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Early pathologic changes in ulcerative colitis
Early
Pathologic Ulcerative
Their Relation WILLIAM
L. DONNELLAN,
the cause of chronic nonspecific ulcerative colitis remains unknown, certain basic pathologic changes which contribute to its complications and to the risks of surgical treatment have been identified. It is the purpose of this paper to describe three constant early alterations which are of direct surgical interest. These are the occurrence of defects in the collagen stroma and fibroblasts of the colonic mucosa; decreased mucosal blood flow, apparently by premucosal shunting; and the occurrence of multiple platelet agglutinations within the small mucosal vessels. Biopsy specimens from fourteen patients with chronic nonspecific ulcerative colitis were examined by light and electron microscopy. Four children aged five, seven, eight, and eleven were included in the study. Four patients were receiving corticosteroids at the time the biopsy specimen was taken. Sections from formalinfixed specimens removed at colectomy were also studied by means of Milligan’s and Van Giesen’s trichrome stains, the periodic acidSchiff (PAS) reaction, Ralph’s stain for hemoglobin, and the Wilder stain for reticulin. A basic pattern of change was found in all the specimens which were examined. OBSERVATIONS tissue
is defective
Vol. 111. January
1966
stroma
in ulcerative
of the colonic colitis.
Chicago, Illinois
normal colon has a thick fiber reticulum under the surface columnar epithelium (Fig. 1) and a network of fine fibrils surrounding the individual cells of the lamina propria. These fibers are argyophilic, but they also stain with the usual methods for collagen. Although they are finer than the collagen of the dermis or tendons, they have the same periodicity of about 640 A”. Their renewal is carried out by fibroblasts which run vertically in the lamina propria and penetrate the reticular layer to branch under the basement membrane of the surface epithelium. (Fig. 2.) In an early stage of colitis, the subepithelial reticular layer becomes slightly widened, and its fibers swell and degenerate (Fig. 3.) This change occurs as early as four weeks after reexposure of the rectosigmoid mucosa to the fecal stream. (Fig. 4 and 5.) Later in the course of the disease, the deeper collagen (reticulin) stroma of the lamina propria also degenerates and disappears. During the first stages of the disease, the fibroblasts are more granular than usual, and often are vacuolated. (Fig. 6.) They disappear from the retic&r layer and are replaced by lymphocytes and plasma cells. There are variable degrees of degeneration of the fibroblasts. Those patients in whom the disease is only moderately severe may retain a nearly normal pattern of the cells (Fig. 6A); in other cases, they are totally disorganized in their relation to the crypts and to the surface epithelium. (Fig. 7.) A second early finding is marked dilatation of the surface capillaries. These are fed by long ascending capillaries which are no larger than
LTHOUGH
mucosa
Colitis
M.D. AND JOHN M. BEAL, M.D.,
A
connective
in
to Surgical Complications
From the Departments of Surgery and Anatomy, Northwestern University Medical School, and the Children’s Memorial Hospital, Chicago, Illinois. This study was supported in part by U. S. Public Health Service General and Research Support Grants No. l-Sol-FRM370-02 l-sol-5370-04-d.
The
Changes
The 107
Pathologic
Changes
cytoplasm, with widening of the intercellular spaces and vacuolization beneath small sheets of cells. (Fig. 10.) The early edema of ulcerative colitis appears to be the result of fluid leakage from the distended anoxic capillaries. In time the surface capillaries disappear, and an increasing number of plasma cells and lymphocytes comes to lie immediately beneath the surface epithelium. (Fig. 7.) There is complete disappearance of both the subepithelial reticular layer and the
FIG. 7. A, destruction of reticular layer and collagen fibril stroma in child with ulcerative colitis. Vessels dilated, with few red blood cells. Some histiocytes persist beneath capillaries (H) (magnification X 275). B, disorganization of stromal fibroblasts and thinning of reticular layer in moderately severe ulcerative colitis. Note migration of red blood cells into lumen between the columnar epithelial cells (original magnification X 275). 111, January
Colitis
109
B
A
FIG. 6. A, vacuolated fibroblast (Fb) in child with ulcerative colitis. Reticular layer (rl) irregular. Capillaries are well filled with red blood cells (cap) (magnification X 350). B, granular fibroblasts in thirty year old man on cortisone therapy. Note pale stroma and nearly absent reticular layer (original magnification X 350).
Vol.
in Ulcerative
1966
8
9
FIG. 8. Mucosal capillary cut in longitudinal section. Absence of normal content of red blood cells. Anoxic epithelium has separated (ep) from reticular layer (rl) (original magnification X 100). FIG. 9. Deeper lamina propria between crypts in ulcerative colitis. Dilated vessels, one of them filled with a loose platelet thrombus (arrowheads). Plasma cells are grouped about vessels (original magnification X 300).
