Trend and risk factors of diverticulosis in Japan: age, gender, and lifestyle/metabolic-related factors may cooperatively affect on the colorectal diverticula formation.

BACKGROUND: Despite the marked increase of diverticulosis, its risk factors have not been adequately elucidated. We therefore aim to identify significantly associated factors with diverticulosis. We also aim to investigate the present state of diverticulosis in Japan. METHODS: We reviewed the medical records from 1990 to 2010 that included the data of consecutive 62,503 asymptomatic colonoscopy examinees from the general population in Japan. Most recent 3,327 examinees were analyzed with 16 background factors. RESULTS: Among the 62,503 subjects (47,325 men and 15,178 women; 52.1 ± 9.2 years old), diverticulosis was detected in 11,771 subjects (18.8%; 10,023 men and 1,748 women). The incidences of diverticulosis in 1990-2000 and 2001-2010 were respectively 13.0% (3,771 of 29,071) and 23.9% (8,000 of 33,432): the latter was much higher than the former in all age groups and for both genders. Considering the anatomical locations of colorectal diverticula, left-sided ones have markedly increased with age but not significantly changed with times. Univariate analyses of the 3,327 subjects showed significant association of diverticulosis with four basic factors (age, sex, body mass index, blood pressure), three life style-related factor (smoking, drinking, severe weight increase in adulthood), and two blood test values (triglyceride, HbA1c). The multiple logistic analysis calculating standardized coefficients (ß) and odds ratio (OR) demonstrated that age (ß = 0.217-0.674, OR = 1.24-1.96), male gender (ß = 0.185, OR = 1.20), smoking (ß = 0.142-0.200, OR = 1.15-1.22), severe weight increase in adulthood (ß = 0.153, OR = 1.17), HbA1c (ß = 0.136, OR = 1.15), drinking (ß = 0.109, OR = 1.11), and serum triglyceride (ß = 0.098, OR = 1.10) showed significantly positive association with diverticulosis whereas body mass index and blood pressure did not. CONCLUSIONS: The large-scale data of asymptomatic colonoscopy examinees from the general population from 1990 to 2010 indicated that the prevalence of diverticulosis is still increasing in Japan. Age, male gender, smoking, severe weight increase in adulthood, serum HbA1c, drinking, and serum triglyceride showed significant positive association with diverticulosis.

Altered expression pattern of molecular factors involved in colonic smooth muscle functions: an immunohistochemical study in patients with diverticular disease.

BACKGROUND: The pathogenesis of diverticular disease (DD) is thought to result from complex interactions among dietary habits, genetic factors and coexistence of other bowel abnormalities. These conditions lead to alterations in colonic pressure and motility, facilitating the formation of diverticula. Although electrophysiological studies on smooth muscle cells (SMCs) have investigated colonic motor dysfunctions, scarce attention has been paid to their molecular abnormalities, and data on SMCs in DD are lacking. Accordingly, the main purpose of this study was to evaluate the expression patterns of molecular factors involved in the contractile functions of SMCs in the tunica muscularis of colonic specimens from patients with DD. METHODS AND FINDINGS: By means of immunohistochemistry and image analysis, we examined the expression of Cx26 and Cx43, which are prominent components of gap junctions in human colonic SMCs, as well as pS368-Cx43, PKCps, RhoA and αSMA, all known to regulate the functions of gap junctions and the contractile activity of SMCs. The immunohistochemical analysis revealed significant abnormalities in DD samples, concerning both the expression and distribution patterns of most of the investigated molecular factors. CONCLUSION: This study demonstrates, for the first time, that an altered pattern of factors involved in SMC contractility is present at level of the tunica muscularis of DD patients. Moreover, considering that our analysis was conducted on colonic tissues not directly affected by diverticular lesions or inflammatory reactions, it is conceivable that these molecular alterations may precede and predispose to the formation of diverticula, rather than being mere consequences of the disease.

The enteric serotonergic system is altered in patients with diverticular disease.

