PHACTR1 modulates vascular compliance but not endothelial function: a translational study

AIMS

The non-coding locus at 6p24 located in Intron 3 of PHACTR1 has consistently been implicated as a risk allele in myocardial infarction and multiple other vascular diseases. Recent murine studies have identified a role for Phactr1 in the development of atherosclerosis. However, the role of PHACTR1 in vascular tone and in vivo vascular remodelling has yet to be established. The aim of this study was to investigate the role of PHACTR1 in vascular function.

METHODS AND RESULTS

Prospectively recruited coronary artery disease (CAD) patients undergoing bypass surgery and retrospectively recruited spontaneous coronary artery dissection (SCAD) patients and matched healthy volunteers were genotyped at the PHACTR1 rs9349379 locus. We observed a significant association between the PHACTR1 loci and changes in distensibility in both the ascending aorta (AA = 0.0053 ± 0.0004, AG = 0.0041 ± 0.003, GG = 0.0034 ± 0.0009, P < 0.05, n = 58, 54, and 7, respectively) and carotid artery (AA = 12.83 ± 0.51, AG = 11.14 ± 0.38, GG = 11.69 ± 0.66, P < 0.05, n = 70, 65, and 18, respectively). This association was not observed in the descending aorta or in SCAD patients. In contrast, the PHACTR1 locus was not associated with changes in endothelial cell function with no association between the rs9349379 locus and in vivo or ex vivo vascular function observed in CAD patients. This finding was confirmed in our murine model where the loss of Phactr1 on the pro-atherosclerosis ApoE-/- background did not alter ex vivo vascular function.

CONCLUSION

In conclusion, we have shown a role for PHACTR1 in arterial compliance across multiple vascular beds. Our study suggests that PHACTR1 has a key structural role within the vasculature.

Women and authorship in an international journal dedicated to cardiovascular diseases: analysis of the last decade

Introduction and purpose

Scientific production has become very important in the progression of the healthcare profession, and the studies made in this field reflect a gender gap in the authorship of such production. In the last decade, a review of the publications made over 35 years in 6 high impact factor journals has evidenced a lesser proportion of women among the first and last signing authors (1,2). Nevertheless, the presence of women as preferential authors is desproportionately low considering the number of female cardiologists in Spain in the year 2017 (40%) (3). The Revista Española de Cardiología (REC) is an international journal dedicated to cardiovascular diseases. Our study investigates the authorship gender differences from publications in the REC.

Methods

A cross-sectional study was made of the REC issues published between January 2011 and December 2020. For each article we recorded the doi identifier, the year of publication, the type of article, the number of authors, the number of female authors, and the number of women with preferential authorship. Preferential authorship was defined as first signing author, corresponding author or last author. A gender-based analysis of the number of authors, the type and year of publication and preferential authorship was carried out. Female participation was calculated from the female/male ratio, with an analysis of the trend observed over the years.

Results

Of 2859 articles documented, 4275 signing authors were women and 12,061 were men.

699, 548 and 481 women were the first, corresponding and the last author, respectively. Table 1 shows the percentage of articles in which a woman was a preferential author, as well as the percentage of women that would have to be present in the general population to cancel statistical significance. The number of articles in which a woman was the first or the corresponding author was seen to increase (p=0.008 and p=0.002, respectively), while no significant changes were observed in relation to last authorship (p=0.09). The percentage of articles in which at least one woman held at least one of the three preferential authorship positions tended to increase over time (p=0.056). In the year 2011, a total of 90 articles out of 252 (35.7%) had at least one woman among the three preferential authors, while in the year 2020 the figure was 123 out of 296 (41.6%) (Figure 1).

Conclusions

Although the participation of female authors in the scientific production of the REC has increased during the last decade, authorship gender inequalities persist.

Funding Acknowledgement

Type of funding sources: None.

Longer-term safety of alirocumab with 24,610 patient-years of placebo-controlled observation: further insights from the ODYSSEY OUTCOMES trial

Background

In the ODYSSEY OUTCOMES trial (NCT01663402), alirocumab, a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9), lowered low-density lipoprotein cholesterol from ∼2.3 mmol/L to ∼1.0 mmol/L at 4 months, reduced the risk of major adverse cardiovascular events (MACE: coronary heart disease death, nonfatal myocardial infarction, fatal/nonfatal ischemic stroke, unstable angina requiring hospitalization), and was associated with fewer deaths compared with placebo in 18924 patients (pts) with recent acute coronary syndrome followed for up to 5 years (yrs).

Purpose

In the ODYSSEY OUTCOMES trial, the overall safety of alirocumab and placebo was similar, except for an excess of local injection-site reactions with alirocumab. However, the safety among pts eligible for longer follow-up has not been fully explored.

Methods

The present post hoc analyses describe the efficacy and safety of alirocumab in a pre-specified subgroup (for efficacy) of pts eligible for a minimum of 3 and up to 5 yrs of follow-up.

Results

There were 8242 pts (43.5%) eligible for ≥3 yrs follow-up, of whom 8228 received at least one dose of study medication, comprising 24,610 pt-years of observation with a median follow-up of 3.3 yrs; 6651 pts were eligible for 3 up to 4 yrs, and 1574 patients were eligible for 4–5 yrs, follow-up. As previously reported in a pre-specified analysis of this subgroup, alirocumab significantly reduced death (4.7% vs. 5.9%; p=0.01) compared with placebo. In the present post hoc analysis, alirocumab also significantly reduced MACE vs. placebo (12.0% vs. 14.2%; Hazard Ratio 0.83 [95% CI 0.74 to 0.94]; p=0.003). In a safety analysis, 3217 (78.3%) vs. 3303 (80.2%) pts in the alirocumab vs. placebo group had at least one adverse event (AE) of whom 27.5% vs. 29.4% had a serious AE (Fig. 1). The frequency of permanent discontinuation of study drug due to AEs, incident diabetes, diabetes worsening or complications, neurocognitive events, elevations of ALT&gt;3, AST&gt;3, bilirubin&gt;2, and creatine phosphokinase&gt;10 times the upper limit of normal, were similar with alirocumab vs. placebo (Fig. 1). While pt-reported local injection-site reactions occurred more frequently with alirocumab, the Kaplan-Meier cumulative incidence for time to first local injection site reaction in the longer-term follow-up subgroup was &lt;5% over ∼4 yrs, with most occurring within the first 6 months (Fig. 2).