FIG. 10. Subepithelial capillary and reticular complex in active ulcerative colitis. Marked thinning and disappearance of reticular fibers (rl). Vacuolation of interepithelial spaces denotes anoxia (vat). Edema fluid of low protein content (arrow) under epithelium. Capillary is empty (original magnification X 7.000).
Donnellan
and Beal
12
11
FIG. 11. Left, masses of agglutinated platelets in surface vessels. Severe ulcerative colitis. Epithelium (Ep) is cuboidal. Total disorganization of stromal pattern (original magnification X 500). Right, electron micrograph of small mucosal vessel containing agglutinated platelets (~1). Polymorphonuclear leukocyte filling lumen at upper part of micrograph (N) (original magnification X 8.000). FIG. 12. Epithelial cation X 350).
necrosis in relation to obliterated
surface capillaries. At this stage, the epithelium is atrophic, and ulceration may have begun. The third change of direct surgical interest is an increasing obliteration of the capillaries of the lamina propria by small masses of agglutinated platelets. (Fig. 11.) When the feeding vessels to an entire unit of the mucosal blood supply have been occluded, small infarctions occur and ulceration is produced. (Fig. 12.) With ulceration, there is bacterial invasion and an outpouring of polymorphonuclear leukocytes, with the formation of microabscesses and penetrating ulceration. The agglutinated platelets remain intact in most cases and do not release thromboactive materials. If they do degenerate, fibrin coagulation occurs and the stage is set for extending thrombosis. (Fig. 13.) Drainage of the activated blood into the pelvic plexus may result in the formation of loose clots with subsequent pulmonary embolization. In those patients treated with corticosteroids, the blood supply to the mucosa is improved, and the round cell infiltration is decreased. The collagen defect and abnormalities of the fibroblasts persist. (Fig. 6B.) COMMENTS
The observations described are drawn from a number of studies which we have carried out
mucosal vessel (arrows)
(original
magnifi-
for ulcerative colitis. The general systemic effects of the disease, the relationship of bleeding to mucosal ulceration, and the well known hypersensitivity phenomena which are seen in the mucosa have not been discussed. The three alterations, that is, poor fibroplasia, mucosal anoxia, and the agglutination of platelets in the mucosal vessels, are of immediate importance to the problems encountered in the surgical therapy of the disorder. They help to explain many complications which occur both before and after operation. When a rectoanal fistula has formed during the course of ulcerative colitis, it is often impossible to effect a cure by direct surgicalattack. Biopsy of the rectal mucosa in these cases reveals a large number of small platelet thrombi and generalized mucosal anoxia. The trauma of fistulectomy or fistulotomy causes extension of this process to the margins of the wound, and healing does not occur. The granulation of these wounds is also poor, perhaps related to changes in the fibroblasts similar to those seen in the colonic mucosa. The use of colocolic anastomosis in the treatment of ulcerative colitis is a hazardous procedure. It is difficult or impossible to discern the degree of mucosal involvement at operation and, thus, whether or not good healing will occur. Local ileus is one of the first signs of American Journal
ofSurgery
Pathologic
Changes
in Ulcerative
Colitis
111
FIG. 13. Degenerating platelets (plat) with early deposition of fibrin. Marked stromal edema. Absence of Derivascular collagen fibrils (original magnification x 15,000).