OBJECTIVE: Disturbances of the enteric serotonergic system have been implicated in several intestinal motility disorders. Patients with diverticular disease (DD) have been reported to exhibit abnormal intestinal motility and innervation patterns. Gene expression profiles of the serotonergic system and distribution of the serotonin type 4 receptor (5HT-4R) were thus studied in patients with DD. DESIGN: Colonic specimens from patients with DD and controls were subjected to quantitative PCR for serotonin receptors 2B, 3A, 4, serotonin transporter and synthesising enzyme tryptophan hydroxylase. Localisation of 5HT-4R was determined by dual-label immunocytochemistry using smooth muscle actin (α-SMA) and pan-neuronal markers (PGP 9.5) and quantitative analysis was carried out. Site-specific gene expression analysis of 5HT-4R was assessed within myenteric ganglia and muscle layers. Correlation of 5HT-4R with muscarinic receptors 2 and 3 (M2R, M3R) messenger RNA expression was determined. RESULTS: 5HT-4R mRNA expression was downregulated in the tunica muscularis and upregulated in the mucosa of patients with DD, whereas the other components of the serotonergic system remained unchanged. 5HT-4R was detected in ganglia and muscle layers, but was decreased in the circular muscle layer and myenteric ganglia of patients with DD. 5HT-4R mRNA expression correlated with M2R/M3R mRNA expression in controls, but not in patients with DD. CONCLUSIONS: The serotonergic system is compromised in DD. Altered expression of 5HT-4R at mRNA and protein levels may contribute to intestinal motor disturbances reported in patients with DD. The findings support the hypothesis that DD is associated and possibly promoted by an enteric neuromuscular pathology.

Absence of mucosal inflammation in uncomplicated diverticular disease.

BACKGROUND: Uncomplicated diverticular disease is a common condition in patients older than 50 years. Symptoms are aspecific and overlapping with those of irritable bowel syndrome. Nowadays, patients are often treated with antinflammatory drugs (5-aminosalicilic acid). AIM: Our purpose was to evaluate the presence of inflammation in the colonic mucosa of patients with symptomatic uncomplicated diverticular disease compared with subjects without diverticula. METHODS: Endoscopic biopsies of colon from 10 patients with symptomatic uncomplicated diverticular disease and 10 from subjects without diverticula (controls) were taken. Specimens were homogenised and IL2, IL4, IL5, IL8, IL10, IL12p70, IL13, IFN gamma, TNF alfa (searchlight multiplex technique), TGF beta, transglutaminase type 2 and caspase 9 were measured. Histochemistry for transglutaminase type 2 and TUNEL were performed on the histological sections, in addition to morphologic evaluation, as markers of tissue remodelling and apoptosis. For statistical analysis Student's t test and Spearman correlation test were used. RESULTS: No histological differences were detected between the patients with an uncomplicated diverticular disease and controls. Mean values of mucosal cytokines and of the other tested parameters did not show statistically significant differences between patients with uncomplicated diverticular disease and controls. CONCLUSIONS: Even if based on a small number of patients, the study demonstrates the absence of inflammation in the mucosa of subjects affected by uncomplicated diverticular disease.

Tachykinin NK2 receptor and functional mechanisms in human colon: changes with indomethacin and in diverticular disease and ulcerative colitis.

Neurokinin A (NKA) is an important spasmogen in human colon. We examined inflammatory disease-related changes in the tachykinin NK(2) receptor system in human sigmoid colon circular muscle, using functional, radioligand binding, and quantitative reverse transcription-polymerase chain reaction methods. In circular muscle strips, indomethacin enhanced contractile responses to NKA (p < 0.01) and to the NK(2) receptor-selective agonist [Lys(5),MeLeu(9),Nle(10)]-NKA(4-10) (p < 0.05) in both normal and acute diverticular disease (DD) specimens, indicating NK(2) receptor-mediated release of relaxant prostanoids. Contractile responses to both tachykinins were reduced in strips from DD (p < 0.001) and ulcerative colitis (UC) (p < 0.05) specimens. Responses to acetylcholine were no different in other strips from the same disease patients, demonstrating that the change in responsiveness to tachykinins in disease is specifically mediated by the NK(2) receptor. In membranes from UC specimens, receptor affinity for (125)I-NKA (median K(D) 0.91 nM, n = 16) was lower (p < 0.01) than that in age-matched control specimens (K(D) 0.55 nM, n = 40), whereas K(D) (0.65 nM, n = 28) in DD was no different from control. No disease-related changes in receptor number (B(max)) were found (mean, 2.0-2.5 fmol/mg of wet weight tissue), suggesting that the reduced contractile responses in disease are not due to a loss of receptor number. Different mechanisms may account for the reduced contractility in DD compared with UC. A gender-related difference in receptor density was seen in controls, with B(max) lower in females (1.77 fmol/mg, n = 15) than in males (2.60 fmol/mg, n = 25, p = 0.01). In contrast, no gender-related differences were seen in NK(2) receptor mRNA in control colonic muscle, indicating that the gender difference is a post-translational event.

