Morphological evaluation of experimental autologous rectus fascia sheath vascular grafts used for arterial replacement in a dog model

Although experimental autologous patch or tubular conduit vascular grafts made from the internal rectus fascia sheath (IRFS) have been reported in the literature, thorough morphological evaluation and verification of the histological arterialisation of such grafts are lacking. Four purpose-bred Beagle dogs were utilised to create eight arterial internal rectus fascia sheath (ARFS) grafts implanted between bisected ends of the external iliac arteries. Four out of the eight ARFS grafts were patent after three months. Haematoxylin-eosin and Azan staining verified that the grafts gained a vessel-like layered structure with the presence of large amounts of collagen fibres. Although the inner surface of the intact IRFS was originally covered with claudin-5-negative and pancytokeratin-positive mesothelial cells in control samples, the internal cells of the ARFS grafts became claudin-5 positive and pancytokeratin negative like in intact arteries. Spindle-shaped cells of the wall of ARFS grafts were α-smooth muscle actin (α-SMA) positive just like the smooth muscle cells of intact arteries, but α-SMA immunoreactivity was negative in the intact IRFS. According to these findings, the fibroblast cells of the ARFS graft have changed into myofibroblast cells. The study has proved that ARFS grafts may be used as an alternative in arterial replacement, since the graft becomes morphologically and functionally similar to the host vessel via arterialisation

Antagonism of LPS and IFN-gamma induced iNOS expression in human atrial endothelia by morphine, anandamide, and estrogen

AIM: To determine whether inducible nitric oxide synthase (iNOS) stimulation of human atrial fragments can be diminished by the naturally occurring signal molecules, such as morphine, anandamide, and estrogen. The use of iNOS as an indicator is justified since it has been associated with initiation of various types of cellular damage either directly or indirectly. METHODS: Western blots were performed on control and drug-exposed atrial tissue before and after lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) exposure. RESULTS: Preincubation of the tissue with morphine, anandamide or estrogen prior to, but not after, the addition of LPS + IFN-gamma, blocked iNOS expression. The nitric oxide donor SNAP also blocked iNOS induction while preincubation of atrial fragments with an inhibitor of NOS, L-NAME, prior to morphine or anandamide exposure, restored LPS + IFN-gamma induction of iNOS. CONCLUSION: These data suggest a direct regulatory link at the transcriptional level between constitutive (c) NOS and iNOS in human atrial tissue

μ3 Opiate receptor expression in lung and lung carcinoma: ligand binding and coupling to nitric oxide release

The mu 3 opiate receptor subtype is expressed in human surgical specimens of both normal lung and non-small-cell lung carcinoma. Nitric oxide (NO) release is mediated through the mu 3 receptor, and in lung carcinoma, morphine-stimulated NO release is significantly higher and prolonged than in normal lung. Using reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern blot analysis we show that specific mu opioid receptor transcripts are present in lung carcinoma and other cells with the mu 3 profile. Our findings identify a unique role for the mu 3 opiate receptor in opiate-mediated NO release and suggest that endogenous opiates, through their release of NO, may play a role in cancer progression

Morphine and anandamide stimulate intracellular calcium transients in human arterial endothelial cells: coupling to nitric oxide release

Both morphine and anandamide significantly stimulated cultured endothelial intracellular calcium level increases in a concentration-dependent manner in cells pre-loaded with fura 2/AM. Morphine is more potent than anandamide (approximately 275 vs. 135 nM [Ca]i), and the [Ca]i for both ligands was blocked by prior exposure of the cells to their respective receptor antagonist, i.e., naloxone and SR 171416A. Various opioid peptides did not exhibit this ability, indicating a morphine-mu3-mediated process. In comparing the sequence of events concerning morphine's and anandamide's action in stimulating both [Ca]i and nitric oxide production in endothelial cells, we found that the first event precedes the second by 40+/-8 sec. The opiate and cannabinoid stimulation of [Ca]i was attenuated in cells leeched of calcium, strongly suggesting that intracellular calcium levels regulate cNOS activity