Transcription Factor Condensates Mediate Clustering of MET Regulon and Enhancement in Gene Expression

Some transcription factors (TFs) can form liquid-liquid phase separated (LLPS) condensates. However, the functions of these TF condensates in 3D genome organization and gene regulation remain elusive. In response to methionine (met) starvation, budding yeast TF Met4 and a few co-activators, including Met32, induce a set of genes involved in met biosynthesis. Here, we show that the endogenous Met4 and Met32 form co-localized puncta-like structures in yeast nuclei upon met depletion. Recombinant Met4 and Met32 form mixed droplets with LLPS properties in vitro. In relation to chromatin, Met4 puncta co-localize with target genes, and at least a subset of these target genes are clustered in 3D in a Met4-dependent manner. A MET3pr-GFP reporter inserted near several native Met4 binding sites becomes co-localized with Met4 puncta and displays enhanced transcriptional activity. A Met4 variant with a partial truncation of an intrinsically disordered region (IDR) shows less puncta formation, and this mutant selectively reduces the reporter activity near Met4 binding sites to the basal level. Overall, these results support a model where Met4 and co-activators form condensates to bring multiple target genes into a vicinity with higher local TF concentrations, which facilitates a strong response to methionine depletion.

Factors associated with emergency admission for people dying from cancer in Northern Ireland: an observational data linkage study

BACKGROUND

Many people living with cancer are admitted as an emergency, some just prior to diagnosis and others in their last year of life. Factors associated with accessing emergency care for people dying of cancer are complex and not well understood. This can make it difficult to have the resources and staffing in place to best care for individuals in their last year of life and their families.

METHODS

This study uses routinely collected administrative data from people who died of cancer in N. Ireland (NI) during 2015 and explores how personal characteristics (e.g., gender, age) and disease related factors (e.g., tumour site, cancer stage at initial diagnosis) were associated with having an emergency admission to hospital in the last year and the last 28 days of their lives, using multivariate logistic regression.

RESULTS

Almost three in four people had at least one emergency admission in the last year of life, and over one in three had an emergency admission the last 28 days of life. Patterns were similar for both time outcomes with males, people with haematological, lung or brain cancers, younger persons, those diagnosed with late-stage cancer, and people diagnosed close to time of death, being significantly more likely to have an emergency admission. While there was no significant association between deprivation and emergency admission rates, those living in urban areas were more likely to have an emergency admission in their last month of life compared to rural dwellers. Late diagnosis was evident with 538 people (12.8% of all deaths from cancer) being diagnosed within one month of death and 1242 (29%) within 3 months of death.

CONCLUSION

The high level of emergency admissions points to gaps in routine end-of-life care, and the need for additional training for hospital staff including frontline emergency department (ED) staff who are often the 'gatekeepers' to emergency inpatient care for people living with cancer. The levels of late diagnosis indicate a need for increased population awareness of cancer symptoms and system change to promote earlier diagnosis.

The challenge of providing medical follow-up for sexual assault victims: can we predict who will attend? A retrospective cross-sectional study

This study examined the impact of a pathway between a sexual assault service and a public sexual health service developed to improve rates of post-sexual assault medical follow-up. Follow-up attendances improved in the first 12months of the pathway (2014) compared with attendances in 2013 (17.8%vs 9.6%, P =0.01). Factors independently associated with attendance at follow-up were being prescribed HIV post-exposure prophylaxis and knowing the assailant. Those with physical injuries were less likely to attend. The prevalence of sexually transmissible infections in this cohort, 8% at the acute presentation and 5% at follow-up, suggests a need for alternatives to clinic-based follow-up.

Direct current cardioversion in pregnancy: a multicentre study

OBJECTIVE

Direct current cardioversion (DCCV) in pregnancy is rarely required and typically only documented in single case reports or case series. A recent UK confidential enquiry reported on several maternal deaths where appropriate DCCV appeared to have been withheld.

DESIGN

Retrospective cohort study.

SETTING

Seventeen UK and Ireland specialist maternity centres.

SAMPLE

Twenty-seven pregnant women requiring DCCV in pregnancy.

MAIN OUTCOME MEASURES

Maternal and fetal outcomes following DCCV.

