Serum hyaluronic acid concentrations are increased in cystic fibrosis patients with liver disease

Hyaluronan promotes intracellular ROS production and apoptosis in TNFα-stimulated neutrophils

Background

Hyaluronan (HA) is an important structural component of the extracellular matrix and has well-described roles in maintaining tissue integrity and homeostasis. With inflammation, HA metabolism (synthesis and degradation) increases and results in higher concentrations of soluble HA. Previously, we demonstrated that (soluble) HA primed resting neutrophils for the oxidative burst in response to a secondary stimulus. Notably, HA-mediated priming was not dependent on degranulation, which is a hallmark of priming by classical agents such as TNFα. In this study, we queried the ability of HA to prime neutrophils to different stimuli and its capacity to modulate neutrophil function in the presence of TNFα.

Methods

Blood neutrophils from healthy donors were stimulated ex vivo with HA in the absence and presence of classic neutrophil agonists, inclusive of TNFα. Western blotting was used to assess the activation (phosphorylation) of p38 MAPK, and key neutrophil functions associated with priming and activation, such as intracellular and extracellular ROS production, degranulation, and apoptosis, were evaluated by standard chemiluminescence assays (ROS) and flow cytometry.

Results

Hyaluronan is capable of atypical priming and, with TNFα, co-priming neutrophils for an enhanced (rate and/or magnitude) oxidative burst to various secondary stimuli. In addition, HA can augment intracellular ROS production that is directly induced by TNFα in resting neutrophils, which coincided with the activation of p38 MAPK and apoptosis.

Conclusions

These data demonstrate that the extracellular matrix component HA is a key modulator of neutrophil function(s) in the presence of inflammatory agents such as TNFα. Moreover, it provides additional evidence for the diversity and complexity of neutrophil priming and activation during inflammation.

Targeting of Glycosaminoglycans in Genetic and Inflammatory Airway Disease

In the lung, glycosaminoglycans (GAGs) are dispersed in the extracellular matrix (ECM) occupying the interstitial space between the capillary endothelium and the alveolar epithelium, in the sub-epithelial tissue and in airway secretions. In addition to playing key structural roles, GAGs contribute to a number of physiologic processes ranging from cell differentiation, cell adhesion and wound healing. Cytokine and chemokine–GAG interactions are also involved in presentation of inflammatory molecules to respective receptors leading to immune cell migration and airway infiltration. More recently, pathophysiological roles of GAGs have been described. This review aims to discuss the biological roles and molecular interactions of GAGs, and their impact in the pathology of chronic airway diseases, such as cystic fibrosis and chronic obstructive pulmonary disease. Moreover, the role of GAGs in respiratory disease has been heightened by the current COVID-19 pandemic. This review underlines the essential need for continued research aimed at exploring the contribution of GAGs in the development of inflammation, to provide a better understanding of their biological impact, as well as leads in the development of new therapeutic agents.

Comorbidity-associated glutamine deficiency is a predisposition to severe COVID-19

SARS-CoV-2 vaccinations have greatly reduced COVID-19 cases, but we must continue to develop our understanding of the nature of the disease and its effects on human immunity. Previously, we suggested that a dysregulated STAT3 pathway following SARS-Co-2 infection ultimately leads to PAI-1 activation and cascades of pathologies. The major COVID-19-associated metabolic risks (old age, hypertension, cardiovascular diseases, diabetes, and obesity) share high PAI-1 levels and could predispose certain groups to severe COVID-19 complications. In this review article, we describe the common metabolic profile that is shared between all of these high-risk groups and COVID-19. This profile not only involves high levels of PAI-1 and STAT3 as previously described, but also includes low levels of glutamine and NAD+, coupled with overproduction of hyaluronan (HA). SARS-CoV-2 infection exacerbates this metabolic imbalance and predisposes these patients to the severe pathophysiologies of COVID-19, including the involvement of NETs (neutrophil extracellular traps) and HA overproduction in the lung. While hyperinflammation due to proinflammatory cytokine overproduction has been frequently documented, it is recently recognized that the immune response is markedly suppressed in some cases by the expansion and activity of MDSCs (myeloid-derived suppressor cells) and FoxP3+ Tregs (regulatory T cells). The metabolomics profiles of severe COVID-19 patients and patients with advanced cancer are similar, and in high-risk patients, SARS-CoV-2 infection leads to aberrant STAT3 activation, which promotes a cancer-like metabolism. We propose that glutamine deficiency and overproduced HA is the central metabolic characteristic of COVID-19 and its high-risk groups. We suggest the usage of glutamine supplementation and the repurposing of cancer drugs to prevent the development of severe COVID-19 pneumonia.

