Mental Imagery to Reduce Alcohol-related harm in patients with alcohol use disorder and alcohol-related liver damaGE: the MIRAGE randomised pilot trial results

OBJECTIVE

The healthcare burden of alcohol-related liver disease (ARLD) is increasing. ARLD and alcohol use disorder (AUD) is best managed by reduction or cessation of alcohol use, but effective treatments are lacking. We tested whether people with ARLD and AUD admitted to hospital could be recruited to and retained in a trial of Functional Imagery Training (FIT), a psychological therapy that uses mental imagery to reduce alcohol craving. We conducted a multicentre randomised pilot trial of treatment as usual (TAU) versus FIT+TAU in people admitted to hospital with ARLD and AUD.

DESIGN

Participants were randomised to TAU (a single session of brief intervention) or FIT+TAU (TAU with one hospital-based FIT session then eight telephone sessions over 6 months). Pilot outcomes included recruitment rate and retention at day 180. Secondary outcomes included fidelity of FIT delivery, alcohol use, and severity of alcohol dependence.

RESULTS

Fifty-four participants (mean age 49; 63% male) were recruited and randomised, 28 to TAU and 26 to FIT+TAU. The retention rate at day 180 was 43%. FIT was delivered adequately by most alcohol nurses. 50% of intervention participants completed FIT sessions 1 and 2. There were no differences in alcohol use or severity of alcohol dependence between treatment groups at day 180.

CONCLUSION

Participants with ARLD and AUD could be recruited to a trial of FIT versus FIT+TAU. However, retention at day 180 was suboptimal. Before conducting a definitive trial of FIT in this patient group, modifications in the intervention and recruitment/retention strategy must be tested.

TRIAL REGISTRATION NUMBER

ISRCTN41353774.

Quality standards for the management of alcohol-related liver disease: consensus recommendations from the British Association for the Study of the Liver and British Society of Gastroenterology ARLD special interest group

OBJECTIVE

Alcohol-related liver disease (ALD) is the most common cause of liver-related ill health and liver-related deaths in the UK, and deaths from ALD have doubled in the last decade. The management of ALD requires treatment of both liver disease and alcohol use; this necessitates effective and constructive multidisciplinary working. To support this, we have developed quality standard recommendations for the management of ALD, based on evidence and consensus expert opinion, with the aim of improving patient care.

DESIGN

A multidisciplinary group of experts from the British Association for the Study of the Liver and British Society of Gastroenterology ALD Special Interest Group developed the quality standards, with input from the British Liver Trust and patient representatives.

RESULTS

The standards cover three broad themes: the recognition and diagnosis of people with ALD in primary care and the liver outpatient clinic; the management of acutely decompensated ALD including acute alcohol-related hepatitis and the posthospital care of people with advanced liver disease due to ALD. Draft quality standards were initially developed by smaller working groups and then an anonymous modified Delphi voting process was conducted by the entire group to assess the level of agreement with each statement. Statements were included when agreement was 85% or greater. Twenty-four quality standards were produced from this process which support best practice. From the final list of statements, a smaller number of auditable key performance indicators were selected to allow services to benchmark their practice and an audit tool provided.

CONCLUSION

It is hoped that services will review their practice against these recommendations and key performance indicators and institute service development where needed to improve the care of patients with ALD.

Assessment of immune function and prediction of survival and infection in patients with severe alcoholic hepatitis: An exploratory study

Background and Aim

Alcoholic hepatitis (AH), a severe complication of long-term alcohol misuse, has a 30% 90-day mortality. Infections are common and associated with higher mortality. There is currently no accurate method to predict infection in these patients. We aimed to test a measure of immune function, the QuantiFERON Monitor (QFM), in predicting clinical outcomes in patients with severe AH.

Methods

Peripheral blood was taken at baseline, and QFM performed according to the manufacturer's instructions. In parallel, QFM samples were analyzed with a cytokine multiplex. Clinical outcomes of mortality at 28 and 90 days and development of infection were recorded prospectively.

