Occult hepatocellular carcinoma: a case report of a special icteric-type hepatoma and literature review

Hepatocellular carcinoma (HCC) presenting with obstructive jaundice due to bile duct tumour thrombi is classified as icteric-type hepatoma. This report describes a case of unusual icteric-type HCC with common bile duct thrombus, which is herein named 'occult HCC', as no detectable primary lesion in liver was defined pre-operatively and intra-operatively. A thrombectomy followed by a T biliary drainage tube placement was carried out, and the final post-operative pathological evaluation demonstrated the tumour thrombus originated from a moderately differentiated HCC. The clinicopathological features and logical clinical interventions of this rare type of HCC were discussed with a review of the literature. The HCC patients with bile duct thrombi receiving palliative biliary drainage alone had a poor outcome. With respect to improving prognosis, a curative resection of primary HCC and tumour thrombi was suggested on the basis of performing an intensive post-operative monitoring for early detection of primary liver lesion.

Multidrug resistant gram-negative bacilli as predominant bacteremic pathogens in liver transplant recipients

BACKGROUND

Bacteremias, which are often caused by gram-negative bacteria, are the most frequently occurring infectious complications after liver transplantation (LT). The aim of this study was to investigate bacteremic incidence, pathogenic spectrum, risk factors for bacteremia due to multidrug resistant (MDR) gram-negative bacilli, and its impact on mortality after LT.

METHODS

A cohort analysis of prospectively recorded data was done in 475 LT recipients, who were divided into 3 categories: cases with gram-negative bacteremia, cases with MDR gram-negative bacteremia, and cases without bacteremia as controls.

RESULTS

In 475 LT recipients, there were 152 (32.0%) patients with gram-negative bacillus bacteremia in the first 6 months after LT. Out of 152 patients, there were 225 bacteremic episodes, which accounted for 69.7% in a total 323 bacteremic episodes. A total of 190 bacteremic episodes were caused by Stenotrophomonas maltophilia, Enterobacteriaceae, Ochrobactrum anthropi, Pseudomonas, and Acinetobacter baumanii, all of which were the most frequent gram-negative isolates in this study, and MDR bacilli constituted 56.3%. The most frequent source was intravascular catheters. There were 70 patients with MDR gram-negative bacillus bacteremia. Independent risk factors for bacteremia due to MDR gram-negative bacillus were as follows: post-LT abdominal infection (P<0.0001, odds ratio [OR] 0.066, 95% confidence interval [CI] 0.019-0.226), post-LT reoperative episodes (P<0.0001, OR 10.505, 95% CI 3.055-36.121), or one or more episodes of acute rejection (P=0.042, OR 4.457, 95% CI 0.988-20.103). In the first 6 months after LT, MDR gram-negative bacillus bacteremia-related mortality was significantly higher than that due to antibiotic-susceptible bacillus (38.6% vs. 14.6%, P<0.001).

CONCLUSION

Post-LT bacteremias caused by MDR gram-negative bacilli are common, and associated with allograft acute rejection, post-LT reoperation, and abdominal infection. The increasing isolates of MDR gram-negative bacilli pose a great challenge for clinical treatment.

The antibacterial mechanism of carvacrol and thymol against Escherichia coli

AIMS

To investigate the antibacterial mechanism of carvacrol and thymol against Escherichia coli.

METHODS AND RESULTS

The time-kill curve results showed that carvacrol and thymol at 200 mg l(-1) could inhibit the growth of E. coli. Flow cytometry and fluorescent dyes were used to explore the effect of two components on membrane permeability and membrane potential. In membrane permeability experiment, the mean fluorescence intensity of cells treated with 200 mg l(-1) carvacrol or thymol were lower than nonexposed cells. The ratio of red to green fluorescence intensity of DiOC2(3) reflected the change of membrane potential. Carvacrol and thymol at 200 mg l(-1) caused the ratio of red/green decreasing from 0.42 of control to 0.08 and 0.07, respectively.

CONCLUSIONS

Carvacrol and thymol had desired antimicrobial effect on E. coli. The antibacterial effects were attributed to their ability to permeabilize and depolarize the cytoplasmic membrane.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study showed the potential use of flow cytometry as a suitable method to investigate the mode of antibacterial action of essential oil components.

