Dersimelagon in Erythropoietic Protoporphyrias

BACKGROUND

Erythropoietic protoporphyria and X-linked protoporphyria are inborn errors of heme biosynthesis that cause elevated circulating levels of metal-free protoporphyrin and phototoxicity. Both disorders are characterized by excruciating phototoxic attacks after exposure to visible light. Dersimelagon is a new, orally administered, selective melanocortin 1 receptor agonist that increases levels of skin eumelanin.

METHODS

We conducted a randomized, placebo-controlled, phase 2 trial to investigate the efficacy and safety of dersimelagon with respect to the time to onset and the severity of symptoms associated with sunlight exposure in patients with erythropoietic protoporphyria or X-linked protoporphyria. Patients 18 to 75 years of age were randomly assigned in a 1:1:1 ratio to receive placebo or dersimelagon at a dose of 100 or 300 mg once daily for 16 weeks. The primary end point was the change from baseline to week 16 in the time to the first prodromal symptom associated with sunlight exposure. Patients recorded daily sunlight exposure and symptom data in an electronic diary. Quality of life and safety were also assessed.

RESULTS

Of the 102 patients (93 with erythropoietic protoporphyria and 9 with X-linked protoporphyria) who underwent randomization, 90% completed the treatment period. The mean daily time to the first prodromal symptom associated with sunlight exposure increased significantly with dersimelagon: the least-squares mean difference from placebo in the change from baseline to week 16 was 53.8 minutes in the 100-mg dersimelagon group (P = 0.008) and 62.5 minutes in the 300-mg dersimelagon group (P = 0.003). The results also suggest that quality of life improved in patients receiving dersimelagon as compared with placebo. The most common adverse events that occurred or worsened during treatment were nausea, freckles, headache, and skin hyperpigmentation.

CONCLUSIONS

At both doses evaluated, dersimelagon significantly increased the duration of symptom-free sunlight exposure in patients with erythropoietic protoporphyria or X-linked protoporphyria. (Funded by Mitsubishi Tanabe Pharma; Endeavor ClinicalTrials.gov number, NCT03520036.).

A pilot study of oral iron therapy in erythropoietic protoporphyria and X-linked protoporphyria

The use of iron supplementation for anemia in erythropoietic protoporphyria (EPP) is controversial with both benefit and deterioration reported in single case reports. There is no systematic study to evaluate the benefits or risks of iron supplementation in these patients. We assessed the potential efficacy of oral iron therapy in decreasing erythrocyte protoporphyrin (ePPIX) levels in patients with EPP or X-linked protoporphyria (XLP) and low ferritin in an open-label, single-arm, interventional study. Sixteen patients (≥18 years) with EPP or XLP confirmed by biochemical and/or genetic testing, and serum ferritin ≤30 ng/mL were enrolled. Baseline testing included iron studies, normal hepatic function, and elevated plasma porphyrins and ePPIX levels. Oral ferrous sulfate 325 mg twice daily was administered for 12 months. The primary efficacy outcome was the relative difference in total ePPIX level between baseline and 12 months after starting treatment with iron. Secondary measures included improvement in serum ferritin, plasma porphyrins, and clinical symptoms. Thirteen patients had EPP (8 females, 5 males) and 3 had XLP (all females) and the mean age of participants was 38.8 years (SD 14.5). Ten patients completed all study visits limiting interpretation of results. In EPP patients, a transient increase in ePPIX levels was observed at 3 months in 9 of 12 (75%) patients. Iron was discontinued in 2 of these patients after meeting the protocol stopping rule of a 35% increase in ePPIX. Seven patients withdrew before study end. Ferritin levels increased on iron replacement indicating an improvement in iron status. A decrease in ePPIX was seen in both XLP patients who completed the study (relative difference of 0.67 and 0.5 respectively). No substantial changes in ePPIX were seen in EPP patients at the end of the study (n = 8; median relative difference: -0.21 (IQR: −0.44, 0.05). The most common side effects of iron treatment were gastrointestinal symptoms. Hepatic function remained normal throughout the study. Our study showed that oral iron therapy repletes iron stores and transiently increases ePPIX in some EPP patients, perhaps due to a transient increase in erythropoiesis, and may decrease ePPIX in XLP patients. Further studies are needed to better define the role of iron repletion in EPP.

Trial registration: NCT02979249.

Efficacy and safety of givosiran for acute hepatic porphyria: 24-month interim analysis of the randomized phase 3 ENVISION study

BACKGROUND & AIMS

Upregulation of hepatic delta-aminolevulinic acid synthase 1 with accumulation of potentially toxic heme precursors delta-aminolevulinic acid and porphobilinogen is fundamental to the pathogenesis of acute hepatic porphyria.

AIMS

evaluate long-term efficacy and safety of givosiran in acute hepatic porphyria.

METHODS

Interim analysis of ongoing ENVISION study (NCT03338816), after all active patients completed their Month 24 visit. Patients with acute hepatic porphyria (≥12 years) with recurrent attacks received givosiran (2.5 mg/kg monthly) (n = 48) or placebo (n = 46) for 6 months (double-blind period); 93 received givosiran (2.5 mg or 1.25 mg/kg monthly) in the open-label extension (continuous givosiran, n = 47/48; placebo crossover, n = 46/46). Endpoints included annualized attack rate, urinary delta-aminolevulinic acid and porphobilinogen levels, hemin use, daily worst pain, quality of life, and adverse events.

RESULTS

Patients receiving continuous givosiran had sustained annualized attack rate reduction (median 1.0 in double-blind period, 0.0 in open-label extension); in placebo crossover patients, median annualized attack rate decreased from 10.7 to 1.4. Median annualized days of hemin use were 0.0 (double-blind period) and 0.0 (open-label extension) for continuous givosiran patients and reduced from 14.98 to 0.71 for placebo crossover patients. Long-term givosiran led to sustained lowering of delta-aminolevulinic acid and porphobilinogen and improvements in daily worst pain and quality of life. Safety findings were consistent with the double-blind period.

CONCLUSIONS

Long-term givosiran has an acceptable safety profile and significantly benefits acute hepatic porphyria patients with recurrent attacks by reducing attack frequency, hemin use, and severity of daily worst pain while improving quality of life.

Hepatocellular Carcinoma in Acute Hepatic Porphyrias: Results from the Longitudinal Study of the U.S. Porphyrias Consortium

BACKGROUND AND AIMS

The risk for hepatocellular carcinoma (HCC) is increased in acute hepatic porphyrias (AHP). The aim of this study was to explore the clinicopathologic characteristics, outcomes, and frequency of HCC in patients with AHP in the United States.