mucosal involvement in colitis [I], and the handling of the bowel may lead to local activation of the disease with prolonged obstruction at the anastomosis. This is one of the reasons that local resection of diseased bowel has been condemned for most cases of ulcerative colitis. Leaks at the suture line, renewal of quiescent disease, localized ileus with obstruction, and other untoward events often follow such conservative attempts. The union of normal ileum to involved portions of the rectum and lower sigmoid has the advantage of bringing an excellent blood supply and normal fibroplasia to at least one side of the anastomosis. Even such proponents of this technic as Aylett, however, have to record frequent complications of healing. One problem is that rapid involvement of the ileal mucosa at the suture line may occur after construction of the anastomosis. Involvement of the ileum, seen in from 17 to 35 per cent of all cases of colitis [2], is apparently of a “backwash” type, and it may first appear only when the ileocecal valve is removed at operation [3]. It is for reasons of poor healing at the suture line that Aylett now recommends temporary protective ileostomy when colectomy and ileoproctostomy are carried out, since one in four of the anastomoses leaks [4]. It is our impression that, whatever the cause of ulcerative colitis, one of its associated early Vol. 111, January 1966
features is a reversible shunting of blood from the mucosa through arteriovenous communications in the submucosa 151.This sort of change could be mediated by psychologic, toxic, or immunologic events. Although other basic mechanisms would then be required to account for the inflammatory infiltration, either round cell or polymorphonuclear, which is a constant histologic finding, the rapidity of the reactivation or abatement of colitis can best be explained on the basis of reversible vascular alterations. The mucosal anoxia produced by poor blood flow could well lead to significant chemical alterations in the extracellular and cellular environment, and thus to any number of untoward events, including the reactivation of growth of previously quiescent micro-organisms, such as occurs, for example, in recurrent herpes simplex infections. The platelet agglutinations which have been demonstrated in moderately advanced colitis appear to follow the collagen degeneration and the vascular changes which appear earlier in the disease. A basic factor in this type of reversible platelet agglutination is the accumulation about or within the small blood vessels of increased quantities of adenosine diphosphate (ADP) [6]. The concentration of this metabolic intermediate is raised under conditions of cellular anoxia and cell death since the energy required for its reoxidation to adenosine triphos-
112
Donnellan
phate (ATP) is not available. Because of vascular stasis excessive quantities may remain in the mucosa, leading to platelet agglutination in active ulcerative colitis. When the blood supply improves and oxygen is again available for metabolic activity, the platelet aggregates usually disperse. When mucosal infarction and ulceration occur, however, bacterial invasion and the enzymes of the polymorphonuclear leukocytes may result in degeneration of the platelets and the release of thromboactive materials. Thrombosis may then extend into the large vessels of the submucosa and mesentery, leading to that serious form of the disease described by Bargen and others as “thromboulcerative colitis” [7]. The immediate surgical implication is that pelvic thrombosis and pulmonary emboli may be expected to occur with unusual frequency in ulcerative colitis. This tendency is naturally increased after operations in which the involved portions of the colon are not resected. The occurrence of spreading thrombosis within the colonic wall also explains why massive dilatation and perforation of the colon, the socalled “acute toxic megacolon,” are not infrequent during the course of the disease [B]. We have not discussed the role of the eosinophils in ulcerative colitis. According to Svartz [9] these do not appear until there is mucosal ulceration, and they represent an ordinary immunologic response to bacterial invasion. In some of our cases, however, they have been seen before ulceration was apparent either grossly or microscopically. Most authors now believe that the eosinophils are the scavengers of antigen-antibody complexes and that, as stated by Litt, they signal that an immunologic event has taken place [IO]. Since the involved antigen has not been demonstrated in colitis, despite many studies related to its possible “auto-immune” etiology [II J, we can only note that marked eosinophilic accumulation in the colonic mucosa is an occasional phenomenon in the early development of ulcerative colitis, and we await further observations on the role of these cells in the disease process. SUMMARY
Study of colonic biopsy specimens in early ulcerative colitis has revealed a constant pattern of change in the involved mucosa. Degeneration occurs in the thickened layer of collagen fibrils which lies under the surface epithe-
and Beal lium and often progresses to involve the entire pericellular collagen stroma of the lamina propria. The fibroblasts are granular and vacuolated. The small vessels of the mucosa contain reduced numbers of red blood cells, and signs of cellular anoxia appear in the surface epithelium. Early stromal edema gives way to round cell infiltration of the lamina propria. Later in the course of the disease, platelet agglutination occurs in the small mucosal vessels, and the surface capillaries are obliterated. The resulting mucosal infarctions are associated with the accumulation of polymorphonuclear leukocytes, apparently in response to ordinary bacterial invasion of the devitalized mucosa. The agglutination of the intact platelets is usually reversible, but occasionally the platelets break down, with the release of thromboactive materials. This may lead to true thrombosis, with enlargement of the areas of mucosal ulceration and the occurrence of pulmonary emboli from areas of pelvic venous thrombosis. The significance of these observations in the surgical management of ulcerative colitis is discussed. REFERENCES