A novel mechanism whereby BRCA1/1a/1b fine tunes the dynamic complex interplay between SUMO-dependent/independent activities of Ubc9 on E2-induced ERalpha activation/repression and degradation in breast cancer cells

BRCA1 dysfunction is associated with hormone-responsive cancers. We have identified a consensus SUMO modification site in the amino-terminal region of BRCA1/1a/1b proteins and the mutation in this potential SUMO acceptor site (K 109 to R) impaired their ability to bind and repress ligand-dependent ERalpha transcriptional activity in breast cancer cells. Furthermore, we have found SUMO E2-conjugating enzyme Ubc9 to bind BRCA1 proteins. We have mapped BRCA1 [within amino acids (aa) 1-182] as the minimum domain that is sufficient for in vitro binding to Ubc9 as well as for regulating ERalpha activity. BRCA1 Mutant #1 (K109 to R) was impaired in its ability to both bind, as well as modulate Ubc9 mediated SUMO-dependent/independent E2-induced ERalpha transcriptional activity in breast cancer cells. Similarly, BRCA1 cancer-predisposing mutation (61Cys-Gly) abrogated the ability to both bind Ubc9 as well as inhibit ERalpha activity suggesting physiological significance. Addition of BRCA1 but not Mutant #1 to E2-induced ERalpha in the presence of SUMO-1 and Ubc9 resulted in the degradation of ERalpha suggesting BRCA1 to be a putative SUMO-1 and Ubc9-dependent E3 ubiquitin ligase for ERalpha. This is the first report demonstrating the participation of Ubc9 in BRCA1 E3 ubiquitin ligase mediated degradation of ERalpha. These results suggest a novel function for BRCA1 in regulating the dynamic cycles of SUMO and ubiquitin modifications required for ERalpha turn over and deregulation of this molecular switch due to lack of BRCA1 results in ERalpha-negative/positive breast cancers. This study will help in designing novel BRCA1 function-based targeted treatment for breast cancers.

Distribution of pathogenic Yersinia enterocolitica in China

Yersinia enterocolitica (1,295 strains) was isolated from diarrhea patients, livestock, poultry, wild animals, insect vectors, food, and the environment. They were studied for epidemiology distribution using bacterial biochemical metabolism tests, their virulence genes, and pulsed-field gel electrophoresis (PFGE) sub-typing. The data showed that 416 of the 1,295 strains were pathogenic, where the pathogenic Chinese isolates were of serotypes O:3 and O:9. These two serotypes were found in livestock and poultry, with swine serving as the major reservoir. The geographic distribution of pathogenic isolates was significantly different, where most of the strains were isolated from the cold northern areas, whereas some serotype O:3 strains were recovered from the warm southern areas. By the analysis of the data of the Ningxia Hui Autonomous Region, we find the phenomenon of 'concentric circle distribution' around animal reservoirs and human habitation. The clustering of PFGE showed that the patterns of the pathogenic strains isolated from diarrhea patients were identical compared to those from the animals in the same area, thus, suggesting that the human infection originated from the animals.

Radioprotection by fullerenols ofStylonychia mytilusexposed to γ-rays

The aim was to study the protective effects of fullerenols, C60(OH)x, on Stylonychia mytilus cells exposed to 60Co gamma-rays and the probable mechanisms of fullerenols protection. Ciliated protozoans Smytilus, kept in solutions of fullerenols at different concentrations, were irradiated with 60Co gamma-rays to various dose levels. Surviving cells were counted each day over 5 days after irradiation, and the surviving fraction was calculated. The relations of the surviving fraction to radiation dose and to fullerenols concentration were studied. Superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and lipofusion (LIP) levels in S. mytilus were also measured. The surviving fraction of S. mytilus decreased with increasing gamma-ray doses from 100 to 2000 Gy. Fullerenols enhanced the surviving fraction, except for the highest gamma-ray dose level. The maximum protection by fullernols occurred at a concentration of 0.10 mg ml(-1). However, fullerenols at concentration of 0.25 mg ml(-1) yielded a surviving fraction lower than that for the control sample. Fullerenols at a concentration of 0.10 mg ml(-1) increased the SOD and CAT activities in the gamma-ray plus fullerenols (gamma + F) group compared with the levels in both the gamma-ray (gamma) group (p < 0.01) and the control group (p < 0.01). The MDA and LIP levels in the gamma + F groups (p < 0.01) were significantly lower than that in both the control group (p < 0.05) and the gamma group (p < 0.01). At a concentration of 0.25 mg ml(-1), fullerenols reduced the SOD and CAT activities, but increased the MDA and LIP level compared with the control. There was no significant difference in SOD and CAT activities between the gamma + F group and gamma group. While the MDA and LIP level in the gamma + F and gamma groups were similar at a dose of 500 Gy, the LIP level in the gamma + F group was significantly higher than that in the gamma group (p < 0.01) at a dose of 2000 Gy. Fullerenols are good radiation protectors for the protozoan S. mytilus exposed to gamma-rays. The effectiveness of radioprotection depends on both fullerenols concentration and gamma-ray dose. The protective effect of fullerenols on damage induced by gamma-rays seems to be mediated, at least in part, through their anti-oxidative and radical scavenging activities.