Conclusions

In an 8228-pt subgroup of the ODYSSEY OUTCOMES trial eligible for at least 3, and up to 5 yrs follow-up, the safety of alirocumab was similar to placebo except for an excess of local injection site reactions. This subgroup also derived significant benefit from reduced MACE and death. Thus, alirocumab appears to be both a safe and effective lipid-modifying treatment when used for up to 5 yrs.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Sanofi and Regeneron

Lipoprotein(a) and the effect of alirocumab on coronary and non-coronary revascularization following acute coronary syndrome

Background

Many patients require arterial revascularization after an index ACS. Lipoprotein(a) is thought to play a pathogenic role in atherothrombosis. In the ODYSSEY OUTCOMES trial, the PCSK9 inhibitor alirocumab reduced major adverse cardiovascular events after ACS, with greater reduction among those with higher lipoprotein(a).

Objectives

We determined whether the risk of first coronary or any (coronary, peripheral artery or carotid) revascularization after ACS was modified by the level of lipoprotein(a) and treatment with alirocumab or placebo.

Methods

The ODYSSEY OUTCOMES trial (NCT01663402) compared alirocumab with placebo in 18,924 patients with ACS and elevated atherogenic lipoproteins despite optimized statin treatment. Treatment effects were summarized by competing-risks proportional hazard models.

Results

A total of 1559 (8.2%) patients had coronary, 204 (1.1%) peripheral artery, and 40 (0.2%) carotid revascularization after randomization. Alirocumab reduced first coronary revascularization (9.6% vs. 11.3% at 4 years; hazard ratio [HR] 0.88, 95% confidence interval [CI] 0.80–0.97; p=0.01) and any first revascularization (10.8% vs. 13.0%; HR 0.85, 95% CI 0.78–0.94; p=0.001). Baseline lipoprotein(a) quartile was directly associated with risk of coronary or any revascularization in the placebo arm (ptrend &lt;0.0001) and inversely related to treatment HRs (ptrend &lt;0.001). The greatest benefits of alirocumab on coronary or any revascularization were observed in patients with baseline lipoprotein(a) in the top quartile (≥59.6 mg/dL) (figures).

Conclusions

Alirocumab reduced revascularization after ACS. The risk of revascularization and reduction in that risk with alirocumab were greatest in patients with elevated lipoprotein(a) at baseline.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): SanofiRegeneron Pharmaceuticals

Time-resolved near backscatter imaging system on Laser MegaJoule

The newly operating near-backscattering imaging (NBI) system on the Laser MegaJoule (LMJ) is briefly described with emphasis on the temporally resolved measurements and their synchronization with the LMJ laser pulse through target shots taken as part of the diagnostic commissioning campaign. The NBI measures the stimulated Brillouin and Raman scattered light around two quadruplets (one inner and one outer) of the upper LMJ hemisphere. The temporal resolution is achieved with a unique system: a specifically designed wide-open optical lens images 40 points of a diffuser onto an array of optical fibers with the scattered light recorded on a multiplexed photodiode array.

Breast Edema after Conservative Surgery for Early-Stage Breast Cancer: A Retrospective Single-Center Assessment of Risk Factors

Breast-conserving surgery (BCS) is the standard of care for early-stage breast cancer. We retrospectively enrolled 530 patients (mean age: 62.96 ± 12.69 years) undergoing BCS between January 1, 2018, and December 31, 2019. During the COVID-19 pandemic, all patients with at least 1 year of follow-up were telephonically asked after surgery to provide clinical signs and symptoms attributable to postoperative breast cancer-related lymphedema of the breast (BCRL-B). Thirty-one (5.8%) patients reported breast edema and were visited to measure the tissue dielectric constant (TDC) and to assess the induration of the skin. There was a difference seen in treatment with lumpectomy + ALND performed more frequently in patients with (29%) than without (12%) BCRL-B. In the subgroup of patients with BCRL-B (n=31), significantly higher values of local total water were calculated in the nine patients who underwent Lump + ALND procedure (1.86 ± 0.48 vs. 1.48 ± 0.38; p = 0.046). Among patients with BCRL-B (n=31), in eight patients (25.8%) tissue induration measured with SkinFibroMeter was >0.100 N, thus suggesting tissue fibrosis. Cumulative survival probability at 1-year after surgery was 0.992. No statistical differences in 1-year survival after surgery were found for type of surgery (p = 0.890) or absence/presence of BCRL-B (p = 0.480). In univariate logistic regression, only lumpectomy + ALND surgery (p = 0.009) and any subsequent axillary lymph node removal surgery (p = 0.003) were associated with BCRL-B. Both of these variables were also found to be statistically significant in the multivariate regression model. Further prospective research is warranted to analyze potentential predictors of BCRL-B and to reduce/ prevent this complication.

Cervical Spinal Cord Degeneration in Spinocerebellar Ataxia Type 7

BACKGROUND AND PURPOSE

Spinocerebellar ataxia type 7 is an autosomal dominant neurodegenerative disease caused by a cytosine-adenine-guanine (CAG) repeat expansion. Clinically, spinocerebellar ataxia type 7 is characterized by progressive cerebellar ataxia, pyramidal signs, and macular degeneration. In vivo MR imaging studies have shown extensive gray matter degeneration in the cerebellum and, to a lesser extent, in a range of cortical cerebral areas. The purpose of this study was to evaluate the impact of the disease in the spinal cord and its relationship with the patient's impairment.

MATERIALS AND METHODS

Using a semiautomated procedure applied to MR imaging data, we analyzed spinal cord area and eccentricity in a cohort of 48 patients with spinocerebellar ataxia type 7 and compared them with matched healthy controls. The motor impairment in the patient group was evaluated using the Scale for Assessment and Rating of Ataxia.

RESULTS

Our analysis showed a significantly smaller cord area (t = 9.04, P < .001, d = 1.31) and greater eccentricity (t = -2.25, P =. 02, d = 0.32) in the patient group. Similarly, smaller cord area was significantly correlated with a greater Scale for Assessment and Rating of Ataxia score (r = -0.44, P = .001). A multiple regression model showed that the spinal cord area was strongly associated with longer CAG repetition expansions (P = .002) and greater disease duration (P = .020).

CONCLUSIONS

Our findings indicate that cervical spinal cord changes are progressive and clinically relevant features of spinocerebellar ataxia type 7, and future investigation of these measures as candidate biomarkers is warranted.