Unraveled roles of hyaluronan in severe COVID-19

Coronavirus disease 2019 (COVID-19) is a pandemic viral pneumonia caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2). Most of the severe COVID-19 patients come up with trouble breathing, persistent pressure in the chest and developing to acute respiratory distress syndrome (ARDS) with a high mortality rate. Infected lung brings about uncontrolled inflammation followed by the fluid leakage and accumulation of extracellular matrix. Hyaluronan (HA) is an essential component of the extracellular matrix (ECM) and plays crucial roles in both biological and pathological states. It is also primarily located within the respiratory airways and is uprising during COVID-19 infection. Hitherto, the association between COVID-19 pathophysiology and HA is still unclear. Herein, we provide an overview of the pathophysiology of SARS-CoV-2 infection in conjunction with the involvement of HA and the diminution of HA for therapeutic potential of COVID-19. For severe patients, HA depletion may be beneficial for preventing ARDS while monitoring and managing HA level in lung may improve survival rate of patients.

Hyaluronan primes the oxidative burst in human neutrophils

Hyaluronan (HA) is a glycosaminoglycan that in its natural, high molecular mass (HMM) form, promotes tissue repair and homeostasis. With inflammation, HA metabolism and HMM HA fragmentation to low molecular mass (LMM) forms is greatly enhanced. Considerable evidence suggests that LMM HA may act as a damage-associated molecular pattern to initiate innate immune responses. However, the responsiveness of myeloid cells to LMM HA is controversial and largely unknown for neutrophils. Peripheral blood cells from healthy donors were incubated ex vivo with pharmaceutical grade HA of different molecular mass (HMM, LMM, and HA fragments <10 kDa). Key innate immune functions were assessed, namely production of cytokines and reactive oxygen species release (ROS), granule mobilization, and apoptosis. None of the tested sizes of HA altered cytokine production by PBMC and neutrophils. Also, HA had no effect on neutrophil granule mobilization and apoptosis. In contrast, HA primed neutrophils for rapid and robust release of ROS in response to a secondary stimulus (N-formyl-methionyl-leucyl phenylalanine). Priming occurred within 20 min of exposure to HA and was similar for all tested molecular mass. The observed effect was independent of granule mobilization and associated with the activation of intracellular signaling pathways involving Src family kinases, glycogen synthase kinase-3, and the proline-rich Akt substrate of 40 kDa. Our findings provide new evidence that HA, irrespective of molecular mass, is a specific priming agent of the neutrophil oxidative burst, which is a critical, early component of an innate immune response.

Synovial fluid pretreatment with hyaluronidase facilitates isolation of CD44+ extracellular vesicles

Extracellular vesicles (EVs) in synovial fluid (SF) are gaining increased recognition as important factors in joint homeostasis, joint regeneration, and as biomarkers of joint disease. A limited number of studies have investigated EVs in SF samples of patients with joint disease, but knowledge on the role of EVs in healthy joints is lacking. In addition, no standardized protocol is available for isolation of EVs from SF. Based on the high viscosity of SF caused by high concentrations of hyaluronic acid (HA) - a prominent extracellular matrix component - it was hypothesized that EV recovery could be optimized by pretreatment with hyaluronidase (HYase). Therefore, the efficiency of EV isolation from healthy equine SF samples was tested by performing sequential ultracentrifugation steps (10,000g, 100,000g and 200,000g) in the presence or absence of HYase. Quantitative EV analysis using high-resolution flow cytometry showed an efficient recovery of EVs after 100,000g ultracentrifugation, with an increased yield of CD44+ EVs when SF samples were pretreated with HYase. Morphological analysis of SF-derived EVs with cryo-transmission-electron microscopy did not indicate damage by high-speed ultracentrifugation and revealed that most EVs are spherical with a diameter of 20-200 nm. Further protein characterization by Western blotting revealed that healthy SF-derived EVs contain CD9, Annexin-1, and CD90/Thy1.1. Taken together, these data suggest that EV isolation protocols for body fluids that contain relatively high amounts of HA, such as SF, could benefit from treatment of the fluid with HYase prior to ultracentrifugation. This method facilitates recovery and detection of CD44+ EVs within the HA-rich extracellular matrix. Furthermore, based on the findings presented here, it is recommended to sediment SF-derived EVs with at least 100,000g for optimal EV recovery.

Hyaluronic acid as a biomarker of fibrosis in chronic liver diseases of different etiologies

Chronic liver diseases represent a significant public health problem worldwide. The degree of liver fibrosis secondary to these diseases is important, because it is the main predictor of their evolution and prognosis.

Hyaluronic acid is studied as a non-invasive marker of liver fibrosis in chronic liver diseases, in an attempt to avoid the complications of liver puncture biopsy, considered the gold standard in the evaluation of fibrosis. We review the advantages and limitations of hyaluronc acid, a biomarker, used to manage patients with chronic viral hepatitis B or C infection, non-alcoholic fatty liver disease, HIV-HCV coinfection, alcoholic liver disease, primary biliary cirrhosis, biliary atresia, hereditary hemochromatosis and cystic fibrosis.

