Lamina propria

Tis Carcinoma in situ intraepithelial or invasion of lamina propria... 

Agace WW, Roberts Al, Wu L, Greineder C, Ebert EC, Parker CM. Human intestinal lamina propria and intraepithelial lymphocytes express receptors specific for chemokines induced by inflammation. Eur J Immunol 2000 30 819-826. 

Jang MH, Sougawa N, Tanaka T, et al. CCR7 is critically important for migration of dendritic cells in intestinal lamina propria to mesenteric lymph nodes. J Immunol 2006 176(2) 803-810. 

The third mucosal layer is that lining the entire length of the small intestine and which represents a continuous sheet of epithelial cells. These epithelial cells (or enterocytes) are columnar in shape, and the luminal cell membrane, upon which the microvilli reside, is called the apical cell membrane. Opposite this membrane is the basal (or basolateral) plasma membrane, which is separated from the lamina propria by a basement membrane. A sketch of this cell is shown in Fig. 5. The primary function of the villi is absorption. 

Mucosa. The innermost layer of the wall is the mucosa, which consists of a mucous membrane, the lamina propria, and the muscularis mucosa. The mucous membrane provides important protective and absorptive functions for the digestive tract. The nature of the epithelial cells lining the tract varies from one region to the next. Rapidly dividing stem cells continually produce new cells to replace worn out epithelial cells. The average life span of these epithelial cells is only a few days. The lamina propria is a thin middle layer of connective tissue. This region contains the capillaries and small lymphatic vessels that take up the digested nutrient molecules. The muscularis mucosa is a thin layer of smooth muscle. Contraction of this muscle may alter the effective surface area for absorption in the lumen. 

Fig. 11.4. Model for cholinergic signalling in the intestinal mucosa, providing a possible rationale for AChE secretion by parasitic nematodes. ACh released from enteric cholinergic motor neurons stimulates chloride secretion, mucus secretion and Paneth cell exocytosis through muscarinic receptors. Secretory responses may be modulated by mast cell mediators, either directly or via the induction of neural reflex programmes. The role of muscarinic receptor-positive cells in the lamina propria of rats infected with N. brasiliensis is undetermined, as are potential mechanisms of trans-epithelial transport of the enzymes. Adapted from Cooke (1984).

T cell activation in the lamina propria is associated with epithelial cell shedding, leading to loss of villi. It has been postulated that this is mediated by increased production of matrix metalloproteases (MMP), which, by degrading the lamina propria matrix, represent a major pathway by which T cells cause injury in the gut (Pender et al., 1997). Production of MMPs also facilitates movement of cells out of the vasculature into sites of inflammation and contributes substantially to the degradation of connective tissue during inflammatory disease (Stetler-Stevenson, 1996). Furthermore, MMPs are required for the release of soluble TNF-a from its membrane... 

Intestinal infections that cause persistent diarrhea normally result in histopathological changes to the intestine including villus blunting, crypt hypertrophy and inflammatory infiltrate in the lamina propria. These histopathological disarrangements are seen in Cryptosporidium, Cy-clospora and microsporidial infections [28], Furthermore, it has been documented that there are substantial disruptions of intestinal barrier function as measured by lactu-lose mannitol permeability ratios in patients with AIDS... 

Fiorucci S, Distrutti E, Mencarelli A, Barban-ti M, Palazzini E, Morelli A Inhibition of intestinal bacterial translocation with rifaximin modulates lamina propria monocytic cells reactivity and protects against inflammation in a rodent model of colitis. Digestion 2002 66 246-256. 

Substance P, calcitonin-gene-related peptide (CGRP), and neurokinin A have been identified by immunocytochemistry in primary sensory neurones and in cutaneous sensory nerve terminals and these are often in close proximity to mast cells [54, 56], For example, in Lewis rats that were infected with the parasitic larvae of Nippostrongylis brasiliensis in order to induce a proliferation of mucosal mast cells, nearly two-thirds of the lamina propria mast cells were in intimate contact with peptidergic nerves containing SP and CGRP, while an additional 20% of the mast cells were within 2 gm [54], All three peptides are... 

Figure 8.1 (A) Cross-sectional view of the organization of the small intestine, illustrating the serosa, the longitudinal and circular muscle layers (=muscularis externa), the submucosa, and the intestinal mucosa. The intestinal mucosa consists of four layers, the inner surface cell monolayer of enterocytes, the basal membrane, the lamina propria (connective tissue, blood capillaries), and the muscularis mucosae, (B) Schematic representation of an enterocyte (small intestinal epithehal cell) (according to Tso and Crissinger [151], with permission).

The tracheo-bronchial epithelium forms the interface between the conducting airways and inspired air. As described above, the epithelium is layered upon a connective tissue substratum consisting of a basement membrane, lamina propria, and submucosa [6], The submucosa contains elastic fibres, a muscularis mucosa, connective tissues and seromucous glands. Lymphatics are also located in the bronchial walls [2],... 

The adherence mechanisms involved in Salmonella infection have been studied in great deal. Disease associated with S. enterica serovars is initiated by attachment to and invasion of hosf cells, followed by subse-quenf inflammation of the lamina propria and lymph nodes (Darwin and Miller, 1999). Several genetically defined fimbrial or piliar adhesins con-tribufe fo fhe initial attachment and the overall infection process of Salmonella. Some of fhese include t)q)e 1 fimbriae (Fim), plasmid-encoded (PE) fimbriae, long polar (LP) fimbriae, and thin aggregative fimbriae (curli). However, many ofher putative fimbrial operons have been identified within various S. enterica serovar genomes, but the expression of fhese proteins is currently undefined. 

Sun CM, Hall JA, Blank RB, Bouladoux N, Oukka M, Mora JR, Belkaid Y Small intestine lamina propria dendritic cells promote de novo generation of Foxp3 Treg cells via retinoic acid. J Exp Med 2007 204 1775-1785. 

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