Increased presence of serotonin-producing cells in colons with diverticular disease may indicate involvement in the pathophysiology of the condition.

INTRODUCTION: Serotonin is an important neuroendocrine transmitter participating in the control of colonic motor activity through neural and biochemical mechanisms in the Enteric Nervous System (ENS). A possible pathophysiological factor for diverticular disease (DD) is altered colonic motility. The study compared the distribution of serotonin cells (SC) in the colonic mucosa of patients with diverticular disease to controls. METHODS: Sixteen paraffin specimens with sigmoid diverticular disease were selected and sections of bowel without diverticula from the same specimen were used as its own control. The resection margins from sixteen colonic specimens excised for sigmoid cancer were additional controls. Immunocytochemical staining for serotonin cells was performed on 4-mum tissue sections with polyclonal antibody (NCL-SEROTp). The number of serotonin-positive cells per ten microscopic fields (x200) was assessed in all groups and the staining distribution was defined as low (0-33%), moderate (>33-66%) and high (>66%) according to the percentage of the entire cell containing contrast material. The control specimens were blinded before analysis. Student's t test was used for statistical analysis and significance level was set as P < 0.05. RESULTS: The mean number of serotonin-positive cells per ten fields in the colonic mucosa of specimens with diverticular disease was significantly higher [252.44 (SD 90.64)] than the specimen's own control [147.31 (SD 50.16)] and at normal resection margins of cancer specimens [228.38 (SD 120.10)]. The paired analysis between diverticular disease specimens and its own control (paired t test) showed significant differences for moderate (P = 0.008), high (P = 0.001) and total (P = 0.002) number of serotonin cells. There was no evidence of significance between mean DD and cancer values. DISCUSSION: Increased presence of SCs and the higher proportion of high and moderate staining cells (indicating increased hormone content) indicate the possible role of serotonin in DD. This may be contributing to the pathogenesis of the condition by altered colonic motility in the affected segments in a similar way as in irritable bowel syndrome.

Significant increase of colonic mutated crypts correlates with age in sporadic cancer and diverticulosis cases, with higher frequency in the left- than right-side colorectum.

Mild periodic acid-Schiff (mPAS) staining can discriminate non-O-acetylated (mPAS-positive) from O-acetylated (mPAS-negative) epithelial sialoglycoproteins in human colonic mucosa, allowing the three haplotypes expressed from a single polymorphic autosomal gene (oat) to be distinguished. In heterozygotes, we previously demonstrated wholly mPAS-positive (stem cell mutated) crypts and clusters of two or more mPAS-positive crypts to be significantly increased with duration of ulcerative colitis. To establish whether such an increase in the number of mutated crypts with age also occurs in normal individuals or in cases with diverticulosis, the O-acetylation phenotype in the non-cancerous colonic mucosa of 47 sporadic colorectal cancer patients who were heterozygotes for oat was tested with mild-PAS staining. PAS-positive crypts were assessed histologically in relation to age and compared between the left (sigmoid colon and rectum) and right (cecum and ascending colon) sides of the colorectum. Wholly mPAS-positive (stem cell mutated) crypts and foci in heterozygotes were found to be increased significantly (P < 0.0001) in the left side with aging (r = 0.598 and 0.643, respectively). Such a positive correlation with aging was also confirmed in 19 diverticulosis cases without cancer (r = 0.797 and 0.793, respectively). The frequency of mutated crypts and foci on the right side was significantly lower than on the left side in both spontaneous colorectal cancer and diverticulosis cases. The results provide support for an intimate relationship between accumulation of mutated crypts with aging, possibly with significance for colorectal cancer development. Furthermore, the environment in the right side of the colon may be different from that in the left side in this regard.

