1. The Role of Doxycycline as an Inhibitor of Intimal Hyperplasia after Balloon Angioplasty Arterial Injury A. Harris, D.J.H. Mountain PhD, S. Kirkpatrick, D.C. Cassada MD, M.H. Goldman MD, S.L. Steven, M.B. Freeman, A.M. Tummers, O.H. Grandas MD, j. Chalk The University of Tennessee Medical Center Vascular Research Lab Knoxville, TN
Background
This research is funded by the American Heart Association, and its purpose is to delineate whether doxycycline is capable of inhibiting intimal hyperplasia after vascular injury.
Intimal hyperplasia is the result of vascular media smooth muscle cells migrating to the intima, the innermost surface of the vessel. This is often the cause of graft failure or decreased graft patency.
Women receiving hormone replacement therapy have an accelerated rate of intimal hyperplasia after vascular injury. This is due to the effects of estrogen and progesterone upregulating matrix metalloproteinases that aid in vascular medial smooth muscle cell migration.
Hypothesis
Doxycycline will inhibit intimal hyperplasia and may potentially be used pre and post surgery to prolong viability of vascular grafts and lessen the number of graft replacements.
Method
The research method used two groups of lab rats. One control group and one experimental group. Both groups had their left carotid arteries receive a balloon angioplasty (injured) and right carotids not manipulated.
The right carotid arteries are referred to as shams and are used as reference to show no preexisting vascular disease.
The control group received injections of saline while the experimental group received injections of doxycycline.
The top two pictures are the right and left carotid arteries from one lab rat in the control group.
The bottom two pictures are the right and left carotid arteries from one lab rat in the experimental group.
Results/Conclusions
As shown in the pictures, the rat receiving doxycycline after angioplasty had no intimal hyperplasia after five days. This is a promising start, but future research needs to use an extended time frame to compare the long term effects of doxycycline on intimal hyperplasia.
Intimal Hyperplasia
This right carotid artery did not have a balloon angioplasty and received two daily injections of saline for five days. It does not show any intimal hyperplasia.
This left carotid artery had a balloon angioplasty and received two daily injections of saline for five days. The bottom right side of the vessel shows intimal hyperplasia.
This right carotid artery did not have a balloon angioplasty and received doxycycline injections twice a day for five days. No intimal hyperplasia is present. This is used to show no preexisting vascular disease.
This left carotid artery received a balloon angioplasty and doxycycline injections twice a day for five days. It does not show evidence of intimal hyperplasia.