APPROACH AND RESULTS

This cross-sectional analysis evaluated patients with HCC in a multicenter, longitudinal study of AHP. Among 327 patients with AHP, 5 (1.5%) were diagnosed with HCC. Of the 5 HCC cases, 4 had acute intermittent porphyria and 1 had variegate porphyria, confirmed by biochemical and/or genetic testing. All patients were white females, with a median age of 27 years (range 21-75) at diagnosis. The median age at HCC diagnosis was 69 years (range 61-74). AHP was asymptomatic in 2 patients; 2 reported sporadic attacks; and 1 reported recurrent attacks (>4 attacks/year). All patients had a single HCC lesion on liver imaging that was 1.8-6.5 centimeters in diameter. Serum alpha fetoprotein levels were below 10 ng/mL in all 4 patients with available results. Four patients underwent liver resection, and 1 was treated with radioembolization. No significant inflammation or fibrosis was found in adjacent liver tissues of 3 patients who underwent liver resection. Two patients developed recurrence of HCC at 22 and 26 months following liver resection. All patients are alive with survival times from HCC diagnosis ranging from 26-153 months.

CONCLUSION

In this U.S. study, 1.5% of patients with AHP had HCC. HCC in AHP occurred in the absence of cirrhosis, which contrasts with other chronic liver diseases. Patients with AHP, regardless of clinical attacks, should be screened for HCC, beginning at age 50. The pathogenesis of hepatocarcinogenesis in AHP is unknown and needs further investigation.

Phase 3 Trial of RNAi Therapeutic Givosiran for Acute Intermittent Porphyria

BACKGROUND

Up-regulation of hepatic delta-aminolevulinic acid synthase 1 (ALAS1), with resultant accumulation of delta-aminolevulinic acid (ALA) and porphobilinogen, is central to the pathogenesis of acute attacks and chronic symptoms in acute hepatic porphyria. Givosiran, an RNA interference therapy, inhibits ALAS1 expression.

METHODS

In this double-blind, placebo-controlled, phase 3 trial, we randomly assigned symptomatic patients with acute hepatic porphyria to receive either subcutaneous givosiran (2.5 mg per kilogram of body weight) or placebo monthly for 6 months. The primary end point was the annualized rate of composite porphyria attacks among patients with acute intermittent porphyria, the most common subtype of acute hepatic porphyria. (Composite porphyria attacks resulted in hospitalization, an urgent health care visit, or intravenous administration of hemin at home.) Key secondary end points were levels of ALA and porphobilinogen and the annualized attack rate among patients with acute hepatic porphyria, along with hemin use and daily worst pain scores in patients with acute intermittent porphyria.

RESULTS

A total of 94 patients underwent randomization (48 in the givosiran group and 46 in the placebo group). Among the 89 patients with acute intermittent porphyria, the mean annualized attack rate was 3.2 in the givosiran group and 12.5 in the placebo group, representing a 74% lower rate in the givosiran group (P<0.001); the results were similar among the 94 patients with acute hepatic porphyria. Among the patients with acute intermittent porphyria, givosiran led to lower levels of urinary ALA and porphobilinogen, fewer days of hemin use, and better daily scores for pain than placebo. Key adverse events that were observed more frequently in the givosiran group were elevations in serum aminotransferase levels, changes in serum creatinine levels and the estimated glomerular filtration rate, and injection-site reactions.

CONCLUSIONS

Among patients with acute intermittent porphyria, those who received givosiran had a significantly lower rate of porphyria attacks and better results for multiple other disease manifestations than those who received placebo. The increased efficacy was accompanied by a higher frequency of hepatic and renal adverse events. (Funded by Alnylam Pharmaceuticals; ENVISION ClinicalTrials.gov number, NCT03338816.).

EXPLORE: A Prospective, Multinational, Natural History Study of Patients with Acute Hepatic Porphyria with Recurrent Attacks

BACKGROUND AND AIMS

Acute hepatic porphyria comprises a group of rare genetic diseases caused by mutations in genes involved in heme biosynthesis. Patients can experience acute neurovisceral attacks, debilitating chronic symptoms, and long-term complications. There is a lack of multinational, prospective data characterizing the disease and current treatment practices in severely affected patients.

APPROACH AND RESULTS

EXPLORE is a prospective, multinational, natural history study characterizing disease activity and clinical management in patients with acute hepatic porphyria who experience recurrent attacks. Eligible patients had a confirmed acute hepatic porphyria diagnosis and had experienced ≥3 attacks in the prior 12 months or were receiving prophylactic treatment. A total of 112 patients were enrolled and followed for at least 6 months. In the 12 months before the study, patients reported a median (range) of 6 (0-52) acute attacks, with 52 (46%) patients receiving hemin prophylaxis. Chronic symptoms were reported by 73 (65%) patients, with 52 (46%) patients experiencing these daily. During the study, 98 (88%) patients experienced a total of 483 attacks, 77% of which required treatment at a health care facility and/or hemin administration (median [range] annualized attack rate 2.0 [0.0-37.0]). Elevated levels of hepatic δ-aminolevulinic acid synthase 1 messenger ribonucleic acid levels, δ-aminolevulinic acid, and porphobilinogen compared with the upper limit of normal in healthy individuals were observed at baseline and increased further during attacks. Patients had impaired quality of life and increased health care utilization.

CONCLUSIONS

Patients experienced attacks often requiring treatment in a health care facility and/or with hemin, as well as chronic symptoms that adversely influenced day-to-day functioning. In this patient group, the high disease burden and diminished quality of life highlight the need for novel therapies.

Evaluating quality of life tools in North American patients with erythropoietic protoporphyria and X-linked protoporphyria

BACKGROUND

Erythropoietic protoporphyria (EPP) and X-linked Protoporphyria (XLP) are rare photodermatoses presenting with severe phototoxicity. Although anecdotally, providers who treat EPP patients acknowledge their life-altering effects, tools that fully capture their impact on quality of life (QoL) are lacking.

METHODS

Adult patients with EPP/XLP were given four validated QoL tools: the Patient Reported Outcomes Measurement Information System 57 (PROMIS-57), the Hospital Anxiety and Depression Scale (HADS), the Illness Perception Questionnaire Revised (IPQR), and an EPP-Specific tool. All patients received the PROMIS-57 while the HADS, IPQR, and EPP-Specific tools were introduced at a later date. Associations between responses and clinical phenotypes were explored.

RESULTS

Two hundred and two patients were included; 193 completed PROMIS-57, 104 completed IPQR, 103 completed HADS, and 107 completed the EPP-Specific tool. The IPQR showed that patients strongly believed EPP/XLP had a negative impact on their lives. Mean scores in anxiety and depression domains of both HADS and PROMIS-57 were normal; however, anxiety scores from HADS were borderline/abnormal in 20% of patients. The EPP-Specific tool revealed a decreased QoL in most patients. The PROMIS-57 showed that 21.8% of patients have clinically significant pain interference. Several tool domains correlated with measures of disease severity, most being from the PROMIS-57.

CONCLUSIONS

Impaired QoL is an important consequence of EPP/XLP. PROMIS-57 was most sensitive in evaluating impaired QoL in EPP/XLP. Further research is needed to compare the effectiveness of it for assessing response to treatment.