The role of hyaluronan in the pathobiology and treatment of respiratory disease

Hyaluronan, a ubiquitous naturally occurring glycosaminoglycan, is a major component of the extracellular matrix, where it participates in biological processes that include water homeostasis, cell-matrix signaling, tissue healing, inflammation, angiogenesis, and cell proliferation and migration. There are emerging data that hyaluronan and its degradation products have an important role in the pathobiology of the respiratory tract. We review the role of hyaluronan in respiratory diseases and present evidence from published literature and from clinical practice supporting hyaluronan as a novel treatment for respiratory diseases. Preliminary data show that aerosolized exogenous hyaluronan has beneficial activity against airway inflammation, protects against bronchial hyperreactivity and remodeling, and disrupts the biofilm associated with chronic infection. This suggests a role in airway diseases with a predominant inflammatory component such as rhinosinusitis, asthma, chronic obstructive pulmonary disease, cystic fibrosis, and primary ciliary dyskinesia. The potential for hyaluronan to complement conventional therapy will become clearer when data are available from controlled trials in larger patient populations.

The effect of the decoy molecule PA401 on CXCL8 levels in bronchoalveolar lavage fluid of patients with cystic fibrosis

BACKGROUND

The chemokine interleukin-8 (CXCL8) is a key mediator of inflammation in airways of patients with cystic fibrosis (CF). Glycosaminoglycans (GAGs) possess the ability to influence the chemokine profile of the CF lung by binding CXCL8 and protecting it from proteolytic degradation. CXCL8 is maintained in an active state by this glycan interaction thus increasing infiltration of immune cells such as neutrophils into the lungs. As the CXCL8-based decoy PA401 displays no chemotactic activity, yet demonstrates glycan binding affinity, the aim of this study was to investigate the anti-inflammatory effect of PA401 on CXCL8 levels, and activity, in CF airway samples in vitro.

METHODS

Bronchoalveolar lavage fluid (BALF) was collected from patients with CF homozygous for the ΔF508 mutation (n=13). CXCL8 in CF BALF pre and post exposure to PA401 was quantified by ELISA. Western blot analysis was used to determine PA401 degradation in CF BALF. The ex vivo chemotactic activity of purified neutrophils in response to CF airway secretions was evaluated post exposure to PA401 by use of a Boyden chamber-based motility assay.

RESULTS

Exposure of CF BALF to increasing concentrations of PA401 (50-1000pg/ml) over a time course of 2-12h in vitro, significantly reduced the level of detectable CXCL8 (P<0.05). Interestingly, PA401 engendered release of CXCL8 from GAGs exposing the chemokine susceptible to proteolysis. Subsequently, a loss of PA401 was observed (P<0.05) due to proteolytic degradation by elastase like proteases. A 25% decrease in neutrophil chemotactic efficiency towards CF BALF samples incubated with PA401 was also observed (P<0.05).

CONCLUSION

PA401 can disrupt CXCL8:GAG complexes, rendering the chemokine susceptible to proteolytic degradation. Clinical application of a CXCL8 decoy, such as PA401, may serve to decrease the inflammatory burden in the CF lung in vivo.

Liver disease in cystic fibrosis: an update

CONTEXT

Cystic fibrosis (CF) is the most widespread autosomal recessive genetic disorder that limits life expectation amongst the Caucasian population. As the median survival has increased related to early multidisciplinary intervention, other manifestations of CF have emerged especially for the broad spectrum of hepatobiliary involvement. The present study reviews the existing literature on liver disease in cystic fibrosis and describes the key issues for an adequate clinical evaluation and management of patients, with a focus on the pathogenetic, clinical and diagnostic-therapeutic aspects of liver disease in CF.

EVIDENCE ACQUISITION

A literature search of electronic databases was undertaken for relevant studies published from 1990 about liver disease in cystic fibrosis. The databases searched were: EMBASE, PubMed and Cochrane Library.

RESULTS

CF is due to mutations in the gene on chromosome 7 that encodes an amino acidic polypeptide named CFTR (cystic fibrosis transmembrane regulator). The hepatic manifestations include particular changes referring to the basic CFTR defect, iatrogenic lesions or consequences of the multisystem disease. Even though hepatobiliary disease is the most common non-pulmonary cause of mortality in CF (the third after pulmonary disease and transplant complications), only about the 33%of CF patients presents clinically significant hepatobiliary disease.

CONCLUSIONS

Liver disease will have a growing impact on survival and quality of life of cystic fibrosis patients because a longer life expectancy and for this it is important its early recognition and a correct clinical management aimed at delaying the onset of complications. This review could represent an opportunity to encourage researchers to better investigate genotype-phenotype correlation associated with the development of cystic fibrosis liver disease, especially for non-CFTR genetic polymorphisms, and detect predisposed individuals. Therapeutic trials are needed to find strategies of fibrosis prevention and to avoid its progression prior to development its related complications.

Incidence and clinical significance of elevated liver function tests in cystic fibrosis clinical trials

RATIONALE

Emergence of elevated liver function tests (LFTs) during a clinical trial may be due to underlying disease factors of the participants, thus cofounding safety assessments of therapies. Limited data exist addressing the frequency of elevated LFTs in the chronic disease setting of cystic fibrosis (CF). The objectives of this study were to characterize emergence rates of elevated LFTs in CF trials and their association with clinical outcomes.

