Crypt Area Research Articles

Regenerative signals for intestinal epithelial organoid units transplanted on biodegradable polymer scaffolds for tissue engineering of small intestine.

Our laboratory is investigating the tissue engineering of small intestine using intestinal epithelial organoid units seeded onto highly porous biodegradable polymer tubes. This study investigated methods of stimulation for optimizing neointestinal regeneration. Intestinal epithelial organoid units harvested from neonatal Lewis rats were seeded onto porous biodegradable polymer tubes and implanted into the omentum of adult Lewis rats in the following groups: (1) the control group (group C), implantation alone (n=9); (2) the small bowel resection (SBr) group, after 75% SBr (n=9); (3) the portacaval shunt (PCS) group, after PCS (n=8); and (4) the partial hepatectomy (PH) group, after 75% PH (n=8). Neointestinal cyst size was recorded using ultrasonography. Constructs were harvested at 10 weeks and were examined using histology. Morphometric analysis of the neomucosa was obtained using a computer image analysis program (NIH Image, version 1.59). Cyst development was noted in all animals. Cyst lengths and diameters were significantly larger in the SBr group at 7 and 10 weeks compared with the other three groups (P<0.05; analysis of variance [ANOVA], Fisher's protected least significant difference). Histology revealed a well-vascularized tissue with a neomucosa lining the lumen with invaginations resembling crypt-villus structures. Morphometric analysis demonstrated a significantly greater villus number, height, area, and mucosal surface in the SBr group compared with the other three groups and a significantly greater crypt number and area in the PCS group compared with group C (P<0.05; ANOVA, Fisher's protected least significant difference). Intestinal epithelial organoid units transplanted on porous biodegradable polymer tubes can successfully vascularize, survive, and regenerate into complex tissue resembling small intestine. SBr and, to a lesser extent, PCS provide significant regenerative stimuli for the morphogenesis and differentiation of tissue-engineered small intestine.

REGENERATIVE SIGNALS FOR INTESTINAL EPITHELIAL ORGANOID UNITS TRANSPLANTED ON SYNTHETIC BIODEGRADABLE POLYMER SCAFFOLDS FOR THE TISSUE ENGINEERING OF SMALL INTESTINE

101 Our laboratory is investigating the tissue-engineering of small intestine using intestinal epithelial organoid units seeded on biodegradable polymer tubes. Previous studies have demonstrated the formation of cysts with tissue morphology resembling small intestine. This study investigates methods of stimulation for optimizing neointestinal regeneration. Intestinal epithelial organoid units (4-6 × 104 units) harvested from neonatal Lewis rats were seeded onto synthetic biodegradable polymer tubes (n=34) created from nonwoven sheets of PGA fibers sprayed on the outer surface with 5% PLA. These organoid unit/polymer constructs were implanted into the omentum of adult male Lewis rats (175-250 grams) in the following conditions: 1). C: control, implantation alone (n=9); 2). SBR: after 75% small bowel resection (n=9); 3). PCS: after portacaval shunt (n=8); and 4). PH: after 75% partial hepatectomy (n=8). Ultrasonography was performed at 3, 7, and 10 weeks to document neointestinal cyst size and growth. The constructs were harvested at 10 weeks and examined by histology. Morphometric analysis of the neomucosa including villus number, villus height, mucosal surface area, crypt number, and crypt area was obtained using a video-microscope integrated computer program (NIH Image, version 1.59) by a blinded observer. Cyst development was noted in all animals. Ultrasonography demonstrated no significant differences in cyst size at 3 weeks. As shown in the table, at 7 and 10 weeks, cyst lengths and diameters were significantly greater in the SBR group compared to the other groups (*P<0.05, ANOVA, Fisher's PLSD). Histology revealed a neomucosa lining the lumen of the cyst with invaginations resembling crypt-villus structures. Morphometric analysis demonstrated a significantly greater villus number (18±2), villus height (133.9±22.6µm), and mucosal surface area (8533.3±977.6µm2) in the SBR group compared to the other groups (C: 11.4±3.6, 87.1±7.8µm, 5998.4±416.5 µm2; PCS: 12.3±1.8, 89.9±10.3µm, 6131.6±548.4 µm2; PH: 12±4, 97.3±9.6µm, 6000.1±777.1 µm2; P<0.01, ANOVA, Fisher's PLSD), and a significantly greater crypt number (23.3±2.2) and crypt area (68127.3±12431.5µm2) in the PCS group compared to control (14.6±5.7; 40150.8±16388.7µm2; P<0.01, ANOVA, Fisher's PLSD).TableIntestinal epithelial organoid units transplanted on biodegradable polymer tubes can successfully survive and regenerate into complex tissue resembling small intestine. Small bowel resection, and to a lesser extent, portacaval shunt, contribute significant regenerative stimuli for the morphogenesis and differentiation of tissue-engineered small intestine.