RESULTS

Twenty-seven women had a total of 29 DCCVs in pregnancy. Of these, 19 (70%) initial presentations were to Emergency Departments and eight (30%) to maternity settings. There were no maternal deaths. Seventeen of the women (63%) had a prior history of heart disease. Median gestation at DCCV was 28 weeks, median gestation at delivery was 35 weeks, with a live birth in all cases. The abnormal heart rhythms documented at the first cardioversion were atrial fibrillation in 12/27 (44%) cases, atrial flutter in 8/27 (30%), supraventricular tachycardia in 5/27 (19%) and atrial tachycardia in 2/27 (7%). Fetal monitoring was undertaken following DCCV on 14/29 (48%) occasions (10 of 19 (53%) at ≥26 weeks) and on 2/29 (7%) occasions, urgent delivery was required post DCCV.

CONCLUSIONS

Direct current cardioversion in pregnancy is rarely required but should be undertaken when clinically indicated according to standard algorithms to optimise maternal wellbeing. Once the woman is stable post DCCV, gestation-relevant fetal monitoring should be undertaken. Maternity units should develop multidisciplinary processes to ensure pregnant women receive the same standard of care as their non-pregnant counterparts.

Lip symmetry following rotation advancement cleft lip repair in 5-year-old children treated by Ralph Millard and Ron Pigott

Objective

To compare the symmetry of the lip following Rotation-Advancement cleft lip repair by Millard and Pigott and to investigate the effect on the symmetry of cleft side and gender by using different surgical protocols. Symmetry following cleft surgery was compared to that of non-cleft children.

Design

Retrospective study of photographs of children aged 5 years.

Setting

Three decades of post-operative photographs of children treated by Millard and Pigott.

Patients

Eighty-nine children treated by Millard, 87 by Pigott and 91 non-cleft children.

Interventions

Photographs were assessed using the Symnose Computer program, a rapid semi-objective quantitative assessment of lip symmetry.

Main Outcome Measure(s)

Asymmetry score for each surgeon, and non-cleft children.

Results

There was no significant difference in the median lip % mismatch score of Millard, 36.65% and Pigott, 38.52%. Right-sided clefts showed better symmetry than left-sided clefts for Millard (p<.001). This was reversed for Pigott (P=.0121). There was a difference (P<.001) between the symmetry of the two cleft cohorts and the non-cleft children (asymmetry 19.9%), and between Millard's outcomes following different lip surgical protocols (P < .0001), but no difference between Pigott's outcomes using different palate surgical protocols (P = 0.59).

Conclusions

Cleft lip repair by Millard and Pigott resulted in similar lip asymmetry (37% and 39% symmetry mismatch, respectively). Lip surgical protocol and cleft side may affect lip asymmetry. Palate surgery did not affect lip asymmetry. Following cleft surgery, children were more asymmetric than non-cleft children.

974 Improving Safety for Tracheostomy and Laryngectomy Patients Within A Regional Head and Neck Unit

Aim

To improve the safety of tracheostomy and laryngectomy patients within a UK-based regional head and neck unit.

Method

This audit was conducted against standards taken from the National Tracheostomy Safety Project (NTSP). Inclusion criteria were all patients with a tracheostomy or laryngectomy on the ward, there were no exclusion criteria. Data was collected per inpatient episode for a one month period pre- and post- implementation of each intervention (1st March to 31st May 2020).

Results

Pre-intervention results showed that none of the 19 neck-breathing inpatients during March 2020 had a bedhead sign or emergency algorithm displayed, however all patients had required bedside equipment and the only unavailable ward equipment was capnography. Laminated bedhead signs and algorithms were implemented and 33% neck-breathing patients had signs displayed during April 2020. Further intervention in May 2020 to educate ward staff led to 90% of patients having a bedhead sign displayed and 80% having an algorithm displayed.

Conclusions

Overall, our unit has very high standards of care for neck-breathing patients. The use of bedhead signs and emergency airway algorithms is an integral part of providing safe care for neck-breathing patients and all members of staff are responsible for their use. The COVID-19 crisis has impacted on the number of elective procedures being performed which has impacted upon the numbers for the post-intervention arms of our audit. Reduced staffing due to sickness during the pandemic may have contributed to the substandard results.

Vanishing congenital lung malformations: What is the incidence of true regression?

BACKGROUND

A congenital lung malformation (CLM) that is diagnosed on prenatal ultrasound exam may subsequently become undetectable on later scans, a "vanishing" CLM.