METHODS

The cohort was comprised of participants of three completed multicenter CF trials. LFTs were collected as safety endpoints, and hospitalization rates and changes in pulmonary function and weight were used to assess the association between elevated LFTs and clinical outcome.

RESULTS

93/376 (25%) participants had ≥1 emergent elevated LFT exceeding the normal reference range over an average 8.3 month follow-up, and only 12/93 (13%) had a value determined by the physician as clinically significant. The emergence of an elevated LFT was not significantly associated with a greater rate of decline in pulmonary function or weight as compared to participants with normal LFTs. The emergence of an elevated LFT value was however associated with a higher hospitalization risk (relative risk:1.67, 95% confidence interval:1.11, 2.53).

CONCLUSIONS

Elevated LFTs are common among CF trials, although in most cases they are not deemed clinically significant. These elevated LFTs are associated with more frequent hospitalizations, but additional studies are needed to determine the causality of this association. Therapeutic trials in CF must define a priori criteria for clinical significance of elevated LFTs to enable unbiased safety assessments.

Nebulized hypertonic saline decreases IL-8 in sputum of patients with cystic fibrosis

RATIONALE

Inflammation within the cystic fibrosis (CF) lung is mediated by inflammatory chemokines, such as IL-8. IL-8 is protected from proteolytic degradation in the airways by binding to glycosaminoglycans, while remaining active. Evidence that increased hypertonicity of airway secretions induced by hypertonic saline treatment alters levels of IL-8 is lacking.

OBJECTIVES

To investigate the antiinflammatory effect of hypertonic saline (HTS) treatment within the CF lung by focusing on IL-8.

METHODS

Degradation of IL-8 in CF lung secretions after treatment with glycosaminoglycan lyases and HTS was analyzed by Western blot analysis and ELISA. The ex vivo chemotactic activity of purified neutrophils in response to CF airway secretions was evaluated post nebulization of HTS (7% saline).

MEASUREMENTS AND MAIN RESULTS

In vivo CF bronchoalveolar lavage fluid (BALF) IL-8 levels were significantly higher than the control group (P < 0.05). Digesting glycosaminoglycans in CF BALF displaced IL-8 from glycosaminoglycan matrices, rendering the chemokine susceptible to proteolytic cleavage. High sodium concentrations also liberate IL-8 in CF BALF in vitro, and in vivo in CF sputum from patients receiving aerosolized HTS, resulting in degradation of IL-8 and decreased neutrophil chemotactic efficiency.

CONCLUSIONS

Glycosaminoglycans possess the ability to influence the chemokine profile of the CF lung by binding and stabilizing IL-8, which promotes neutrophil chemotaxis and activation. Nebulized hypertonic saline treatment disrupts the interaction between glycosaminoglycans and IL-8, rendering IL-8 susceptible to proteolytic degradation with subsequent decrease in neutrophil chemotaxis, thereby facilitating resolution of inflammation.

Paediatric cholestatic liver disease: Diagnosis, assessment of disease progression and mechanisms of fibrogenesis

Cholestatic liver disease causes significant morbidity and mortality in children. The diagnosis and management of these diseases can be complicated by an inability to detect early stages of fibrosis and a lack of adequate interventional therapy. There is no single gold standard test that accurately reflects the presence of liver disease, or that can be used to monitor fibrosis progression, particularly in conditions such as cystic fibrosis. This has lead to controversy over how suspected liver disease in children is detected and diagnosed. This review discusses the challenges in using commonly available methods to diagnose hepatic fibrosis and monitor disease progression in children with cholestatic liver disease. In addition, the review examines the mechanisms hypothesised to be involved in the development of hepatic fibrogenesis in paediatric cholestatic liver injury which may ultimately aid in identifying new modalities to assist in both disease detection and therapeutic intervention.

Determination of the relationship of serum hyaluronic Acid levels to the degree of liver fibrosis in biopsies of patients with chronic viral hepatitis B and C

BACKGROUND AND AIMS

Determining the stage of liver fibrosis and the grade of necroinflammation is important in predicting the prognosis and treatment response of patients with chronic viral hepatitis. Liver biopsy is associated with several technical problems and complications; therefore, its repetitive performance as a procedure in evaluating treatment response and in following up patients is not recommended. This study was performed to determine the correlation of serum hyaluronic acid (HA) levels with the stage and grade of histopathologic liver changes in patients with chronic hepatitis B and C.

METHODS

This analytical cross-sectional study was performed on 69 patients with chronic hepatitis B or C in Mashhad, Iran, who were referred to our clinic and underwent liver biopsy and blood sampling simultaneously in 2006-2007. None of the patients were on medication that would affect the serum levels of (HA) and patients with signs of arthropathy were excluded from the study.

RESULTS

Out of the 69 patients i this study, 48 (69.6%) were male and 21 (30.4%) were female. The causative virus in 29 patients (42%) was hepatitis C and in the rest (n = 40, 58%) hepatitis B. The severity of liver fibrosis (stage) had a direct correlation (r = 0.25, P = 0.042) with the levels of (HA) and an inverse correlation with the platelet level (r = 0.37, P = 0.002). The degree of liver necroinflammation (grade) did not have a significant correlation with the levels of (HA) and alanine transaminase (r = -0.01, P = 0.9; r = 0.21, P = 0.09 respectively); instead, there was an inverse correlation with platelet levels (r = 0.36, P = 0.003).