Altered stem cell regeneration in irradiated intestinal crypts of senescent mice.

Ageing is associated with a progressive deterioration in the functions of many organs within the body. In tissue with high cell turnover, the maintenance of the stem cells is of particular importance. Any accumulation of damage in stem cells may affect their function and hence threaten the homeostasis and regenerative capacity of the tissue. The small intestine represents a good model for the study of stem cells because of its spatial and hierarchical organisation. We have examined the effect of age on stem cell regenerative capacity after irradiation, using the microcolony assay. Crypt survival levels, the growth rate of surviving crypts, and the number of cells able to repopulate a crypt have been investigated by irradiating groups of 6-7 month old and 28-30 month old ICRFa male mice. After high doses of irradiation, the surviving crypts in old mice were both smaller and fewer in number than in young mice. The growth rate of surviving crypts was determined by measuring the crypt area and the number of cells/crypt at various times after 14 Gy irradiation. There was a growth delay of between about one half and one day in the older mice. Surprisingly, the number of clonogenic cells per crypt was estimated to be greater in the older mice. These studies indicate important age-related alterations in the capacity to regenerate the crypts after radiation damage.

Expression of major histocompatibility complex class II antigens in the canine intestine

Immunohistochemical techniques were used to assess major histocompatibility complex (MHC) class II expression by enterocytes and lamina propria cells in the canine intestinal tract. Duodenal enterocyte class II expression was faint and limited to the lower crypt region whereas jejunal and ileal enterocyte expression was stronger, being present in both crypt and villus areas. Enterocyte staining was of greatest intensity in crypts adjacent to Peyer's patches and intense membrane staining of most Peyer's patch lymphocytes was also seen. Enterocyte MHC class II expression in the colon was largely limited to the lower crypt region. Within the lamina propria, of all intestinal sites examined, a heterogeneous population of cells were MHC class II positive and these had morphological features of macrophages and dendritic cells. Lymphocytes, plasma cells, fibroblasts and vascular endothelium were not stained. Definition of constitutive expression of MHC class II within the canine intestine may be important in identifying upregulation of this molecule in inflammatory bowel diseases.

Regional proliferative patterns in the colon of patients at risk for hereditary nonpolyposis colorectal cancer.

Patients from a hereditary nonpolyposis colorectal cancer (HNPCC) kindred (Lynch Type 1 and Type 2) have an increased risk of developing large-bowel cancer. Tumors occur at a young age and are characteristically right-sided. Colonic mucosal proliferation is known to be increased in several groups of patients at risk of colorectal cancer. This study was performed to assess the pattern of mucosal proliferation at different sites in the colon of patients at risk of HNPCC and to determine whether this pattern differs from normal patients. Mucosal biopsies were obtained at colonoscopy from 21 patients at risk for HNPCC (16 females; mean age, 42 years) and from 7 normal patients (4 females; mean age, 38 years), and mucosal proliferation was quantified using the whole crypt mitotic count (WCMC) technique. In patients from HNPCC families, WCMC and crypt area were significantly greater in the cecum than in the transverse colon and left colon (P < 0.001). Compared with normal patients, WCMC in HNPCC patients was significantly greater in the cecum only (P < 0.05). A significant right-to-left shift was also observed in normal patients, but the percentage increase from right to left was two-fold greater in HNPCC patients. These results confirm a proximal-to-distal proliferative gradient in the human colon and suggest that this may be exaggerated in HNPCC. This increased proximal proliferative rate may be a factor in the development of right-sided cancer in these patients.

