Serum levels of substance P are decreased in patients with type 1 diabetes

Abstract

Morphological and immunohistochemical studies in diabetic subjects have shown a depletion of the neuropeptide substance P (SP) in the central and peripheral nervous system. This is the first study investigating serum levels of substance P in type 1 diabetes patients (n=50) and controls (n=75) by means of an enzyme immunoassay. The serum level of SP was significantly decreased in the diabetic group compared to the control group (10.12+/-0.29 vs. 12.25+/-0.38 pg/ml; p<0.0001). In diabetic patients, there was no correlation of substance P levels with age, serum creatinine, albuminuria, total cholesterol, HDL- or LDL-cholesterol, triglycerides, HbA1c, type or duration of diabetes and gender. Furthermore, there was no difference in serum levels of SP in patients with or without retinopathy, but SP was significantly decreased in patients with neuropathy (9.59+/-0.48 vs. 10.78+/-0.83 pg/ml; p=0.04). These data show that SP is decreased in serum of type 1 diabetes patients, especially in those with diabetic neuropathy. Subsequent and already ongoing prospective studies in well validated diabetic patients with neuropathy may characterize the impact of this neurogenic marker in the course of diabetic neuropathy.

Highly Sensitive and Rapid Assay of Substance P and Streptolysin O in Human Serum Using Immuno-liposomes and Gramicidin Channels

“…This concentration was in the range of the reported SP levels in human serum. [10][11][12] The SP level was the same as that obtained at 50-times dilution. This shows that SP bound to serum proteins was almost fully dissociated.…”

Inflammatory and Angiogenic Abnormalities in Diabetic Wound Healing: Role of Neuropeptides and Therapeutic Perspectives

“…Morphological and immunohistochemical studies in type 1 diabetic subjects have shown a depletion of SP in the central and peripheral nervous system, especially in those with diabetic neuropathy [107]. Also, the number of SP-positive fibers are decreased in the dermis of diabetic patients with diabetic neuropathy [108].…”

Topical application of substance P promotes wound healing in streptozotocin-induced diabetic rats

“…The most common complications of delayed wound healing of diabetics are: reduction in chemotactic and phagocytic activities of neutrophils [1], decreased vasculogenesis [2], decreased endothelial nitric oxide synthase (eNOS) activity [3] and reduction of substance P (SP) level [4]. Abnormal nerve distribution and neuroinflammation are also connected with the chronic nonhealing wounds in DM.…”