A rare missense variant in the ATP2C2 gene is associated with language impairment and related measures

At least 5% of children present unexpected difficulties in expressing and understanding spoken language. This condition is highly heritable and often co-occurs with other neurodevelopmental disorders such as dyslexia and ADHD. Through an exome sequencing analysis, we identified a rare missense variant (chr16:84405221, GRCh38.p12) in the ATP2C2 gene. ATP2C2 was implicated in language disorders by linkage and association studies, and exactly the same variant was reported previously in a different exome sequencing study for language impairment (LI). We followed up this finding by genotyping the mutation in cohorts selected for LI and comorbid disorders. We found that the variant had a higher frequency in LI cases (1.8%, N = 360) compared with cohorts selected for dyslexia (0.8%, N = 520) and ADHD (0.7%, N = 150), which presented frequencies comparable to reference databases (0.9%, N = 24 046 gnomAD controls). Additionally, we observed that carriers of the rare variant identified from a general population cohort (N = 42, ALSPAC cohort) presented, as a group, lower scores on a range of reading and language-related measures compared to controls (N = 1825; minimum P = 0.002 for non-word reading). ATP2C2 encodes for an ATPase (SPCA2) that transports calcium and manganese ions into the Golgi lumen. Our functional characterization suggested that the rare variant influences the ATPase activity of SPCA2. Thus, our results further support the role of ATP2C2 locus in language-related phenotypes and pinpoint the possible effects of a specific rare variant at molecular level.

Dulaglutide is cardioprotective with or without background metformin in patients with diabetes and established or high risk for coronary vascular disease. A subgroup analysis of the REWIND Trial

Background

The 2019 ESC/EASD European Guidelines for Diabetes, Prediabetes and Coronary Artery Disease introduced a paradigm shift in the management of patients with type 2 diabetes (T2D) at high risk for or already established cardiovascular (CV) disease by recommending a GLP-1 receptor agonist (GLP-1 RA) as initial glucose lowering therapy in patients without any previous antihyperglycaemic treatment. This recommendation has been questioned since outcome trials of GLP-1-RA were usually conducted with metformin as background therapy.

Purpose

The aim of this report is to determine whether the effect of dulaglutide on cardiovascular events varies according to baseline metformin therapy. It was tested by a subgroup analysis of the Researching Cardiovascular Events with a Weekly Incretin in Diabetes (REWIND) trial.

Methods

REWIND, a multicentre, double-blind, placebo-controlled trial, comprised 9901 participants (women: 46.3%; mean age: 66.2 years) with T2D and either a previous CV event (31%) or a high CV risk (69%). They were randomised (1:1) to either sc. dulaglutide (1.5 mg/week) or placebo in addition to standard of care. The primary outcome was the first of a composite of non-fatal myocardial infarction or stroke or CV death. Secondary outcomes were a microvascular composite endpoint, all-cause death and heart failure. The effect of dulaglutide study outcomes in patients with and without baseline metformin was evaluated by means of a Cox regression hazard model with baseline metformin, dulaglutide assignment and the interaction between dulaglutide and metformin as independent variables. Adjusted hazard ratios (HR) and 95% confidence intervals (CI) were estimated using a Cox regression model with additional adjustments for factors that differed at baseline between people on vs. those not on baseline metformin selected by a backward regression model. A p&lt;0.05 was considered significant (see Figure 1).

Results

Patients without metformin at baseline (n=1864; 19%) were older, leaner, more likely to be women and had a higher proportion of prior CV events, heart failure and renal disease than patients with metformin (n=8037; 81%). During a median follow-up of 5.4 years (IQR 5.1–5.9), the primary outcome occurred in 976 (12%) participants with baseline metformin and in 281 (15%) without metformin. There was no significant difference in the effect of dulaglutide on the primary outcome in the groups with vs. without metformin at baseline (HR 0.93 [CI 0.82–1.06] vs. 0.78 [CI 0.61–0.99]; p for interaction=0.16). The effect of dulaglutide on the secondary outcomes was also not modified by concomitant metformin use (all interaction p&gt;0.1).

Conclusion

This exploratory analysis suggests that the cardioprotective effect of dulaglutide does not depend on baseline metformin therapy. This supports the recommendation of using agents with proven cardioprotective efficacy without metformin in patients with diabetes and additional cardiac risk factors.

Figure 1. Forest plot

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Eli Lilly and Company

Low-dose colchicine in patients treated with percutaneous coronary interventions for myocardial infarction in the Colchicine Cardiovascular Outcomes Trial (COLCOT)

Background/Introduction

Experimental and clinical evidence supports the role of inflammation in atherosclerosis and its complications. Colchicine is an orally administered, potent anti-inflammatory medication that was shown to significantly lower the risk of ischemic cardiovascular events compared to placebo among subjects with a recent myocardial infarction (MI) in the main COLCOT trial. Patients treated with percutaneous coronary intervention (PCI) after MI represent an important subpopulation that may derive particularly important benefits from colchicine.

Purpose

To assess the impact of low-dose colchicine on cardiovascular events in subjects treated with PCI for an index MI.

Methods

We performed an international, randomized, double-blind trial involving patients recruited within 30 days after a MI (main COLCOT trial; n=4745). In this trial, patients were eligible if they had a confirmed myocardial infarction within 30 days before enrollment, had completed any planned percutaneous revascularization procedures and were treated medically according to national guidelines that included the intensive use of statins. Subjects were randomly assigned to receive oral colchicine 0.5 mg once daily or matching placebo. Among the entire COLCOT study population, 4408 subjects were treated with PCI for the index MI and form the COLCOT-PCI study population. We analyzed the time to the first positively adjudicated event of the composite of CV death, resuscitated cardiac arrest, acute MI, stroke or urgent hospitalization for angina requiring coronary revascularization (primary endpoint).

Results

In the main COLCOT trial, low-dose colchicine led to a significantly lower risk of the primary endpoint (hazard ratio, 0.77; 95% confidence interval [CI], 0.61 to 0.96; p=0.02). In the COLCOT-PCI subpopulation, low-dose colchicine was associated with a large reduction in the risk of a primary endpoint event (hazard ratio, 0.72; 95% confidence interval [CI], 0.57 to 0.92; p=0.008). The hazard ratios for individual components of the composite primary endpoint were 0.71 (95% CI, 0.37 to 1.33) for death from cardiovascular causes, 0.84 (95% CI, 0.26 to 2.75) for resuscitated cardiac arrest, 0.90 (95% CI, 0.66 to 1.21) for myocardial infarction, 0.25 (95% CI, 0.08 to 0.76) for stroke, and 0.42 (95% CI, 0.25 to 0.71) for urgent hospitalization for angina requiring coronary revascularization.

