Title:  Prediction of diabetes impaired wound healing by urinary nitrate assay

United States Patent:  6,312,663

Appl. No.:  516584

Wound healing is impaired in many diabetics, who suffer increased risk of chronic foot ulceration and amputation. Diabetic patients with poor healing ability were found to possess significantly lower fasting urinary nitrate levels than diabetic patients with normal healing ability or non-diabetic controls, implicating decreased endogenous nitric oxide activity as the mediator of diabetes-impaired wound healing. Methods and kits are provided for predicting the wound healing ability of diabetic patients based on the levels of nitric oxide related products such as nitrate or nitrite in urine or other specimens. Methods are also provided for treating non-wound healing diabetics and monitoring diabetic ulcer treatment.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a method of determining whether a diabetic subject is a wound healing diabetic or a non-wound healing diabetic. The method comprises the steps of: (a) collecting a specimen from the subject; (b) determining the level of a nitric oxide related product in the specimen; and (c) comparing the level of the nitric oxide related product in the specimen with a threshold value which discriminates between wound healing and non-wound healing diabetics. If the level of the nitric oxide related product is above the threshold value, then the subject is a wound healing diabetic. If the level of the nitric oxide related product is approximately at or below the threshold value, then the subject is a non-wound healing diabetic.

It is also an object of the invention to provide a method of treating a diabetic subject. The method comprises the steps of: (a) collecting a specimen from the subject; (b) determining the level of a nitric oxide related product in the specimen; and (c) comparing the level of the nitric oxide related product in the specimen with a threshold value which discriminates between wound healing and non-wound healing diabetics; and (d) treating the subject according to whether the subject is a wound healing diabetic or a non-wound healing diabetic.

It is a further object of the invention to provide a method of monitoring the effectiveness of treatment of a non-wound healing diabetic patient. The method comprises the steps of: (a) administering to the patient a therapeutic agent designed to raise the level of nitric oxide in the patient; (b) collecting a specimen from the subject; and (c) determining the level of a nitric oxide related product in the specimen as a measure of the effectiveness of the treatment.

It is yet another object of the invention to provide a kit for determining whether a diabetic subject is a wound healing diabetic or a non-wound healing diabetic. The kit comprises reagents for determining the level of a nitric oxide related product in a specimen and instructions for obtaining the specimen, using the reagents, and interpreting the results.

Claim 1 of 34 Claims

I claim:

1. A method of determining whether a diabetic subject is a wound healing diabetic or a non-wound healing diabetic, comprising the step of:

comparing the level of a nitric oxide-related product in a specimen from the diabetic subject with a threshold value which discriminates between wound healing and non-wound healing diabetics, wherein if the level of the nitric oxide-related product is above the threshold value the subject is a wound healing diabetic, and if the level of the nitric oxide-related product is approximately at or below the threshold value the subject is a non-wound healing diabetic.

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