Broncho-alveolar Lavage Matrix Metalloproteases as a Sensitive Measure of Bronchiolitis Obliterans

Bronchiolitis obliterans (BO) is a survival-limiting factor in lung transplantation. There are no common BO markers in use. Since BO is associated with extracellular matrix remodeling, we asked whether matrix metalloproteases (MMPs) and their tissue inhibitors (TIMPs) could serve as BO markers. In 72 lung transplant patients (34 BO syndrome (BOS) 0, 15 BOS 0-p, and 23 BOS 1) serum and broncho-alveolar lavage (BAL) MMP and TIMP levels were examined by ELISA. The BAL cell counts were additionally analyzed. The serum MMP-2, MMP-8, MMP-9 and TIMP-2 levels were not different in all groups. In contrast, the BAL MMP-8, -9 and TIMP-1 levels were significantly elevated in BOS 0-p (p = 0.003; p = 0.007; p = 0.0003, respectively) and BOS 1 (p = 0.003; p = 0.001; p = 0.0004, respectively) as compared to BOS 0 patients. The BAL MMP-8, -9 and TIMP-1 levels were significant predictors of BOS 0-p (p = 0.01; p = 0.01; p = 0.01, respectively) and BOS-1 (p = 0.007; p = 0.01; p = 0.006, respectively) in receiver operating characteristic analysis. Except for BAL macrophages that were significantly decreased in BOS 0-p versus BOS 0 patients; other cell counts were not different between the groups. BAL MMP-8, -9 and TIMP-1 might be useful markers to detect BO in lung transplant patients.     

Scanning and transmission electron microscopy of venous sphincters in the rat lung

The rat pulmonary microvasculature was studied using scanning and transmission electron microscopy of vascular corrosion casts and tissue sections. Special emphasis was placed on small pulmonary venous vessels. The shape of vascular casts was analyzed and interpreted concerning the wall composition of corresponding vessels studied in tissue sections. On the casts of pulmonary venules and small pulmonary veins, narrow or wider annular constrictions were regularly observed. Within these constrictions, marks of circularly running grooves were seen as an additional structural detail, which obviously mimic impressions of single or grouped smooth muscle cells. The depth of the constrictions varies; it may be more or less pronounced, occasionally narrowing down the luminal diameter to approximately 50%. These constrictions are caused by muscular sphincters. In tissue sections of small pulmonary veins, sphincter regions were identified as abruptly appearing single or grouped true smooth muscle cells. Smooth muscle cells may be arranged side by side in a group or bundle or even staked in two or three layers. Between the sphincter regions, the venous wall consists merely of endothelium and an accompanying connective tissue layer. The smooth muscle cells of a sphincter are regularly positioned between endothelial layer and elastic lamina. The smooth muscle cells next to the endothelium form myoendothelial junctions. Autonomic nerves near the sphincters were never seen. The venous sphincters described are suggested to be effective devices involved in blood flow regulation. Blood-borne substances or local tissue hormones might govern sphincter function. © 1992 Wiley-Liss, Inc.     

Serum Matrix Metalloprotease-1 and Vascular Endothelial Growth Factor–A Predict Cardiac Allograft Rejection

Cardiac allograft rejection is currently diagnosed from endomyocardial biopsies (EMB) that are invasive and impractical to repeat. A serological marker could facilitate rejection monitoring and minimize EMB-associated risks. We investigated the relation of serum matrix metalloprotease (MMP)-1 and vascular endothelial growth factor (VEGF)-A concentrations to cardiac allograft rejection, using 1176 EMBs and serum samples obtained from 208 recipients. Acute cellular rejection was diagnosed in 186 EMBs. Mean week 1 and week 2 serum MMP-1 concentrations predicted rejection (p = 0.001, AUC = 0.80). At the optimal cut-off level of ≥7.5 ng/mL, MMP-1 predicted rejection with 82% sensitivity and 72% specificity. Initial serum MMP-1 <5.3 ng/mL (lowest quartile) was associated with rejection-free outcome in 80% of patients. Both MMP-1 (p < 0.001, AUC = 0.67–0.75) and VEGF-A (p < 0.01, AUC = 0.62–0.67) predicted rejection on the next EMB, while rejection at EMB was identified only by VEGF-A (p < 0.02, AUC = 0.70–0.77). Patients receiving combined cyclosporine-A and everolimus had the lowest serum MMP-1 concentrations. While serum MMP-1 predicts rejection-free outcome and VEGF-A identifies rejection on EMB, both markers predict rejection in follow-up of cardiac transplant recipients. Combination of serum MMP-1 and VEGF-A concentration may be a noninvasive prognostic marker of cardiac allograft rejection, and could have important implications for choice of surveillance and immunosuppression protocols.     