International Porphyria Molecular Diagnostic Collaborative: an evidence-based database of verified pathogenic and benign variants for the porphyrias

With the advent of precision and genomic medicine, a critical issue is whether a disease gene variant is pathogenic or benign. Such is the case for the three autosomal dominant acute hepatic porphyrias (AHPs), including acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria, each resulting from the half-normal enzymatic activities of hydroxymethylbilane synthase, coproporphyrinogen oxidase, and protoporphyrinogen oxidase, respectively. To date, there is no public database that documents the likely pathogenicity of variants causing the porphyrias, and more specifically, the AHPs with biochemically and clinically verified information. Therefore, an international collaborative with the European Porphyria Network and the National Institutes of Health/National Center for Advancing Translational Sciences/National Institute of Diabetes and Digestive and Kidney Diseases (NIH/NCATS/NIDDK)-sponsored Porphyrias Consortium of porphyria diagnostic experts is establishing an online database that will collate biochemical and clinical evidence verifying the pathogenicity of the published and newly identified variants in the AHP-causing genes. The overall goal of the International Porphyria Molecular Diagnostic Collaborative is to determine the pathogenic and benign variants for all eight porphyrias. Here we describe the overall objectives and the initial efforts to validate pathogenic and benign variants in the respective heme biosynthetic genes causing the AHPs.

Phase 1 Trial of an RNA Interference Therapy for Acute Intermittent Porphyria

BACKGROUND

Induction of delta aminolevulinic acid synthase 1 ( ALAS1) gene expression and accumulation of neurotoxic intermediates result in neurovisceral attacks and disease manifestations in patients with acute intermittent porphyria, a rare inherited disease of heme biosynthesis. Givosiran is an investigational RNA interference therapeutic agent that inhibits hepatic ALAS1 synthesis.

METHODS

We conducted a phase 1 trial of givosiran in patients with acute intermittent porphyria. In part A of the trial, patients without recent porphyria attacks (i.e., no attacks in the 6 months before baseline) were randomly assigned to receive a single subcutaneous injection of one of five ascending doses of givosiran (0.035, 0.10, 0.35, 1.0, or 2.5 mg per kilogram of body weight) or placebo. In part B, patients without recent attacks were randomly assigned to receive once-monthly injections of one of two doses of givosiran (0.35 or 1.0 mg per kilogram) or placebo (total of two injections 28 days apart). In part C, patients who had recurrent attacks were randomly assigned to receive injections of one of two doses of givosiran (2.5 or 5.0 mg per kilogram) or placebo once monthly (total of four injections) or once quarterly (total of two injections) during a 12-week period, starting on day 0. Safety, pharmacokinetic, pharmacodynamic, and exploratory efficacy outcomes were evaluated.

RESULTS

A total of 23 patients in parts A and B and 17 patients in part C underwent randomization. Common adverse events included nasopharyngitis, abdominal pain, and diarrhea. Serious adverse events occurred in 6 patients who received givosiran in parts A through C combined. In part C, all 6 patients who were assigned to receive once-monthly injections of givosiran had sustained reductions in ALAS1 messenger RNA (mRNA), delta aminolevulinic acid, and porphobilinogen levels to near normal. These reductions were associated with a 79% lower mean annualized attack rate than that observed with placebo (exploratory efficacy end point).

CONCLUSIONS

Once-monthly injections of givosiran in patients who had recurrent porphyria attacks resulted in mainly low-grade adverse events, reductions in induced ALAS1 mRNA levels, nearly normalized levels of the neurotoxic intermediates delta aminolevulinic acid and porphobilinogen, and a lower attack rate than that observed with placebo. (Funded by Alnylam Pharmaceuticals; ClinicalTrials.gov number, NCT02452372 .).

An 18-Year-Old With Acute-on-Chronic Abdominal Pain

An 18-year-old woman with a complex past medical history presented with 2 days of vomiting and lower abdominal pain. She had been admitted for the majority of the previous 5 months for recurrent pancreatitis and had undergone a cholecystectomy. Additional symptoms included nausea, anorexia, constipation, and a 40-lb weight loss over 4 months. She appeared uncomfortable, and an examination was remarkable for tachycardia, hypertension, and diffuse abdominal tenderness to light palpation. Her initial laboratory test results revealed mildly elevated liver enzymes (aspartate aminotransferase 68 U/L, alanine aminotransferase 80 U/L) and a normal lipase. She was admitted for pain control and nutritional support. Over the next few days, the lipase increased to 1707 U/L. Despite optimizing her management for acute pancreatitis, the patient's symptoms persisted. Further history gathering and laboratory testing ultimately revealed her diagnosis. Our expert panel reviews her hospital course and elucidates the management of our eventual diagnosis.

Acute hepatic porphyrias: Recommendations for evaluation and long-term management

The acute hepatic porphyrias are a group of four inherited disorders, each resulting from a deficiency in the activity of a specific enzyme in the heme biosynthetic pathway. These disorders present clinically with acute neurovisceral symptoms which may be sporadic or recurrent and, when severe, can be life-threatening. The diagnosis is often missed or delayed as the clinical features resemble other more common medical conditions. There are four major subgroups: symptomatic patients with sporadic attacks (<4 attacks/year) or recurrent acute attacks (≥4 attacks/year), asymptomatic high porphyrin precursor excretors, and asymptomatic latent patients without symptoms or porphyrin precursor elevations. Given their clinical heterogeneity and potential for significant morbidity with suboptimal management, comprehensive clinical guidelines for initial evaluation, follow-up, and long-term management are needed, particularly because no guidelines exist for monitoring disease progression or response to treatment. The Porphyrias Consortium of the National Institutes of Health's Rare Diseases Clinical Research Network, which consists of expert centers in the clinical management of these disorders, has formulated these recommendations. These recommendations are based on the literature, ongoing natural history studies, and extensive clinical experience. Initial assessments should include diagnostic confirmation by biochemical testing, subsequent genetic testing to determine the specific acute hepatic porphyria, and a complete medical history and physical examination. Newly diagnosed patients should be counseled about avoiding known precipitating factors. The frequency of follow-up depends on the clinical subgroup, with close monitoring of patients with recurrent attacks who may require treatment modifications as well as those with clinical complications. Comprehensive care should include subspecialist referrals when needed. Annual assessments include biochemical testing and monitoring for long-term complications. These guidelines provide a framework for monitoring patients with acute hepatic porphyrias to ensure optimal outcomes. (Hepatology 2017;66:1314-1322).

Clinical, Biochemical, and Genetic Characterization of North American Patients With Erythropoietic Protoporphyria and X-linked Protoporphyria

Importance

Autosomal recessive erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are rare photodermatoses presenting with variable degrees of painful phototoxicity that markedly affects quality of life. The clinical variability, determinants of severity, and genotype/phenotype correlations of these diseases are not well characterized.

Objective

To describe the baseline clinical characteristics, genotypes, and determinants of disease severity in a large patient cohort with EPP or XLP.

Design, Setting, and Participants

A prospective observational study was conducted among patients with confirmed diagnoses of EPP or XLP from November 1, 2010, to December 6, 2015, at 6 academic medical centers of the Porphyrias Consortium of the National Institutes of Health Rare Diseases Clinical Research Network. Detailed medical histories, including history of phototoxicity and treatment, were collected on standardized case report forms. Patients underwent baseline laboratory testing, total erythrocyte protoporphyrin (ePPIX) testing, and molecular genetic testing. Data were entered into a centralized database.

Main Outcomes and Measures

Results of biochemical and genetic tests were explored for association with clinical phenotype in patients with EPP or XLP.