Results

Forty-nine patients were recruited (mean age 51, 59% male and mean discriminant function 57.8). Interferon (IFN)-γ release measured by standard QFM was significantly higher in survivors compared to non-survivors at 28 (102 vs 16 IU/mL, P = 0.02) and 90 days (115 vs 32 IU/mL; P = 0.046). The area under the receiver operating characteristic curve (AUROC) was 0.79 for 28-day mortality. IFN-γ, IL-10, and IL-23 release measured by multiplex were significantly lower in patients who developed a subsequent infection compared to those who did not (115 vs 27 IU/mL, P = 0.037; 457 vs 202 pg/mL, P = 0.008; and 1039 vs 663 pg/mL, p = 0.01, respectively).

Conclusion

Immune dysfunction is associated with poorer outcomes in patients with severe AH. Measurement of IFN-γ release by standard QFM accurately predicts early mortality, which can be applied to clinical practice as a biomarker of survival. Adaptation of the test to measure IL-10 could be used as a biomarker of subsequent infection to guide clinical treatment decisions.

The Liverpool alcohol-related liver disease algorithm identifies twice as many emergency admissions compared to standard methods when applied to Hospital Episode Statistics for England

BACKGROUND

Emergency admissions in England for alcohol-related liver disease (ArLD) have increased steadily for decades. Statistics based on administrative data typically focus on the ArLD-specific code as the primary diagnosis and are therefore at risk of excluding ArLD admissions defined by other coding combinations.

AIM

To deploy the Liverpool ArLD Algorithm (LAA), which accounts for alternative coding patterns (e.g., ArLD secondary diagnosis with alcohol/liver-related primary diagnosis), to national and local datasets in the context of studying trends in ArLD admissions before and during the COVID-19 pandemic.

METHODS

We applied the standard approach and LAA to Hospital Episode Statistics for England (2013-21). The algorithm was also deployed at 28 hospitals to discharge coding for emergency admissions during a common 7-day period in 2019 and 2020, in which eligible patient records were reviewed manually to verify the diagnosis and extract data.

RESULTS

Nationally, LAA identified approximately 100% more monthly emergency admissions from 2013 to 2021 than the standard method. The annual number of ArLD-specific admissions increased by 30.4%. Of 39,667 admissions in 2020/21, only 19,949 were identified with standard approach, an estimated admission cost of £70 million in under-recorded cases. Within 28 local hospital datasets, 233 admissions were identified using the standard approach and a further 250 locally verified cases using the LAA (107% uplift). There was an 18% absolute increase in ArLD admissions in the seven-day evaluation period in 2020 versus 2019. There were no differences in disease severity or mortality, or in the proportion of admissions with decompensation of cirrhosis or alcoholic hepatitis.

CONCLUSIONS

The LAA can be applied successfully to local and national datasets. It consistently identifies approximately 100% more cases than the standard coding approach. The algorithm has revealed the true extent of ArLD admissions. The pandemic has compounded a long-term rise in ArLD admissions and mortality.

HPB O07 Complication profile of laparoscopic common bile duct exploration: Results from R-ALiCE Study

Background

There are two ways of managing common bile duct stones (CBDS); a two-stage and a single-stage approach. The two-stage procedure is the most common way of managing CBDS in the UK. In the two-stage approach, patients have pre-operative confirmation of CBDS followed by endoscopic retrograde cholangio pancreatography (ERCP) and delayed cholecystectomy. The single-stage approach is an equally effective but less favoured approach, which involves simultaneous intra-operative imaging followed by laparoscopic CBD exploration and cholecystectomy. Evidence supports that the single-stage approach is associated with reduced costs, length of stay, and better stone-free survival compared to the two-stage approach. Despite the evidence favouring the single-stage approach, it is still not widely used, and one of the reasons for this could be the lack of complication profile data from extensive multi-centre studies. We undertook a large multi-centre study called R-ALiCE (Retrospective- Audit of Laparoscopic Common Bile duct Exploration). One of the study's aims was to evaluate the outcome profile of LCBDE in the UK.

