Human wound contraction: collagen organization, fibroblasts, and myofibroblasts.

The closure of ungrafted sacrococcygeal pilonidal sinus excisional wounds was studied in 15 patients. Wound punch biopsies were taken on a regular basis, and histologic sections were made. To document changes, computer-assisted morphometric image analysis was employed. Initial average wound depth was 37.8 +/- 4.6 mm, and complete closure (0 wound depth) was reached by 68 days. Wound contraction contributed 88 percent to wound closure, whereas the deposition of scar only contributed 12 percent. Maximum cells density within granulation tissue was reached by day 18. Myofibroblasts, identified by alpha-smooth muscle actin immunostaining, first appeared on day 11. Unlike those observed in laboratory animals, myofibroblasts were a minor cell population of granulation tissue, never exceeding 10 percent of the cells. The pattern of collagen fiber organization was documented by polarized light microscopy of Sirius red-stained sections. Early granulation tissue collagen fibers demonstrated a fine greenish birefringence, whereas more mature granulation tissue collagen fibers were thicker, displaying orange-yellowish birefringence. Myofibroblasts were associated exclusively with thicker collagen fibers, whereas fibroblasts were associated with both fine and thick collagen fibers. It is proposed that human wound contraction involves a volume change whereby normal dermal and adipose tissues are pulled into the defect by forces generated within fibroblasts.

Reduced bone formation in patients with osteoporosis associated with inflammatory bowel disease.

The pathophysiology of bone loss associated with inflammatory bowel disease has not been clearly defined. In this study we have performed a detailed histomorphometric analysis of iliac crest bone obtained from 19 patients with inflammatory bowel disease in whom a diagnosis of osteoporosis had been made. Eleven subjects were receiving prednisolone at the time of their biopsy. Comparison with control values demonstrated a highly significant reduction in trabecular bone area in the patient group (p < 0.001). Wall width, adjusted appositional rate and bone formation rate were all significantly reduced in the patient group (p < 0.001) and the formation period was significantly increased (p < 0.001). Resorption cavities were slightly smaller in the patient group, differences in maximum cavity depth and cavity length achieving statistical significance (p < 0.005 and p < 0.05 respectively). The mineral appositional rate was significantly reduced in the patients with inflammatory bowel disease (p < 0.001) and the mineralization lag time significantly increased (p < 0.001); however, osteoid area, perimeter and seam width were not significantly different from controls. These results demonstrate that osteoporosis associated with inflammatory bowel disease is characterized by reduced bone formation at the cellular and tissue level; the proportionately greater change in wall width than in resorption cavity depth is consistent with a negative remodelling balance. Although none of the patients had osteomalacia as defined by the criteria of increased osteoid seam width and mineralization lag time, the higher mineralization lag time in the patient group indicates a mild mineralization defect.

Relation between the mucosal flora and Paneth cell population of human jejunum and ileum.

The Paneth cell population in surgically resected human jejunum and ileum was estimated using image analysis of the granule area in patients who had not received antibiotics. The mucosa was cultured aerobically and anaerobically. In the jejunum 22 samples were sterile and five yielded bacteria; in the ileum four were sterile and three were non-sterile. The mean Paneth cell granule area in the sterile jejunum was 122.7 +/- 37.2 micron2 and in the non-sterile samples 67.2 +/- 36.6 micron2 (p less than 0.006). The corresponding values for the ileum were 137.9 +/- 109.8 and 100.5 +/- 9.1 (NS). Thus an increase in the Paneth cell population may occur in response to changes in the intestinal luminal environment. Failure of this response and resultant Paneth cell deficiency may lead to bacterial overgrowth.

Changes in the Paneth cell population of human small intestine assessed by image analysis of the secretory granule area.

Estimates of the Paneth cell population in human jejunum and ileum were made using measurement of the granule area in micron2 by image analysis in a defined number of crypts. This figure was preferable to granule area per mm as there was a significant difference in crypts per mm between biopsies and surgical samples. In the jejunum no significant difference was found between normal children and adults with and without peptic ulcer. In adults with subtotal or partial villous atrophy the decrease in area was not statistically significant and there was no decrease in area in children with partial villous atrophy and coeliac disease. There was a marked increase in granule area in the jejunum of patients who had had a previous partial gastrectomy which was statistically significant. In the ileum patients with carcinoma of the caecum had higher values than patients with non-inflammatory non-malignant conditions but this was not statistically significant and two patients with Crohn's disease had an increased granule area. Paneth cell populations are affected by alterations in the intestinal luminal environment due to previous surgery or neoplastic or inflammatory disease.