CIGARETTE SMOKE-INDUCED HYPERCAPNIC EMPHYSEMA IN C3H MICE IS ASSOCIATED WITH INCREASES OF MACROPHAGE METALLOELASTASE AND SUBSTANCE P IN THE LUNGS

The authors tested whether macrophage metalloelastase (MMP-12) and substance P (SP) were increased in the cigarette smoke (CS)-exposed female C3H/HeN mice with hypercapnic emphysema. The authors found that as compared to control (filtered air), 16 weeks of CS exposure significantly up-regulated mRNA and protein levels of MMP-12, the ratio of MMP-12/tissue inhibitor of matrix metalloproteinase-1, and SP/preprotachykinin-A (a precursor to SP) in the lungs. Importantly, a significant correlation was found between MMP-12 and SP, and between MMP-12/SP and the degrees of hypoxemia/hypercapnia denoted in CS-exposed mice. These data suggest a possible involvement of SP and MMP-12 in the pathogenesis of severe COPD.

Multi-mJ, 200-fs, cw-pumped, cryogenically cooled, Yb,Na:CaF2 amplifier

Using a novel (to our knowledge) broadband Yb-doped Yb3+,Na+:CaF2 crystal cooled in a closed loop to 130 K we demonstrate a chirped pulse regenerative laser amplifier delivering the energy of up to 3 mJ at a repetition rate of 1 kHz and an average output power of 6 W at 20 kHz. The gain narrowing in the laser crystal is compensated by shaping the amplitude of the seed pulse spectrum. As the result, at the highest amplified pulse energy we obtain a 12 nm FWHM bandwidth supporting a 130 fs pulse duration, assuming ideal compression. Amplified pulses were recompressed from 250 ps to 195 fs with a 1700 lines/mm transmission grating compressor.

A novel mutant-enriched liquidchip for detection of circulating EGFR mutations in advanced non-small cell lung cancer patients

e14526

Background: We developed a novel technology, Mutant-enriched liquidchip (MEL), which integrates the sensitive mutant enriched PCR and quantitative high throughput liquidchip (suspension array), to detect circulating EGFR mutations (Exon 19 deletion and exon 21 L858R mutation) in patients with advanced non-small cell lung cancer (NSCLC). Methods: To enrich mutant EGFR, a unique restriction site is introduced into the mutation alleles so that the wild type sequence can be selectively removed by restriction digestion, and the undigested mutated DNA is amplified by PCR. The product is then hybridized to complementary probes (including 15 types of exon 19 deletion and exon 21 L858R mutation) which had been conjugated to beads coding with different fluorescent dye, followed by measuring through Luminex 200 system. Plasmid DNA mixture with different EGFR genotypes was applied to determine the sensitivity and accuracy of MEL. Afterwards, the MEL was validated in 49 patients whose EGFR genotypes of tissue specimen had been tested with direct sequencing The circulating genomic DNA was obtained from serum sample of other 201 Chinese stage IIIB or IV NSCLC patients without EGFR-TKI administration, and the EGFR mutation status was analyzed by using of MEL. Results: The results shows that MEL is capable of detecting as few as 20 copies of mutant EGFR alleles with a sensitivity limit of at least mutant/wild-type ratio of 0.1%. It also shows that MEL can not only confirm EGFR mutations status in tissue specimens already known by direct sequencing (13/49), but also detect mutations in some of those showing wild type by sequencing (16/49). Overall, 54% of patients had circulating EGFR mutation. 34% of patients had an exon 19 deletion and 29.6% had L858R. 63.1% of mutations were found in females and 67.6% in never-smokers. Conclusions: This novel MEL method allows for highly sensitive and reproducible detection of human somatic mutations in heterogeneous specimens, and could be applicable to test EGFR mutations non-invasively in advanced NSCLC patients for predicting response to targeted therapy.

No significant financial relationships to disclose.