Phenotypic characterisation of intestinal lymphocytes in ovine paratuberculosis by immunohistochemistry

Characterisation of the T-cell subsets in intestinal lesions in sheep with paratuberculosis may contribute to our understanding of the pathogenesis of this disease. To determine the phenotype and distribution of lymphocytes in the normal sheep intestinal mucosa and in Mycobacterium avium subspecies paratuberculosis infected sheep, immunohistochemistry was performed on 12 normal sheep and 18 naturally infected, clinically diseased sheep of which 12 showed lepromatous and six tuberculoid forms of the disease. Immunoperoxidase staining was carried out on frozen sections of ileum using monoclonal antibodies against ovine CD4, CD8, and γδ·T-cell receptor (TCR) markers. In all three sample groups, cells appeared to be non-randomly distributed throughout the lamina propria. Higher densities of lymphocytes were present in villus than in crypt areas. CD8 + cells were located principally around the epithelial basement membrane, whereas CD4 + cells were localised towards the central villus area of the lamina propria. Lymphocytes bearing the γδ T-cell receptor were more widely distributed, both in epithelial and lamina propria compartments. Ileum with tuberculoid lesions had higher densities of CD4 and γδ T-cell subsets while lepromatous lesions had lower densities of CD4 and CD8 cells compared with normal tissues. The median relative percentage of CD4 + cells was increased and that of CD8 + cells decreased in tuberculoid cases, with a corresponding increase in the CD4:CD8 ratio, while the relative percentage of γδ + cells was increased in lepromatous cases.

Milk Growth Factors Enriched from Cheese Whey Ameliorate Intestinal Damage by Methotrexate When Administered Orally to Rats

Currently, there are no truly effective therapies for the treatment of chemotherapy-induced intestinal mucositis, a debilitating side effect with a pathophysiology common to many chemotherapy regimens. We tested the efficacy of a growth factor extract derived from cheese whey against experimental intestinal mucositis in rats. Rats were subcutaneously injected with the chemotherapeutic drug methotrexate on d 1, 2 and 3 to induce severe damage in the small bowel and bacterial translocation across the gut. Whey extract (15 to 514 mg/d) was given orally for 5–12 d, starting on d 1. Controls were fed an isonitrogenous diet. Histological indices of villus and crypt integrity were utilized to assess potential efficacy of the extract. Administration of the whey extract for 5 d increased the villus surface length indices in the jejunum and ileum by 52% and 56%, respectively (P < 0.001) compared with controls not receiving the whey extract. The crypt area index was 64% greater (P < 0.001) in the jejunum, but not significantly greater in the duodenum or ileum compared with controls not receiving whey extract. Similarly, sucrase activity was significantly higher in the ileum (P < 0.001) but not significantly elevated in the jejunum, whereas bacterial translocation (incidence and number of colonies) was significantly reduced compared with controls not receiving whey extract. We conclude that oral whey growth factor extract reduces methotrexate-induced damage in the small bowel, which suggests clinical applications for the treatment of intestinal mucositis.

IgA nephropathy with poorly developed lymphoepithelial symbiosis of the palatine tonsils.