CONCLUSIONS

Our study results correspond with those of other international studies; thus suggesting that the (HA) serum level is a useful marker in determining the severity of fibrosis in patients with chronic viral hepatitis. To form a definite conclusion, further studies on large groups should be performed.

LL-37 complexation with glycosaminoglycans in cystic fibrosis lungs inhibits antimicrobial activity, which can be restored by hypertonic saline

There is an abundance of antimicrobial peptides in cystic fibrosis (CF) lungs. Despite this, individuals with CF are susceptible to microbial colonization and infection. In this study, we investigated the antimicrobial response within the CF lung, focusing on the human cathelicidin LL-37. We demonstrate the presence of the LL-37 precursor, human cathelicidin precursor protein designated 18-kDa cationic antimicrobial protein, in the CF lung along with evidence that it is processed to active LL-37 by proteinase-3. We demonstrate that despite supranormal levels of LL-37, the lung fluid from CF patients exhibits no demonstrable antimicrobial activity. Furthermore Pseudomonas killing by physiological concentrations of exogenous LL-37 is inhibited by CF bronchoalveolar lavage (BAL) fluid due to proteolytic degradation of LL-37 by neutrophil elastase and cathepsin D. The endogenous LL-37 in CF BAL fluid is protected from this proteolysis by interactions with glycosaminoglycans, but while this protects LL-37 from proteolysis it results in inactivation of LL-37 antimicrobial activity. By digesting glycosaminoglycans in CF BAL fluid, endogenous LL-37 is liberated and the antimicrobial properties of CF BAL fluid restored. High sodium concentrations also liberate LL-37 in CF BAL fluid in vitro. This is also seen in vivo in CF sputum where LL-37 is complexed to glycosaminoglycans but is liberated following nebulized hypertonic saline resulting in increased antimicrobial effect. These data suggest glycosaminoglycan-LL-37 complexes to be potential therapeutic targets. Factors that disrupt glycosaminoglycan-LL-37 aggregates promote the antimicrobial effects of LL-37 with the caveat that concomitant administration of antiproteases may be needed to protect the now liberated LL-37 from proteolytic cleavage.

A single centre experience of liver disease in adults with cystic fibrosis 1995-2006

BACKGROUND

Liver disease is an important cause of death in adults with cystic fibrosis (CF). Ursodeoxycholic acid (UDCA) may slow progression. Managing varices and timely evaluation for liver transplantation are important.

METHODS

Adults with CF underwent annual review. Abnormalities of liver function tests or ultrasound prompted referral to the CF/liver clinic where UDCA was commenced. Endoscopic surveillance for varices was undertaken if ultrasound suggested portal hypertension.

RESULTS

154 patients were followed for a median 5 years. 43 had significant liver disease, 29 had cirrhosis with portal hypertension and 14 had ultrasound evidence of cirrhosis without portal hypertension. All started UDCA. Only one patient developed chronic liver failure and none required liver transplantation. 27 underwent endoscopy; 1 required variceal banding, the others had insignificant varices. Ultrasound was normal in 97 patients while five had steatosis; nine further patients had splenomegaly but no other evidence of portal hypertension. Neither spleen size nor platelet count correlated with portal hypertension.

CONCLUSIONS

Liver disease was common in adults with CF but disease progression was rare. Thus liver disease detected and closely monitored in adults appeared to have a milder course than childhood CF. Splenomegaly, unrelated to portal hypertension may be a consequence of CF.

Prediction of severe hyperbilirubinaemia using the Bilicheck transcutaneous bilirubinometer

OBJECTIVES

To determine the sensitivity and specificity of different levels of bilirubin measured by the transcutaneous bilirubinometer Bilicheck on forehead and sternum for predicting severe hyperbilirubinaemia of total serum bilirubin (TSB)>or=300 micromol/L in Malay, Chinese and Indian infants.

DESIGN

A prospective observational study.

SETTING

A tertiary care University hospital.

METHODS

A total of 345 healthy jaundiced term infants were recruited prior to commencement of phototherapy or exchange transfusion. Transcutaneous bilirubin (TcB) level was measured with the Bilicheck from infants' foreheads (TcBh) and sternums (TcBs) within 30 min of serum bilirubin measurement by the diazo method in the hospital laboratory.

RESULTS

The median serum TSB level of these infants was 233.0 micromol/L (range: 108.0-589.0). Ninety-five (27.5%) infants had TSB>or=300 micromol/L. There was good correlation between log10TSB and TcB measured from the forehead (r=0.80, P<0.0001) and the sternum (r=0.86, P<0.0001). At TcBh cut-off of 250 micromol/L, the Bilicheck detected TSB>or=300 micromol/L with a sensitivity of 100% and a specificity of 39.2%, the area under the receiver operative characteristic curve being 0.89 (95% confidence interval 0.85, 0.92). At TcBs cut-off of 200 micromol/L, the Bilicheck detected TSB>or=300 micromol/L with a sensitivity of 100% and a specificity of 33.6%, the area under receiver operative characteristic curve being 0.93 (95% confidence interval 0.90, 0.96).