Prostaglandin synthesis of the trachea in rats and guinea pigs

The synthesis of 5 prostaglandins in the trachea of rats and guinea pigs is studied by means of radio-thin-layer chromatography. The role of PGs in physiological and pathophysiological processes is discussed.     

Colon cancer cell-derived tumor necrosis factor-alpha mediates the tumor growth-promoting response in macrophages by up-regulating the colony-stimulating factor-1 pathway

The interplay between malignant and stromal cells is essential in tumorigenesis. We have previously shown that colony-stimulating factor (CSF)-1, matrix metalloprotease (MMP)-2, and vascular endothelial growth factor (VEGF)-A production by stromal cells is enhanced by CSF-1-negative SW620 colon cancer cells. In the present study, the mechanisms by which colon cancer cells up-regulate host factors to promote tumorigenesis were investigated. Profiling of tumor cell cytokine expression in SW620 tumor xenografts in nude mice showed increased human tumor necrosis factor (TNF)-alpha mRNA expression with tumor growth. Incubation of macrophages with small interfering (si) RNAs directed against TNF-alpha or TNF-alpha-depleted SW620 cell conditioned medium versus SW620 cell conditioned medium failed to support mouse macrophage proliferation, migration, and expression of CSF-1, VEGF-A, and MMP-2 mRNAs. Consistent with these results, human TNF-alpha gene silencing decreased mouse macrophage TNF-alpha, CSF-1, MMP-2, and VEGF-A mRNA expression in macrophages cocultured with human cancer cells. In addition, inhibition of human TNF-alpha or mouse CSF-1 expression by siRNA reduced tumor growth in SW620 tumor xenografts in mice. These results suggest that colon cancer cell-derived TNF-alpha stimulates TNF-alpha and CSF-1 production by macrophages, and that CSF-1, in turn, induces macrophage VEGF-A and MMP-2 in an autocrine manner. Thus, interrupting tumor cell-macrophage communication by targeting TNF-alpha may provide an alternative therapeutic approach for the treatment of colon cancer.     

Valvular density alone cannot account for sites of chronic venous insufficiency and ulceration in the lower extremity.

OBJECTIVE: Class 6 chronic venous stasis is associated with abnormal venous hemodynamics and ulceration. Ulcers primarily occur over bones and tendon prominences but very rarely over muscular compartments. We hypothesized that the anatomical distribution of venous stasis ulcers in the lower extremity is related to a lower density of venous valves. METHODS: The venous vasculature of six normal human legs was cast with resin, and their microvenous valvular anatomy was examined. Skin samples were obtained from the skin overlying the 1) Achilles' tendon, 2) anterior tibia, 3) medial malleolus, 4) lateral malleolus, 5) dorsal surface of the foot, 6) planta pedis, 7) dorsal aspect of the great toe; and from the skin regions overlying the 8) gastrocnemius, 9) tibialis anterior, and 10) peroneus muscles. The valvular and venous densities were determined in a scanning electron microscope, normalized to the size of specimens, and the valvular index was calculated. Analysis of variance with Bonferroni t-test was used to compare the valvular index between the regions. RESULTS: Venous valves were observed in all tissue regions. The diameter of veins with valves ranged from 18 microm to 803 microm. The valvular index for regions overlying bones/tendons (i.e., regions 1-7) was significantly higher versus those overlying muscular regions (i.e., regions 8-10) (p < 0.05). The valvular index was not different (p = 0.51) when regions 1 and 2 (where ulcers almost never occur) were compared to regions 3, 4, 5, 6, and 7 (where ulcers frequently occur); nor were there differences between the vascular indexes of regions overlying muscle. The largest venous valves were observed in the plantar region, and the smallest-sized ones were present in the peroneal region. CONCLUSIONS: This study shows that the density of venous valves is actually higher in regions of the human lower extremity overlying bones and tendons, where venous stasis ulcers are common, than those overlying muscular areas, where ulcers are rarely seen. Thus, valvular quantity alone cannot account for the higher clinical incidence of ulceration. It is likely that muscular pumping and/or valvular quality are important factors in preventing the development of venous stasis and ulceration in the lower extremity.