Morphology of colorectal lymphoid aggregates in cancer, diverticular and inflammatory bowel diseases.

The present study compares the characteristics of colorectal lymphoid aggregates in patients with carcinoma, diverticular disease, Crohn's disease, or ulcerative colitis of the large bowel. A total of 77 patients (41 colorectal cancer, 27 diverticular disease, six ulcerative colitis, three Crohn's disease) undergoing colorectal resection were included. Acetic acid staining, hematoxylin and eosin staining, CD3, CD20, and MIB1 immunostaining were employed in order to assess density, diameter, subepithelial or basal location, cellular profile, and proliferation of lymphoid aggregates in normal-appearing and actively inflamed large bowel. In normal-appearing tissue, mean density of lymphoid aggregates was lower in patients with ulcerative colitis and Crohn's disease than in those with colorectal cancer or diverticular disease. A larger mean diameter of aggregates was observed in patients with Crohn's disease. In inflammatory bowel diseases, a marked increase of the mean density of lymphoid aggregates was observed in actively affected specimens. In Crohn's disease more than in ulcerative colitis, the aggregates had a predominant basal or transmural distribution. In diverticular disease, active inflammation determined a less significant increase of subepithelial aggregates harboring a lower proportion of germinal centers. No significant variations of CD3, CD20, and MIB1 were recorded among the four disease groups. The lymphoid aggregate derangements observed not only in the actively affected mucosa but also in the unaffected colorectal lining of patients with Crohn's disease and ulcerative colitis support a relevant involvement of lymphoid aggregate system in the pathogenesis of inflammatory bowel diseases.

Smooth muscle cholinergic denervation hypersensitivity in diverticular disease.

BACKGROUND: Evidence from clinical and laboratory investigations into the causes of diverticular disease suggests that disturbances in cholinergic activity are important, the effector mechanisms of which have yet to be established. We aimed to investigate the role of smooth muscle and neural cholinergic activity in the pathogenesis of this disease. METHODS: Two investigators independently did a blinded immunohistochemical image analysis of localising antibodies to choline acetyltransferase, co-localised with protein gene product (PGP)--a marker of general neural tissue-and smooth muscle muscarinic M3 receptors, on three histological sections of sigmoid colons from ten patients with diverticular disease and ten controls, after resections for rectal tumours. We also did isotonic organ bath experiments to assess muscle strip sensitivities to exogenous acetylcholine. FINDINGS: In circular muscle, activity of choline acetyltransferase was lower in patients with diverticular disease than in controls: median percentage surface area of choline acetyltransferase over PGP was 17.5% (range 10.0-37.0) in patients with diverticular disease and 47.0% (29.0-54.0) in controls (p<0.0001). M3 receptors were upregulated in patients with diverticular disease compared with controls: the median surface area was 13.2% (6.0-23.3) in patients with diverticular disease and 2.5% (1.6-3.7) in controls (p<0.0001). The sensitivity to exogenous acetylcholine was increased in patients with diverticular disease (mean -log EC(50) 5.6 [SD 0.3]) compared with controls (4.9 [0.5]; difference 0.7 [95% CI 0.3-1.1], p=0.006). In longitudinal muscle, choline acetyltransferase activity was lower in patients with diverticular disease (median 19.5%, range 12.0-30.0) than in controls (47.0%, 35.0-60.0; p<0.0001), with upregulation of M3 receptors in diverticular disease (diverticular disease 7.8% [1.9-20.4], controls 1.7% [0.8-3.0]; p<0.0001). However, sensitivity to exogenous acetylcholine did not differ between the two groups (diverticular disease mean 5.6% [SD 0.3], controls 5.2% [0.4]; difference 0.4% [95% CI -0.02-0.7], p=0.06). INTERPRETATION: Our results suggest that cholinergic denervation hypersensitivity can affect smooth muscle. Upregulation of smooth muscle M3 receptors might account for specific clinical, physiological, and pharmacological abnormalities associated with diverticular disease.