Methods

R-ALiCE Study was a multi-centre collaborative cohort study that collected data on all LCBDEs performed over five years (2015–2019) in 18 centres across the UK. A total of 1796 patients were enrolled on the study, and 1689 patients were included in the final analysis. The reasons for exclusion of 107 patients were: incomplete data: 13, open surgery: 11, LCBDE was not performed: 55, young adult=1, and 27 patients outside the time frame.

Results

The median age of patients (68.2% females) was 59 years (interquartile range: 43–71). One-third of patients had underlying cardiovascular co-morbidities, 14.6% had respiratory co-morbidities, and 3.1% had underlying liver disease. Almost 50% were obese (body mass index), and 28.2% were overweight. Fifty-six percent of (945) patients had an emergency/semi-elective procedure, while 44% (743) had an elective procedure. The median surgery duration was 123.9 minutes (range: 29–420). Laparoscopic to open conversion rate was 5%. Transcystic-exploration (TC-LCBDE) was attempted in 71.6% of all cases with a success rate of 77.6%. Transcholedochal-exploration (TD-LCBDE) was attempted in 41.1% of all cases: 12.5% were TC-LCBDE progressed to TD-LCBDE and 28.3% were direct TD-LCBDE. Overall, 30-day all-cause complication rate was 18.9% (319). Complication rate between TC and TD were: bile leak rate was 1.4% vs. 8.8% (p=0.000), retained stones 4.9% vs 5.6%(p=0.527), pancreatitis (0.9% vs 1% (p=0.828) and intrabdominal collections 1.8% vs 7.2%. Thirty-five percent of bile leaks were Grade A and 39% Grade B. The overall complication rate was 12.8% for TC and 27.7% for TD. Overall 30-day mortality was zero.

Conclusions

This is the largest LCBDE cohort study in the world and confirms that overall complications of LCBDE are low, and LCBDE can be safely performed for patients with simultaneous gallstones and bile duct stones. Transcystic approach should always be attempted as first line in selected patients to reduce the risk of complications.

The effect of increasing intestinal short-chain fatty acid concentration on gut permeability and liver injury in the context of liver disease: A systematic review

BACKGROUND AND AIM

The gut barrier protects the liver through tight junctions, which are disrupted in liver disease either from dysbiosis, inflammation, or the effects of ingested compounds such as alcohol. Strengthening of the gut barrier may ameliorate liver injury of varying etiologies. Short chain fatty acids (SCFAs) have been shown to improve gut barrier function. This systematic review aims to synthesize all studies that have trialed SCFA supplementation as a therapy for liver disease.

METHODS

A systematic review assessing the impact of SCFA supplementation on liver injury and intestinal permeability was conducted. All forms of intervention that specifically increased intestinal SCFA concentration and measured both liver injury and permeability were eligible. Two independent reviewers assessed each study for outcomes, risk of bias, and quality using checklists relevant to the study's methodology.

RESULTS

Seventeen studies were identified; two utilized a human model (15 murine). Fifty-eight markers of liver injury were identified, with 26 different measures of permeability. Given the numerous designs, no meta-analysis was possible. SCFA supplements included oral and enteral butyrate, probiotics, and prebiotics. Fourteen studies demonstrated improved permeability. All studies showed a significant amelioration of liver injury.

CONCLUSIONS

Short chain fatty acid supplementation to reduce intestinal permeability represents a potential therapy in a variety of liver disease models. A large number of outcome measures were reported however not all are practical in human studies. Future work should evaluate methods to increase luminal SCFA concentrations and the effect of this on gut permeability and liver inflammation in people with liver disease.