Conclusion

Low-dose colchicine markedly reduces the risk of ischemic cardiovascular events in patients treated with PCI for their index MI.

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): Government of Quebec and Canadian Institutes of Health Research

Effect of alirocumab on incidence of atrial fibrillation after acute coronary syndromes: insights from ODYSSEY OUTCOMES

Background

Atrial fibrillation (AF) is a marker of risk in patients presenting with acute coronary syndromes (ACS). The potential effect of inhibiting proprotein convertase subtilisin/kexin type 9 (PCSK9) on the incidence of AF is unknown.

Methods

The ODYSSEY OUTCOMES trial compared randomized treatment with the PCSK9 inhibitor alirocumab or placebo in patients with recent ACS and residual dyslipidaemia despite optimal statin therapy. The current analysis determined: 1) whether alirocumab treatment influenced incident AF; 2) whether a history of AF influenced the risk of major adverse cardiovascular events (MACE); and 3) whether there was interaction between AF at baseline and randomized treatment on MACE. AF was determined from the medical history and investigator reports of adverse events.

Results

Of 18,924 participants, 662 (3.5%) had a history of AF at randomization and 18,262 (96.5%) had no history of AF. Of the latter category, 499 (2.7%) had incident AF. Older age, randomization in South America or Eastern Europe, history of heart failure or myocardial infarction, and higher body mass index were factors associated with incident AF. Treatment with alirocumab or placebo did not influence incident AF (2.2% vs 2.6%, respectively; hazard ratio 0.90, 95% confidence interval 0.75–1.08; Figure). Patients with a history of AF had a greater burden of comorbidities, including cerebrovascular disease, peripheral artery disease, hypertension and heart failure; they also had higher rates of MACE (Table). There was no significant interaction between AF and randomized treatment on risk of MACE (P interaction=0.78)

Conclusions

Although treatment with alirocumab did not significantly modify the risk of incident AF after ACS in this analysis, future studies with more sensitive and systematic methods of ascertainment may be warranted. History of AF is a strong predictor of risk of recurrent MACE after ACS.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Sanofi, Regeneron Pharmaceuticals, Inc

Evolving concepts in ventral hernia repair and physical therapy: prehabilitation, rehabilitation, and analogies to tendon reconstruction

PURPOSE

The abdominal wall and musculoskeletal tendons share many anatomic, physiologic, and functional characteristics. This review aims to highlight these similar characteristics and to present a rationale why the treatment principles of successful musculoskeletal tendon reconstruction, including principles of surgical technique and physical therapy, can be used in the treatment of complex abdominal wall reconstruction or ventral hernia repair.

METHODS

The MEDLINE/PubMed database was used to identify published literature relevant to the purpose of this review.

CONCLUSIONS

There are several anatomical and functional similarities between the linea alba and musculoskeletal tendons. Because of this reason, many of the surgical principles for musculoskeletal tendon repair and ventral hernia repair overlap. Distribution of tension is the main driving principle for both procedures. Suture material and configuration are chosen to maximize tension distribution among the tissue edges, as seen in the standard of care multistrand repairs for musculoskeletal tendons, as well as in the small bites for laparotomy technique described in the STITCH trial. Physical therapy is also one of the mainstays of tendon repair, but surprisingly, is not routine in ventral hernia repair. The evidence surrounding physical therapy prehabilitation and rehabilitation protocols in other disciplines is significant. This review challenges the fact that these protocols are not routinely implemented for ventral hernia repair, and presents the rationale and feasibility for the routine practice of physical therapy in ventral hernia repair.

Substrate Supporting Disc Method for Confirmed Detection of Total Coliforms and E. coli in all Foods: Collaborative Study

The Coli Complete® substrate supporting disc (SSD) method for simultaneous confirmed total coliform count and Escherichia coli determination in all foods was compared with AOAC most probable number (MPN) methods, 966.23 and 966.24. Twenty-nine laboratories participated in this collaborative study in which 6 food types were analyzed. Four food types, raw ground beef, pork sausage, raw liquid milk, and nut meats, were naturally contaminated with coliform bacteria. Two foods, dry egg and fresh frozen vegetables, were seeded with coliforms. Three food types, ground beef, raw liquid milk, and pork sausage, were naturally contaminated with E. coli. Although pork sausage was naturally contaminated, the level was very low (&lt;10/50 g); therefore, additional E. coli were inoculated into 1 lot of this food type. Three food types, nut meats, dry egg, and fresh frozen vegetables, were inoculated with E. coli. For naturally contaminated samples, duplicate determinations were made on 3 separate lots for each food type. For inoculated samples, low, medium, and high contamination levels plus uninoculated control samples were examined in duplicate. Data were analyzed separately for total coliform bacteria and for E. coli. Mean log MPN counts were determined by the SSD method and the appropriate AOAC MPN method. Results were then analyzed for repeatability, reproducibility, and mean log MPN statistical equivalence. Results were statistically equivalent for all total coliform levels in all food types except frozen vegetable and raw nut meat uninoculated control samples and 1 lot of pork sausage where the SSD method produced statistically significant greater numbers. For the E. coli determinations, results were statistically equivalent across all samples and all levels for each food type. The SSD method has been adopted first action by AOAC International for confirmed detection of total coliforms and E. coli in all foods.

2387Recurrent cardiovascular events and mortality in relation to antiplatelet therapy in patients with myocardial infarction without obstructive coronary artery disease (MINOCA)

Background

Approximately 10% of patients presenting with myocardial infarction (MI) do not have obstructive coronary artery disease (MINOCA). The role of antiplatelet therapy and outcomes in this group remain unclear. We assessed prognosis and the effect of an intensified clopidogrel regimen in MINOCA patients.

Methods

We analyzed data from the CURRENT-OASIS 7 trial, which randomized 25,086 patients with acute coronary syndromes (ACS) referred for early intervention to receive either double-dose (600mg day 1; 150mg days 2–7; then 75mg daily) or standard-dose (300mg day 1; then 75mg daily) clopidogrel. We evaluated clinical outcomes at 30-days in patients with versus without obstructive CAD and in relation to standard versus double-dose clopidogrel.