OBJECTIVE

The purpose of our study is to characterize the prenatal natural history and postnatal outcomes of "vanishing" lesions treated at our institution.

METHODS

We performed a retrospective chart review of 107 patients diagnosed prenatally with CLM at our institution. Comparisons were made using Kruskal-Wallis or t-test for continuous variables and Fisher's exact test or Chi-Square test for categorical variables. Multivariable analysis using logistic regression was performed.

RESULTS

Of the 104 patients, 59 (56.7%) had lesions that became sonographically undetectable on serial ultrasound scans. Patients with lesions that vanished prenatally tended to need less Neonatal Intensive Care Unit (NICU) admission at birth (persistent CLM: 54.8%vs vanished CLM: 28.8%), decreased need for supplemental O2 at birth (persistent CLM: 31.0%vs vanished CLM: 11.9%), and decreased delay in feeds (persistent CLM: 26.2%vs vanished CLM: 8.5%) compared to those with persistent CLM. After multivariate analysis controlling for maternal steroid administration and sex, admission to NICU maintained a slight statistical significance, with patients in the vanishing CLM group 2.5 times less likely to be admitted to the NICU. None of our patients whose lesions vanished prenatally required mechanical ventilation. Eighty-six patients underwent postnatal computed tomography (CT) chest. Only 2 patients had lesions that regressed on postnatal CT.

CONCLUSION

Lesions that vanish on prenatal imaging may be associated with improved clinical outcomes. The rate of true regression at our institution was as low as 2.3%.

POS0224 SELECTIVITY OF CLINICAL JAK INHIBITORS AND THE IMPACT ON NATURAL KILLER (NK) CELL FUNCTIONAL RESPONSES

Background:

Janus kinase (JAK) inhibitors (JAKinibs) show similar efficacy in rheumatoid arthritis (RA). However, in vitro studies have shown differences in JAK selectivity profiles for baricitinib (BARI), tofacitinib (TOFA), upadacitinib (UPA) and filgotinib (FIL).1,2 These lead to distinct pharmacologic profiles in cellular signaling assays that may impact clinical efficacy or safety1. NK cells are innate lymphocytes important in anti-pathogen responses and immune surveillance, which function via production of cytokines and cell killing3. NK cell proliferation and IFNγ production are JAK-dependent pathways and may be modulated by JAKinibs. Clinical findings show transient decreases in NK cell numbers in patients treated with JAKinibs, but the link to safety is unclear4

Objectives:

To extend upon findings in proximal cell signaling assays, we compared the selectivity and potency of clinical JAKinibs on NK cell function by assessing proliferation mediated by IL-15 (JAK1/3) and IFN-γ production driven by IL-12 (JAK2/TYK2)+IL-18.

Methods:

NK cells were isolated from healthy donor PBMC, incubated in vitro with 8 concentrations of each evaluated JAKinib (TOFA, BARI, FIL, FIL metabolite, UPA) and stimulated with IL-15 for proliferation or IL-12/18 for IFNγ production. Proliferation was assessed by Cell Trace dye dilution after 6 days and IFNγ production by intracellular flow cytometry 4hrs post-stimulation. Half maximal inhibitory concentration (IC50) values were calculated for CD56bright, CD56dim, and total NK cells. Steady-state pharmacologic profile over a clinical dosing interval was modeled using concentration-time profiles from JAKinib population pharmacokinetic data in RA subjects under the therapeutic dose5-7. For each JAKinib, the time above IC50 and average daily inhibition of IFNγ or proliferation were calculated for each NK cell population in each donor.

Results:

Cellular assays in purified NK cells showed dose-dependent inhibition of IL-15-induced proliferation by all JAKinibs with TOFA showing the highest average inhibition and time above IC50 (35-60% inhibition for 8-15 hrs; TOFA>UPA>BARI≈FIL). The differences between JAKinibs are in line with differences in pSTAT inhibition downstream of IL-151. Interestingly, IL-12/18-induced production of IFNγ, which is mediated via JAK2/TYK2 (IL-12) and non-JAK dependent pathways (IL-18), showed weaker inhibition for all compounds. Moreover, all JAKinibs showed <25% average inhibition of IFNγ production over 24hrs and did not show any time above IC50 for IFNγ production or pSTAT4 inhibition at clinical doses. CD56dim and CD56bright sub-populations of NK cells are proposed to have distinct functions and unique expression of surface receptors. Analysis of the IC50 for pSTAT4 and IFNγ production showed ~2-10-fold weaker inhibition by JAKinibs in CD56bright NK cells, suggesting less dependence on JAK-dependent signals in CD56bright NK cells than CD56dim NK cells.

