title: Impaired neurovascular repair in subjects with diabetes following experimental intracutaneous axotomy.
abstract: Diabetic complications and vascular disease are closely intertwined. Diabetes mellitus is a well-established risk factor for both large and small vessel vascular changes, and conversely other vascular risk factors confer increased risk for diabetic complications such as peripheral neuropathy, nephropathy and retinopathy. Furthermore, axons and blood vessels share molecular signals for purposes of navigation, regeneration and terminal arborizations. We examined blood vessel, Schwann cell and axonal regeneration using validated axotomy models to study and compare patterns and the relationship of regeneration among these different structures. Ten subjects with diabetes mellitus complicated by neuropathy and 10 healthy controls underwent 3 mm distal thigh punch skin biopsies to create an intracutaneous excision axotomy followed by a concentric 4-mm overlapping biopsy at different time points. Serial sections were immunostained against a pan-axonal marker (PGP9.5), an axonal regenerative marker (GAP43), Schwann cells (p75) and blood vessels (CD31) to visualize regenerating structures in the dermis and epidermis. The regenerative and collateral axonal sprouting rates, blood vessel growth rate and Schwann cell density were quantified using established stereology techniques. Subjects also underwent a chemical 'axotomy' through the topical application of capsaicin, and regenerative sprouting was assessed by the return of intraepidermal nerve fibre density through regenerative regrowth. In the healed 3 mm biopsy sites, collateral and dermal regenerative axonal sprouts grew into the central denervated area in a stereotypic pattern with collateral sprouts growing along the dermal-epidermal junction while regenerative dermal axons, blood vessels and Schwann cells grew from their transected proximal stumps into the deep dermis. Vessel growth preceded axon and Schwann cell migration into the denervated region, perhaps acting as scaffolding for axon and Schwann cell growth. In control subjects, Schwann cell growth was more robust and extended into the superficial dermis, while among subjects with diabetes mellitus, Schwann tubes appeared atrophic and were limited to the mid-dermis. Rates of collateral (P=0.0001), dermal axonal regenerative sprouting (P=0.02), Schwann cell migration (P<0.05) and blood vessel growth (P=0.002) were slower among subjects with diabetes mellitus compared with control subjects. Regenerative deficits are a common theme in diabetes mellitus and may underlie the development of neuropathy. We observed that blood vessel growth recapitulated the pattern seen in ontogeny and preceded regenerating nerve fibres, suggesting that enhancement of blood vessel growth might facilitate axonal regeneration. These models are useful tools for the efficient investigation of neurotrophic and regenerative drugs, and also to explore factors that may differentially affect axonal regeneration.
authors: Department of Neurology, Johns Hopkins University, Baltimore, MD 21287-7609, USA.
authors: Gigi J
authors: GJ
authors: Ebenezer
authors: Ryan
authors: R
authors: O'Donnell
authors: Peter
authors: P
authors: Hauer
authors: Nicholas P
authors: NP
authors: Cimino
authors: Justin C
authors: JC
authors: McArthur
authors: Michael
authors: M
authors: Polydefkis
references: Exp Neurol. 1980 Jul;69(1):74-84
references: 6156080
references: J Neurochem. 2006 Feb;96(3):833-42
references: 16336221
references: Dev Biol. 2003 Mar 1;255(1):77-98
references: 12618135
references: Neurology. 1987 Jan;37(1):20-8
references: 3796834
references: Curr Opin Neurobiol. 2005 Feb;15(1):108-15
references: 15721752
references: Exp Neurol. 2008 Oct;213(2):381-7
references: 18675804
references: Genes Dev. 2004 Nov 15;18(22):2822-34
references: 15545635
references: J Anat. 2000 Nov;197 Pt 4:591-605
references: 11197533
