Arterial thrombosis induces early upregulation of intercellular adhesion molecule in the media

Expression of surfactant Protein-A in the Haemophilus influenzae-induced otitis media in a rat model

The objective of this study was to investigate the expression and the role of surfactant protein A (SP-A) in the middle ear (ME) mucosa in response to bacterial infection in a rat model. Otitis media (OM) was induced by surgical inoculation of non-typeable Haemophilus influenza (NTHi) into the ME cavity of Sprague-Dawley rats. The rats were divided into an NTHi-induced OM group and a phosphate-buffered saline-injected control group. The NTHi-induced OM and control groups were subdivided into sets of 6 rats, one for each of the 6 time points (0, 1, 2, 4, 7, and 14 days post-inoculation), at which point the rats were euthanized after inoculation. The concentrations of SP-A in the ME effusion were determined by an enzyme-linked immunosorbent assay (ELISA). Tissue expression of SP-A, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in infected ME mucosa was assessed by immunohistochemical staining. For mRNA expression quantification, RNA was extracted from the ME mucosa and SP-A expression was monitored and compared between the control and OM groups using quantitative polymerase chain reaction (PCR). Expression of IL-1β, IL-6, and TNF-α in the ME mucosa was also evaluated. SP-A expression was evaluated in the effusion of pediatric OM patients (70 ears) who received ventilation-tube insertion by ELISA. SP-A was detected in normal rat ME mucosa before bacterial inoculation. SP-A expression was up-regulated in the NTHi-induced OM group (p = 0.046). Immunohistochemical staining revealed increased SP-A expression on post-inoculation day 1, 2, and 4 in the OM group. Expression of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) in the ME also increased significantly on post-inoculation day 1, 2, and 4 in the OM group. It correlated with changes in SP-A expression. Expression of SP-A was also identified in the ME effusion of humans. SP-A exists in the ME of the rat and was up-regulated in the ME of NTHi-induced OM. Expression of IL-1β, IL-6, and TNF-α was increased in the ME of the bacteria-induced OM in the rat model. The results suggest that SP-A may play a significant role in the early phase of OM induction and subsequent recovery from it.

Expression of Surfactant Protein-A during LPS-Induced Otitis Media with Effusion in Mice

OBJECTIVE

The objective of this study was to investigate the expression and role of surfactant protein (SP) in the middle ear throughout lipopolysaccharide (LPS)-induced otitis media with effusion (OME).

STUDY DESIGN

Randomized case-controlled animal model.

SETTING

Shandong University, Jinan, China.

SUBJECTS AND METHODS

SP expression was monitored using reverse transcription polymerase chain reaction (PCR) in normal mice (n = 5). Two groups, control phosphate-buffered saline-injected mice (n = 5) and LPS-injected mice (n = 5), were euthanized 5 days following injection. RNA was extracted for reverse transcription PCR and real-time PCR, and temporal bone samples were used for hematoxylin and eosin staining. LPS was injected into mice, and 5 mice per test were euthanized at 0, 12, 24, 48, 72, and 96 hours following injection. For mRNA expression quantification, reverse transcription PCR and real-time PCR were performed, and proinflammatory cytokine levels were measured by enzyme-linked immunosorbent assay.

RESULTS

SP-A and SP-D expression was detected in normal murine Eustachian tubes. SP-A expression was up-regulated after LPS-induced OME (P = .01). At various time points after LPS injection, concentrations of proinflammatory cytokines (tumor necrosis factor-α [TNF-α], interleukin (IL)-1β, and IL-6) in the middle ear increased significantly (P < .05) and correlated with changes in SP-A expression.

CONCLUSION

SP-A and SP-D exist in the murine middle ear. The expression of SP-A and TNF-α, IL-1β, and IL-6 was up-regulated in the middle ear of the LPS-induced OME animal model.

Nitric Oxide-Enhanced Molecular Imaging of Atheroma using Vascular Cellular Adhesion Molecule 1-Targeted Echogenic Immunoliposomes

The aim of this study was to determine whether pre-treatment with nitric oxide-loaded echogenic liposomes (NO-ELIP) plus ultrasound can improve highlighting by molecularly targeted (anti-vascular cell adhesion molecule 1 [VCAM-1]) ELIP of atheroma components. Atherosclerotic animals were treated with anti-VCAM-1-ELIP or immunoglobulin (IgG)-ELIP. Each group was selected at random to receive pre-treatment with standard ELIP plus ultrasound, NO-ELIP without ultrasound and NO-ELIP plus ultrasound. Intravascular ultrasound highlighting data for the same arterial segments were collected before and after treatment. Pre-treatment with NO-ELIP plus ultrasound resulted in a significant increase in acoustic enhancement by anti-VCAM-1-ELIP (21.3 ± 1.5% for gray-scale value, 53.9 ± 3.1% for radiofrequency data; p < 0.001 vs. IgG-ELIP, p < 0.05 vs. pre-treatment with standard ELIP plus ultrasound or NO-ELIP without ultrasound). NO-ELIP plus ultrasound can improve highlighting of atheroma by anti-VCAM-1 ELIP. This NO pre-treatment strategy may be useful in optimizing contrast agent delivery to the vascular wall for both diagnostic and therapeutic applications.