Results

Of the 226 patients in the study (113 female and 113 male patients; mean [SD] age, 36.7 [17.0] years), 186 (82.3%) had EPP with a FECH (OMIM 612386) mutation and the common low-expression FECH allele IVS3-48T>C, and only 1 patient had 2 FECH mutations. Twenty-two patients had XLP (9.7%; 10 male and 12 female patients), and 9 patients (4.0%) had elevated ePPIX levels and symptoms consistent with protoporphyria but no detectable mutation in the FECH or ALAS2 (OMIM 301300) gene. Samples of DNA could not be obtained from 8 patients. Patients' mean (SD) age at symptom onset was 4.4 (4.4) years. Anemia (107 [47.3%]), history of liver dysfunction (62 [27.4%]), and gallstones (53 [23.5%]) were commonly reported. Higher ePPIX levels were associated with earlier age of symptom onset (median ePPIX levels for those who developed symptoms before vs after 1 year of age, 1744 vs 1567 µg/dL; P = .02), less sun tolerance (median ePPIX levels for those reporting symptoms before vs after 10 minutes of sun exposure, 2233 vs 1524 µg/dL; P ≤ .001), and increased risk of liver dysfunction (median ePPIX levels for those with liver dysfunction vs normal liver function, 2016 vs 1510 µg/dL; P = .003). Patients with EPP and FECH missense mutations had significantly lower ePPIX levels than those with other mutations (1462 vs 1702 µg/dL; P = .01). Male patients with XLP had significantly higher ePPIX levels, on average, than did patients with EPP (3574 vs 1669 µg/dL; P < .001). Marked clinical variability was seen in female patients with XLP owing to random X-chromosomal inactivation.

Conclusions and Relevance

These data suggest that higher ePPIX levels are a major determinant of disease severity and risk of liver dysfunction in patients with EPP or XLP. These findings provide a framework for clinical monitoring and management of these disorders.

Pitfalls in Erythrocyte Protoporphyrin Measurement for Diagnosis and Monitoring of Protoporphyrias

BACKGROUND

Laboratory diagnosis of erythropoietic protoporphyria (EPP) requires a marked increase in total erythrocyte protoporphyrin (300-5000 μg/dL erythrocytes, reference interval <80 μg/dL) and a predominance (85%-100%) of metal-free protoporphyrin [normal, mostly zinc protoporphyrin (reference intervals for the zinc protoporphyrin proportion have not been established)]; plasma porphyrins are not always increased. X-linked protoporphyria (XLP) causes a similar increase in total erythrocyte protoporphyrin with a lower fraction of metal-free protoporphyrin (50%-85% of the total).

CONTENT

In studying more than 180 patients with EPP and XLP, the Porphyrias Consortium found that erythrocyte protoporphyrin concentrations for some patients were much higher (4.3- to 46.7-fold) than indicated by previous reports provided by these patients. The discrepant earlier reports, which sometimes caused the diagnosis to be missed initially, were from laboratories that measure protoporphyrin only by hematofluorometry, which is intended primarily to screen for lead poisoning. However, the instrument can calculate results on the basis of assumed hematocrits and reports results as "free" and "zinc" protoporphyrin (with different reference intervals), implying separate measurements of metal-free and zinc protoporphyrin. Such misleading reports impair diagnosis and monitoring of patients with protoporphyria.

SUMMARY

We suggest that laboratories should prioritize testing for EPP and XLP, because accurate measurement of erythrocyte total and metal-free protoporphyrin is essential for diagnosis and monitoring of these conditions, but less important for other disorders. Terms and abbreviations used in reporting erythrocyte protoporphyrin results should be accurately defined.

Afamelanotide for Erythropoietic Protoporphyria

BACKGROUND

Erythropoietic protoporphyria is a severe photodermatosis that is associated with acute phototoxicity. Patients with this condition have excruciating pain and a markedly reduced quality of life. We evaluated the safety and efficacy of an α-melanocyte-stimulating hormone analogue, afamelanotide, to decrease pain and improve quality of life.

METHODS

We conducted two multicenter, randomized, double-blind, placebo-controlled trials of subcutaneous implants containing 16 mg of afamelanotide. Patients in the European Union (74 patients) and the United States (94 patients) were randomly assigned, in a 1:1 ratio, to receive a subcutaneous implant containing either afamelanotide or placebo every 60 days (a total of five implants in the European Union study and three in the U.S study). The type and duration of sun exposure, number and severity of phototoxic reactions, and adverse events were recorded over the respective 180-day and 270-day study periods. Quality of life was assessed with the use of validated questionnaires. A subgroup of U.S. patients underwent photoprovocation testing. The primary efficacy end point was the number of hours of direct exposure to sunlight without pain.

RESULTS

In the U.S. study, the duration of pain-free time after 6 months was longer in the afamelanotide group (median, 69.4 hours, vs. 40.8 hours in the placebo group; P=0.04). In the European Union study, the duration of pain-free time after 9 months was also longer in the afamelanotide group than in the placebo group (median, 6.0 hours vs. 0.8 hours; P=0.005), and the number of phototoxic reactions was lower in the the afamelanotide group (77 vs. 146, P=0.04). In both trials, quality of life improved with afamelanotide therapy. Adverse events were mostly mild; serious adverse events were not thought to be related to the study drug.

CONCLUSIONS

Afamelanotide had an acceptable side-effect and adverse-event profile and was associated with an increased duration of sun exposure without pain and improved quality of life in patients with erythropoietic protoporphyria. (Funded by Clinuvel Pharmaceuticals and others; ClinicalTrials.gov numbers, NCT01605136 and NCT00979745.).

Acute Hepatic Porphyria

The porphyrias comprise a set of diseases, each representing an individual defect in one of the eight enzymes mediating the pathway of heme synthesis. The diseases are genetically distinct but have in common the overproduction of heme precursors. In the case of the acute (neurologic) porphyrias, the cause of symptoms appears to be overproduction of a neurotoxic precursor. For the cutaneous porphyrias, it is photosensitizing porphyrins. Some types have both acute and cutaneous manifestations. The clinical presentation of acute porphyria consists of abdominal pain, nausea, and occasionally seizures. Only a small minority of those who carry a mutation for acute porphyria have pain attacks. The triggers for an acute attack encompass certain medications and severely decreased caloric intake. The propensity of females to acute attacks has been linked to internal changes in ovarian physiology. Symptoms are accompanied by large increases in delta-aminolevulinic acid and porphobilinogen in plasma and urine. Treatment of an acute attack centers initially on pain relief and elimination of inducing factors such as medications; glucose is administered to reverse the fasting state. The only specific treatment is administration of intravenous hemin. An important goal of treatment is preventing progression of the symptoms to a neurological crisis. Patients who progress despite hemin administration have undergone liver transplantation with complete resolution of symptoms. A current issue is the unavailability of a rapid test for urine porphobilinogen in the urgent-care setting.

Role of delta-aminolevulinic acid in the symptoms of acute porphyria

BACKGROUND

Attacks of neuropathic pain, usually abdominal, are characteristic of the acute porphyrias and accompanied by overproduction of heme-precursor molecules, specifically delta-aminolevulinic acid and porphobilinogen. The basis for the acute symptoms in these diseases has been speculative.