Alcohol misuse in patients with alcohol-related liver disease: How can we do better? A narrative review of the literature

BACKGROUND

Ongoing alcohol use is strongly associated with progressive liver damage and higher mortality in patients with alcohol-related liver disease (ArLD). Reduction in alcohol use is therefore the cornerstone of treatment to improve the long-term outcome of these patients. However, a large proportion of patients continue to use alcohol and do not access or engage with alcohol treatment services after a diagnosis of ArLD. We reviewed the literature on factors associated with ongoing alcohol consumption among patients with ArLD to identify barriers or facilitators to their accessing alcohol treatment.

METHODS

A search of MEDLINE and EMBASE was conducted using search strategies relating to ArLD and the psychosocial factors hypothesized to influence alcohol reduction and/or abstinence.

RESULTS

There were few relevant studies pertinent to this population group. Several studies reported a high prevalence of mental health diagnoses associated with the severity of alcohol dependence. Social and environmental factors were shown to be important determinants of alcohol use. Common themes perceived as barriers to treatment from qualitative interviews with ArLD patients across studies included poor communication between the clinical team and patient, lack of symptoms recognized by patients themselves, and perceived loss of control over their condition.

CONCLUSIONS

We recommend that future clinical studies of patient cohorts with ArLD include detailed psychosocial assessments to capture information on mental health and social factors. Qualitative studies are required to explore the patient journey pre and post hospital admission, which should focus on identifying facilitators and barriers to accessing treatment. Well-designed, controlled studies are needed to identify patient, social, and environmental factors associated with relapse to alcohol use after a diagnosis of ArLD. These data will enable us to adapt our support for patients to enhance engagement with services and improve long-term outcomes.

A UK survey on variation in the practice of management of choledocholithiasis and laparoscopic common bile duct exploration (ALiCE Survey)

BACKGROUND

The practice of managing suspected/confirmed common bile duct stones (CBDS) can vary significantly in the UK. We aimed to assess this variability in practice and challenges to form a basis for future consensus.

METHODS

An electronic survey containing 40 questions on various aspects of management of CBDS was sent to surgeons who perform cholecystectomies via five surgical associations.

RESULTS

 A total of 132 surgeons responded to the survey. The speciality of surgeons includes upper gastro-intestinal (68%), general (18%), colorectal (12%), and others (2%). For patients with suspected CBD stones, 80% would choose magnetic resonance cholangio-pancreatography, and 14.4% would proceed to intra-operative imaging. Most surgeons preferred intra-operative cholangiogram over intra-operative ultrasound (83% vs 17%). For the treatment, 62.1% preferred a two-stage approach [endoscopic retrograde cholangio-pancreatography (ERCP) followed by laparoscopic cholecystectomy (LC)] and 33.4% chose a single-stage approach [LC + laparoscopic common bile duct exploration (LCBDE)]. Eighty (60.6%) responders performed LCBDE, and 19 (23.8%) of them performed > 10 LCBDEs in a year. Two third of surgeons (62.5%) preferred a trans-choledochal approach to CBDS. Half of the surgeons that perform LCBDE use a T-tube selectively and 1.6% routinely. The "availability of very good ERCP service" and "lack of formal training" were the two main reasons for surgeons not performing LCBDE. Both surgeons' speciality and whether they perform other complex laparoscopic surgery were significantly associated with choosing a two-stage approach over a one-stage approach (χ² test, speciality p = 0.033, complex surgery p = 0.011).

CONCLUSION

 Our survey confirms the significant variability in the diagnosis and management of CBDS. The two-stage approach is still the most common way of managing CBDS in the UK. The main reasons for the low uptake of the single-stage approach are the availability of good ERCP service, lack of equipment and lack of formal training in the technique of LCBDE.

Trajectory of Serum Bilirubin Predicts Spontaneous Recovery in a Real-World Cohort of Patients With Alcoholic Hepatitis

BACKGROUND AND AIMS

Alcoholic hepatitis (AH) is a severe condition with poor short-term prognosis. Specific treatment with corticosteroids slightly improves short-term survival but is associated with infection and is not used in many centers. A reliable method to identify patients who will recover spontaneously will minimise the numbers of patients who experience side effects of available treatments.