Nitric oxide pretreatment enhances atheroma component highlighting in vivo with intercellular adhesion molecule-1-targeted echogenic liposomes

We present an ultrasound technique for the detection of inflammatory changes in developing atheromas. We used contrast-enhanced ultrasound imaging with (i) microbubbles targeted to intercellular adhesion molecule-1 (ICAM-1), a molecule of adhesion involved in inflammatory processes in lesions of atheromas in New Zealand White rabbits, and (ii) pretreatment with nitric oxide-loaded microbubbles and ultrasound activation at the site of the endothelium to enhance the permeability of the arterial wall and the penetration of ICAM-1-targeted microbubbles. This procedure increases acoustic enhancement 1.2-fold. Pretreatment with nitric oxide-loaded echogenic liposomes and ultrasound activation can potentially facilitate the subsequent penetration of targeted echogenic liposomes into the arterial wall, thus allowing improved detection of inflammatory changes in developing atheromas.

L-arginine improves endothelial vasoreactivity and reduces thrombogenicity after thrombolysis in experimental deep venous thrombosis

PURPOSE

Nitric oxide (NO) is important in regulation of platelet aggregation, endothelial function, and intravascular thrombosis. The purposes of this study were to assess the effect of thrombolysis on endothelial function in a porcine model of deep venous thrombosis (DVT) and to evaluate the effect of NO precursor l-arginine on endothelial function after thrombolytic therapy.

METHODS

DVT was created in bilateral iliac veins by deploying a self-expanding stent-graft that incorporated an intraluminal stenosis, from a groin approach. Five pigs underwent sham operation. After 7 days of DVT, animals were randomized to three groups: saline pulse-spray (saline group, n = 5), thrombolytic pulse-spray with tissue plasminogen activator (alteplase, 8 mg; t-PA group, n = 5), and thrombolytic pulse-spray plus intravenous l-arginine (20 mmol/L; arginine group, n = 5). At 2 weeks iliac vein patency was evaluated at venography and intravascular ultrasound scanning. NO level was determined with a chemiluminescent assay of the nitrite and nitrate metabolites (NO(x)). Thrombogenicity was evaluated with radiolabeled platelet and fibrin deposition. Veins were harvested and evaluated with light microscopy and scanning electron microscopy. Endothelial function was evaluated with organ chamber analysis.

RESULTS

All iliac veins remained patent at 2 weeks. The luminal areas in the sham, saline, t-PA, and arginine groups were 53 +/- 23 mm(2), 14 +/- 11 mm(2), 34 +/- 19 mm(2), and 42 +/- 21 mm(2), respectively. No difference in endothelial cell structure was observed between the three treatment groups at light microscopy or scanning electron microscopy. Although no difference in fibrin deposition was noted among the three treatment groups, decreased platelet deposition occurred in the arginine group compared with the saline or t-PA groups (P <.05). The arginine group showed greater endothelial-dependent relaxation compared with the t-PA or saline groups (73% +/- 23% vs 49% +/- 18% and 32% +/- 21%; P <.05). Local NO(x) level in the arginine group was correspondingly higher compared with the saline or t-PA groups (1.8 +/- 0.3 micromol/L vs 0.3 +/- 0.05 micromol/L and 0.2 +/- 0.04 micromol/L; P <.05).

CONCLUSIONS

NO precursor l-arginine supplementation enhances NO production at sites of venous thrombosis. Moreover, l-arginine preserves endothelial vasoreactivity and reduces platelet deposition after thrombolysis in iliac DVT. These data suggest that l-arginine may preserve endothelial function after thrombolysis and may reduce the likelihood of postthrombotic syndrome.

Effects of thrombolysis and venous thrombectomy on valvular competence, thrombogenicity, venous wall morphology, and function

PURPOSE

The experiments were designed to compare the effects of thrombolytic therapy (TL) and balloon-catheter thrombectomy (TX) on valvular competence, thrombogenicity, venous wall morphology, and function after acute deep venous thrombosis (DVT) in canine veins.

METHODS

The femoral veins of male mongrel dogs were ligated proximally and distally for 48 hours to induce DVT. The thrombosed veins were treated with either TL (n = 5) or TX (n = 9), or no treatment was rendered (n = 6). Sham-operated dogs were used as controls. TL was performed with catheter-directed infusion of urokinase at 4000 U/min for 90 minutes. Three hours after the treatment, the valvular competence was determined with duplex scanning, thrombogenicity determined with deposition of radio-labeled platelet and fibrin, and function determined with response to contractile and relaxing agonists in organ chambers. The structural integrity of the endothelial layer was assessed by means of scanning electron microscopy.

RESULTS

The removal or lysis of the thrombus was successful in all cases. The valvular competence did not differ among the groups. The platelet deposition was the highest after TX (P <.05), and the fibrin deposition was not significantly different among the groups. In the organ chamber experiments, relaxations to adenosine diphosphate and nitric oxide were reduced after TX (P <.05). The contractions to serotonin were enhanced after TX. Scanning electron microscopy results showed a comparable (51% to 75%) endothelial loss with either treatment.

CONCLUSIONS

After experimental acute DVT, the TL and the TX at 3 hours had similar effects on the valvular competence and the endothelial morphology. However, the TL reduced thrombogenicity, which is consistent with the preserved endothelial responses to platelet products. These data suggest that TL may preserve vein function after DVT and may reduce the long-term potential for recurrent DVT and post-thrombotic syndrome.