METHODS

We review genetic acute porphyria, hereditary tyrosinemia, and an acquired condition, lead poisoning. All perturb heme synthesis and present with a similar pain syndrome.

RESULTS

Although each of these conditions has characteristic urine biochemistry, all exhibit excess delta-aminolevulinic acid. Moreover, in all, treatment with hemin reduces delta-aminolevulinic acid and relieves symptoms. In contrast, use of recombinant porphobilinogen deaminase to knock down porphobilinogen in acute porphyria was ineffective.

CONCLUSIONS

There is now convincing evidence that delta-aminolevulinic acid is the cause of pain in the acute porphyrias. The efficacy of hemin infusion is due mainly, if not entirely, to its inhibition of hepatic delta-aminolevulinic acid synthase-1, the enzyme that catalyzes delta-aminolevulinic acid formation. Delta-aminolevulinic acid synthase-1 is a rational target for additional therapies to control symptoms in acute porphyria.

Acute porphyrias in the USA: features of 108 subjects from porphyrias consortium

BACKGROUND

Recent descriptions of the clinical and laboratory features of subjects with acute porphyrias in the US are lacking. Our aim was to describe clinical, biochemical, and genetic features of 108 subjects.

METHODS

Between September 2010 and December 2012, 108 subjects with acute porphyrias (90 acute intermittent porphyrias, 9 hereditary coproporphyrias, 9 variegate porphyrias) were enrolled into an observational study. Genetic testing was performed at a central genetic testing laboratory and clinical information entered into a central database. Selected features were compared with data for adults in the US.

RESULTS

Most subjects (88/108, 81%) were female, with self-reported onset of symptoms in the second through fourth decades of life. The most common symptom was abdominal pain. Appendectomies and cholecystectomies were common before a diagnosis of porphyria. The diagnosis was delayed by a mean of 15 years. Anxiety and depression were common, and 18% complained of chronic symptoms, especially neuropathic and other pains. The incidences of systemic arterial hypertension, chronic kidney disease, seizure disorders, and psychiatric conditions were markedly increased. Mutations of the known causative genes were found in 102/105 of those tested, with novel mutations being found in 37, including in 7/8 subjects with hereditary coproporphyria. Therapy with intravenous hematin was the most effective therapy both for treatment of acute attacks and for prevention of recurrent attacks.

CONCLUSIONS

Acute porphyrias often remain undiagnosed for more than a decade after first symptoms develop. Intravenous hematin is the treatment of choice, both for treatment of acute attacks and for prevention of recurrent attacks.

Loss-of-function ferrochelatase and gain-of-function erythroid-specific 5-aminolevulinate synthase mutations causing erythropoietic protoporphyria and x-linked protoporphyria in North American patients reveal novel mutations and a high prevalence of X-linked protoporphyria

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are inborn errors of heme biosynthesis with the same phenotype but resulting from autosomal recessive loss-of-function mutations in the ferrochelatase (FECH) gene and gain-of-function mutations in the X-linked erythroid-specific 5-aminolevulinate synthase (ALAS2) gene, respectively. The EPP phenotype is characterized by acute, painful, cutaneous photosensitivity and elevated erythrocyte protoporphyrin levels. We report the FECH and ALAS2 mutations in 155 unrelated North American patients with the EPP phenotype. FECH sequencing and dosage analyses identified 140 patients with EPP: 134 with one loss-of-function allele and the common IVS3-48T>C low expression allele, three with two loss-of-function mutations and three with one loss-of-function mutation and two low expression alleles. There were 48 previously reported and 23 novel FECH mutations. The remaining 15 probands had ALAS2 gain-of-function mutations causing XLP: 13 with the previously reported deletion, c.1706_1709delAGTG, and two with novel mutations, c.1734delG and c.1642C>T(p.Q548X). Notably, XLP represented ~10% of EPP phenotype patients in North America, two to five times more than in Western Europe. XLP males had twofold higher erythrocyte protoporphyrin levels than EPP patients, predisposing to more severe photosensitivity and liver disease. Identification of XLP patients permits accurate diagnosis and counseling of at-risk relatives and asymptomatic heterozygotes.

Of mentors, mentoring, and extracellular matrix

D. Montgomery Bissell briefly describes the way he came to a career in academic medicine, how he found mentors, initial projects, and finally a focus on matrix biology and hepatic fibrosis. He draws some lessons from the experience, which should have relevance for physician-scientist trainees, those considering that path, anyone with responsibility for training the next generation, institutional leaders, and the National Institutes of Health.

Hepatic inflammation mediated by hepatitis C virus core protein is ameliorated by blocking complement activation

BACKGROUND

The pathogenesis of inflammation and fibrosis in chronic hepatitis C virus (HCV) infection remains unclear. Transgenic mice with constitutive HCV core over-expression display steatosis only. While the reasons for this are unclear, it may be important that core protein production in these models begins during gestation, in contrast to human hepatitis C virus infection, which occurs post-natally and typically in adults.

AIMS

To more realistically model the effect of core protein production in the adult liver, we developed a mouse with conditional expression of HCV core and examined the effect of core protein production in the adult liver.

METHODS

Liver biopsy samples from transgenic mice with tetracycline(tet)-regulated conditional core protein expression were evaluated immunohistologically. Microarray analysis of HCV core transgenic mice with steatohepatitis pointed to a role of the complement pathway. This was further explored by blocking complement activation by in vivo administration of CD55 (decay accelerating factor for complement), which inhibits activation of C3.

RESULTS

Transgenic mice exhibited low, intermediate, or high HCV core protein expression when fed a permissive diet of standard chow. Aside from hepatic steatosis, hepatic inflammation and fibrosis were seen in mice with intermediate levels of core protein. Microarray analyses of inflamed liver demonstrated activation of both the complement (C3 up-regulation) and coagulation pathways (fibrinogen B up-regulation). Administration of CD55 reduced hepatic inflammation.

CONCLUSION

Transgenic mice that conditionally express intermediate HCV core protein develop inflammation, steatosis, and fibrosis. These effects mediated by HCV core are reduced by administration of CD55, a regulator of the complement pathway. The model may be valuable in investigating the pathogenesis of liver inflammation in chronic hepatitis C.

Attenuated response to liver injury in moesin-deficient mice: impaired stellate cell migration and decreased fibrosis

Hepatic stellate cells (HSCs) respond to injury with a coordinated set of events (termed activation), which includes migration and upregulation of matrix protein production. Cell migration requires an intact actin cytoskeleton that is linked to the plasma membrane by ezrin-radixin-moesin (ERM) proteins. We have previously found that the linker protein in HSCs is exclusively moesin. Here, we describe HSC migration and fibrogenesis in moesin-deficient mice. We developed an acute liver injury model that involved focal thermal denaturation and common bile duct ligation. HSC migration and collagen deposition were assessed by immunohistology and quantitative real-time PCR. Activated HSCs were isolated from wild-type or moesin-deficient mice for direct examination of migration. Activated HSCs from wild-type mice were positive for moesin. Migration of moesin-deficient HSCs was significantly reduced. In a culture assay, 22.1% of normal HSCs migrated across a filter in 36 h. In contrast, only 1.3% of activated moesin-deficient HSCs migrated. Collagen deposition around the injury area similarly was reduced in moesin-deficient liver. The linker protein moesin is essential for HSC activation and migration in response to injury. Fibrogenesis is coupled to migration and reduced in moesin-deficient mice. Agents that target moesin may be beneficial for chronic progressive fibrosis.