Tonsillar abnormalities have been observed in patients with IgA nephropathy (IgAN). In addition, it has been suggested that reticulization of tonsillar crypt epithelium is important in tonsillar immunity. Therefore, we investigated reticulization of this area in patients with IgAN (14 cases) and compared results with those of control patients who exhibited recurrent tonsillitis or tonsillar hypertrophy (12 cases). Immunohistochemical staining of antikeratin antibody PKK1 was employed to visualize reticulization. Tonsils of controls showed well developed reticular crypt epithelia with lymphoepithelial symbiosis and the nonreticulated area was less than 7% of the total crypt epithelia per overall section. In IgAN tonsils, however, nonreticulated crypt epithelium was frequently observed and, in the advanced stage of IgAN, exceeded 50% of total crypt epithelia. The extent of glomerular damage in IgAN patients correlated significantly with the percentage of the area of nonreticulated crypt in palatine tonsils with a correlation coefficient of 0.91. Considered together with our finding that PKK1-positive epithelial reticular cells strongly expressed HLA-DR antigens in normal tonsils, the low level of reticulization in IgAN patients may induce the unusual immunity responsible for the pathogenesis of IgAN.

Astrovirus Infection in Hatchling Turkeys: Histologic, Morphometric, and Ultrastructural Findings

In three separate experiments, 2- or 5-day-old commercial turkey poults were inoculated orally with astrovirus and examined for clinical signs and for gross and microscopic lesions over a period of 14 days. By day 2 postinoculation (PI), inoculated poults had developed diarrhea, generalized loss of intestinal tone, and dilated ceca that contained light-yellow fluid feces and gas; these changes persisted through day 10 PI. Mild crypt hyperplasia was the only change discernible by light microscopy, and it was first noted in the proximal jejunum on day 1 PI, in the distal jejunum and ileum on day 3 PI, and in the duodenum on day 5 PI. A significant (P < 0.05) increase in crypt depth and area was documented by image analysis on day 3 PI. Ultrastructural evaluation revealed intracytoplasmic aggregates of astrovirus in enterocytes on the sides and base of villi in the ileum and distal jejunum on day 3 PI. Based on the findings, it was concluded that astrovirus caused lesions and replicated in both upper and lower segments of the small intestine in turkey poults.

K-ras mutations in putative preneoplastic lesions in human colon.

A mutation in c-K-ras (KRAS2) has long been implicated as one of the important early events in the development of a large proportion of human colon cancers. Aberrant crypt foci, putative preneoplastic lesions identified microscopically in wholemounts of colons, have been shown to occur with high frequency in the colons of animals treated with colon carcinogens and in the grossly normal mucosas of patients with colon cancer. In this study, we asked whether the mutational activation of K-ras occurs in the aberrant crypt foci of human colon. Grossly normal colonic mucosas were obtained from seven patients during surgery and were provided to us by the Western Division of the Cooperative Human Tissue Network located at Case Western Reserve University. A total of 42 samples, consisting of aberrant crypt foci and similarly sized normal crypt areas, were microdissected from the grossly normal colonic mucosas. The DNA region containing codon 12 of K-ras was amplified by polymerase chain reaction and analyzed for mutations by dot-blot hybridization with specific oligonucleotide probes complementary to normal or mutant sequences. Mutations in codon 12 of K-ras were found in 11 (73%) of 15 aberrant crypt foci but not in any of 27 morphologically normal crypt areas from the same patients. The observed high frequency of K-ras mutations in these microscopically identifiable lesions makes mutation in K-ras the earliest identified gene-mutational event in human colon tumorigenesis, establishes that it often occurs prior to the development of polyps, and is consistent with the hypothesis that aberrant crypt foci are the earliest identified precursors of human colon cancer. Further analysis of aberrant crypt foci may identify yet unknown early genetic events that precede human colon cancer.