METHODS

We analysed the trajectory of serum bilirubin concentration over the course of hospital admissions in patients with AH to predict spontaneous survival and the need for treatment.

RESULTS

data from 426 patients were analysed. Based on bilirubin trajectory, patients were categorized into three groups: 'fast fallers' (bilirubin <0.8 x admission value at day 7), 'static' (bilirubin of >0.9 - <1.2 x admission value) and 'rapid risers' (bilirubin of ≥1.2 x admission bilirubin). Fast fallers had significantly better 90-day survival compared to other groups (log rank p < .001), and showed no benefit of corticosteroid therapy (OR for survival at 28 days of treatment, 0.94, 95% CI 0.06 - 8.41). These findings remained even amongst patients with severe disease based on initial DF, GAHS or MELD scores.

CONCLUSIONS

We present an intuitive method of classifying patients with AH based on the trajectory of bilirubin over the first week of admission. It is complimentary to existing scores that identify candidates for corticosteroid treatment or assess response to treatment. This method identifies a group of patients with AH who recover spontaneously and can avoid corticosteroid therapy.

Trace element deficiency is highly prevalent and associated with infection and mortality in patients with alcoholic hepatitis

BACKGROUND

Malnutrition is common in patients with alcohol-related liver disease and is associated with outcome in patients with alcoholic hepatitis. Trace elements (cobalt, copper, iron, selenium and zinc) are micronutrients essential for many cellular processes including antioxidant pathways. The prevalence and relevance of trace element deficiency is unknown in alcoholic hepatitis.

AIM

To determine the prevalence of trace element deficiency and its association with clinical outcomes in patients with alcoholic hepatitis.

METHODS

Serum was obtained from patients with alcoholic hepatitis, alcohol-related cirrhosis and healthy volunteers as part of clinical trials, cohort studies and a biobank. Trace element concentration was measured by inductively coupled plasma mass spectrometry. Association of trace element levels with development of infection within 90 days and mortality within 28 and 90 days was evaluated by multivariate logistic regression.

RESULTS

Sera from 302 patients with alcoholic hepatitis, 46 with alcohol-related cirrhosis and 15 healthy controls were analysed for trace element concentration. The prevalence of zinc deficiency (85%) and selenium deficiency (67%) in alcoholic hepatitis was higher than in alcohol-related cirrhosis (72% [p=0.04] and 37% [p<0.001], respectively). Zinc, selenium, copper and chromium were significantly different between groups. Iron deficiency was a predictor of development of infection within 90 days. Zinc deficiency was a predictor of mortality within 28 and 90 days.

CONCLUSION

Trace element deficiency in patients with alcoholic hepatitis is highly prevalent and associated with infection and mortality. Supplementation with selected trace elements may improve clinical outcomes in this patient group but further insight is required of their biological and clinical effects.

Baseline neutrophil-to-lymphocyte ratio predicts response to corticosteroids and is associated with infection and renal dysfunction in alcoholic hepatitis

BACKGROUND

Treating severe alcoholic hepatitis involves the exposure of patients to corticosteroids for 7 days to assess "response".

AIM

To assess the prognostic and therapeutic implications of baseline neutrophil-to-lymphocyte ratio (NLR) in patients with severe alcoholic hepatitis.

METHODS

Patients recruited to the STOPAH trial and an independent validation group were analysed retrospectively. Area under the receiver operating curve (AUC) analysis was performed. Kaplan-Meier analysis was used to assess survival. Log-rank test and odds ratio (OR) were used for comparative analysis.