Results

Overall, 23,783 MI patients were included, of which 1,599 (6.7%) had MINOCA. MINOCA patients were younger, more frequently presented with non-ST-segment elevation MI and had fewer comorbidities. Rates of all-cause mortality (0.7% versus 2.4%, p=0.0046), cardiovascular mortality (0.6 versus 2.2%, p=0.0056), repeat MI (0.5% versus 2.3%, p=0.0009) and major bleedings (0.7% versus 2.5%, p=0.0001) were significantly lower among patients with MINOCA versus those with obstructive CAD. Compared with the standard-dose clopidogrel regimen, the double-dose regimen appeared to increase the risk of cardiovascular death, MI or stroke in MINOCA patients (0.8% versus 2.1%, hazard ratio (HR) 2.74, P=0.033). There was no difference in those with obstructive CAD (4.7% versus 4.4%, HR 0.93, P=0.226; P-for-interaction=0.023) (see Figure 1A). Major bleeding did not occur more frequently in MINOCA patients with double- versus standard-dose clopidogrel regimen (0.7% versus 0.6%, (HR 1.16 (95% CI 0.35–3.80), p=0.805), but their rate was higher In MI patients with obstructive CAD (2.7% versus 2.2% (HR 1.26 (95% CI 1.06–1.49), p=0.008) (Figure 1B).

Figure 1A & B

Conclusions

Compared to MI patients with obstructive CAD, patients presenting with MINOCA represent a distinct cohort, which is generally younger, has a higher NSTEMI prevalence and fewer comorbidities. Their risk for adverse events, especially repeat MI, stroke, death, and bleeding, is low (<1%) at 30 days. Applying an intensified clopidogrel regimen in MINOCA patients appears to be related to a higher risk for CV death, MI and stroke. Accordingly, more potent antiplatelet regimens might be harmful among MINOCA patients and should not be administered routinely. Nevertheless, there is a need for more prospective studies evaluating the role of dual antiplatelet therapies in MINOCA patients.

Acknowledgement/Funding

The CURRENT-OASIS 7 trial was sponsored by Sanofi-Aventis and Bristol-Myers Squibb.

P1226Very low achieved low-density lipoprotein cholesterol level with alirocumab treatment after acute coronary syndrome: ODYSSEY OUTCOMES

Background

Recent guidelines for cholesterol management recognize uncertainty regarding long-term efficacy and safety of prolonged very low levels of LDL-C on treatment with a PCSK9 inhibitor, including risk of new-onset diabetes. ODYSSEY OUTCOMES used a treat-to-target approach to demonstrate reduction of coronary heart disease death, non-fatal myocardial infarction, ischaemic stroke, or unstable angina (MACE) with the PCSK9 inhibitor alirocumab (ALI) vs placebo (PBO) in 18,924 patients with recent acute coronary syndrome and elevated LDL-C despite intensive statin therapy. ALI was blindly adjusted (75 or 150 mg dose) to target LDL-C 0.6–1.3 mmol/L (25–50 mg/dL). To avoid sustained very low LDL-C, blind substitution of PBO for ALI was intended if 2 consecutive LDL-C levels were <0.39 mmol/L (15 mg/dL). Patients were followed for median of 2.8 years (maximum of 5 years).

Purpose

We report the efficacy and safety of ALI in patients who reached very low LDL-C (consecutively <0.39 mmol/L), compared with matched patients from the PBO group.

Methods

Of 9462 patients randomized to receive ALI, 730 (7.7%) reached very low LDL-C and had substitution of PBO a median 8.3 months after randomization. Using propensity score matching, they were compared (3:1) with 2152 patients initially assigned to PBO. Propensity score matching was also used to compare the incidence of new-onset diabetes in 525 patients without diabetes at baseline who had very low LDL-C levels on ALI with 1675 matched patients in the PBO group. Neurocognitive events and haemorrhagic stroke were also evaluated in relation to very low LDL-C.

Results

Overall, ALI reduced the incidence of MACE (9.5% vs 11.1%; HR 0.85, 95% CI 0.78–0.93; P<0.001). Characteristics used in propensity score matching (and associated with very low LDL-C on ALI) included sex (male), diabetes (present), baseline LDL-C and lipoprotein(a) (lower), region (Asia), statin treatment, smoking, hypertension, and body mass index. Despite being switched to PBO, patients with very low LDL-C on ALI had fewer MACE than matched patients from the PBO group (6.4% vs 8.5%; HR 0.71, 95% CI 0.52–0.98; P=0.039; Figure). Very low LDL-C on ALI was not associated with risk of new-onset diabetes, compared with matched patients from the PBO group (15.1% vs 13.0%; HR 1.10, 95% CI 0.85–1.43; P=0.46). There was no association of very low LDL-C on ALI with neurocognitive events or haemorrhagic stroke.

Conclusions

The overall efficacy of ALI on cardiovascular outcomes was not diminished by the patients who had blinded substitution of PBO for sustained very low LDL-C. Despite a short duration of active treatment, these patients had fewer MACE than matched controls from the PBO group. No adverse consequence of very low LDL-C was identified. However, because patients with sustained very low LDL-C were switched to PBO, the long-term safety of more prolonged very low LDL-C, including risk of new-onset diabetes, deserves further study.

Acknowledgement/Funding

Funded by Sanofi and Regeneron Pharmaceuticals

4115Effect of alirocumab on recurrent cardiovascular events after acute coronary syndrome, according to the intensity of background statin treatment

Background

Statins are a cornerstone of therapy for coronary heart disease. We describe the effects of alirocumab (ALI) in patients (pts) with recent acute coronary syndrome (ACS) and dyslipidaemia per category of statin use.

Methods

ODYSSEY OUTCOMES compared ALI with placebo (PBO) in 18,924 pts with recent ACS and dyslipidaemia despite high-intensity/maximum tolerated statin (atorvastatin 40–80 mg/d or rosuvastatin 20–40 mg/d). Lower doses could be used if there were symptoms, laboratory abnormalities, or contraindications with higher doses. In cases of documented intolerance to ≥2 statins, pts could qualify on no statin treatment. Pts were randomized to ALI (75 mg SC Q2W, with possible uptitration to 150 mg Q2W) or PBO. Median follow-up was 2.8 years. Primary endpoint was major adverse cardiovascular events (MACE: CHD death, non-fatal MI, ischaemic stroke, or unstable angina requiring hospitalization). Pts were categorized by statin therapy at baseline: high intensity (88.8%), low or moderate intensity (8.7%), or no statin use (2.4%). In each category we determined the relative (hazard ratio [HR]) and absolute risk reductions (ARR) for MACE with ALI.