Protein source and their effects upon canine colonic morphology and mucosal energetics

Fifteen adult mongrel dogs were fed one of three diets which varied only in the source of dietary protein (soyprotein, casein or meat) and maintained on their respective diet for a minimum of 14 days prior to experimentation. Mucosal tissues were collected from proximal, mid and distal segments of the colon for composition, morphometric and energetic analysis. The feeding of dogs diets derived from soyprotein, casein or meat resulted in statistical differences being observed for their colonic weight, protein and fat content per unit body weight. The soyprotein fed animals had heavier, more protein dense bowels than dogs fed casein or meat. However, morphometric measurements indicate the casein fed dogs had a greater surface area to mucosal mass ratio and deeper colonic crypts than meat or soyprotein fed animals, respectively. Statistical differences were not detected for the mucosal energetic values associated with diet, however, colonic mucosal metabolic rates were higher for the casein fed dogs. The proximal segment was noted to have colonic crypts of statistically greater depth and width than the more distal segments of the bowel. These results suggest that while the feeding of soyprotein produced a heavier, more protein dense bowel, feeding casein resulted in dogs having healthier colonic tissue as defined by greater surface area and depth of crypts, and enhanced mucosal energetic activity.

Intestinal distribution of hyaluronan in small bowel allografting in the rat

Hyaluronan (hyaluronic acid; HA) was demonstrated and quantified in small bowel tissue at different times after small bowel transplantation. Semiallogeneic or semisyngeneic rat models were used to elicit either unidirectional graft rejection or graft-versus-host disease (GVHD). In normal rat small bowel, HA was present in the villous lamina propria and around medium-sized vessels in the interstitium of the crypt area. During graft rejection a cellular infiltrate and edema appeared in the lamina propria in the crypt area where an accumulation of HA was also demonstrated. There was progressive accumulation of HA in the small bowel during rejection, and on day 6 there was a threefold increase compared to the values in syngeneic grafts. The increase in tissue HA was paralleled by an increase in the total water content of the rejecting graft. In specimens from animals suffering from GVHD, no significant changes in water or HA content and distribution were observed until day 12. The data suggest that accumulation of HA might contribute to the pathophysiology of the transplantation edema and that HA might be of potential diagnostic value in differentiating between graft rejection and GVHD.

Effects of fasting and hibernation on ion secretion in ground squirrel intestine.

Ground squirrels were used to study the effects of fasting and hibernation on small intestinal secretory function. Muscle-stripped sheets of jejunum set up in flux chambers were challenged with a variety of secretory agonists, and changes in short-circuit current (Isc) were recorded. Mucosal wet weights per centimeter and crypt dimensions were not affected by a 3-day fast in active squirrels, but villus height and area were significantly reduced in hibernators that had not eaten for over 6 wk. Tissue conductance was significantly greater in fasted and hibernating squirrels compared with fed animals. Maximal changes in Isc evoked by electrical stimulation of submucosal neurons, normalized to serosal surface area, were greater in fasted compared with fed or hibernating squirrels. When responses were normalized to crypt area, neurally evoked changes in Isc were greatest in the hibernators. Carbachol and serotonin evoked dose-dependent changes in Isc that were greater in fasted compared with fed squirrels at all concentrations. Histamine (100 microM) and theophylline (1 mM) also produced greater increases in Isc in fasted than in fed squirrels. The results suggest that a 3-day fast, or the extended fast of hibernation, results in enhanced secretory capacity in the ground squirrel jejunum.

Intestinal secretion after jejunal bypass in the ground squirrel.

The preceding paper [H. V. Carey, Am. J. Physiol. 263 (Regulatory Integrative Comp. Physiol. 32): R1202-R1208, 1992] demonstrated that a 3-day fast or the extended fast of hibernation enhanced the chloride secretory responses to a variety of agonists in the ground squirrel jejunum. Here we examined the effect of jejunal bypass on intestinal secretory capacity in squirrels that either remained active and continued to feed (ACT), or were induced to hibernate (HIB). Mucosal wet weights were reduced in jejunal segments that had little or no exposure to the luminal stream (all segments from HIB and bypassed segments from ACT) compared with segments in contact with luminal contents (sham and in continuity segments of ACT). Tissue conductances were greater in those segments not exposed to luminal contents. Short-circuit current (Isc) responses to electrical stimulation of submucosal neurons, or to serosal carbachol, were greater in segments not exposed to luminal contents when responses were normalized to serosal surface area. Normalization of secretory responses to crypt area produced a similar pattern. Isc responses to mucosal alanine, which reflect electrogenic Na+ absorption, were greatest in segments with little or no exposure to luminal contents. Tissue wet weights, conductances and secretory responses of bypassed segments of HIB and ACT squirrels were always similar. These results suggest that luminal contents directly influence jejunal secretory capacity.