Role of alphavbeta6 integrin in acute biliary fibrosis

Acute biliary obstruction leads to periductal myofibroblasts and fibrosis, the origin of which is uncertain. Our study provides new information on this question in mice and humans. We show that bile duct obstruction induces a striking increase in cholangiocyte alphavbeta6 integrin and that expression of this integrin is directly linked to fibrogenesis through activation of transforming growth factor beta (TGF-beta). Administration of blocking antibody to alphavbeta6 significantly reduces the extent of acute fibrosis after bile duct ligation. Moreover, in beta6-null mice subjected to the injury, fibrosis is reduced by 50% relative to that seen in wild-type mice, whereas inflammation occurs to the same extent. The data indicate that alphavbeta6, rather than inflammation, is linked to fibrogenesis. It is known that alphavbeta6 binds latent TGF-beta and that binding results in release of active TGFbeta. Consistent with this, intracellular signaling from the TGFbeta receptor is increased after bile duct ligation in wild-type mice but not in beta6(-/-) mice, and a competitive inhibitor of the TGFbeta receptor type II blocks fibrosis to the same extent as antibody to alphavbeta6. In a survey of human liver disease, expression of alphavbeta6 is increased in acute, but not chronic, biliary injury and is localized to cholangiocyte-like cells.

CONCLUSION

Cholangiocytes respond to acute bile duct obstruction with markedly increased expression of alphavbeta6 integrin, which is closely linked to periductal fibrogenesis. The findings provide a rationale for the use of inhibitors of alphavbeta6 integrin or TGFbeta for down-regulating fibrosis in the setting of acute or ongoing biliary injury.

Topological and evolutional relationships between HCV core protein and hepatic lipid vesicles: Studies in vitro and in conditionally transgenic mice

AIM: To investigate a specific association between hepatic steatosis and hepatitis C virus (HCV) core.

METHODS: HeLa cells and primary mouse hepatocytes were transfected with HCV core plasmid, and conditional transgenics in which hepatic over-expression of HCV core is regulated by the tetracycline-off system, were developed. The expression of the HCV core was assessed over one to six months after withdrawal of doxycycline (dox) by immunohistochemistry (IHC) and Western blotting and by sequential liver biopsy. Hepatic steatosis was evaluated using oil red stain. 8-hydroxydeoxyguanosine (8-OHdG) stains and caspase levels were conducted to clarify hepatic oxidative stress and apoptosis rate. Serum aminotransferase was checked.

RESULTS: The transfected hepatocytes had globular cores under the lipid vesicles. In transgenic mice on control diet, core expression was robust, localized to the cytoplasmic vesicle membrane and strongly associated with microvesicular steatosis, which was gradually replaced by macrovesicular steatosis. However, both steatosis and core positive hepatocytes diminished with time. Increases in aminotransferase, caspase and 8-OHdG were associated with peak core expression.

CONCLUSION: The core protein was readily detected and morphologically associated with steatosis in individual hepatocytes both in vitro and in vivo. In vivo, oxidative stress caused by the core potentially reduced the number of core positive hepatocytes and in parallel the level of steatosis. To our knowledge, this is the first animal model that directly shows topological relationship between HCV core and hepatic lipid vesicles.

Hepatic fibrosis 2006: report of the Third AASLD Single Topic Conference

The Third American Associated for the Study of Liver Diseases (AASLD)-sponsored Single Topic Conference on hepatic fibrosis was held in June 2006. The conference was both international, with 6 countries represented, and cross-disciplinary, linking the basic molecular and cellular biology of fibrogenic cells to clinical trial design for emerging antifibrotic therapies. The specific goals of the conference were: (1) to consolidate knowledge about the natural history of fibrosis; (2) to clarify potential endpoints and markers; (3) to emphasize new antifibrotic targets developed on the basis of advances in basic science; and (4) to understand current critical issues pertaining to clinical trial design. Given the tremendous growth of the field and the constraints of a 2-day format, the selection of speakers was a challenge. A number of topics not included in the oral presentations were featured at poster sessions, lending breadth and depth to the meeting as a whole. Surprising new themes emerged about molecular, clinical, and regulatory aspects of the field, and a consensus emerged that hepatic fibrosis has matured into an integrated discipline that promises to significantly improve the prognosis of patients with fibrosing liver disease.

Noninvasive measures of liver fibrosis

As novel therapies for liver fibrosis evolve, non-invasive measurement of liver fibrosis will be required to help manage patients with chronic liver disease. Although liver biopsy is the current and time-honored gold standard for measurement of liver fibrosis, it is poorly suited to frequent monitoring because of its expense and morbidity, and its accuracy suffers from sampling variation. At the current writing, serum markers and imaging methods are available and increasingly in use as alternatives to biopsy. However, many questions remain about their indications, accuracy, and cost-effectiveness, and more investigation is required before they are put into widespread use. The development of safe, inexpensive, and reliable noninvasive fibrosis measurement tools remains a research priority in clinical hepatology.

TWEAK induces liver progenitor cell proliferation

Progenitor ("oval") cell expansion accompanies many forms of liver injury, including alcohol toxicity and submassive parenchymal necrosis as well as experimental injury models featuring blocked hepatocyte replication. Oval cells can potentially become either hepatocytes or biliary epithelial cells and may be critical to liver regeneration, particularly when hepatocyte replication is impaired. The regulation of oval cell proliferation is incompletely understood. Herein we present evidence that a TNF family member called TWEAK (TNF-like weak inducer of apoptosis) stimulates oval cell proliferation in mouse liver through its receptor Fn14. TWEAK has no effect on mature hepatocytes and thus appears to be selective for oval cells. Transgenic mice overexpressing TWEAK in hepatocytes exhibit periportal oval cell hyperplasia. A similar phenotype was obtained in adult wild-type mice, but not Fn14-null mice, by administering TWEAK-expressing adenovirus. Oval cell expansion induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) was significantly reduced in Fn14-null mice as well as in adult wild-type mice with a blocking anti-TWEAK mAb. Importantly, TWEAK stimulated the proliferation of an oval cell culture model. Finally, we show increased Fn14 expression in chronic hepatitis C and other human liver diseases relative to its expression in normal liver, which suggests a role for the TWEAK/Fn14 pathway in human liver injury. We conclude that TWEAK has a selective mitogenic effect for liver oval cells that distinguishes it from other previously described growth factors.