1. CHAUDHARY, N. A. and TRUELOVE, S. C. Human colonic motility: a comparative study of normal subjects, patients with ulcerative colitis, and patients with the irritable colon syndrome. I. Resting patterns of motility. Gastroenterology, 40: 1, 1961. 2. COUNSELL, B. Lesions of the ileum associated with ulcerative colitis. hit. J. Surg., 44: 276, 1956. 3. BROOKE, B. N. Inflammatory disorders of the colon. Dis. Colon & Rectum, 5: 138, 1962. 4. AYLETT, S. Ulcerative colitis treated by total colectomy and ileorectal anastomosis: factors associated with its success or failure. Dis. Colon b Rectum, 5: 206, 1962. 5. BOULTER, P. S. and PARKS, A. G. Submucosal vascular patterns of the alimentary tract and their significance. Bit. J. Surg., 47: 546, 1960. 6. O’BRIEN, J. R. A comparison of platelet aggregation caused by seven compounds and a comparison of their inhibitors. J. Clin. Path., 17:275, 1964. 7. BUIE, L. A., SR. Gross and microscopic criteria for the diagnosis of thromboulcerative colitis. Dis. Colon 6 Rectum, 1: 209, 1958. 8. ROWE, R. J. Dilatation of colon (toxic megacolon) in acute fulminating ulcerative colitis. Dis. Colon & Rectum, 6: 23, 1963. 9. SVARTZ, N. Ulcerative colitis: changes in the intestinal walls and therapeutic considerations. J. Internat. Coil. Surgeons, 41: 134, 1964. 10. LITT, M. Eosinophils and antigen-antibody reactions. Ann. NW York Acad. .%i., 116: 964,1964. American Journal of Surgery
Pathologic Changes in Ulcerative Colitis 11. BROBERGER, 0. Immunologic studies in ulcerative colitis. GastroenteroZogy, 47: 229, 1964. DISCUSSION
JOHN VAN PROHASKA(Chicago, Ill.): This represents indeed advance work in the histologic study of an interesting disease. In time perhaps this will be the avenue through which we may be able to obtain some information that will help us in the differentiation of ulcerative colitis from other inflammatory diseases of the bowel, such as regional enteritis and ileocolitis. JOHN F. PRUDDEN (New York, N. Y.) : Some years ago, Dr. Karl Meyer, Dr. Alfred Gellhom, and myself demonstrated the striking correlation between the lysozyme titer of the stools and mucosa and the severity of the disease process in patients with ulcerative colitis, At the time we regarded this finding as an important clue, and I still do. It was later shown in my laboratory (and this is the connection with D. Donnellan’s paper) that very high concentrations of lysozyme could be produced experimentally in rats or in human subjects with disease by parenteral administration of epinephrine in the former and by its topical application in the latter. Norepinephrine, different only by an amine group, produced no effect whatever. It appears that this evidence and that of Dr. Donnellan fit strongly in with the clinical picture of acute fulminating ulcerative colitis in which the dilated pupils, vasoconstriction, perspiring palms, and tachycardia out of all proportion to the general physical status or to other vital signs all bespeak an intense sympathetic activity. The total plasma catechols are elevated by almost all analytic methods in the condition; however, the epinephrine level is high or variable, depending on whether the Weil-Malherbe or Goldenberg analytic technic is employed. On the basis of this evidence, we believe that the ulcerative component of ulcerative colitis is biochemically based on an abnormality of epinephrine secretion and/or metabolism while the diarrhea is produced at least in part by parasympathotonic excess. This concept is borne out clinically by the occasional appearance of constipating ulcerative colitis as well as the more common so-called mucous
Vol. 111, January
1966
113
or spastic colitis at the opposite end of the autonomic spectrum. Dr. Donnellan’s excellent histologic studies have properly refocused attention on the role of the sympathetic nervous system in colitis. I hope that he will continue and expand their studies. WILLIAM L. DONNELLAN(closing): Many observations have been made regarding the possible cause of colitis. We believed that it was important to try to establish what happened in colitis before we studied why it happened. We know now that there is very definitely a marked decrease in the collagen content of the mucosa. The fact that the vessels are so frequently empty is perhaps a new observation because in a hemorrhagic disease like colitis, one would expect that they would be engorged with blood; however, time after time we have seen that the superficial mucosal vessels are indeed empty of red blood cells. The cause of this, of course, can be many things. Immunologic factors can lead to vasoconstriction which will cause capillary stasis and dilatation. Some endotoxins will do the same thing. The arteriovenous anastomoses which have been described in the submucosa of the colon may provide the mechanism for this shunting of blood away from the mucosa. I do not know the relation of increases in lysozyme to colitis. We have not studied this aspect. Epinephrine may play a part in this condition because it can cause some of the effects which have been described. For example, when it is given experimentally, it aggravates the vascular effects of gamma globulin or the reaction of bacterial endotoxins on the bowel mucosa, when the two substances are administered together. We do not know the cause of colitis. I think we are on the track of it, and at the moment we believe that alterations in the fibroblasts are the prime difficulty. I personally believe that infection of the fibroblasts by micro-organisms of the mycoplasma group are the cause of these alterations. We are working with tissue cultures in an effort to isolate such organisms, but have not so far had any success, except to find that adult colonic mucosa does grow in culture rather well. I hope that in the next two or three years we will be able to say more on that subject.