Conclusion:

NK cell proliferation depends on JAK1 and JAK3-mediated signaling and is differentially inhibited at clinical doses of distinct JAKinibs. In contrast, functional responses downstream of JAK2/TYK2-dependent IL-12/18 were not substantially inhibited by any of the JAKinibs studied. Inhibition of functional and proliferative responses in purified NK cells aligned well with proximal pSTAT inhibition. JAKinib modulation of NK cell proliferation, but not response to IL-12, reflects unique pharmacologic profiles of the drugs studied and could be one component underlying clinical safety observations, including increased risk of viral infections or malignancy4.

References:

[1]Traves PG et al. Ann Rheum Dis 2021 (in press)

[2]McInnes IB, et al. Arthritis Res Ther 2019;21:183.

[3]Cooper MA, Fehniger TA, Caligiuri MA. Trends Immunol 2001 Nov;22(11):633-40.

[4]Winthrop KL. Nat Rev Rheumatol 2017; 13(4):234-243

[5]Zhang X, et al. CPT Pharmacometrics Syst Pharmacol 2017;6(12):804-13.

[6]CDER. Application Number: 203214Orig1s000. NDA 203214: Tofacitinib.

[7]Klunder B et al. Clin Pharmacokinet 2019;58(8):1045-58.

Disclosure of Interests:

Paqui Gonzalez-Traves Shareholder of: Gilead Sciences, Employee of: Gilead Sciences, Laura Simpson Shareholder of: Gilead Sciences, Employee of: Gilead Sciences, Bernard Murray Shareholder of: Gilead Sciences, Employee of: Gilead Sciences, Amy Meng Shareholder of: Gilead Sciences, Employee of: Gilead Sciences, Julie A. Di Paolo Shareholder of: Gilead Sciences, Employee of: Gilead Sciences, Ethan Grant Shareholder of: Gilead Sciences, Employee of: Gilead Sciences, Gundula Min-Oo Shareholder of: Gilead Sciences, Employee of: Gilead Sciences

N-terminal Domain of TDP43 Enhances Liquid-Liquid Phase Separation of Globular Proteins

Liquid-liquid phase separation (LLPS) of proteins is involved in a growing number of cellular processes. Most proteins with LLPS harbor intrinsically disordered regions (IDR), which serve as a guideline to search for cellular proteins that potentially phase separate. Herein, we reveal that oligomerization lowers the barriers for LLPS and could act as a general mechanism to enhance LLPS of proteins domains independent of IDR. Using TDP43 as a model system, we found that deleting its IDR resulted in LLPS that was dependent on the oligomerization of the N-terminal domain (NTD). Replacing TDP43's NTD with other oligomerization domains enhanced the LLPS proportionately to the state of oligomerization. In addition to TDP43, fusing NTD to other globular proteins without known LLPS behavior also drove their phase separation in a manner dependent on oligomerization. Finally, we demonstrate that heterooligomers composed of NTD-fused proteins can be driven into droplets through NTD interactions. Our results potentiate a new paradigm for using oligomerization domains as a signature to systematically identify cellular proteins with LLPS behavior, thus broadening the scope of this exciting research field.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Fetal cardiac findings and hemodynamic changes associated with severe lower urinary tract obstruction in utero

OBJECTIVES

To describe fetal echocardiographic findings associated with lower urinary tract obstruction (LUTO) and to compare anatomic and hemodynamic measurements between fetuses with LUTO and gestational age (GA)-matched controls, with an emphasis on quantitative indices of diastolic function and cardiac output.

METHODS

This was a retrospective cohort study of fetuses diagnosed with severe LUTO with giant bladder, which underwent at least one fetal echocardiogram at our center between January 2005 and June 2018. Fetuses with major congenital heart disease were excluded. Control fetuses did not have any structural or functional abnormalities and were GA-matched to the LUTO fetuses based on the time of the first fetal echocardiogram. Cardiac anatomy and hemodynamic measurements were compared between fetuses with LUTO and controls. In infants with LUTO, serial fetal and postnatal echocardiographic data were assessed, when available, and clinical outcomes were reviewed.

