[11C]Hyaluronan uptake with positron emission tomography in liver disease

Hyaluronic Acid Is a Biomarker for Allograft Dysfunction and Predicts 1-Year Graft Loss After Liver Transplantation

BACKGROUND

Allograft dysfunction after liver transplantation has a profound impact on the risks of death and retransplantation within the first year. We tested whether elevated hyaluronic acid (HA; a glycosaminoglycan cleared by hepatic sinusoidal endothelium) levels may predict excess risk of graft loss.

METHODS

This was a retrospective single-center prognostic cohort study. Patients with either a plasma sample before transplantation, an early post-transplantation sample nearest day 30 (range 10-89 d, 80% within days 15-60), or both were included. Plasma HA was measured with the use of enzyme-linked immunosorbent assays. The primary end point was 1-year graft loss (all-cause mortality and retransplantation). A secondary end point was biliary stricture.

RESULTS

In this study, 169 of 196 patients who received a liver transplant in the study period were included. Pre-transplantation HA (n = 152) did not predict graft loss. Post-transplantation HA (n = 124) was higher among patients with graft loss (median, 177 μg/L [interquartile range (IQR), 89-465] vs 54 μg/L [IQR 37-93]) and was a strong predictor of this outcome (hazard ratio per 50 μg/L, 1.24 [95% confidence interval [CI], 1.14-1.34]). The discriminatory ability of HA was high (area under the receiver operating characteristic curve, 0.86 [95% CI, 0.77-0.94]) and noninferior to other liver function tests. When adjusted for known risk factors of graft loss, HA remained an independent predictor of graft loss.

CONCLUSIONS

High post-transplantation plasma HA level was a strong predictor of 1-year all-cause mortality and retransplantation, whereas pre-transplantation levels were not, despite variety in the time span of blood sampling. Prospective studies are warranted to assess the utility of HA in liver transplantation.

(11)C[double bond, length as m-dash]O bonds made easily for positron emission tomography radiopharmaceuticals

The positron-emitting radionuclide carbon-11 ((11)C, t1/2 = 20.3 min) possesses the unique potential for radiolabeling of any biological, naturally occurring, or synthetic organic molecule for in vivo positron emission tomography (PET) imaging. Carbon-11 is most often incorporated into small molecules by methylation of alcohol, thiol, amine or carboxylic acid precursors using [(11)C]methyl iodide or [(11)C]methyl triflate (generated from [(11)C]carbon dioxide or [(11)C]methane). Consequently, small molecules that lack an easily substituted (11)C-methyl group are often considered to have non-obvious strategies for radiolabeling and require a more customized approach. [(11)C]Carbon dioxide itself, [(11)C]carbon monoxide, [(11)C]cyanide, and [(11)C]phosgene represent alternative reactants to enable (11)C-carbonylation. Methodologies developed for preparation of (11)C-carbonyl groups have had a tremendous impact on the development of novel PET tracers and provided key tools for clinical research. (11)C-Carbonyl radiopharmaceuticals based on labeled carboxylic acids, amides, carbamates and ureas now account for a substantial number of important imaging agents that have seen translation to higher species and clinical research of previously inaccessible targets, which is a testament to the creativity, utility and practicality of the underlying radiochemistry.

Differential effects of hyaluronan synthase 3 deficiency after acute vs chronic liver injury in mice

Background

Hyaluronan (HA) is a ubiquitous extracellular matrix (ECM) glycosaminoglycan synthesized by three different enzymes, hyaluronan synthase (HAS)1, 2, and 3. HA synthesis mediated by HAS3 promotes inflammation and is pathogenic in animal models of human lung and intestinal disease. Liver fibrosis is a common endpoint to chronic liver injury and inflammation for which there is no cure. Although plasma HA is a commonly used biomarker for liver disease, if and how HA contributes to disease pathogenesis remains unclear. Here, we tested the hypothesis that HA synthesized by HAS3 enhances inflammation and fibrosis. To test this hypothesis, we exposed wild-type or Has3−/− mice to carbon tetrachloride (CCl₄) once (acute) or ten (chronic) times.

Results

HAS3-deficient mice exhibited increased hepatic injury and inflammatory chemokine production 48 h after acute CCl₄; this was associated with a threefold reduction in plasma HA levels and alterations in the proportions of specific molecular weight HA polymer pools. Hepatic accumulation of fibrosis-associated transcripts was also greater in livers from HAS3-deficient mice compared to controls after acute CCl₄ exposure. Surprisingly, fibrosis was not different between genotypes. Hepatic matrix metalloproteinase (MMP)13 mRNA and MMP13 activity was greater in livers from Has3-null mice after chronic CCl₄; this was prevented by a MMP13-specific inhibitor. Collectively, these data suggest that Has3, or more likely HA produced by HAS3, limits hepatic inflammation after acute injury and attenuates MMP13-mediated matrix metabolism after chronic injury.

Conclusions

These data suggest that HA should be investigated further as a novel therapeutic target for acute and chronic liver disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13069-016-0041-5) contains supplementary material, which is available to authorized users.

Hyaluronic acid as a marker of hepatic sinusoidal obstruction syndrome secondary to oxaliplatin-based chemotherapy in patients with colorectal liver metastases

BACKGROUND

A considerable number of patients develop sinusoidal obstruction syndrome (SOS) after oxaliplatin-based chemotherapy for colorectal liver metastases (CLMs). SOS is associated with adverse outcomes after major hepatectomy. Hyaluronic acid (HA) is a marker of hepatic sinusoidal endothelial cell function and may serve as an accurate marker of SOS. This study aimed to assess the value of systemic HA levels and fractional extraction (FE) of HA by the splanchnic area and liver as markers of SOS after oxaliplatin-based chemotherapy for CLMs.