references: J Surg Res. 2002 Nov;108(1):122-8
references: 12443724
references: Int Rev Neurobiol. 2002;50:37-57
references: 12198817
references: Diabetes. 2009 Dec;58(12):2893-903
references: 19720799
references: Neurology. 1993 Apr;43(4):817-24
references: 8469345
references: Invest Ophthalmol Vis Sci. 2008 Sep;49(9):3870-8
references: 18487369
references: J Peripher Nerv Syst. 2006 Jun;11(2):142-7
references: 16787512
references: Diabetes. 1989 Oct;38(10):1245-50
references: 2792576
references: J Clin Invest. 2001 May;107(9):1083-92
references: 11342572
references: Acta Neuropathol. 2001 Apr;101(4):367-74
references: 11355308
references: Anat Rec. 1991 Dec;231(4):482-97
references: 1793176
references: Brain. 2004 Jul;127(Pt 7):1606-15
references: 15128618
references: Philos Trans R Soc Lond B Biol Sci. 1996 Mar 29;351(1338):455-62
references: 8730785
references: Arch Neurol. 1998 Dec;55(12):1513-20
references: 9865794
references: J Neurol Sci. 1989 Nov;93(2-3):231-7
references: 2531788
references: Am J Pathol. 1999 Feb;154(2):355-63
references: 10027394
references: Ann Neurol. 1986 May;19(5):440-9
references: 3717907
references: Brain Res. 1999 Nov 6;846(2):219-28
references: 10556639
references: Diabetes. 1981 Oct;30(10):797-803
references: 7274587
references: J Anat. 1999 Jan;194 ( Pt 1):1-14
references: 10227662
references: J Neurochem. 1979 Nov;33(5):1055-60
references: 91664
references: Exp Neurol. 2010 May;223(1):60-71
references: 20080088
references: Anat Rec (Hoboken). 2010 May;293(5):865-70
references: 20186961
references: J Comp Neurol. 2009 May 20;514(3):272-83
references: 19296476
references: Proc Natl Acad Sci U S A. 2002 Sep 3;99(18):11946-50
references: 12181492
references: J Neurosci Methods. 1993 Feb;46(2):107-20
references: 8474255
references: J Peripher Nerv Syst. 2005 Jun;10(2):144-57
references: 15958126
references: Kidney Int. 2009 Mar;75(6):605-16
references: 19037249
references: Nature. 2001 Dec 13;414(6865):813-20
references: 11742414
references: Circulation. 2002 Nov 26;106(22):2781-6
references: 12451003
references: Brain. 2000 Oct;123 ( Pt 10):2118-29
references: 11004128
references: Diabetes Technol Ther. 2001 Spring;3(1):23-8
references: 11469706
references: Diabetes Care. 2008 Jan;31(1):140-5
references: 17934147
references: Dev Cell. 2003 Jul;5(1):45-57
references: 12852851
references: Plast Reconstr Surg. 2007 Jan;119(1):59-70
references: 17255657
references: J Invest Dermatol. 2007 Aug;127(8):2062-5
references: 17410199
references: J Pathol. 1992 Mar;166(3):265-70
references: 1517882
references: Curr Treat Options Neurol. 2005 Jan;7(1):33-42
references: 15610705
references: Diabetes. 1989 Oct;38(10):1307-13
references: 2551761
references: J Diabetes Complications. 1992 Jan-Mar;6(1):49-57
references: 1562759
references: J Neurosci. 2000 Oct 15;20(20):7706-15
references: 11027232
references: Exp Neurol. 2002 Jan;173(1):77-85
references: 11771940
references: Diabetes. 1992 Oct;41 Suppl 2:49-51
references: 1526336
references: Ann Neurol. 2009 Apr;65(4):386-93
references: 19399887
references: J Neuropathol Exp Neurol. 2006 Jan;65(1):26-36
references: 16410746
references: N Engl J Med. 2005 Jun 23;352(25):2650-1; author reply 2650-1
references: 15981312
references: Prog Neurobiol. 2003 Mar;69(4):229-85
references: 12757748
references: Diabet Med. 1996 Feb;13(2):160-4
references: 8641122
references: Diabetes. 2004 Jun;53(6):1564-9
references: 15161762
references: J Comp Neurol. 2003 Feb 24;457(1):24-36
references: 12541322
references: Diabetologia. 1993 Dec;36(12):1266-74
references: 8307254
references: Eur J Neurosci. 2000 Dec;12(12):4243-54
references: 11122336
references: Nature. 2005 Jul 14;436(7048):193-200
references: 16015319
references: Folia Neuropathol. 2005;43(1):31-9
references: 15827888
references: Proc Natl Acad Sci U S A. 1994 Mar 29;91(7):2795-9
references: 8146193
references: Diabetes. 1997 Sep;46 Suppl 2:S43-9
references: 9285498