ABSTRACT
The rate of in vivo degradation was determined for a naturally occurring biomaterial derived from the extracellular matrix of the small intestinal submucosa (SIS). The SIS was labeled by giving weekly intravenous injections of 10 microCi of 14C-proline to piglets from 3 weeks of age until the time of sacrifice at 26 weeks. The resultant SIS prepared from these pigs contained approximately 10(3) fold more 14C than unlabeled tissues. The labeled SIS was used to repair experimental defects in the urinary bladder of 10 dogs. The animals were sacrificed at post-operative times ranging from 3 days to 1 year and the remodeled urinary bladder tissue was harvested for evaluation of 14C by a combination of liquid scintillation counting and accelerator mass spectrometry. The remodeled tissue contained less than 10% of the 14C (disintegrations per minute/gram tissue wet weight) at 3 months post-surgery compared to the SIS biomaterial that was originally implanted. The SIS scaffold was replaced by host tissue that resembled normal bladder both in structure and function. After implantation, 14C was detected in highest concentrations in the blood and the urine. The SIS bioscaffold provides a temporary scaffold for tissue remodeling with rapid host tissue remodeling, degradation, and elimination via the urine when used as a urinary bladder repair device.
Subject(s)
Biocompatible Materials , Carbon Radioisotopes/pharmacokinetics , Intestinal Mucosa/physiology , Urinary Bladder/physiology , Animals , Extracellular Matrix/physiology , Feces/chemistry , Injections, Intravenous , Mass Spectrometry , Scintillation Counting , Sensitivity and Specificity , Swine , Time Factors , Tissue Distribution/physiology , Urinary Bladder/surgeryABSTRACT
Degradable biomaterials to be used as scaffolds for tissue repair will ideally be able to support new blood vessel growth. The present study evaluated the adherence of human dermal microvascular endothelial cells (HMECs) to an acellular resorbable scaffold material derived from the small intestinal submucosa (SIS). HMECs were exposed to hydrated and dehydrated forms of SIS and to plastic surfaces coated with one of four different known components of the SIS extracellular matrix: collagen Type I, collagen Type IV, fibronectin, and laminin. Results showed that adherence of HMECs to hydrated SIS was greater than to any of the other tested surfaces (P < 0.05). Exposure of HMECs to either soluble collagen Type IV or soluble fibronectin prior to exposure of these cells to hydrated SIS showed only partial inhibition of HMEC attachment. We conclude that HMECs find hydrated SIS to be a suitable substrate for adherence and that dehydration of SIS adversely affects the ability of HMECs to adhere in vitro. The cause of HMEC adherence to SIS appears to be a combination of both its composition and architecture.
Subject(s)
Biocompatible Materials/metabolism , Cell Adhesion , Endothelium, Vascular/cytology , Intestinal Mucosa/metabolism , Biocompatible Materials/isolation & purification , Cells, Cultured , Collagen/metabolism , Endothelium, Vascular/metabolism , Extracellular Matrix/chemistry , Extracellular Matrix/metabolism , Fibronectins/metabolism , Humans , Intestinal Mucosa/chemistry , Laminin/metabolism , Microscopy, ElectronABSTRACT
A study was conducted to evaluate the tissue response to a xenogeneic biomaterial when this material was used to repair an experimentally induced Achilles tendon defect in the dog. Twenty dogs had a 1.5 cm segmental defect of the Achilles tendon created surgically which was then repaired with acellular connective tissue derived from porcine small intestinal submucosa (SIS). The animals were sacrificed at 1, 2, 4, 8, 12, 16, 24, and 48 weeks and the neotendons examined for uniaxial longitudinal tensile strength, morphologic appearance, hydroxyproline (collagen) content, and disappearance of the originally implanted SIS material over time. The contralateral normal Achilles tendons served as controls as did four additional dogs that had a 1.5 cm segmental Achilles tendon defect created surgically without subsequent surgical repair with SIS. Results showed the SIS remodeled neotendons to be stronger than the musculotendinous origin or the boney insertion (> 1000 N) by 12 weeks after surgery and to consist of organized collagen-rich connective tissue similar to the contralateral normal tendons. The four dogs in which no SIS was implanted showed inferior strength at the comparable time points of 4, 8, 12, and 16 weeks. Immunohistochemical studies suggest that the SIS biomaterial becomes degraded within the first eight weeks and serves as a temporary scaffold around which the body deposits appropriate and organized connective tissue. SIS is a promising biomaterial worthy of further investigation for orthopedic soft tissue applications.