Ageing and duodenal morphometry.

Small bowel morphometry was studied in 25 subjects under the age of 70 years and 22 over the age of 70. There was no evidence of malabsorption or malnutrition in either group. Two distal duodenal endoscopic biopsy specimens were examined morphometrically. There were no significant correlations between age and areas of duodenal surface epithelium, crypts and lamina propria, heights of villi and surface epithelium, depth of crypts, crypt to villus ratio, number of intraepithelial lymphocytes, duodenal architecture, enterocytes, brush border and Brunner glands. Contrary to previous reports there was no evidence for a significant effect of age on proximal small bowel morphometry.

Effects of the prostaglandin analogue misoprostol on cell proliferation in the canine small intestine

While there are several reports of prostaglandins of the E series being associated with increased mucosal mass in the stomach, their effects on the small intestine are less well documented. A microdissection-based technique was used to measure proliferation and crypt size in the duodenum, jejunum and ileum of dogs given the prostaglandin analogue misoprostol. Six test and six control animals were given an oral dose of 300 micrograms kg-1 day-1 of misoprostol for 11 weeks, a dose-duration combination chosen to optimize the development of gastric hyperplasia. Misoprostol increased both the area of the crypts (P less than 0.001) and the number of mitoses per crypt (P = 0.002) throughout the small intestine. The technique also demonstrated a significant gradient in crypt size and in crypt area from the duodenum to the ileum. There was no statistical interaction between misoprostol and the site studied, suggesting that this trophic effect was systemic or systemically mediated.

Alteration in intestinal morphologic features associated with extensive large-colon resection in horses

SUMMARY Light microscopy, morphometry, and scanning electron microscopy were used to examine the mucosal morphologic features of 7 intestinal specimens (3 from the small intestine; 4 from the large intestine) from each of 8 horses 1 year after sham operation (group 1; n = 3) or extensive large-colon resection (group 2; n = 5). Qualitative light microscopic examination did not reveal differences between groups, but morphometry revealed significantly (P &lt; 0.05) greater intercrypt area and distance in horses with colon resection and this was most pronounced in the cecum and remaining right ventral and dorsal colon. Crypt area and depth were similar for horses with colon resection and sham operation (P &gt; 0.05). Qualitative evaluation of the scanning electron micrographs revealed more prominent crypt orifices in the large intestine of horses with colon resection. The larger intercrypt distance in the colon of horses with resection was not an obvious feature of the qualitative evaluation of the surface with scanning electron microscopy. Small intestinal morphologic features were variable and significant differences were not detected between horses with sham operation and colon resection. Horses adapted to extensive large-colon resection within 1 year by increasing the absorptive (intercrypt) surface area of the remaining large intestine.

Localization of liver fatty acid-binding protein and its mRNA in the liver and jejunum of rats: an immunohistochemical and in situ hybridization study

The localization of liver fatty acid-binding protein (L-FABP) and its mRNA in the liver and jejunum was examined in normal and 3-day-fasted rats by means of immunohistochemistry using a specific antibody to L-FABP and in situ hybridization using a synthetic oligonucleotide complementary to L-FABP mRNA as probe. In the liver from normally fed rats, the signal for L-FABP mRNA in hepatocytes was distributed throughout the lobule, with higher intensity in the periportal than in the centrolobular region. After a 3-d fasting, the mRNA signal declined in intensity throughout the lobule, in accordance with the result of Northern blot analysis. Immunohistochemistry for L-FABP showed intralobular patterns of immunoreactivity similar to those of the mRNA signal in both fed and fasted animals. In the jejunum from fed rats, L-FABP-mRNA signal was abundant in the absorptive epithelial cells lining the lower two-thirds of villus and less abundant in the villus tip cells, while the intensity of L-FABP immunoreactivity remained high in the latter cells. Fasting brought about a downward shift of the mRNA signal to an area including the upper half of the crypt and the lower portions of villus, with decreased intensity in the rest of the villus. Immunohistochemistry also showed a downward extension of the immunoreactivity into the upper crypt area. The present results suggest that in situ hybridization is a useful tool to analyze regulations of the expression of L-FABP gene in the digestive organs in association with epithelial cell migration and dietary condition.