Type I and III collagens in human colon cancer and diverticulosis.

BACKGROUND: Collagens are major proteins in the extracellular matrix, providing tissues with tensile strength. They are also important for cell adhesion and the invasion of malignant tumours. METHODS: Thirty-nine samples of human colon (24 diverticulosis, 6 malignant tumours, 9 controls) were collected during elective surgery. Immunoassays for different domains of type I and III collagens and procollagens were used in soluble tissue extracts and trypsin digests of tissue samples. RESULTS: The contents of cross-linked type I and III collagen telopeptides and total collagen were similar in diverticulosis and healthy tissue, whereas in malignant tissue maturely cross-linked type III collagen was scarce. Furthermore, some of the cross-linked type I telopeptide antigens were exceptionally small in size, indicating that the cross-linking of type I collagen in collagen fibres is impaired in cancer. The rate of type I collagen synthesis was clearly increased in malignancy, but not significantly in diverticulosis. However, type III collagen synthesis was increased in diverticulosis, but not in malignancy. CONCLUSIONS: In colon malignancy, the collagen cross-linking process was aberrant and the synthesis of type I collagen increased. In diverticulosis, the synthesis of type III collagen was increased, suggesting only moderately increased metabolic activity.

Cross linking of collagen is increased in colonic diverticulosis.

Development of colonic diverticulosis is a function of age and declining colonic wall mechanical strength. The latter is partly a consequence of changes in the collagen structure. Collagen from unaffected human colons (n = 20, age range 20-80 years) and those with colonic diverticulosis (n = 5, age range 67-80 years) were obtained at necropsy. The total collagen content was measured as the hydroxyproline content and cross linkage by collagen solubility in weak acid was studied. The colonic total collagen content was constant with age (mean (SD) 15.8 (0.3) mg/100 mg wet weight of tissue). The acid solubility of the collagen, however, increased after the age of 40 years: at over 60 years, colonic diverticulosis was associated with an increased acid solubility ratio compared with values in unaffected colons (15.3 (0.2); compared with 9.2 (0.2), p < 0.001). The cross linking of colonic collagen increases with age. These changes seem to be a factor in the aetiology of colonic diverticulosis.

Relationship between nutritional status indicators and length of hospital stay for patients with diverticular disease.

The length of a patient's stay in a hospital is an indication of the patient's recovery rate. Length of hospital stay has also become an important economic factor for hospitals. This is especially true since 1983 as a result of implementation of the Prospective Payment System based on diagnosis-related groups. In this study, the results of routine laboratory tests of nutritional status were examined for relationships between nutritional status and the length of hospital stay. We conducted a retrospective analysis of 163 patients with diverticulosis and diverticulitis of the colon to determine which nutrition assessment parameters are sensitive in predicting recovery rate (length of hospital stay). We found that serum albumin level was negatively correlated with length of hospital stay. Women without gastrointestinal bleeding stayed an average of 20.1 +/- 8.5 days when serum albumin level was 30 g/L or less vs 11.2 +/- 10.5 days when it was greater than 30 g/L. Hemoglobin and/or hematocrit levels were also negatively correlated with length of hospital stay for this group. Women without bleeding stayed an average of 16.4 +/- 13.4 days when the hemoglobin level was 120 g/L or less vs 10.4 +/- 9.1 days when it was greater than 120 g/L. These results suggest that a patient's nutritional status upon admission has an effect on the length of hospital stay for patients with diverticular disease.

Short chain fatty acid distributions of enema samples from a sigmoidoscopy population: an association of high acetate and low butyrate ratios with adenomatous polyps and colon cancer.

