L5DRG B-cells in diabetic and nondiabetic p75[superscript]+/+ mice and with substantial loss of immunoreactive substance P cells in diabetic p75[superscript]+/+ mice.
  • The loss of immunoreactive CGRP primary sensory neurons of the A-cell phenotype could play a role in the touch-evoked nociception in the model.
  • The neuronal immunoreactive CGRP abnormality possibly is mediated by activation of the p75 neurotrophin receptor.

Statistics:

  • Reduction in immunoreactive CGRP A-cells: 203 (from 692 to 489) in the noncrushed side of p75[superscript]+/+ mice.
  • No effect of diabetes on immunoreactive CGRP B-cell number in p75[superscript]-/- mice.
  • Loss of immunoreactive substance P cells in diabetic p75[superscript]+/+ mice: 50%.

Sources:

  • Jiang, Y., et al. (2004). Selective loss of calcitonin gene-related peptide-expressing primary sensory neurons of the A-cell phenotype in early experimental diabetes. Diabetes, 53(10), 2669-2675.