CONCLUSION

The Bilicheck is not a substitute for measuring serum bilirubin. However, using predetermined TcB cut-off values with reasonable sensitivity and specificity, it is a useful screening tool to identify infants with TSB>or=300 micromol/L requiring blood sampling, hospital admission and treatment.

Hyaluronic acid predicts hepatic fibrosis in children with hepatic disease

BACKGROUND

Hyaluronic acid (HA) is removed by the liver via sinusoidal cell adhesion molecules. This is impeded in fibrosis, leading to a rise in serum HA. As a noninvasive marker of fibrosis, HA may obviate the need for liver biopsy.

OBJECTIVE

To evaluate HA as a marker of hepatic fibrosis, in unselected children undergoing liver biopsy.

METHODS

Ninety-three unselected consecutive children (median age, 7.5 years; range, 0.07-19 years) undergoing a liver biopsy between April 2003 and March 2004 were prospectively recruited. Liver biopsy and fasting HA levels were taken simultaneously. The Ishak score was used to stage fibrosis. Scores of 3 or greater were regarded as significant fibrosis. Hyaluronic acid levels were measured using an enzyme-linked binding protein assay (2002 Corgenix, Inc) (adult reference range, 0-75 ng/mL; pediatric reference range, 0-30 ng/mL).

RESULTS

Twenty-three (25%) of 93 biopsies had significant fibrosis, and HA levels in this group were significantly higher than those with mild fibrosis (Ishak score, <3), (median level, 72 ng/mL vs 30 ng/mL; Mann-Whitney U test; P < 0.005). Hyaluronic acid level of 50 ng/mL had a positive predictive value 40% and negative predictive value 86% for significant fibrosis. An HA level 200 ng/mL has a sensitivity of 26% and specificity of 90%.

CONCLUSIONS

Hyaluronic Acid is a valid noninvasive predictor of hepatic fibrosis in unselected children with liver disease. An HA level of 200 ng/mL strongly suggests significant fibrosis. Hyaluronic acid level of less than 50 ng/mL accurately identifies those who do not have significant fibrosis.

Determination of Serum Fibrosis Indexes in Patients with Capsular Contracture after Augmentation with Smooth Silicone Gel Implants

BACKGROUND

Several studies have confirmed a correlation between the concentration of serum hyaluronan and progressive fibrotic disorders such as liver cirrhosis. The aim of this study was to explore the relationship between serum hyaluronan levels and capsular contracture after aesthetic breast augmentation.

METHODS

The study included 25 female patients (average age, 40 +/- 12 years) with capsular contracture after cosmetic breast augmentation with smooth silicone gel implants (Mentor, Santa Barbara, Calif.). The implants were placed in a submuscular position through an inframammary fold incision. The implant removals were prompted by development of capsular fibrosis (Baker grades I through IV). Samples of capsular tissue were obtained from all patients for standard histologic and immunohistochemical analysis. Blood samples were drawn from all patients immediately before operation. Sera from 20 healthy female patients (average age, 34 +/- 9 years) were used as control.

RESULTS

: Capsular tissue revealed significantly higher thickness in patients with grade III/IV contracture than in women with grade II contracture, according to Baker's classification. There was a moderate (n = 15) or severe (n = 10) chronic inflammatory reaction in the capsules around the implants. Fibroblasts, fibroblast-like cells, and macrophages represented the major cell populations found within the fibrous capsules, along with scattered polymorphonuclear leukocytes, lymphocytes, plasma cells, and mast cells. In addition, activated CD4+ cells were detected. An inner layer with synovia-like metaplasia and multinucleated giant cells was found. There was a significantly higher level (p < 0.05) of hyaluronan serum concentration in patients with capsular contracture (26 +/- 14 microg/liter) compared with control subjects (12 +/- 6 microg/liter). There was a positive correlation between the grade of capsular contracture (Baker grades I through IV) and the hyaluronan serum concentration (Baker grade II, 15 +/- 3 microg/liter; Baker grade III, 34 +/- 13 microg/liter; Baker grade IV, 42 +/- 11 microg/liter) (r = 0.73; p < 0.05).

CONCLUSIONS

Serum hyaluronan levels were significantly elevated in patients with capsular contracture after breast augmentation, and there was a positive correlation with stage of capsular contracture. Further study is necessary to determine whether hyaluronan might be useful as a predictor for the development and progress of capsular fibrosis.

Matrix-derived serum markers in monitoring liver fibrosis in children with chronic hepatitis B treated with interferon alpha

AIM: To evaluate prospectively 4 selected serum fibrosis markers (tenascin, hyaluronan, collagen VI, TIMP-1) before, during and 12 mo after IFN treatment of children with chronic hepatitis B.