RESULTS

Twenty-six fetuses with LUTO and at least one fetal echocardiogram available were identified, one of which was excluded due to hypoplastic left heart syndrome, leaving 25 LUTO fetuses in the final cohort. The mean GA at the first fetal echocardiogram was 25.4 ± 5.1 weeks in the LUTO group and 25.3 ± 5.0 weeks in the control group. Common findings in fetuses with LUTO included cardiomegaly (40%), pericardial effusion (44%), right ventricular (RV) hypertrophy (64%) and left ventricular (LV) hypertrophy (48%). Compared with GA-matched controls, LUTO fetuses had lower ascending aorta Z-score (-0.10 ± 0.94 vs -0.93 ± 1.03; P = 0.02) and aortic isthmus Z-score (-0.14 ± 0.86 vs -1.62 ± 1.11; P < 0.001), shorter mitral valve inflow time indexed to cardiac cycle length (0.46 ± 0.04 vs 0.41 ± 0.06; P = 0.002), and worse (increased) LV myocardial performance index (0.39 ± 0.03 vs 0.44 ± 0.04; P < 0.001). In addition, the ratio of RV to LV cardiac index was higher in LUTO fetuses compared with controls (1.62 ± 0.13 vs 1.33 ± 0.11; P < 0.001). Of the 25 LUTO pregnancies, two were lost to follow-up, three underwent elective termination of pregnancy and three ended in intrauterine fetal demise. Four (16%) patients had mildly hypoplastic left-heart structures, comprising two with aortic arch hypoplasia and two with mitral and aortic stenosis.

CONCLUSION

In addition to presenting with cardiomegaly, pericardial effusion and ventricular hypertrophy, fetuses with LUTO demonstrate LV diastolic dysfunction and appear to redistribute cardiac output as compared to control fetuses, which may contribute to the development of left-heart hypoplasia. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

The effect of copper sulphate on the growth of the alga Chlorella

• The actions of dilutions and potencies of copper sulphate on the growth of Chlorella were studied in order to determine whether a potency of copper sulphate was beneficial to a culture of Chlorella which had been poisoned by copper sulphate.

• The growth rate of Chlorella in Chu 10 culture medium was greatly reduced by a concentration of copper sulphate of 10−5 Molar (M). Algae grown in Moyse culture medium, which contain 3·2×10−7 M copper sulphate, were less sensitive to copper sulphate. Chlorella whose growth had been inhibited by copper sulphate was, when resuspended in fresh culture medium, more sensitive to further added copper sulphate than normal algae.

• Potencies of copper sulphate prepared in the laboratory, in the concentration range 4c (4×10−8 M) to 15c had no effect on the growth of either normal or poisoned algae.

• Several batches of a 15c potency prepared by A. Nelson & Co., Ltd. increased the rate of growth of both unpoisoned and poisoned algae. These results are attributed to the fact that the batches of potency contained a general growth stimulant, rather than to a stimulatory homœopathic action of the potency itself which would have affected the poisoned algae only.

Abstract P4-13-01: Oncoplastic breast conservations – The Scottish Audit: Surgical techniques, oncological outcomes, complication rates and variations in practice across the country based on the analysis of 589 patients

Introduction: current evidence for oncoplastic breast conservation (OBC) is based on single institutional series. We studied the outcomes of OBC practice in Scotland and compare individual breast units.

Methods: a predefined database of patients treated with OBC was completed retrospectively in 11 breast units in Scotland. Patients were treated with OBC from 2005 onwards were included. For statistical calculations Chi-test, ANOVA and Pearson correlation analysis were used.

Results: Altogether 589 patients were included. Median age was 56 years [21-86]. Patients were diagnosed between September 2005 and March 2017. Number of patients treated with OBC per unit ranged between 4 and 145. High volume units were doing a mean of 19.3 OBCs per year [17.3 – 26.5] vs. low volume units doing 11.1 OBCs per year [7 .7– 14.4] (p=0.012).