We investigated the distribution of short chain fatty acids (SCFA) in enema samples taken from subjects before sigmoidoscopy as an indicator of possible microbial community differences between subjects subsequently diagnosed as normal or having colonic disorders. The major SCFA in all groups were acetic, propionic, and butyric acids. A significantly higher ratio of acetate to total SCFA and lower ratio of butyrate to total SCFA was found for polyp-colon cancer subjects than for normal subjects. There were no significant differences in the ratios of acetate, propionate, or butyrate between the diverticulosis or inflammatory bowel groups and the normal group. There were no significant sex differences nor were there correlations with the ratios of acetate, propionate or butyrate and age, subject weight, or dry weights of samples. Significant differences in concentrations of individual acids were found between normal and certain diagnostic groups. The difference in proportions of individual SCFA between groups suggest differences in fermentation patterns of the colonic microflora.

Submucosal collagen changes in the normal colon and in diverticular disease.

Full thickness specimens of normal colon (n = 15), and colon from patients with diverticular disease (n = 5) were obtained at operation or autopsy. In the isolated submucosa the ultrastructure of the constituent collagen fibres was examined by transmission electron microscopy. Collagen fibrils in the left colon become smaller (p less than 0.001) and more tightly packed (p less than 0.001) than those in the right colon with increasing age. This difference is accentuated in diverticular disease (p less than 0.01). Factors which contribute to the development of colonic diverticulosis, such as raised intraluminal pressure, may be responsible for premature change in submucosal structure.

Does super efficient starch absorption promote diverticular disease?

The amount of starch escaping absorption in the small intestine was measured in eight patients with symptomatic diverticular disease and eight controls. Unabsorbed starch was calculated from breath hydrogen measurements after a potato meal compared with the hydrogen response to lactulose. The proportion of unabsorbed starch was low in all the patients (mean 3.3%) and was only about a quarter of that in the controls (12.4%; p less than 0.01). These findings confirm that unabsorbed starch provides an important quantity of carbohydrate reaching the colon and suggest that super efficient starch absorption, by reducing this provision, may promote the development of diverticular disease.

A study of histochemical changes in mucus from patients with ulcerative colitis, Crohn's disease, and diverticular disease of the colon.

The colonic mucosa produces a protective and lubricating layer of mucus. In certain conditions, the quantity and quality of this mucus is impaired. This study assessed the histochemical changes in mucus in inflammatory bowel disease compared with the severity and extent of the condition. Biopsy specimens were taken from 62 patients (32 with ulcerative colitis; ten with colonic Crohn's disease; ten with diverticular disease; ten with normal controls) and sections stained with high iron diamine-alcian blue to distinguish sulphated mucins from sialomucins. Normal subjects showed a predominance of sulphated mucins. The patients with Crohn's and diverticular disease also demonstrated this normal pattern. Of the 20 patients with ulcerative colitis, and without demonstrable dysplastic changes, only one showed a moderate increase in sialomucins. However, of the 12 patients with extensive colitis and dysplastic changes, ten had an increase in sialomucins. Thus, the predominant sialomucin pattern was seen mainly in patients with dysplasia. It may, therefore, indicate patients at high risk of malignancy.

Elastosis in diverticular disease of the sigmoid colon.

Diverticular disease of the sigmoid colon is an increasingly common clinical problem in the ageing population of western industrialised countries but the mechanism by which the disease develops remains unknown. The muscular abnormality is the most striking and consistent feature and this has been studied by light and electron microscopy in 25 surgical specimens of uncomplicated diverticular disease and in 25 controls. This is the first ultrastructural study of human colonic muscle to be published and shows that the muscle cells in diverticular disease are normal; neither hypertrophy nor hyperplasia is present. There is, however, an increase in the elastin content of the taeniae coli by greater than 200% compared with controls: elastin is laid down between the muscle cells and the normal fascicular pattern of the taeniae coli is distorted. There is no alteration in the elastin content of the circular muscle. As elastin is laid down in a contracted form, this elastosis may be responsible for the shortening or 'contracture' of the taeniae which in turn leads to the characteristic concertina-like corrugation of the circular muscle. Such a structural change could explain the altered behaviour of the colon wall in diverticular disease and its failure to change on treatment with bran.