Phase I study of chidamide (CS055/HBI-8000), a novel histone deacetylase inhibitor, in patients with advanced solid tumors and lymphomas

3529

Background: Chidamide (CS055/HBI-8000) is a new benzamide type of histone deacetylase (HDAC) inhibitor with low nanomolar activity against HDAC1, 2, 3 and 10. This Phase I study evaluated the safety and tolerability of chidamide in patients (pts) with advanced solid tumors and lymphomas. Methods: 31 pts with refractory or relapsed advanced solid tumors (22) and lymphomas (9) were enrolled in this study. Escalating doses of 5, 10, 17.5, 25, 32.5 and 50 mg Chidamide (each with 3 to 7 pts) were administered orally either twice or three times per week for 4 consecutive weeks every 6 weeks. Results: No dose limiting toxicities (DLTs) were identified in the 2 x per week cohorts (22 pts) up to 50 mg; G2 and G3 hematological toxicities (leukopenia/neutropenia and thrombocytopenia) were observed at 50 mg. DLTs were reported as G3 diarrhea or vomiting in 2 pts in the 3 x per week cohort at 50 mg. Common adverse events were G1/G2, fatigue (n = 11), thrombocytopenia (n = 9), anorexia (n = 8), nausea/vomiting (n = 7), leukopenia/neutropenia (n = 6), hypochromia (n = 6), and diarrhea (n = 5). No cystitis, pericarditis, pericardial effusion or prolonged QTc intervals were observed. Single dose PK analysis in pts with 25, 32.5 and 50 mg revealed T1/2 of 16.8–18.3 h, Tmax of 1–2 h in most cases, and a dose-related increase in Cmax and AUC. Multiple dose PK analysis in pts with 32.5 mg 3 x per week suggested drug accumulation with this regimen. Significant induction of histone (H3) acetylation was observed in peripheral white blood cells, which lasted for 2–3 days in most pts after single dosing. 25 pts with total treatment cycles of 49 (range 1–6) were evaluable for efficacy. 4 pts with T-cell lymphomas (4/5 evaluable) and 1 pt with submandibular adenoid cystic carcinoma achieved PR, and 11 pts (2 B-cell lymphomas and 9 solid tumors) experienced SD. Conclusions: Chidamide was well-tolerated in pts with advanced solid tumors and lymphomas in the tested regimens. In addition, the compound exhibited a relatively long half-life, a long-lasting biomarker response and encouraging antitumor activity at well-tolerated doses. The overall phase I results recommend the 2 x per week regimen for phase II studies.

[Table: see text]

Preoperative hepatic and regional arterial chemotherapy in the prevention of liver metastasis after colorectal cancer surgery

4090

Background: To investigate whether preoperative hepatic and regional arterial chemotherapy are able to prevent liver metastasis and improve overall survival in patients receiving curative colorectal cancer resection. Methods: Patients with Stage II or Stage III colorectal cancer (CRC) were randomly assigned to receive preoperative hepatic and regional arterial chemotherapy (PHRAC group, n=256) or surgery alone (control group, n=253). The primary endpoint was disease-free survival, whereas the secondary endpoints included liver metastasis-free survival and overall survival. Results: There were no significant differences in overall morbidity between PHRAC and Control groups. During the follow-up period (median, 42 months), the median liver metastasis time for patients with stage III CRC was significantly longer in the PHRAC group (16±3 months v.s. 8±1 months, P=0.01). In stage III patients, there was also significant difference between the two groups with regard to the incidence of liver metastasis (18.9% vs 27.3%, P=0.01), 5-year disease-free survival (70.2% vs 52.0%, P=0.0076), 5-year overall survival (80.3% vs 69.5%, P=0.020) and the median survival time (40.1± 4.6 months vs 36.3 ± 3.2 months, P=0.03). In the PHRAC arm, the risk ratio of recurrence was 0.63 (95% CI, 0.51–0.79, P=0.0001), of death was 0.50(95% CI, 0.32–0.67; P=0.005), and of liver metastasis was 0.70 (95% CI, 0.52–0.86; p=0.01). In contrast, PHRAC seemed to be no benefit for stage II patients. Toxicities, such as hepatic toxicity and leucocyte decreasing, were mild and could be cured with medicine. Conclusions: Preoperative hepatic and regional arterial chemotherapy, in combination with surgical resection, could be able to reduce and delay the occurrence of liver metastasis and therefore improve survival rate in patients with stage III colorectal cancer.

No significant financial relationships to disclose.