Pathologic Ulcerative
Their Relation WILLIAM
L. DONNELLAN,
the cause of chronic nonspecific ulcerative colitis remains unknown, certain basic pathologic changes which contribute to its complications and to the risks of surgical treatment have been identified. It is the purpose of this paper to describe three constant early alterations which are of direct surgical interest. These are the occurrence of defects in the collagen stroma and fibroblasts of the colonic mucosa; decreased mucosal blood flow, apparently by premucosal shunting; and the occurrence of multiple platelet agglutinations within the small mucosal vessels. Biopsy specimens from fourteen patients with chronic nonspecific ulcerative colitis were examined by light and electron microscopy. Four children aged five, seven, eight, and eleven were included in the study. Four patients were receiving corticosteroids at the time the biopsy specimen was taken. Sections from formalinfixed specimens removed at colectomy were also studied by means of Milligan’s and Van Giesen’s trichrome stains, the periodic acidSchiff (PAS) reaction, Ralph’s stain for hemoglobin, and the Wilder stain for reticulin. A basic pattern of change was found in all the specimens which were examined. OBSERVATIONS tissue
is defective
Vol. 111. January
1966
stroma
in ulcerative
of the colonic colitis.
Chicago, Illinois
normal colon has a thick fiber reticulum under the surface columnar epithelium (Fig. 1) and a network of fine fibrils surrounding the individual cells of the lamina propria. These fibers are argyophilic, but they also stain with the usual methods for collagen. Although they are finer than the collagen of the dermis or tendons, they have the same periodicity of about 640 A”. Their renewal is carried out by fibroblasts which run vertically in the lamina propria and penetrate the reticular layer to branch under the basement membrane of the surface epithelium. (Fig. 2.) In an early stage of colitis, the subepithelial reticular layer becomes slightly widened, and its fibers swell and degenerate (Fig. 3.) This change occurs as early as four weeks after reexposure of the rectosigmoid mucosa to the fecal stream. (Fig. 4 and 5.) Later in the course of the disease, the deeper collagen (reticulin) stroma of the lamina propria also degenerates and disappears. During the first stages of the disease, the fibroblasts are more granular than usual, and often are vacuolated. (Fig. 6.) They disappear from the retic&r layer and are replaced by lymphocytes and plasma cells. There are variable degrees of degeneration of the fibroblasts. Those patients in whom the disease is only moderately severe may retain a nearly normal pattern of the cells (Fig. 6A); in other cases, they are totally disorganized in their relation to the crypts and to the surface epithelium. (Fig. 7.) A second early finding is marked dilatation of the surface capillaries. These are fed by long ascending capillaries which are no larger than
LTHOUGH
mucosa
Colitis
M.D. AND JOHN M. BEAL, M.D.,
A
connective
in
to Surgical Complications
From the Departments of Surgery and Anatomy, Northwestern University Medical School, and the Children’s Memorial Hospital, Chicago, Illinois. This study was supported in part by U. S. Public Health Service General and Research Support Grants No. l-Sol-FRM370-02 l-sol-5370-04-d.
The
Changes
The 107
Pathologic
Changes
cytoplasm, with widening of the intercellular spaces and vacuolization beneath small sheets of cells. (Fig. 10.) The early edema of ulcerative colitis appears to be the result of fluid leakage from the distended anoxic capillaries. In time the surface capillaries disappear, and an increasing number of plasma cells and lymphocytes comes to lie immediately beneath the surface epithelium. (Fig. 7.) There is complete disappearance of both the subepithelial reticular layer and the
FIG. 7. A, destruction of reticular layer and collagen fibril stroma in child with ulcerative colitis. Vessels dilated, with few red blood cells. Some histiocytes persist beneath capillaries (H) (magnification X 275). B, disorganization of stromal fibroblasts and thinning of reticular layer in moderately severe ulcerative colitis. Note migration of red blood cells into lumen between the columnar epithelial cells (original magnification X 275). 111, January
Colitis
109
B
A
FIG. 6. A, vacuolated fibroblast (Fb) in child with ulcerative colitis. Reticular layer (rl) irregular. Capillaries are well filled with red blood cells (cap) (magnification X 350). B, granular fibroblasts in thirty year old man on cortisone therapy. Note pale stroma and nearly absent reticular layer (original magnification X 350).
Vol.
in Ulcerative
1966
8
9
FIG. 8. Mucosal capillary cut in longitudinal section. Absence of normal content of red blood cells. Anoxic epithelium has separated (ep) from reticular layer (rl) (original magnification X 100). FIG. 9. Deeper lamina propria between crypts in ulcerative colitis. Dilated vessels, one of them filled with a loose platelet thrombus (arrowheads). Plasma cells are grouped about vessels (original magnification X 300).