Results

Overall, ALI reduced MACE (HR 0.85, 95% CI 0.78–0.93; P<0.001). HRs were consistent across statin categories (Table). Baseline LDL-C increased across high-intensity, low/moderate-intensity, and no statin categories. Correspondingly, there was a gradient of the risk of MACE in the PBO group across these categories (10.8%, 10.7%, and 26%). With ALI treatment, the mean reduction in LDL-C from baseline to Month 4 increased across the 3 statin categories and correspondingly the ARRs for MACE were 1.3%, 3.2%, and 8.0% (P interaction <.001).

LDL-C values and MACE events All patients High-intensity statin Low-/moderate-intensity statin No statin Interaction P-value N=18,924 (100%) N=16,811 (88.8%) N=1653 (8.7%) N=460 (2.4%) (treatment x statin category) PBO (N=9462) ALI (N=9462) PBO (N=8431) ALI (N=8380) PBO (N=804) ALI (N=849) PBO (N=227) ALI (N=233) LDL-C at baseline, mmol/L, mean (SE)* 2.39 (0.01) 2.39 (0.01) 2.35 (0.01) 2.35 (0.01) 2.41 (0.03) 2.43 (0.03) 3.76 (0.08) 3.82 (0.08) Change in LDL-C from baseline to Month 4, mmol/L, mean (SE) 0.03 (0.01) −1.4 (0.01) 0.03 (0.01) −1.37 (0.01) 0.01 (0.02) −1.47 (0.02) −0.004 (0.06) −2.27 (0.06) <0.001 MACE, n (%)* 1052 (11.1) 903 (9.5) 907 (10.8) 797 (9.5) 86 (10.7) 64 (7.5) 59 (26.0) 42 (18.0) HR (95% CI) 0.85 (0.78−0.93) 0.88 (0.80−0.96) 0.69 (0.50−0.95) 0.65 (0.43−0.96) 0.14 ARR (%) (95% CI) 1.6 (0.7−2.4) 1.3 (0.3−2.2) 3.2 (0.4−5.9) 8.0 (0.4−15.5) <0.001 *P<0.001 for difference among statin categories.

Conclusions

In ODYSSEY OUTCOMES, patients unable to receive high-intensity statin treatment showed greater ARRs with ALI, consistent with higher baseline LDL-C concentration and greater absolute LDL-C reduction. Patients unable to receive high-intensity statin treatment are an important group to consider for treatment with ALI after ACS.

Acknowledgement/Funding

Funded by Sanofi and Regeneron Pharmaceuticals

A novel mutation in SPART gene causes a severe neurodevelopmental delay due to mitochondrial dysfunction with complex I impairments and altered pyruvate metabolism

Loss-of-function mutations in the SPART gene cause Troyer syndrome, a recessive form of spastic paraplegia resulting in muscle weakness, short stature, and cognitive defects. SPART encodes for Spartin, a protein linked to endosomal trafficking and mitochondrial membrane potential maintenance. Here, we identified with whole exome sequencing (WES) a novel frameshift mutation in the SPART gene in 2 brothers presenting an uncharacterized developmental delay and short stature. Functional characterization in an SH-SY5Y cell model shows that this mutation is associated with increased neurite outgrowth. These cells also show a marked decrease in mitochondrial complex I (NADH dehydrogenase) activity, coupled to decreased ATP synthesis and defective mitochondrial membrane potential. The cells also presented an increase in reactive oxygen species, extracellular pyruvate, and NADH levels, consistent with impaired complex I activity. In concordance with a severe mitochondrial failure, Spartin loss also led to an altered intracellular Ca²⁺ homeostasis that was restored after transient expression of wild-type Spartin. Our data provide for the first time a thorough assessment of Spartin loss effects, including impaired complex I activity coupled to increased extracellular pyruvate. In summary, through a WES study we assign a diagnosis of Troyer syndrome to otherwise undiagnosed patients, and by functional characterization we show that the novel mutation in SPART leads to a profound bioenergetic imbalance.-Diquigiovanni, C., Bergamini, C., Diaz, R., Liparulo, I., Bianco, F., Masin, L., Baldassarro, V. A., Rizzardi, N., Tranchina, A., Buscherini, F., Wischmeijer, A., Pippucci, T., Scarano, E., Cordelli, D. M., Fato, R., Seri, M., Paracchini, S., Bonora, E. A novel mutation in SPART gene causes a severe neurodevelopmental delay due to mitochondrial dysfunction with complex I impairments and altered pyruvate metabolism.

Abstract OT2-04-05: Phase II trial of pre-operative stereotactic ablative radiotherapy (SABR) in early-stage breast cancer

Background:

Post-operative accelerated partial breast irradiation (APBI) has demonstrated efficacy in preventing in-breast tumor recurrence. Pre-operative administration of APBI may be advantageous as an intact breast tumor is smaller than its corresponding lumpectomy cavity, is easier to distinguish on treatment-planning images, and results in smaller and more accurately delineated target volumes. Pre-operative APBI may reduce the incidence of positive margins following breast-conserving surgery (BCS). Investigation is needed in the correlation of MR imaging with pathologic response 6 weeks after SABR. Also, evidence suggests that SABR induces immune activation in the tumor microenvironment; evaluation of excised tumor tissue will give insight into these processes.

Trial Design:

Treatment Planning and Delivery: CT simulation and treatment are performed in the prone position. Diagnostic MRI is fused to planning CT. GTV is delineated on registered breast MRI and includes the intact breast tumor. CTV is 15mm expansion of GTV. PTV is 3 mm expansion of CTV. VMAT or IMRT are permitted. Daily image-guidance aligning to tumor and biopsy-fiducial is mandatory. All subjects undergo pre-operative SABR to 28.5 Gy in 3 fractions of 9.5 Gy on different days separated by ≤48 hours. CTCAE v4 is used to assess toxicity 4-5 weeks after SABR. Pre-operative diagnostic MRI is performed 5-6 weeks following SABR. Imaging parameters to be evaluated include changes in tumor size, enhancement, and tumor margin description. BCS will be 6-8 weeks following SABR.

Tissue pathology: Margin status and degree of pathologic response are recorded from breast-conserving excisions, specimens are archived for future analysis.

Eligibility Criteria:

Inclusion criteria are women age ≥50 with biopsy proven invasive breast adenocarcinoma with tumor size ≤2cm on MRI, cN0 M0, ER+/HER2-, without history of invasive malignancy or prior breast/thoracic radiotherapy.