Pathological features of advanced gastric cancer (GC): Relationship to human epidermal growth factor receptor 2 (HER2) positivity in the global screening programme of the ToGA trial

4556

Background: HER2 positivity is thought to be a negative prognostic factor in GC, correlating with poor survival rates. Reported HER2-positivity rates in GC have varied widely (6–35%). The ToGA trial is evaluating the addition of trastuzumab (Herceptin) to chemotherapy in HER2-positive advanced GC. It is the first randomised Phase III trial to provide prospective information on HER2-positivity rates in GC. Enrollment is complete, with 3,883 patients screened in 24 countries. The pathological features of GC and the relationship with HER2 positivity will be examined. Methods: Advanced GC tumour samples were centrally screened by immunohistochemistry (IHC; HercepTest) and fluorescence in situ hybridisation (FISH; PharmDx) in parallel. A HER2-scoring system modified from the protocol in breast cancer (BC) was used: a score of IHC 3+ and/or FISH positive was defined as HER2 positive. Results: Final data showed an overall HER2-positivity rate of 22.1% evaluated from 3807 patients. The HER2-positivity rate was similar between Europe (23.6%) and Asia (23.5%). HER2-positivity rates were higher in gastro-oesophageal junction (GEJ) than stomach cancer (33.2% vs 20.9%; p<0.001) and in intestinal than diffuse/mixed cancer (32.2% vs 6.1%/20.4%; p<0.001). This is reflected in above-average HER2-positivity rates in countries with the highest GEJ:stomach cancer ratios (France 0.56 [HER2 positivity 26.9%]; Germany 0.53 [23.7%]; UK 0.33 [25.8%]) and intestinal:diffuse cancer ratios (UK 3.4 [HER2 positivity 25.8%]; Australia 2.6 [32.8%]; Japan 2.8 [27.8%]). The modified HER2-scoring system showed concordance between IHC and FISH results of 87.5%. In BC most IHC 0/1 samples are FISH negative but, in ToGA, the frequency of IHC 0/1 samples testing FISH positive was almost as high as IHC 2/FISH-positive samples (23% vs 26%). Conclusions: The overall HER2-positivity rate in advanced GC in ToGA is 22.1%. Variations in tumour location and type mostly explain the difference in HER2-positivity rates between countries. Efficacy data will enable further evaluation of the clinical significance of HER2 IHC and FISH scoring patterns.

[Table: see text]

Analysis of signal pathway activation in hepatocellular carcinoma: Association with clinical outcomes to sorafenib in Chinese patients

e15529

Background: The pathogenesis of hepatocellular carcinoma invovles multi-stage development of molecular aberrations affecting signaling pathways that regulate cancer growth and progression. Treatment strategies have focused on inhibition of the Ras effector pathway with inhibitors of Raf, such as sorafenib in HCC. Greater understanding of the cellular response to sorafenib is needed to tailor targeted therapy for individual patients and identify those more likely to benefit. Methods: We performed immunohistochemistry on a tissue microarray of tumor and adjacent liver tissue from 40 HBV-infected HCC patients who were treated with sorafenib, and 20 normal liver. We compared the levels of 8 signaling proteins including growth factor receptors (PDGFRa, VEGFR1, VEGFR2, VEGFR3, c-kit, c-met, IGF-R, EGFR), tumor suppressors (PTEN) and their downstream phosphorylated (p-) signal transducers (p-RAF, p-MEK1/2, p-ERK1/2; PI3K, p-AKT, NFkB, axin, β-catenin,p-GSK3β, p-mTOR, p-S6, p-70S6K, p-JNK, p-SRC, p-STAT3, c-fos, c-jun) in cancer cells and endothelial cells of HCC to those in non-neoplastic liver. Results: The overall profiles of signalling protein expression levels, activation states and subcellular distribution in HCC cells and endothelial cells were distinguishable from non-neoplastic hepatocytes. The ERK pathway activation was correlated with low level of nuclear β-cat and high level of p-mTOR (p<0.05). Long survival (>6m) patients were characterized by high level of nuclear pERK and low level of p-AKT, p-GSK3β (p<0.05) in tumor cells. The high microvessel density and the presence of micrometastases correlated with high level of VEGFR, p-ERK and p-SRC in endothelial cells. Conclusions: Sorafenib may affect signalling through the Ras/Raf/MAPK/ERK pathway. HBV-related HCC patients with. overactivation of signal transduction cascade MAPK/ERK and PI3K/AKT pathways in tumor cells and/or endothelial cells may benefit from the targeted treatment.

No significant financial relationships to disclose.

