title: Cold hypersensitivity increases with age in mice with sickle cell disease.
abstract: Sickle cell disease (SCD) is associated with acute vaso-occlusive crises that trigger painful episodes and frequently involves ongoing, chronic pain. In addition, both humans and mice with SCD experience heightened cold sensitivity. However, studies have not addressed the mechanism(s) underlying the cold sensitization or its progression with age. Here we measured thermotaxis behavior in young and aged mice with severe SCD. Sickle mice had a marked increase in cold sensitivity measured by a cold preference test. Furthermore, cold hypersensitivity worsened with advanced age. We assessed whether enhanced peripheral input contributes to the chronic cold pain behavior by recording from C fibers, many of which are cold sensitive, in skin-nerve preparations. We observed that C fibers from sickle mice displayed a shift to warmer (more sensitive) cold detection thresholds. To address mechanisms underlying the cold sensitization in primary afferent neurons, we quantified mRNA expression levels for ion channels thought to be involved in cold detection. These included the transient receptor potential melastatin 8 (Trpm8) and transient receptor potential ankyrin 1 (Trpa1) channels, as well as the 2-pore domain potassium channels, TREK-1 (Kcnk2), TREK-2 (Kcnk10), and TRAAK (Kcnk4). Surprisingly, transcript expression levels of all of these channels were comparable between sickle and control mice. We further examined transcript expression of 83 additional pain-related genes, and found increased mRNA levels for endothelin 1 and tachykinin receptor 1. These factors may contribute to hypersensitivity in sickle mice at both the afferent and behavioral levels.
authors: Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA Department of Pediatrics and Children's Research Institute, Division of Hematology/Oncology, Medical College of Wisconsin, Milwaukee, WI, USA Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, USA.
authors: Katherine J
authors: KJ
authors: Zappia
authors: Sheldon R
authors: SR
authors: Garrison
authors: Cheryl A
authors: CA
authors: Hillery
authors: Cheryl L
authors: CL
authors: Stucky
mesh_terms: D000367:Age Factors; D000375:Aging; D000755:Anemia, Sickle Cell / Q000150:complications* / Q000235:genetics; D000818:Animals; D003080:Cold Temperature / Q000009:adverse effects; D056587:Cryopyrin-Associated Periodic Syndromes / Q000209:etiology* / Q000473:pathology; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism; D005727:Ganglia, Spinal / Q000473:pathology; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology*; D006441:Hemoglobin A / Q000235:genetics; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology; D017288:Pain Threshold / Q000502:physiology*; D024683:Potassium Channels, Tandem Pore Domain / Q000235:genetics / Q000378:metabolism; D011984:Sensory Receptor Cells / Q000378:metabolism; D012867:Skin / Q000294:innervation / Q000473:pathology; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism
chemical_list: D019332:Endothelin-1; D024683:Potassium Channels, Tandem Pore Domain; D050052:TRPC Cation Channels; D050053:TRPM Cation Channels; C492297:TRPM8 protein, mouse; C096351:transient receptor potential cation channel, subfamily C, member 1; C028672:hemoglobin AA; D006441:Hemoglobin A
keywords: Aging; C fiber; Endothelin 1; KCNK; TRPA1; TRPM8