METHODS: Forty-seven consecutive patients with chronic hepatitis B (range 4-16 years, mean 8 years) underwent IFN treatment (3 MU tiw for 20 wk). Fibrosis stage and inflammation grade were assessed in a blinded fashion before and 12 mo after end of treatment. Serum fibrosis markers were determined using automated assays.

RESULTS: IFN treatment improved histological inflammation but did not change fibrosis in the whole group or in subgroups. Only hyaluronan correlated significantly with histological fibrosis(r = 0.3383, P = 0.021). Basal fibrosis markers did not differ between responders (42.5%) and nonresponders(57.5%). During IFN treatment only serum tenascin decreased significantly in the whole group and in nonresponders. When pretreatment values were compared to values 12 mo after therapy, TIMP-1 increased in all patients and in nonresponders, and hyaluronan decreased in all patients and in responders.

CONCLUSION: Tenascin reflects hepatic fibrogenesis and inflammation which decreases during IFN treatment of children with chronic hepatitis B. TIMP-1 correlates with nonresponse and hyaluronan with histological fibrosis.

Diagnostic accuracy of serum biochemical fibrosis markers in children with chronic hepatitis B evaluated by receiver operating characteristics analysis

AIM

To investigate the diagnostic accuracy of potent serum biochemical fibrosis markers in children with chronic hepatitis B evaluated by receiver operating characteristics (ROC) analysis.

METHODS

We determined the serum level of apolipoprotein A-I (APO A-I), haptoglobin (HPT) and a-2 macroglobulin (A2M) with an automatic nephelometer in 63 children (age range 4-17 years, mean 10 years) with biopsy-verified chronic HBeAg-positive hepatitis B. Fibrosis stage and inflammation grade were assessed in a blinded fashion according to Batts and Ludwig. We defined mild liver fibrosis as a score < or =2 and advanced fibrosis as a score equal to 3. ROC analysis was used to calculate the power of the assays to detect advanced liver fibrosis (AccuROC, Canada).

RESULTS

Serum concentrations of APO A-I, HPT and A2M were not significantly different in patients with chronic hepatitis B compared to controls. However, APO A-I level of 1.19 ng/L had a sensitivity of 85.7% and a specificity of 60.7% (AUC = 0.7117, P = 0.035) to predict advanced fibrosis. All other serum biochemical markers and their combination did not allow a useful prediction. None of these markers was a good predictor of histologic inflammation.

CONCLUSION

Apolipoprotein A-I may be a suitable serum marker to predict advanced liver fibrosis in children with chronic hepatitis B.

Serologic and histologic findings in patients with capsular contracture after breast augmentation with smooth silicone gel implants: is serum hyaluronan a potential predictor?

BACKGROUND

In this study, breast implant capsular tissues and blood samples from 25 cases were studied to characterize the relationship between capsular findings and serum analysis. The serum fibrosis indexes hyaluronan and the aminoterminal propeptide of procollagen type III (PIIINP) are fairly well correlated in several other studies with the inflammation grade and fibrosis in patients with progressive fibrotic disorders such as liver cirrhosis.

METHODS

The study enrolled 25 female patients (average age, 40 +/- 12 years) with capsular contracture after bilateral cosmetic breast augmentation using smooth silicone gel implants (Mentor). The implants were placed in a submuscular position through an incision in the inframammary fold. The implant removals were prompted by development of capsular fibrosis (Baker grades 1-4). Samples of capsular tissue were obtained from all the patients for standard histologic and immunohistochemical analyses. Blood samples were drawn from all the patients immediately before surgery. Sera from 20 healthy female patients (average age, 34 +/- 9 years) who had undergone plastic surgery for reduction mammaplasty were used as controls.

RESULTS

Histology. Capsular tissue was significantly thicker in patients with grades 3 and 4 contracture than in women with grade 2 contracture according the classification by Baker. There was a moderate (n = 15) or severe (n = 10) chronic inflammatory reaction in the capsules around the implants. Fibroblasts and macrophages represented the major cell population found in the fibrous capsules. In addition, activated CD4+ cells were detected. An inner layer with synovia-like metaplasia and multinucleated giant cells was found. Fibroblast-like cells formed the most common cell type in the capsules, along with macrophages, scattered polymorphonuclear leukocytes, lymphocytes, plasma cells, and mast cells. Serum analysis. There was a significantly higher level (p < 0.05) of hyaluronan serum concentration in patients with capsular contracture (26 +/- 14 microg/l) than in control subjects (12 +/- 6 microg/l). There was a positive correlation between the grade of capsular contracture (Baker 1-4) and the hyaluronan serum concentration (Baker 1-2: 15 +/- 3 microg/l; Baker 3-4: 35 +/- 12 microg/l) (r2 = 0.73; p < 0.05).

CONCLUSION

: In this study, serum hyaluronan levels were significantly elevated in patients with constrictive fibrosis after breast augmentation, and there was a positive correlation with the stage of capsular contracture. Serum hyaluronan concentration may help in defining patients at risk for capsular fibrosis. If treatment with new drugs can be started as a preventive measure, it may be possible to reduce the rate of patients who require surgical intervention.