FIG. 10. Subepithelial capillary and reticular complex in active ulcerative colitis. Marked thinning and disappearance of reticular fibers (rl). Vacuolation of interepithelial spaces denotes anoxia (vat). Edema fluid of low protein content (arrow) under epithelium. Capillary is empty (original magnification X 7.000).
Donnellan
and Beal
12
11
FIG. 11. Left, masses of agglutinated platelets in surface vessels. Severe ulcerative colitis. Epithelium (Ep) is cuboidal. Total disorganization of stromal pattern (original magnification X 500). Right, electron micrograph of small mucosal vessel containing agglutinated platelets (~1). Polymorphonuclear leukocyte filling lumen at upper part of micrograph (N) (original magnification X 8.000). FIG. 12. Epithelial cation X 350).
necrosis in relation to obliterated
surface capillaries. At this stage, the epithelium is atrophic, and ulceration may have begun. The third change of direct surgical interest is an increasing obliteration of the capillaries of the lamina propria by small masses of agglutinated platelets. (Fig. 11.) When the feeding vessels to an entire unit of the mucosal blood supply have been occluded, small infarctions occur and ulceration is produced. (Fig. 12.) With ulceration, there is bacterial invasion and an outpouring of polymorphonuclear leukocytes, with the formation of microabscesses and penetrating ulceration. The agglutinated platelets remain intact in most cases and do not release thromboactive materials. If they do degenerate, fibrin coagulation occurs and the stage is set for extending thrombosis. (Fig. 13.) Drainage of the activated blood into the pelvic plexus may result in the formation of loose clots with subsequent pulmonary embolization. In those patients treated with corticosteroids, the blood supply to the mucosa is improved, and the round cell infiltration is decreased. The collagen defect and abnormalities of the fibroblasts persist. (Fig. 6B.) COMMENTS
The observations described are drawn from a number of studies which we have carried out
mucosal vessel (arrows)
(original
magnifi-
for ulcerative colitis. The general systemic effects of the disease, the relationship of bleeding to mucosal ulceration, and the well known hypersensitivity phenomena which are seen in the mucosa have not been discussed. The three alterations, that is, poor fibroplasia, mucosal anoxia, and the agglutination of platelets in the mucosal vessels, are of immediate importance to the problems encountered in the surgical therapy of the disorder. They help to explain many complications which occur both before and after operation. When a rectoanal fistula has formed during the course of ulcerative colitis, it is often impossible to effect a cure by direct surgicalattack. Biopsy of the rectal mucosa in these cases reveals a large number of small platelet thrombi and generalized mucosal anoxia. The trauma of fistulectomy or fistulotomy causes extension of this process to the margins of the wound, and healing does not occur. The granulation of these wounds is also poor, perhaps related to changes in the fibroblasts similar to those seen in the colonic mucosa. The use of colocolic anastomosis in the treatment of ulcerative colitis is a hazardous procedure. It is difficult or impossible to discern the degree of mucosal involvement at operation and, thus, whether or not good healing will occur. Local ileus is one of the first signs of American Journal
ofSurgery
Pathologic
Changes
in Ulcerative
Colitis
111
FIG. 13. Degenerating platelets (plat) with early deposition of fibrin. Marked stromal edema. Absence of Derivascular collagen fibrils (original magnification x 15,000).
