The incidence of diabetes is rising throughout the world due to increased industrialization, and nationally with the """"""""greying"""""""" of America. Neuropathy is a highly debilitating consequence of diabetes in about 10% of patients. Particularly distressing problems include third nerve palsy, muscular weakness, bowel dysfunction, bladder dysfunction, impotence, heart rate abnormalities, severe unremitting pain, diabetic foot, and limb amputation. The economic costs to the individual and society are considerable, and there is a pressing need for new modalities of treatment, as well as a better understanding of the underlying cause of neuropathy. These are among recommendations of the National Diabetes Advisory Board. The long-term goal of this project is to study the medically relevant neurobiology of insulin-like growth factors (IGFs). This renewal application proposes continued study of two highly promising, independent but interrelated hypotheses: (i) Exogenously administered IGFs can prevent or ameliorate the syndrome of diabetic neuropathy, and (ii) IGFs play a role in the pathogenesis of diabetic neuropathy. A new theory for pathogenesis is proposed, and preliminary tests of key predictions of the theory have been validated. In a striking observation, it was found that locally infused IGF-II can prevent impairment of conduction velocity in diabetic rats, despite continued hyperglycemia.
The specific aims are to determine whether infused IGFs can prevent and/or reverse impairment of a range of neural functions known to be afflicted in diabetic rats, including conduction velocity, nerve regeneration, size spectra of neuronal cell bodies, and functional regeneration. Moreover, experiments will determine whether endogenous IGF mRNA content is reduced in afflicted nerve and nerve targets in diabetic rats. The results may directly lead to new therapies for treatment of diabetic neuropathy. The main studies will be done with rats, mice will provide NGF, and fertile eggs will be used to bioassay IGFs and NGF.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS024327-07
Application #
2265169
Study Section
Pathology A Study Section (PTHA)
Project Start
1993-09-30
Project End
1996-08-31
Budget Start
1994-09-01
Budget End
1995-08-31
Support Year
7
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Colorado State University-Fort Collins
Department
Physiology
Type
Schools of Veterinary Medicine
DUNS #
112617480
City
Fort Collins
State
CO
Country
United States
Zip Code
80523
Wuarin, L; Namdev, R; Burns, J G et al. (1996) Brain insulin-like growth factor-II mRNA content is reduced in insulin-dependent and non-insulin-dependent diabetes mellitus. J Neurochem 67:742-51
Zhuang, H X; Snyder, C K; Pu, S F et al. (1996) Insulin-like growth factors reverse or arrest diabetic neuropathy: effects on hyperalgesia and impaired nerve regeneration in rats. Exp Neurol 140:198-205
Ishii, D N (1995) Implication of insulin-like growth factors in the pathogenesis of diabetic neuropathy. Brain Res Brain Res Rev 20:47-67
Ishii, D N; Guertin, D M; Whalen, L R (1994) Reduced insulin-like growth factor-I mRNA content in liver, adrenal glands and spinal cord of diabetic rats. Diabetologia 37:1073-81
Wuarin, L; Guertin, D M; Ishii, D N (1994) Early reduction in insulin-like growth factor gene expression in diabetic nerve. Exp Neurol 130:106-14
Donlon, T A; Krensky, A M; Wallace, M R et al. (1990) Localization of a human T-cell-specific gene, RANTES (D17S136E), to chromosome 17q11.2-q12. Genomics 6:548-53
Carsten, R E; Whalen, L R; Ishii, D N (1989) Impairment of spinal cord conduction velocity in diabetic rats. Diabetes 38:730-6
Fernyhough, P; Mill, J F; Roberts, J L et al. (1989) Stabilization of tubulin mRNAs by insulin and insulin-like growth factor I during neurite formation. Brain Res Mol Brain Res 6:109-20