The gallbladder and biliary tract in cystic fibrosis

Chronic liver disease is a major complication of cystic fibrosis. Its incidence and severity are variable, and diagnosis relies on a combination of clinical evaluation, biochemical testing, and radiologic assessment. Identifying patients who have early disease is critical, and the administration of ursodeoxycholic acid appears to be beneficial. The pathogenesis is incompletely understood, and factors that contribute to the variability in incidence and severity are unknown. Fortunately, only a small proportion of individuals progress to advanced liver disease; however, in this population, there is significant morbidity and impairment in quality of life. Liver transplantation can be performed successfully in patients with end-stage liver disease. Future treatments involve targeted gene therapy and activation of mutant forms of the cystic fibrosis transmembrane conductance regulator.

Inhibition of antithrombin by hyaluronic acid may be involved in the pathogenesis of rheumatoid arthritis

Thrombin is a key factor in the stimulation of fibrin deposition, angiogenesis, proinflammatory processes, and proliferation of fibroblast-like cells. Abnormalities in these processes are primary features of rheumatoid arthritis (RA) in synovial tissues. Tissue destruction in joints causes the accumulation of large quantities of free hyaluronic acid (HA) in RA synovial fluid. The present study was conducted to investigate the effects of HA and several other glycosaminoglycans on antithrombin, a plasma inhibitor of thrombin. Various glycosaminoglycans, including HA, chondroitin sulfate, keratan sulfate, heparin, and heparan, were incubated with human antithrombin III in vitro. The residual activity of antithrombin was determined using a thrombin-specific chromogenic assay. HA concentrations ranging from 250 to 1000 μg/ml significantly blocked the ability of antithrombin to inhibit thrombin in the presence of Ca²⁺ or Fe³⁺, and chondroitin A, B and C also reduced this ability under the same conditions but to a lesser extent. Our study suggests that the high concentration of free HA in RA synovium may block antithrombin locally, thereby deregulating thrombin activity to drive the pathogenic process of RA under physiological conditions. The study also helps to explain why RA occurs and develops in joint tissue, because the inflamed RA synovium is uniquely rich in free HA along with extracellular matrix degeneration. Our findings are consistent with those of others regarding increased coagulation activity in RA synovium.

Serum markers of hepatic fibrogenesis in cystic fibrosis liver disease

BACKGROUND/AIMS

Hepatic fibrosis contributes to adverse outcome in cystic fibrosis (CF). Early detection of CF liver disease (CFLD) may identify patients at risk of significant complications. To evaluate the utility of serum markers to detect hepatic fibrosis in children with CFLD vs. CF patients without liver disease (CFnoLD) and controls.

METHODS

Sera from 36 CFLD, 30 CFnoLD and 39 controls were assessed for tissue inhibitor of matrix metalloproteinase (MMP) (TIMP)-1, collagen (CL)-IV, MMP-2, hyaluronic acid (HA) and prolyl hydroxylase (PH) by enzyme immunoassay and were correlated with hepatic fibrosis score in CFLD.

RESULTS

TIMP-1, PH and CL-IV were increased in CFLD vs. CFnoLD and controls. Fibrosis score was negatively correlated with TIMP-1 (r=-0.34, P=0.06) and PH (r=-0.48, P=0.008). Receiver-operating characteristics analysis showed CL-IV (AUC 0.785, P<0.0001) and TIMP-1 (AUC 0.765, P<0.0001) differentiated CFLD from CFnoLD and controls, while PH (AUC 0.814, P<0.0001) predicted early fibrogenesis. Diagnostic accuracy improved using logistic regression combining (i) CL-IV, TIMP-1, PH to identify CFLD (AUC 0.831, P<0.0001) and (ii) TIMP-1, PH to identify CFLD patients with no fibrosis (AUC 0.852, P<0.02).

CONCLUSIONS

Elevated TIMP-1, CL-IV, PH may be indicators of hepatic fibrogenesis in CF. Increased TIMP-1, PH may be early markers of CFLD.

Hepatobiliary complications of cystic fibrosis

Cystic fibrosis (CF) is the most common potentially lethal genetic disease in the Caucasian population. The disease results from mutations in the gene for the cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated Cl(-) channel in the apical membrane of most secretory epithelia. In the liver, CFTR is located in biliary epithelial cells or cholangiocytes and gallbladder epithelia, where it appears to play a role in normal bile formation. However, how a defective CFTR protein leads to associated liver and biliary disease in a subset of patients with CF is unknown. Improvements in life expectancy have led to an increasing recognition of hepatobiliary complications from CF. Whereas the biliary tract disease is usually clinically evident, the liver involvement may progress silently, only manifesting as end-stage liver disease and portal hypertension. Unlike the pancreatic involvement in CF, a genotype-phenotype correlation is not apparent in the expression of liver disease, suggesting the presence of as yet unidentifiable "genetic modifiers" influencing disease expression. This review focuses on the pathogenesis, clinical manifestations, screening, diagnosis, and treatment of CF hepatobiliary disease.