mucosal involvement in colitis [I], and the handling of the bowel may lead to local activation of the disease with prolonged obstruction at the anastomosis. This is one of the reasons that local resection of diseased bowel has been condemned for most cases of ulcerative colitis. Leaks at the suture line, renewal of quiescent disease, localized ileus with obstruction, and other untoward events often follow such conservative attempts. The union of normal ileum to involved portions of the rectum and lower sigmoid has the advantage of bringing an excellent blood supply and normal fibroplasia to at least one side of the anastomosis. Even such proponents of this technic as Aylett, however, have to record frequent complications of healing. One problem is that rapid involvement of the ileal mucosa at the suture line may occur after construction of the anastomosis. Involvement of the ileum, seen in from 17 to 35 per cent of all cases of colitis [2], is apparently of a “backwash” type, and it may first appear only when the ileocecal valve is removed at operation [3]. It is for reasons of poor healing at the suture line that Aylett now recommends temporary protective ileostomy when colectomy and ileoproctostomy are carried out, since one in four of the anastomoses leaks [4]. It is our impression that, whatever the cause of ulcerative colitis, one of its associated early Vol. 111, January 1966
features is a reversible shunting of blood from the mucosa through arteriovenous communications in the submucosa 151.This sort of change could be mediated by psychologic, toxic, or immunologic events. Although other basic mechanisms would then be required to account for the inflammatory infiltration, either round cell or polymorphonuclear, which is a constant histologic finding, the rapidity of the reactivation or abatement of colitis can best be explained on the basis of reversible vascular alterations. The mucosal anoxia produced by poor blood flow could well lead to significant chemical alterations in the extracellular and cellular environment, and thus to any number of untoward events, including the reactivation of growth of previously quiescent micro-organisms, such as occurs, for example, in recurrent herpes simplex infections. The platelet agglutinations which have been demonstrated in moderately advanced colitis appear to follow the collagen degeneration and the vascular changes which appear earlier in the disease. A basic factor in this type of reversible platelet agglutination is the accumulation about or within the small blood vessels of increased quantities of adenosine diphosphate (ADP) [6]. The concentration of this metabolic intermediate is raised under conditions of cellular anoxia and cell death since the energy required for its reoxidation to adenosine triphos-
112
Donnellan
phate (ATP) is not available. Because of vascular stasis excessive quantities may remain in the mucosa, leading to platelet agglutination in active ulcerative colitis. When the blood supply improves and oxygen is again available for metabolic activity, the platelet aggregates usually disperse. When mucosal infarction and ulceration occur, however, bacterial invasion and the enzymes of the polymorphonuclear leukocytes may result in degeneration of the platelets and the release of thromboactive materials. Thrombosis may then extend into the large vessels of the submucosa and mesentery, leading to that serious form of the disease described by Bargen and others as “thromboulcerative colitis” [7]. The immediate surgical implication is that pelvic thrombosis and pulmonary emboli may be expected to occur with unusual frequency in ulcerative colitis. This tendency is naturally increased after operations in which the involved portions of the colon are not resected. The occurrence of spreading thrombosis within the colonic wall also explains why massive dilatation and perforation of the colon, the socalled “acute toxic megacolon,” are not infrequent during the course of the disease [B]. We have not discussed the role of the eosinophils in ulcerative colitis. According to Svartz [9] these do not appear until there is mucosal ulceration, and they represent an ordinary immunologic response to bacterial invasion. In some of our cases, however, they have been seen before ulceration was apparent either grossly or microscopically. Most authors now believe that the eosinophils are the scavengers of antigen-antibody complexes and that, as stated by Litt, they signal that an immunologic event has taken place [IO]. Since the involved antigen has not been demonstrated in colitis, despite many studies related to its possible “auto-immune” etiology [II J, we can only note that marked eosinophilic accumulation in the colonic mucosa is an occasional phenomenon in the early development of ulcerative colitis, and we await further observations on the role of these cells in the disease process. SUMMARY
Study of colonic biopsy specimens in early ulcerative colitis has revealed a constant pattern of change in the involved mucosa. Degeneration occurs in the thickened layer of collagen fibrils which lies under the surface epithe-
and Beal lium and often progresses to involve the entire pericellular collagen stroma of the lamina propria. The fibroblasts are granular and vacuolated. The small vessels of the mucosa contain reduced numbers of red blood cells, and signs of cellular anoxia appear in the surface epithelium. Early stromal edema gives way to round cell infiltration of the lamina propria. Later in the course of the disease, platelet agglutination occurs in the small mucosal vessels, and the surface capillaries are obliterated. The resulting mucosal infarctions are associated with the accumulation of polymorphonuclear leukocytes, apparently in response to ordinary bacterial invasion of the devitalized mucosa. The agglutination of the intact platelets is usually reversible, but occasionally the platelets break down, with the release of thromboactive materials. This may lead to true thrombosis, with enlargement of the areas of mucosal ulceration and the occurrence of pulmonary emboli from areas of pelvic venous thrombosis. The significance of these observations in the surgical management of ulcerative colitis is discussed. REFERENCES
