The water channel aquaporin-4 (AQP4) is a protein widely expressed on plasma membrane of a variety of epithelial cells. In this study we investigated the expression of AQP4 in the gastrointestinal tract of the pig using immunohistochemical staining. We found no presence of AQP4 in the different regions of the pig stomach. In the porcine small intestine moderate immunoreactivity to AQP4 was detected in enterocytes (along the villi and in the bottom of the crypts), duodenal Brunner's glands and in enteric ganglia in cells lying in close vicinity to myenteric as well as submucous neurons. In superficial epithelial cells of the colonic mucosa as well as of caecal and colonic glands a very strong immunoreactivity to AQP4 was found. Both in the myenteric and submucous ganglia of the large intestine AQP4-positive cells surrounding enteric neurons were observed. We concluded that AQP4 expression in the porcine gastrointestinal tract showed some species-dependent differences in relation to other species. Based on the presented distribution pattern of AQP4, it is likely that the aquaporin plays a role in mucous (but not acid) secretion and intestinal absorptive processes in the pig.
Aquaporins, gut, small intestine, large intestine, pig
Calretinin (CR) as a buffer and sensor protein plays an important role in regulatory processes of Ca 2+ and anty-apoptotic cellular protection. In the present study, immunohistochemical peroxidase-antiperoxidase (PAP) method was used in order to determine the numbers, morphology, morphometry and distribution pattern of CR in neurons of the chinchilla's claustrum (Cl) and endopiriform nucleus (EN). In Cl and EN the presence of several classes of neurons with different immunoreactivity to CR was found. In Cl, CR-immunoreactive (IR) neurons were predominantly found in close vicinity to insular border while CR-IR neurons were evenly scattered throughout EN. In general, immunoreaction to CR was observed in neuronal cytoplasm, nucleus and in fibres-like nerve extensions. Statistical analysis showed the differences between average large diameter as well as cross-sectional area of CR-IR neurons present in Cl and EN. It is suggested, that CR acting as a calcium binding protein may play a role in neuronal network. Further co-localization studies are necessary to fully elucidate neurophysiology and neuropathology of the chinchilla's Cl and EN neurons.
Background
Despite the continuous improvements in prevention and detection of colorectal cancer (CRC), there is an urgent need to find a sensitive, specific, and noninvasive biomarker to improve the early diagnosis and prognosis of CRC. We aimed to evaluate the tissue TEM8 expression and the serum TEM8 concentration in CRC patients.
Methods
The study enrolled 42 CRC patients and 35 controls. Immunohistochemical staining was performed to assess the TEM8 tissue expression, whereas the serum TEM8 concentration was evaluated with the ELISA assay.
Results
The expression of TEM8 observed in all primary colorectal tumor samples was significantly correlated with the TNM stages and the presence of lymphovascular invasion. The serum TEM8 concentration was significantly higher in CRC patients than in the controls. The TEM8 level was strongly associated with the TNM stage, depth of invasion, and lymph node and distant metastasis. Patients with a high serum TEM8 concentration had a worse overall survival (OS) rate than CRC patients with a low serum TEM8 level.
Conclusion
TEM8 may serve as a biomarker for the diagnosis of CRC and it has value in predicting the prognosis of patients with CRC.
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