Role of CD44 in Epithelial Wound Repair

The hyaluronic acid receptor, CD44, exists as multiple splice variants that appear to have a role in migration of tumor cells. The role of this receptor and its variants in normal wound repair is poorly understood. A central feature of wound repair in the liver is activation and migration of perisinusoidal stellate cells. We have examined CD44 expression by stellate cells from normal or injured rat liver, finding that it increases with injury and involves a distinct set of CD44 splice variants. Among the latter, variants containing the v6 exon (CD44v6) are strikingly increased. Analysis of migration of primary cells on transwell filter inserts reveals that only cells isolated from injured liver are migratory. Also, they move more rapidly on hyaluronic acid than on collagen I or collagen IV. A polyclonal antibody to recombinant CD44v6 blocks migration by 50%, whereas antibody to CD44v4 has no effect. The inhibition is specific for cells migrating on hyaluronic acid and is reversed by synthetic peptide representing the N terminus of the v6 protein. In conclusion, activated stellate cells use CD44v6 and hyaluronic acid for migration. Given the evidence that migration is required for progression of injury with scar formation, blockers of CD44v6 expression or function are candidates for preventing the deleterious effects of chronic fibrosis.

Regulation of fibronectin splicing in sinusoidal endothelial cells from normal or injured liver

Fn containing an extra type III domain (EIIIA in the rat, ED1 or EDA in humans) is commonly termed "fetal" fibronectin, but it is prominent during the injury response of adult tissues and mediates important early events in the response. This form is particularly apparent in acute liver injury, where it has been shown that sinusoidal endothelial cells produce EIIIA-fibronectin. This fibronectin isoform arises by alternative splicing of the primary transcript. In the present experiments, we have studied the regulation of fibronectin splicing in primary sinusoidal endothelial cells by transfecting a minigene containing the EIIIA exon and its flanking introns, driven by various promoters. The results indicate that fibronectin splicing in endothelial cells from normal liver is in part promoter-dependent. However, in cells from injured liver in which expression of both total and EIIIA-fibronectin is strikingly increased, promoter effects disappear. Because fibronectin splicing is known to be regulated in part by TGFbeta, we also examined the effect of a soluble inhibitor of the TGFbeta type 2 receptor. This agent had no effect on splicing by normal endothelial cells. By contrast, for endothelial cells from the injured liver, the splicing pattern reverted to that of normal cells, i.e., it became promoter-dependent. We conclude that, in the setting of injury in vivo, TGFbeta overrides the promoter dependence of fibronectin splicing in normal cells. The data suggest that TGFbeta modifies the spliceosome, if not through its known signaling intermediates, then through the products of genes regulated by this cytokine.

Fibronectin transcription in liver cells: promoter occupation and function in sinusoidal endothelial cells and hepatocytes

Hepatocytes (Heps) and sinusoidal endothelial cells (SECs) perform different roles in normal and pathological liver functions through the differential expression of fibronectin (FN) polypeptides. Nonetheless, the molecular basis underlying cell-type specific FN expression remains unknown. Using liver cell isolation techniques followed by short-term primary culture and transient transfection, here, we compare the transcriptional regulation of the FN promoter in Heps and SEC in conditions that closely resemble in vivo physiology. Transfection experiments allowed us to reveal cell-type specific regulatory elements operating through the proximal regions of the FN promoter. To investigate this further, we examined the occupation patterns of key elements of the FN promoter such as the -170 CRE and -150 CCAAT sites. Transcriptional activity of mutagenised promoter constructs confirmed that in Heps, these two sites behave as a composite element critical for normal promoter activity. In addition, DNA-binding experiments demonstrate that the -170 CRE element displays a clear cell-type specific occupation with binding activities for ATF-2 and ATF-3 being specific to Heps. These results establish the starting point to investigate the molecular basis of changes in transcriptional regulation of the FN gene involved in liver pathology.

Chronic liver injury, TGF-beta, and cancer

Cells termed myofibroblasts are prominent in the injury response of all epithelial tissues. They exhibit proliferation, migration, production of collagen and other extracellular matrix (ECM) molecules, and contraction, all for containing the injury and closing the wound. When the injury is limited in time, the final stage of the repair involves a dismantling of the cellular apparatus and restoration of normal tissue structure. With multiple cycles of repair, however, there is net accumulation of ECM, to the detriment of tissue structure and function. Repair-related ECM coalesces into fibrous bundles and, over time, undergoes changes that render it resistant to degradation. The result is a scar. In the skin, a scar may have cosmetic importance only. In the liver, however, extensive scarring is the setting for unregulated growth and neoplasia; also, fibrous bands disrupt normal blood flow, leading to portal hypertension and its complications. With regard to therapy for fibrosis, the first consideration is elimination of the injury factor. However, given that many liver diseases do not have effective therapies at present, strategies targeting fibrogenesis per se are under development. The main source of myofibroblast-like cells and ECM production in the liver is the perisinusoidal stellate cell, which responds to injury with a pleiotypic change termed activation. Activation is orchestrated by cytokines and the ECM itself. Among the cytokines involved in this process, transforming growth factor-beta (TGF-beta) is particularly prominent. The early changes in ECM include de novo production of a specific "fetal" isoform of fibronectin, which arises from sinusoidal endothelial cells. It is stimulated by TGF-beta and acts directly on stellate cells to promote their activation. Based on these and other advances in understanding the fundamentals of the injury response, several strategies now exist for altering fibrogenesis, ranging from agents that block TGF-beta to traditional Chinese herbal extracts. Arrest of fibrogenesis, even with underlying cirrhosis, is likely to extend life or prolong the time to transplant. Whether it reduces the risk of hepatocellular carcinoma remains to be proven. Although TGF-beta antagonists are effective anti-fibrogenic agents, they will require detailed safety testing because of the finding that several forms of epithelial neoplasia are associated with altered regulation of TGF-beta.

Transforming growth factor-beta initiates wound repair in rat liver through induction of the EIIIA-fibronectin splice isoform

A prominent feature of the hepatic response to injury is production of a fetal isoform of fibronectin, a splice variant containing the EIIIA region, which appears very early after injury and derives from sinusoidal endothelial cells. Previous studies have shown that it is instrumental in initiating the cellular response to injury, specifically the conversion of resting stellate cells to myofibroblast-like cells. The present work describes the regulation of this change in fibronectin expression. Using sinusoidal endothelial cells from normal or injured liver in primary culture, we show that exogenous transforming growth factor beta (TGFbeta) stimulates [EIIIA]Fn expression. To assess the role of TGFbeta in vivo, we used a chimeric IgG containing the extracellular portion of the TGFbeta type II receptor as a competitive inhibitor of the cytokine. Administered to animals at the time of injury, the inhibitor reduced expression of [EIIIA]Fn mRNA by 50% as compared to controls (P < 0.01). There was a corresponding decrease in [EIIIA]Fn protein production as judged by immunohistochemistry. Cell fractionation experiments indicated that the changes observed in whole-liver extracts were localized to sinusoidal endothelial cells. We conclude that TGFbeta initiates wound repair in part by stimulating endothelial expression of [EIIIA]Fn. Results with the soluble inhibitor of the TGFbeta type II receptor suggest a novel strategy for modulating wound repair in vivo.