1. CHAUDHARY, N. A. and TRUELOVE, S. C. Human colonic motility: a comparative study of normal subjects, patients with ulcerative colitis, and patients with the irritable colon syndrome. I. Resting patterns of motility. Gastroenterology, 40: 1, 1961. 2. COUNSELL, B. Lesions of the ileum associated with ulcerative colitis. hit. J. Surg., 44: 276, 1956. 3. BROOKE, B. N. Inflammatory disorders of the colon. Dis. Colon & Rectum, 5: 138, 1962. 4. AYLETT, S. Ulcerative colitis treated by total colectomy and ileorectal anastomosis: factors associated with its success or failure. Dis. Colon b Rectum, 5: 206, 1962. 5. BOULTER, P. S. and PARKS, A. G. Submucosal vascular patterns of the alimentary tract and their significance. Bit. J. Surg., 47: 546, 1960. 6. O’BRIEN, J. R. A comparison of platelet aggregation caused by seven compounds and a comparison of their inhibitors. J. Clin. Path., 17:275, 1964. 7. BUIE, L. A., SR. Gross and microscopic criteria for the diagnosis of thromboulcerative colitis. Dis. Colon 6 Rectum, 1: 209, 1958. 8. ROWE, R. J. Dilatation of colon (toxic megacolon) in acute fulminating ulcerative colitis. Dis. Colon & Rectum, 6: 23, 1963. 9. SVARTZ, N. Ulcerative colitis: changes in the intestinal walls and therapeutic considerations. J. Internat. Coil. Surgeons, 41: 134, 1964. 10. LITT, M. Eosinophils and antigen-antibody reactions. Ann. NW York Acad. .%i., 116: 964,1964. American Journal of Surgery
Pathologic Changes in Ulcerative Colitis 11. BROBERGER, 0. Immunologic studies in ulcerative colitis. GastroenteroZogy, 47: 229, 1964. DISCUSSION
JOHN VAN PROHASKA(Chicago, Ill.): This represents indeed advance work in the histologic study of an interesting disease. In time perhaps this will be the avenue through which we may be able to obtain some information that will help us in the differentiation of ulcerative colitis from other inflammatory diseases of the bowel, such as regional enteritis and ileocolitis. JOHN F. PRUDDEN (New York, N. Y.) : Some years ago, Dr. Karl Meyer, Dr. Alfred Gellhom, and myself demonstrated the striking correlation between the lysozyme titer of the stools and mucosa and the severity of the disease process in patients with ulcerative colitis, At the time we regarded this finding as an important clue, and I still do. It was later shown in my laboratory (and this is the connection with D. Donnellan’s paper) that very high concentrations of lysozyme could be produced experimentally in rats or in human subjects with disease by parenteral administration of epinephrine in the former and by its topical application in the latter. Norepinephrine, different only by an amine group, produced no effect whatever. It appears that this evidence and that of Dr. Donnellan fit strongly in with the clinical picture of acute fulminating ulcerative colitis in which the dilated pupils, vasoconstriction, perspiring palms, and tachycardia out of all proportion to the general physical status or to other vital signs all bespeak an intense sympathetic activity. The total plasma catechols are elevated by almost all analytic methods in the condition; however, the epinephrine level is high or variable, depending on whether the Weil-Malherbe or Goldenberg analytic technic is employed. On the basis of this evidence, we believe that the ulcerative component of ulcerative colitis is biochemically based on an abnormality of epinephrine secretion and/or metabolism while the diarrhea is produced at least in part by parasympathotonic excess. This concept is borne out clinically by the occasional appearance of constipating ulcerative colitis as well as the more common so-called mucous
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or spastic colitis at the opposite end of the autonomic spectrum. Dr. Donnellan’s excellent histologic studies have properly refocused attention on the role of the sympathetic nervous system in colitis. I hope that he will continue and expand their studies. WILLIAM L. DONNELLAN(closing): Many observations have been made regarding the possible cause of colitis. We believed that it was important to try to establish what happened in colitis before we studied why it happened. We know now that there is very definitely a marked decrease in the collagen content of the mucosa. The fact that the vessels are so frequently empty is perhaps a new observation because in a hemorrhagic disease like colitis, one would expect that they would be engorged with blood; however, time after time we have seen that the superficial mucosal vessels are indeed empty of red blood cells. The cause of this, of course, can be many things. Immunologic factors can lead to vasoconstriction which will cause capillary stasis and dilatation. Some endotoxins will do the same thing. The arteriovenous anastomoses which have been described in the submucosa of the colon may provide the mechanism for this shunting of blood away from the mucosa. I do not know the relation of increases in lysozyme to colitis. We have not studied this aspect. Epinephrine may play a part in this condition because it can cause some of the effects which have been described. For example, when it is given experimentally, it aggravates the vascular effects of gamma globulin or the reaction of bacterial endotoxins on the bowel mucosa, when the two substances are administered together. We do not know the cause of colitis. I think we are on the track of it, and at the moment we believe that alterations in the fibroblasts are the prime difficulty. I personally believe that infection of the fibroblasts by micro-organisms of the mycoplasma group are the cause of these alterations. We are working with tissue cultures in an effort to isolate such organisms, but have not so far had any success, except to find that adult colonic mucosa does grow in culture rather well. I hope that in the next two or three years we will be able to say more on that subject.