Retinal nerve fibre layer thickness measurement reproducibility improved with spectral domain optical coherence tomography

BACKGROUND/AIMS

To investigate retinal nerve fibre layer (RNFL) thickness measurement reproducibility using conventional time-domain optical coherence tomography (TD-OCT) and spectral-domain OCT (SD-OCT), and to evaluate two methods defining the optic nerve head (ONH) centring: Centred Each Time (CET) vs Centred Once (CO), in terms of RNFL thickness measurement variability on SD-OCT.

METHODS

Twenty-seven eyes (14 healthy subjects) had three circumpapillary scans with TD-OCT and three raster scans (three-dimensional or 3D image data) around ONH with SD-OCT. SD-OCT images were analysed in two ways: (1) CET: ONH centre was defined on each image separately and (2) CO: ONH centre was defined on one image and exported to other images after scan registration. After defining the ONH centre, a 3.4 mm diameter virtual circular OCT was resampled on SD-OCT images to mimic the conventional circumpapillary RNFL thickness measurements taken with TD-OCT.

RESULTS

CET and CO showed statistically significantly better reproducibility than TD-OCT except for 11:00 with CET. CET and CO methods showed similar reproducibility.

CONCLUSIONS

SD-OCT 3D cube data generally showed better RNFL measurement reproducibility than TD-OCT. The choice of ONH centring methods did not affect RNFL measurement reproducibility.

Endoscopic decompression using a transanal drainage tube for acute obstruction of the rectum and left colon as a bridge to curative surgery

OBJECTIVE

The aim of this study was to clarify the usefulness of the management of acute left colon and rectum obstruction because of colorectal carcinoma using a transanal ileus drainage tube before curative surgery.

METHOD

Forty-six patients (24 males and 22 females, aged 24-94 years, mean = 56.2) treated between September 2005 and March 2007 for acute left colon and rectal obstruction were identified in a colorectal obstruction database, and their clinical and radiological features were reviewed. After a cleaning enema was administered, urgent colonoscopy was performed. Subsequently, endoscopic decompression using a ileus tube was attempted.

RESULTS

Endoscopic decompression using the ileus tube was technically successful in 45 of 46 patients (97.8%). Perforation occurred in one patient 3 days later and emergent operation was performed. The site of obstruction was the rectum in 15 patients, the sigmoid colon in 18, the descending colon in 13. Following adequate cleansing of the colon, patients' abdominal girth were decreased from 91 +/- 4 cm before drainage to 82 +/- 2 cm 7 days later, and one-stage surgery after 8 +/- 1 days (SD; range 7-10 days) were performed. No anastomotic leakage or postoperative stenosis occurred after operation.

CONCLUSION

Management of acute left colon and rectum obstruction because of colorectal carcinoma using the ileus tube was found to be effective and safe, considered as a bridged method before curative surgery.

Endogenous activated protein C signaling is critical to protection of mice from lipopolysaccaride-induced septic shock

SUMMARY BACKGROUND

Activated protein C (APC) is known to protect animals from sepsis. Endogenous protein C is important in protection. It is unknown whether the cytoprotective or anticoagulant properties of protein C (PC) are responsible for the protective effect of endogenous PC.

OBJECTIVE

To determine if signaling by endogenous activated protein C contributes to survival in sepsis.

METHODS

We used an immunochemical approach to either block all of the known activities of protein C using mAb MPC1609 or, alternatively, selectively block the anticoagulant activity of activated protein C while sparing some of its cytoprotective activities using mAb MAPC1591.

RESULTS

MPC1609 blocked APC binding to endothelium whereas MAPC1591 enhanced binding. MPC1609 prevented APC protection of endothelial barrier function whereas MAPC1591 did not. Injection of MPC1609, but not MAPC1591, with a sublethal dose of lipopolysaccharide (LPS) caused lethality. At 18 h, the mice injected with MPC1609 plus LPS had much higher interleukin-6 (IL-6) levels than mice injected with LPS alone or LPS plus MPC1591. In these mice treated with LPS plus MPC1609, higher blood urea nitrogen (BUN) and creatinine levels suggested that an acute renal failure might contribute to a slow clearance of IL-6.

CONCLUSIONS

These studies demonstrate for the first time that cytoprotective activities of APC, and not the anticoagulant activity, is required for protection in this sepsis model. Similar anti-human antibodies may prove useful in clinical conditions such as trauma and hemophilia where cytoprotection is desirable, but the anticoagulant activity of endogenous activated protein C may contribute to bleeding.