RESULTS

Baseline NLR was available for 789 STOPAH patients. The AUC for NLR was modest for 90-day outcome (0.660), but was associated with infection, acute kidney injury (AKI) and severity of alcoholic hepatitis. Ninety-day survival was not affected by prednisolone treatment if NLR < 5 or > 8 but mortality was reduced with prednisolone treatment when the NLR was 5-8 (21.0% cf. 34.5%; P = 0.012). Prednisolone treatment increased the chance of Lille response if the NLR was  ≥ 5 (56.5% cf. 41.1%: P = 0.01; OR 1.86) but increased the risk of day 7 infection (17.3% cf. 7.4%: P = 0.006; OR 2.60) and AKI (20.8% cf. 7.0%: P = 0.008; OR 3.46) if the NLR was > 8. Incorporation of NLR into a modified Glasgow alcoholic hepatitis score (mGAHS) improved the AUC to 0.783 and 0.739 for 28-day and 90-day outcome, respectively.

CONCLUSION

The NLR is associated with AKI and infection in severe alcoholic hepatitis. The NLR identifies those most likely to benefit from corticosteroids at baseline (NLR 5-8). The mGAHS has a good predictive value for 28- and 90-day outcomes.

Application of prognostic scores in the STOPAH trial: Discriminant function is no longer the optimal scoring system in alcoholic hepatitis

BACKGROUND & AIMS

'Static' prognostic models in alcoholic hepatitis, using data from a single time point, include the discriminant function (DF), Glasgow alcoholic hepatitis score (GAHS), the age, serum bilirubin, international normalized ratio and serum creatinine (ABIC) score and the model of end-stage liver disease (MELD). 'Dynamic' scores, incorporating evolution of bilirubin at seven days, include the Lille score. The aim of this study was to assess these scores' performance in patients from the STOPAH trial.

METHODS

Predictive performance of scores was assessed by area under the receiver operating curve (AUC). The effect of different therapeutic strategies upon survival was assessed by Kaplan-Meier analysis and tested using the log-rank test.

RESULTS

A total of 1,068 patients were studied. The AUCs for the DF were significantly lower than for MELD, ABIC and GAHS for both 28- and 90-day outcomes: 90-day values were 0.670, 0.704, 0.726 and 0.713, respectively. 'Dynamic' scores and change in 'static' scores by Day 7 had similar AUCs. Patients with consistently low 'static' scores had low 28-day mortalities that were not improved with prednisolone (MELD <25: 8.6%; ABIC <6.71: 6.6%; GAHS <9: 5.9%). In patients with high 'static' scores without gastrointestinal bleeding or sepsis, prednisolone reduced 28-day mortality (MELD: 22.2% vs. 28.9%, p = 0.13; ABIC 14.6% vs. 21%, p = 0.02; GAHS 21% vs. 29.3%, p = 0.04). Overall mortality from treating all patients with a DF ≥32 and Lille assessment (90-day mortality 26.8%) was greater than combining newer 'static' and 'dynamic' scores (90-day mortality: MELD/Lille 21.8%; ABIC/Lille 23.7%; GAHS/Lille 20.6%).

CONCLUSION

MELD, ABIC and GAHS are superior to the DF in alcoholic hepatitis. Consistently low scores have a favourable outcome not improved with prednisolone. Combined baseline 'static' and Day 7 scores reduce the number of patients exposed to corticosteroids and improve 90-day outcome.

LAY SUMMARY

Alcoholic hepatitis is a life-threatening condition. Several scores exist to determine the outcome of these patients as well as to identify those who may benefit from treatment. This study looked at the performance of existing scores in patients who had been recruited to the largest alcoholic hepatitis clinical trial: STOPAH. 'Static' scores are calculable at the start of assessment. The three newer static scores (ABIC, GAHS and MELD) were shown to be superior to the oldest score (DF). ABIC and GAHS could also identify patients who had a survival benefit 28 days after starting prednisolone treatment. 'Dynamic' scores relate to the change in disease over the first week of treatment. Combination of the 'static' scores 'with the 'dynamic' scores or change in 'static' scores allowed identification of patients who could benefit from prednisolone up to 90 days.

