Studies on the biology of collagen during wound healing. 3. Dynamic metabolism of scar collagen and remodeling of dermal wounds

Enzyme activity in human scars, hypertrophic scars and keloids

Biopsies from non-hypertrophic and hypertrophic scars and from normal skin have been studied histochemically for activities of nicotanamide adenine dinucleotide diaphorase, lactate dehydrogenase, acid phosphatase, beta-D glucuronidase and alkaline phosphatase. The activities of all enzymes studied except alkaline phosphatase were found to be increased in hypertrophic scars as compared with non-hypertrophic scars and normal skin.

Collagen development in granulation tissue as compared with collagen of skin and aorta from injured and non-injured rats

Granulation tissue in rats was produced by subcutaneous implantation of viscose cellulose sponges. Granulomas, aortae, and skin samples were taken 4, 8, 14, 22, 33, and 42 days after the sponge implantation and compared with age-matched non-operated rats. 14C-proline was given 4 hours before death to animals killed on day 0, 14, and 42. The 14C-OH-proline activity in salt insoluble collagen was higher in granulation tissue and aorta than in skin. This indicates a faster formation, or an increased stability of the intermolecular cross-links in granulation tissue and aorta, than in skin. The percentage of free OH-proline was than in skin, reflecting a relatively increased collagen degradation in granulation tissue. An increased collagen degradation may also, in part, explain a registered higher alpha/beta ratio in collagen from granulation tissue than from skin, as well as the increase in alpha/beta ratio in the older granulomas. The sponge implantation did not affect the collagen of aorta and skin, but caused a decrease in the dry weight of aorta and skin, and an increase in the number of granulocytes in the blood.

Subcutaneous extraperitoneal repair of ventral hernias: a biological basis for fascial transplantation

Two fundamental biological differences between normal fascia and scar tissue are rate of collagen turnover and physical weave of collagen subunits. Both factors account for unsatisfactory results following ventral hernia repair unless scar tissue is excised and normal fiscia used. Removal of scar and identification of normal fascia often require extensive dissection, entrance into the peritoneal cavity, and sometimes requires lysis of intestinal adhesions with occasional injury to bowel. Simple imbrication of the hernia sac, as in treatment of a direct inguinal hernia, without excision usually results in recurrence of the hernia because of remodeling and attenuation of scar tissue. A new procedure, based upon the technique of direct inguinal hernia repair without opening peritoneum, has been performed on 12 patients with large ventral hernias. The procedures, performed entirely in a subcutaneous plane, involves imbrication of scar, transfer of a massive fascial onlay graft, and use of an internal stent. Patients have been followed for one to 5 years; there have been no recurrences. Inductive influence of the fascial transplant has been measured in two patients; a tenfold increase in net collagen synthesis and deposition occurs for at least one year following transplantation of fascia to an imbricated scar recipient area.

Recurrent inguinal hernia. Follow-up study of 100 postoperative patients

This review of recurrent inguinal hernia evaluates the possible causes of recurrence and the most effective operative procedures for successful repair. Emphasis is placed upon precise dissection technic so that whatever fascia is available after the primary operation may be utilized for the subsequent repair. A detailed study is devoted to the histologic features of fascia, emphasizing its lack of vascularization as the possible reason for its strength and permanency throughout life. In operations for recurrent inguinal hernia, rectus sheath pedunculated grafts should be used more frequently, and in extreme cases cord excision may be required. A follow-up study of one hundred postoperative cases, with a failure rate of 7 per cent, is presented.

Effects of cortisone acetate, methylprednisolone and medroxyprogesterone on wound contracture and epithelization in rabbits

Standardized flank wounds were made on 20 rabbits divided into the following five groups: Group 1 served as controls, Group 2 were given cortisone acetate 6.25 mg/kg/day (I.M.), Group 3--methylprednisolone (Solu-Medrol) 1 mg/kg/day, Group 4--medroxyprogesterone (Depo-Provera) 35 mg/kg/day, Group 5--methylprednisolone 1 mg/kg/day and medroxyprogresterone 35 mg/kg/day. Wound contracture and epithelization was measured by planimetry of photographs taken twice weekly; weekly weights were recorded, and the maturation phase of wound healing followed in the control and methylprednisolone groups. All three steroids prolonged the latent phase of wound healing, slowed the rate and decreased the total amount of contracture. Cortisone showed the most inhibition of wound contracture and was the only steroid to inhibit epithelization suggesting it may have a slightly different or more potent mode of action. When the methylprednisolone group was followed for seven weeks on daily injections, the maturation phase of wound healing was inhibited, and this inhibition persisted during the next nine weeks after the drug was withdrawn. Only the control and the medroxyprogesterone group gained weight. Combining medroxyprogesterona and methylprednisolone resulted in the severest weight loss of 20% with a 60% mortality.

A new approach to the control of esophageal stenosis

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