Correlative morphometry and morphology of normal equine intestinal mucosa and comparison after adaptation to extensive large colon resection

Light microscopy, morphometry and scanning electron microscopy (SEM) were used to examine the mucosal morphology of seven intestinal specimens (three from the small intestine and four from the large intestine) from two horses not subjected to surgery and three horses one year after sham-operation for colon resection. Qualitative and quantitative evaluation revealed similar morphology for all horses except that the unoperated horses had significantly (P < 0.05) fewer goblet cells in the crypts of the large intestine. In the small intestine, SEM demonstrated that villus shape varied and ranged from coned to broad and flat. In the large intestine, SEM of the right ventral and dorsal colon revealed more prominent crypt openings than in the caecum. The small colon contained the most prominent crypt openings with the least variation among horses. In the small intestine, light microscopy and morphometry revealed a greater number of goblet cells and a decreased width to the enterocytes in an aboral direction from the cranial jejunum to the ileum. In the large intestine, the crypt area and crypt depth increased significantly and the intercrypt area decreased significantly in an aboral direction from the caecum to the small colon (P < 0.05). In comparison to the normal morphology, horses one year after extensive large colon resection had significantly greater intercrypt area in the caecum and remaining large colon.

The histopathological study of human palatine tonsils--especially age changes

The purpose of this study was to quantitatively and qualitatively analyze the age-related histopathological changes of human palatine tonsil. As for specimens of total 118 tonsils, 52 palatine tonsils obtained at autopsy and 66 palatine tonsils obtained by tonsillectomy from patients with the diagnosis of chronic tonsillitis were used. Of these specimens, 71 were from male and 47 were from female, and the age ranged from 6 months to 89 years. The palatine tonsil was routinely sectioned longitudinal at its median, toward the tonsil hilus. 4 microns thick sections were prepared and then stained with hematoxylin-eosin, and according to the elastica-van Gieson staining method. The I-BAS one picture analyzer of ZEISS Co. was used to determine the areas covered with the parenchymal (lymphatic tissue) and extraparenchymal tissue (crypt, fibrous connective tissue and fatty generation) of the palatine tonsil. The results obtained are as follows; 1) The ratio of the parenchymal area to the total area of tonsils, in both specimens obtained at autopsy and tonsillectomy, decreased with age. 2) The average area of lymphoid follicles, in both specimens obtained at autopsy and tonsillectomy, decreased with age. 3) The number of lymphoid follicles per unit area, in both specimens obtained at autopsy and tonsillectomy, did not show any correlation with age. However, the number remarkably decreased in patients with the age of above 70. 4) The lymphocyte infiltration number per unit area of crypt epithelium, in both specimens obtained at autopsy and tonsillectomy, decreased with age. 5) The ratio of crypt area to the total area, in both specimens obtained at autopsy and tonsillectomy, did not show any correlation with age. However, increasing tendency with age was seen. 6) The ratio of fibrous connective tissue area to the total area for, in both specimens obtained at autopsy and tonsillectomy, increased with age. 7) Collagen fibers and elastic fibers, in both specimens obtained at autopsy and tonsillectomy, showed the tendency to proliferate with age. 8) Fatty degeneration was shown to begin in specimens of about 25 years old in age, and subsequently, was seen in most of specimens of above 35 years in age. Fatty degeneration tends to increase with age. The above results indicate that the parenchymal and extraparenchymal tissues of the palatine tonsil undergo both quantitative and qualitative changes with age.