CD14++CD16+ Monocytes Are Enriched by Glucocorticoid Treatment and Are Functionally Attenuated in Driving Effector T Cell Responses

Human peripheral monocytes have been categorized into three subsets based on differential expression levels of CD14 and CD16. However, the factors that influence the distribution of monocyte subsets and the roles that each subset plays in autoimmunity are not well studied. In this study, we show that circulating monocytes from patients with autoimmune uveitis exhibit a skewed phenotype toward intermediate CD14(++)CD16(+) cells, and that this is associated with glucocorticoid therapy. We further demonstrate that CD14(++)CD16(+) monocytes from patients and healthy control donors share a similar cell-surface marker and gene expression profile. Comparison of the effects of intermediate CD14(++)CD16(+) monocytes with classical CD14(++)CD16(-) and nonclassical CD14(+)CD16(++) monocytes revealed that the intermediate CD14(++)CD16(+) subset had an attenuated capacity to promote both naive CD4(+) T cell proliferation and polarization into a Th1 phenotype, and memory CD4(+) T cell proliferation and IL-17 expression. Furthermore, CD14(++)CD16(+) cells inhibit CD4(+) T cell proliferation induced by other monocyte subsets and enhance CD4(+) T regulatory cell IL-10 expression. These data demonstrate the impact of glucocorticoids on monocyte phenotype in the context of autoimmune disease and the differential effects of monocyte subsets on effector T cell responses.

Development and validation of a tool to select patients for admission to medical short stay units

Medical short stay units help to increase patient flow and decrease length of stay, but selecting appropriate patients for admission to such units is difficult. The selection tool used in our unit was effective but cumbersome to apply. We collected prospective data on 297 unselected emergency medical admissions and developed a new scoring system based on four key variables using regression analysis. The model predicted a length of stay of <72 h with an area under the receiver operating characteristic curve of 0.68. The model was then used to select patients for admission to the short stay unit in our trust. Length of stay on the short stay unit had decreased by an average of 2.73 days with our original selection tool, but remained unchanged at an average of 3.02 days using the new simpler tool (p > 0.05). This model could now be adopted by other units.

C. elegans EGL-9 and mammalian homologs define a family of dioxygenases that regulate HIF by prolyl hydroxylation

HIF is a transcriptional complex that plays a central role in mammalian oxygen homeostasis. Recent studies have defined posttranslational modification by prolyl hydroxylation as a key regulatory event that targets HIF-alpha subunits for proteasomal destruction via the von Hippel-Lindau ubiquitylation complex. Here, we define a conserved HIF-VHL-prolyl hydroxylase pathway in C. elegans, and use a genetic approach to identify EGL-9 as a dioxygenase that regulates HIF by prolyl hydroxylation. In mammalian cells, we show that the HIF-prolyl hydroxylases are represented by a series of isoforms bearing a conserved 2-histidine-1-carboxylate iron coordination motif at the catalytic site. Direct modulation of recombinant enzyme activity by graded hypoxia, iron chelation, and cobaltous ions mirrors the characteristics of HIF induction in vivo, fulfilling requirements for these enzymes being oxygen sensors that regulate HIF.

Mutagenesis studies on the iron binding ligands of clavaminic acid synthase

Mutagenesis studies on conserved histidine residues identified as possible metal binding ligands in clavaminic acid synthase isozyme 2 were consistent with His-145 and His-280 acting as iron ligands, in support of crystallographic and previous mutagenesis studies. Mutagenesis of the four cysteines and a glutamine residue, conserved in both clavaminic acid synthase isozymes 1 and 2, demonstrated that none of these residues is essential for activity.

PaaSiCats: novel polyamino acid catalysts

The abilities of five polyamino acids (Paa's) to catalyse the asymmetric epoxidation of enones 1-7 under three sets of reaction conditions were compared: polyneo-pentylglycine and polyleucine showed distinct advantages in most circumstances. All five polymers were adsorbed onto silica and from this further study, immobilised polyneo-pentylglycine (PLNSi) and polyleucine (PLLSi) were shown to be the catalysts of choice for the asymmetric epoxidation of less-reactive alpha,beta-unsaturated ketones.