METHODS

Forty patients were studied. The presence of SOS was assessed histopathologically. Blood samples from the radial artery and portal and hepatic veins were collected. HA levels were determined by ELISA and the FE of HA was estimated.

RESULTS

SOS was present in 23 patients, 11 of whom demonstrated moderate or severe SOS. Preoperative HA levels were significantly higher in patients with moderate or severe SOS (group B, n = 11) compared to patients with no or mild SOS (group A, n = 29) (51.6 ± 10.2 ng/mL vs. 32.1 ± 3.5 ng/mL, p = 0.030). A cutoff HA level of 44.1 ng/mL yielded a sensitivity of 67 % and specificity of 83 % for detection of SOS. The positive predictive value was 50 % and the negative predictive value 91 %. Both groups exhibited a similar FE of HA by the splanchnic area (-7.9 ± 8.5 % in Group A vs. 7.3 ± 3.6 % in Group B, p = 0.422) and liver (-10.7 ± 6.2 % in Group A vs. 4.6 ± 2.3 % in Group B, p = 0.265).

CONCLUSIONS

Systemic HA levels can be used to detect patients at risk of SOS after oxaliplatin-based chemotherapy for CLMs. Additional investigations into the presence of SOS are indicated in patients with elevated HA levels.

New horizons for imaging lymphatic function

In this review, we provide a comprehensive summary of noninvasive imaging modalities used clinically for the diagnosis of lymphatic diseases, new imaging agents for assessing lymphatic architecture and cancer status of lymph nodes, and emerging near-infrared (NIR) fluorescent optical imaging technologies and agents for functional lymphatic imaging. Given the promise of NIR optical imaging, we provide example results of functional lymphatic imaging in mice, swine, and humans, showing the ability of this technology to quantify lymph velocity and frequencies of propulsion resulting from the contractility of lymphatic structures.

Hyaluronic acid and aspartate aminotransferase levels normalized by liver function can reflect sinusoidal impairment in chronic liver disease

BACKGROUND/AIM

To evaluate the relationship between hyaluronic acid/aminopyrine breath test (HA/ABT) ratio and fibrosis score in chronic hepatitis, and between HA/ABT and clinical staging (child-turcotte-pugh'score, CTP; and model for end stage liver disease, MELD) in cirrhosis, as well as to evaluate the aspartate aminotransferase (AST)/ABT in relation to the HA/ABT.

METHODS

We studied 48 patients with histologically proven chronic hepatitis C (CHC) and 35 patients with compensated cirrhosis (CIR).

RESULTS

HA/ABT and AST/ABT showed a more significant correlation with the fibrosis score than HA or ABT or AST alone in the 48 CHC patients: r=0.568 (P<0.0001), r=0.610 (P<0.0001), r=0.450 (P=0.0021), r=-0.449 (P=0.0021), and r=0.472(P=0.0012), respectively. Progressive liver damage (fibrosis 1-2 vs fibrosis 3-6 vs cirrhosis) was significantly (P<0.05) reflected by both HA/ABT (mean+/-SEM: 4.0+/-0.9 vs 18.1+/-4.2 vs 149.9+/-33.1) and AST/ABT (6.3+/-1.8 vs 12.7+/-1.6 vs 42.1+/-14.6). A strong relationship was found between HA/ABT and AST/ABT (r=0.755 P<0.0001). In cirrhotic patients, the most significant relationship was observed between HA/ABT and CTP r=0.483 and P=0.0049, and MELD r=0.523 and P=0.0023.

CONCLUSION

Considering that HA levels in chronic hepatitis depend on the progressive impairment of sinusoidal endothelial cells (SEC), related to progressive fibrosis, HA/ABT ratio would seem to be the most specific reflection of progressive impairment of the SEC. AST/ABT could be used as a possible surrogate of HA in identifying SEC impairment in chronic hepatitis.

Phase I and pharmacokinetic evaluation of intravenous hyaluronic acid in combination with doxorubicin or 5-fluorouracil

BACKGROUND

Pre-clinically, hyaluronan (HA) has been demonstrated to systemically target chemotherapeutic drugs to tumours while ameliorating treatment toxicities. This study is a preliminary clinical investigation to determine if HA could be safely used in combination with 5-fluorouracil (5-FU) and doxorubicin (DOX).

METHODS

Thirty patients with metastatic cancer were intravenously administered 500 mg/m2 HA in combination with escalating doses of DOX (30-60 mg/m2) or 5-FU (cumulative dose of 1,350-2,250 mg/m2 per cycle). The effect of pre-administration of 20 mg/m2 of folinic acid on HA/5-FU chemotherapy was also investigated. Patients were randomized to receive either HA/chemotherapy or chemotherapy alone in their first treatment cycle and vice versa for the second cycle. Patients received HA and chemotherapy in all subsequent cycles.

RESULTS

Treatment was well tolerated, tumour responses were observed and the co-administration of HA did not alter the pharmacokinetics of clinically relevant doses of 5-FU or DOX.

CONCLUSION

High doses of intravenous high-molecular-weight HA can be safely co-administered with clinical doses of chemotherapy without significantly altering the toxicity or pharmacokinetics of the drugs or HA.