Exclusion criteria are active scleroderma or lupus erythematosus with skin involvement, MRI defined tumor within 10 mm of skin, implanted hardware prohibiting appropriate treatment planning or delivery, neoadjuvant chemotherapy, carrier of BRCA1 or 2 gene mutation, pregnancy.

Specific Aims:

The primary endpoint is pathologic complete response (pCR) in the breast tumor, secondary endpoints are incidence of adequate surgical margins (defined as “no tumor on ink”) and MRI response following SABR. Analyses of tumor immune response and microenvironment on pathologic specimens following SABR will also be performed.

Statistical Methods:

Fisher's exact test will be performed to examine associations between patient/tumor characteristics and pCR and surgical margins; these associations will be explored with multivariable logistic and linear regressions.

Accrual:

Present accrual is 9 subjects.

Expected accrual is 22 subjects; if ≥3 pCR are noted in the initial cohort, accrual will be expanded to 40 subjects.

Citation Format: Liveringhouse CL, Diaz R, Ahmed KA, Lee MC, Czerniecki B, Laronga C, Khakpour N, Weinfurtner RJ, Rosa M, Montejo ME. Phase II trial of pre-operative stereotactic ablative radiotherapy (SABR) in early-stage breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr OT2-04-05.

Abstract P3-12-19: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Chowdhary M, Lee A, Gao S, Barry PN, Diaz R, Decker RH, Wilson LD, Evans SB, Moran MS, Knowlton CA, Patel KR. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-12-19.

Abstract P4-08-15: Locoregional recurrence in invasive breast cancer and association with tumor infiltrating leukocyte (TIL) presence

Background:

The presence of TILs has been correlated with clinical outcomes and response to therapy in breast cancer. However, evaluation of TILs in breast cancer has largely been based on pathologic examination of tumor samples. Here, we report the relationship between invasive breast cancer locoregional recurrence (LRR) and the presence of TILs estimated by transcriptomic analysis with the deconvolution algorithm CIBERSORT.

Methods:

Patients were identified from an IRB-approved prospective tissue collection protocol at one academic institution and two community hospitals. 526 primary breast tumor samples were identified and gene expression profiling was assessed with high density Affymetrix microarray chips. Proportions of 22 different TIL types in samples were inferred based on the CIBERSORT algorithm, which uses gene expression data to estimate TIL presence. TIL presence was determined by dichotomization at the level of the first quartile among all samples (&gt;Q1=TIL presence). Patient characteristics and clinical outcomes were obtained by chart review. Time to event analysis was performed using Kaplan Meier (KM) estimates and the log-rank test. Associations between patient factors, tumor factors, TIL presence, and LRR were explored with univariable (UVA) and multivariable (MVA) analyses. Factors significant on UVA (p&lt;0.10) were included on MVA. P&lt;0.05 was considered statistically significant on MVA.

Results:

526 women with invasive breast cancer and available genomic profiling were retrospectively identified for analysis. Median age at diagnosis was 58 years. 70% of tumors were Stage I-II. 69% were luminal subtypes and 17% were triple negative. 37% received mastectomy, 25% received mastectomy + radiation, and 32% received breast conserving therapy. 64% received chemotherapy, and 62% received hormonal therapy. Median follow-up was 74.4 months. There were 61 LRRs. We found significant differences in time to LRR when comparing presence vs. no presence of resting memory CD4+ T-cells (RMCD4+) (p=0.01), activated natural killer cells (ANK) (p=0.003), and neutrophils (PMNs) (p=0.03). On UVA, factors associated with LRR were patient age at diagnosis (p=0.009), pathologic T stage (p=0.045), Estrogen receptor status (p=0.03), biologic subtype (p=0.01), lymphovascular invasion (LVI) (p=0.018), positive margins (p&lt;0.0001), receipt of hormonal therapy (0.014), and presence of tumor infiltrating RMCD4+ (p=0.012), ANK (p=0.0004), and PMNs (p=0.033). On MVA, factors remaining significant were LVI (HR 2.16 CI 1.13-4.13, p=0.011), positive margins (HR 4.36 CI 1.57-12.11, p=0.018), receipt of hormonal therapy (HR 0.31 CI 0.12-0.77, p=0.042), and presence of RMCD4+ (HR 0.48 CI 0.26-0.88, p=0.017), ANK (HR 0.43 CI 0.23-0.83, p=0.012), and PMNs (HR 2.15 CI 1.02-4.53, p=0.043).

Conclusion:

In this study of 526 women with invasive breast cancer, we identified that enrichment of certain TILs is associated with LRR. These results suggest genomic-based assays of TIL presence may be useful to predict LRR in invasive breast cancer.

Citation Format: Liveringhouse CL, Grass GD, Figura NB, Mills MN, Purcell JD, Rosensweig SR, Blumencranz PW, Allen KG, Ahmed KA, Harrison LB, Torres-Roca JF, Robinson TJ, Diaz R. Locoregional recurrence in invasive breast cancer and association with tumor infiltrating leukocyte (TIL) presence [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-15.

Clinical outcomes and the role of adjuvant therapy sequencing in Type II uterine cancer following definitive surgical treatment

PURPOSE OF INVESTIGATION

Because of rarity, consensus on adjuvant therapies for Type II endometrial cancers (BC) remains undefined. Reporting their institutional outcomes, the present authors assessed the impact of adjuvant therapies on recurrence and overall survival in women with 2009 FIGO Stage I-III Type II BC.

MATERIAL AND METHODS

The authors identified 108 women, treated with definitive surgery between 2000-2013, with pathologically-confirmed Type II EC (non-endometrioid [NEM, n=801 and high grade endometrioid [G3EEC, n=28]) Cox proportional hazard models were used to assess the effect of prognostic variables on disease-free (DFS) and overall survival (OS). Kaplan-Meier method was used to assess survival.

RESULTS

Of the 108 women, 83 (77%) were African American (AA). Fifty-nine (55%), 12 (11%), and 37 (34%) were Stage I, II, and III, respectively. Ninety-seven patients received adjuvant therapy: 52 (radiation only), four (chemotherapy only), and 40 (combined). During follow-up (median 41 months), 44 patients (41%) recurred. Five-year DFS was 53% overall (48% [NEM], 80% [G3EEC]). Five-year OS was 75% overall (68% [NEM], 95% [G3EEC]). On multivariate analysis, lower stage and adjuvant radiation improved DFS. Higher stage, NEM, and increasing age were poor prognostic indicators of OS.