23 different oncoplastic surgical techniques were applied. Range of oncoplastic techniques used was associated with case-loads: high volume units used a wider range (8 – 14 different techniques) compared to low volume units (3 – 6) (p=0.004). Volume displacement was done in 515 patients (91.3%), volume replacement in 49 patients (8.7%). OBC was carried out as a joint operation between a breast and a plastic surgeon in 66.3% (389 patients). Immediate contralateral symmetrisation rate was significantly higher when the procedure was carried out as a joint operation (70.7% vs. not joint operations: 29.8%; p&lt;0.001).

Incomplete excision rate was 10.4% (60 of 578). Incomplete excision was significantly higher after invasive lobular carcinoma (18.9%; 10 of 43; p=0.0292). After neoadjuvant chemotherapy incomplete excision rate was significantly lower (3%; 2 of 66 vs. no neoadjuvant chemotherapy: 11%; 35 of 319; p=0.031).

Neodjuvant systemic treatment rate was 28.6% (142 of 496 patients). Of those 68 patients received neoadjuvant chemotherapy (13.7%) and 74 patients had neoadjuvant hormonal treatment (14.9%). Neoadjuvant systemic treatment rate varied amongst the units from 9.7% to 57.2% for patients with invasive carcinoma.

259 patients diagnosed with (non)invasive carcinoma had a median follow-up time of 5 years [35-124]. Of these 7 patients (2.7%) developed isolated local recurrence. 5-year local recurrence rate after DCIS was higher than after pure invasive ductal carcinoma (DCIS: 8.3%; 3 of 36 vs. ductal: 1.6%; 3 of 181; p=0.02567). 5-year disease-free survival of these patients was 91.7%, overall survival was 93.8%, and cancer-specific survival was 96.1%.

145 of 510 patients developed complications, which is 28.4% overall complication rate. 71 patients had major complications (13.9%) and 74 patients had minor complications (14.5%). Overall complication rate was significantly lower after neoadjuvant chemotherapy (15.9%; 11 of 69) compared to patients who did not receive neoadjuvant chemotherapy (27.9%; 127 of 455 patients) (p=0.035).

Conclusion: this national audit demonstrated similar outcomes overall compared to relevant published data. Units should be urged to build stronger collaboration in order to reduce variability in OBC practices.

None of the authors have conflict of interest to declare.

Citation Format: Romics L, Macaskill J, Fernandez T, Morrow E, Simpson L, Pitsinis V, Barber M, Tovey S, Masannat Y, Young O, Mansell J, Stallard S, Doughty J, Dixon M. Oncoplastic breast conservations – The Scottish Audit: Surgical techniques, oncological outcomes, complication rates and variations in practice across the country based on the analysis of 589 patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-13-01.

Randomised clinical study: inulin short-chain fatty acid esters for targeted delivery of short-chain fatty acids to the human colon

BACKGROUND

Short-chain fatty acids (SCFA) produced through fermentation of nondigestible carbohydrates by the gut microbiota are associated with positive metabolic effects. However, well-controlled trials are limited in humans.

AIMS

To develop a methodology to deliver SCFA directly to the colon, and to optimise colonic propionate delivery in humans, to determine its role in appetite regulation and food intake.

METHODS

Inulin SCFA esters were developed and tested as site-specific delivery vehicles for SCFA to the proximal colon. Inulin propionate esters containing 0-61 wt% (IPE-0-IPE-61) propionate were assessed in vitro using batch faecal fermentations. In a randomised, controlled, crossover study, with inulin as control, ad libitum food intake (kcal) was compared after 7 days on IPE-27 or IPE-54 (10 g/day all treatments). Propionate release was determined using (13) C-labelled IPE variants.

RESULTS

In vitro, IPE-27-IPE-54 wt% propionate resulted in a sevenfold increase in propionate production compared with inulin (P < 0.05). In vivo, IPE-27 led to greater (13) C recovery in breath CO2 than IPE-54 (64.9 vs. 24.9%, P = 0.001). IPE-27 also led to a reduction in energy intake during the ad libitum test meal compared with both inulin (439.5 vs. 703.9 kcal, P = 0.025) and IPE-54 (439.5 vs. 659.3 kcal, P = 0.025), whereas IPE-54 was not significantly different from inulin control.

CONCLUSIONS

IPE-27 significantly reduced food intake suggesting colonic propionate plays a role in appetite regulation. Inulin short-chain fatty acid esters provide a novel tool for probing the diet-gut microbiome-host metabolism axis in humans.