In vivo inhibition of rat stellate cell activation by soluble transforming growth factor beta type II receptor: a potential new therapy for hepatic fibrosis

Transforming growth factor beta (TGF-beta) is a well characterized cytokine that appears to play a major role in directing the cellular response to injury, driving fibrogenesis, and, thus, potentially underlying the progression of chronic injury to fibrosis. In this study, we report the use of a novel TGF-beta receptor antagonist to block fibrogenesis induced by ligation of the common bile duct in rats. The antagonist consisted of a chimeric IgG containing the extracellular portion of the TGF-beta type II receptor. This "soluble receptor" was infused at the time of injury; in some experiments it was given at 4 days after injury, as a test of its ability to reverse fibrogenesis. The latter was assessed by expression of collagen, both as the mRNA in stellate cells isolated from control or injured liver and also by quantitative histochemistry of tissue sections. When the soluble receptor was administered at the time of injury, collagen I mRNA in stellate cells from the injured liver was 26% of that from animals receiving control IgG (P < 0.0002); when soluble receptor was given after injury induction, collagen I expression was 35% of that in control stellate cells (P < 0.0001). By quantitative histochemistry, hepatic fibrosis in treated animals was 55% of that in controls. We conclude that soluble TGF-beta receptor is an effective inhibitor of experimental fibrogenesis in vivo and merits clinical evaluation as a novel agent for controlling hepatic fibrosis in chronic liver injury.

Evidence for a role of the alternatively spliced ED-I sequence of fibronectin during ovarian follicular development

This study was aimed at testing the hypothesis that different forms of fibronectin (FN), produced as a consequence of the alternative splicing of the precursor messenger RNA, play specific roles during development of the ovarian follicle. In particular, we were interested in determining the effect of the ED-I (also termed ED-A) type III repeat, which is absent in the plasma form. Analysis of FN levels in follicular fluids corresponding to different stages of development of bovine follicles revealed marked changes in the concentrations of ED-I+ FN, whereas total FN levels remained relatively constant. ED-I+ FN levels were higher in small follicles, corresponding to the phase of granulosa cell proliferation. The hypothesis of a physiological role for ED-I+ FN was further supported by the finding of a regulation of the alternative splicing of FN in primary cultures of bovine granulosa cells by factors known to control ovarian follicular development. cAMP produced a 10-fold decrease in the relative proportion of the ED-I region. In contrast, transforming growth factor-beta elicited a 2-fold stimulation of overall FN synthesis and a 4-fold increase in the synthesis of ED-I containing FN. This effect was evident at the protein (Western blots) and messenger RNA (Northern blots) levels. Although a negative correlation (P < 0.001) was detected between ED-I+ FN and estradiol levels in follicular fluid, this steroid was unable to modulate in vitro the alternative splicing of FN. A possible mitogenic effect of ED-I+ FN was suggested by the observation that a recombinant peptide corresponding to the ED-I domain stimulated DNA synthesis in a bovine granulosa cell line (BGC-1), whereas a peptide corresponding to the flanking type III sequences had no effect. The hypothesis of ED-I+ FN as a growth regulatory factor was further strengthened by the fact that depletion of FN from BGC-1-conditioned medium, which contained ED-I+ FN, abrogated its mitogenic activity, whereas plasma FN was without effect. We propose that changes in the primary structure of FN may mediate some of the effects of gonadotropin and intraovarian factors during follicular development.

Hepatic fibrosis as wound repair: a progress report

The injury response of the liver fits within the general paradigm of wound repair. The overall repair response requires close coordination of several cell types and synthetic processes and is orchestrated by an interacting group of cytokines, extracellular matrix (ECM) proteins, and products of metabolism such as oxygen radicals. Many cytokines act over short distances, engaging specific receptors on their parent cell (autocrine) or on immediately adjacent cells (paracrine). The most prominent of these is transforming growth factor-beta (TGFbeta). The ECM also mediates cellular crosstalk and does so in two ways. Firstly, as a binder of cytokines, it is capable of concentrating, presenting, or sequestering these factors at specific locations. Secondly, like cytokines, individual ECM proteins interact with cells via specific receptors, many of which belong to the integrin family. Engagement of a receptor leads to its activation, followed by intracellular signaling events and modification of cell behavior. Recent work has identified a specific integrin on stellate cells (alpha1beta1) as critical to the contractility of these cells. Finally, contrary to the view once held of ECM as relatively inert "ground substance", this extracellular complex is highly dynamic, its cytokine- and cell-binding activities being subject to rapid change. Therefore, matrix proteinases also are important, both during the initiation of fibrosis in association with stellate cell activation, and during the resolution of the injury. As current research reveals the key elements of this regulatory network, new therapeutic modalities are emerging. The goal of therapy is to modify the extent of the repair response without deleting it. Strategies directed at several levels of regulation are under consideration, including agents that block cytokine effects (e.g., TGFbeta receptor antagonists) and direct inhibitors of stellate cell activation or contraction.

Porphyria and porphyrinology--the past fifteen years

The porphyrias are diseases caused by defective biosynthesis of heme. Leavened by digressions on porphyria trivia, this article presents selected highlights from the last 15 years of research on the chemistry, diagnosis, and treatment of the porphyrias. Thanks largely to genetic analysis and new light shed on the magical chemistry of heme biosynthesis, this period has seen great advances in the understanding of porphyria. Sequence analyses of the genes for all of the enzymes required for heme biosynthesis have revealed the porphyrias as highly heterogeneous, with multiple mutations underlying each type. As a result of technical advances, clinical porphyrin analyses are easier and more detailed, but their misapplication to "multiple chemical sensitivity syndrome" or "intoxication porphyria" is unfortunate. The prospect of gene therapy shines ever brighter but is neither safe nor effective enough to be considered for porphyria. As practical spin-offs, porphyrins are in use increasingly for diagnosis and treatment of cancer and as herbicides and pesticides. Accounts of alleged porphyria in "Prominent People" in the popular press continue to appear, generating fanciful misconceptions, often at the expense of patients with these fascinating diseases.

Two novel antifibrotics, HOE 077 and Safironil, modulate stellate cell activation in rat liver injury: differential effects in males and females

The perisinusoidal stellate cells of the liver in an injury milieu undergo activation, acquiring a myofibroblast-like phenotype. In this state, they are the principal source of collagen and related proteins in fibrosis. The present studies evaluate the mechanism of action of two novel antifibrotic compounds, HOE 077 and Safironil, which were designed as competitive inhibitors of collagen protein synthesis. Fibrosis was induced in rats by administration of carbon tetrachloride, and activation was monitored as the level of collagen I mRNA or smooth muscle alpha-actin. Both male and female rats were studied. Stellate cell activation, rather than collagen synthesis, proved to be the target of both HOE 077 and Safironil in the intact liver. In culture, the drugs not only prevented the activation of stellate cells but also accelerated their deactivation. They were no more effective in co-cultures containing hepatocytes than in pure stellate cell cultures, indicating that metabolic conversion of HOE 077 was not required. Interestingly, the response of cells from females was greater than that of male cells, leading to the conclusion that stellate activation is sexually dimorphic. This finding may be relevant to the observation that fibrosis in chronic viral hepatitis progresses less rapidly and that hepatocellular carcinoma is less frequent in females than in males.