CONCLUSION

Representing a large single institutional cohort for Type II BC, the present study's observed sur- vival rates are consistent with previous studies, despite the relatively high frequency of carcinosarcoma and Stage III/nodal disease. The protective effect on recurrence was not lost when radiation was delayed for chemotherapy. The present results support a multimodal adjuvant approach for treating all stages of invasive NEM EC.

Prime-boost using separate oncolytic viruses in combination with checkpoint blockade improves anti-tumour therapy

The anti-tumour effects associated with oncolytic virus therapy are mediated significantly through immune-mediated mechanisms, which depend both on the type of virus and the route of delivery. Here, we show that intra-tumoral oncolysis by Reovirus induced the priming of a CD8+, Th1-type anti-tumour response. By contrast, systemically delivered Vesicular Stomatitis Virus expressing a cDNA library of melanoma antigens (VSV-ASMEL) promoted a potent anti-tumour CD4+ Th17 response. Therefore, we hypothesised that combining the Reovirus-induced CD8+ T cell response, with the VSV-ASMEL CD4+ Th17 helper response, would produce enhanced anti-tumour activity. Consistent with this, priming with intra-tumoral Reovirus, followed by an intra-venous VSV-ASMEL Th17 boost, significantly improved survival of mice bearing established subcutaneous B16 melanoma tumours. We also show that combination of either therapy alone with anti-PD-1 immune checkpoint blockade augmented both the Th1 response induced by systemically delivered Reovirus in combination with GM-CSF, and also the Th17 response induced by VSV-ASMEL. Significantly, anti-PD-1 also uncovered an anti-tumour Th1 response following VSV-ASMEL treatment that was not seen in the absence of checkpoint blockade. Finally, the combination of all three treatments (priming with systemically delivered Reovirus, followed by double boosting with systemic VSV-ASMEL and anti-PD-1) significantly enhanced survival, with long-term cures, compared to any individual, or double, combination therapies, associated with strong Th1 and Th17 responses to tumour antigens. Our data show that it is possible to generate fully systemic, highly effective anti-tumour immunovirotherapy by combining oncolytic viruses, along with immune checkpoint blockade, to induce complementary mechanisms of anti-tumour immune responses.

An essential cell-autonomous role for hepcidin in cardiac iron homeostasis

Hepcidin is the master regulator of systemic iron homeostasis. Derived primarily from the liver, it inhibits the iron exporter ferroportin in the gut and spleen, the sites of iron absorption and recycling respectively. Recently, we demonstrated that ferroportin is also found in cardiomyocytes, and that its cardiac-specific deletion leads to fatal cardiac iron overload. Hepcidin is also expressed in cardiomyocytes, where its function remains unknown. To define the function of cardiomyocyte hepcidin, we generated mice with cardiomyocyte-specific deletion of hepcidin, or knock-in of hepcidin-resistant ferroportin. We find that while both models maintain normal systemic iron homeostasis, they nonetheless develop fatal contractile and metabolic dysfunction as a consequence of cardiomyocyte iron deficiency. These findings are the first demonstration of a cell-autonomous role for hepcidin in iron homeostasis. They raise the possibility that such function may also be important in other tissues that express both hepcidin and ferroportin, such as the kidney and the brain.

DOI:http://dx.doi.org/10.7554/eLife.19804.001

Many proteins inside cells require iron to work properly, and so this mineral is an essential part of the diets of most mammals. However, because too much iron in the body is also bad for health, mammals possess several proteins whose role is to maintain the balance of iron. Two proteins in particular, called hepcidin and ferroportin, are thought to be important in this process. Some ferroportin is found in the cells that line the gut (where iron is absorbed into the body) and is required to release this iron into the bloodstream. It is also found in the spleen, which is where iron is removed from old red blood cells so that it can be recycled. The liver produces hepcidin to control when ferroportin is active in the gut and spleen.

Both hepcidin and ferroportin are also found in heart cells. In 2015, a study reported that that heart ferroportin plays an important role in heart activity. However, it was not clear what role hepcidin plays in this organ.

Now, Lakhal-Littleton et al. – including many of the researchers from the previous work – have genetically engineered mice such that they specifically lacked heart hepcidin, or had a version of ferroportin in their heart that does not respond to hepcidin. The experiments show that these changes caused fatal heart failure in the mice because ferroportin releases iron from heart cells in an uncontrolled manner. Lakhal-Littleton et al. were able to prevent heart failure by injecting the animals with iron directly into the bloodstream. These findings show that hepcidin produced outside the liver has a role in controlling the levels of iron in the body’s organs.

Other organs such as the brain, kidney and placenta all have their own forms of hepcidin and ferroportin; further work could investigate the roles of these proteins. Finally, another challenge for the future will be to test whether new drugs that are being developed to block or mimic hepcidin from the liver have the potential to treat heart conditions in humans.

DOI:http://dx.doi.org/10.7554/eLife.19804.002

Induced Disruption of the Iron-Regulatory Hormone Hepcidin Inhibits Acute Inflammatory Hypoferraemia

Withdrawal of iron from serum (hypoferraemia) is a conserved innate immune antimicrobial strategy that can withhold this critical nutrient from invading pathogens, impairing their growth. Hepcidin (Hamp1) is the master regulator of iron and its expression is induced by inflammation. Mice lacking Hamp1 from birth rapidly accumulate iron and are susceptible to infection by blood-dwelling siderophilic bacteria such as Vibrio vulnificus. In order to study the innate immune role of hepcidin against a background of normal iron status, we developed a transgenic mouse model of tamoxifen-sensitive conditional Hamp1 deletion (termed iHamp1-KO mice). These mice attain adulthood with an iron status indistinguishable from littermate controls. Hamp1 disruption and the consequent decline of serum hepcidin concentrations occurred within hours of a single tamoxifen dose. We found that the TLR ligands LPS and Pam3CSK4 and heat-killed Brucella abortus caused an equivalent induction of inflammation in control and iHamp1-KO mice. Pam3CSK4 and B. abortus only caused a drop in serum iron in control mice, while hypoferraemia due to LPS was evident but substantially blunted in iHamp1-KO mice. Our results characterise a powerful new model of rapidly inducible hepcidin disruption, and demonstrate the critical contribution of hepcidin to the hypoferraemia of inflammation.