The Human Gut Microbiota: A Dynamic Biologic Factory

The human body constitutes a living environment for trillions of microorganisms, which establish the microbiome and, the largest population among them, reside within the gastrointestinal tract, establishing the gut microbiota. The term "gut microbiota" refers to a set of many microorganisms [mainly bacteria], which live symbiotically within the human host. The term "microbiome" means the collective genomic content of these microorganisms. The number of bacterial cells within the gut microbiota exceeds the host's cells; collectively and their genes quantitatively surpass the host's genes. Immense scientific research into the nature and function of the gut microbiota is unraveling its roles in certain human health activities such as metabolic, physiology, and immune activities and also in pathologic states and diseases. Interestingly, the microbiota, a dynamic ecosystem, inhabits a particular environment such as the human mouth or gut. Human microbiota can evolve and even adapt to the host's unique features such as eating habits, genetic makeup, underlying diseases, and even personalized habits. In the past decade, biologists and bioinformaticians have concentrated their research effort on the potential roles of the gut microbiome in the development of human diseases, particularly immune-mediated diseases and colorectal cancer, and have initiated the assessment of the impact of the gut microbiome on the host genome. In the present chapter, we focus on the biological features of gut microbiota, its physiology as a biological factory, and its impacts on the host's health and disease status.

Public health and medical preparedness for mass casualties from the deliberate release of synthetic opioids

The large amounts of opioids and the emergence of increasingly potent illicitly manufactured synthetic opioids circulating in the unregulated drug supply in North America and Europe are fueling not only the ongoing public health crisis of overdose deaths but also raise the risk of another type of disaster: deliberate opioid release with the intention to cause mass harm. Synthetic opioids are highly potent, rapidly acting, can cause fatal ventilatory depression, are widely available, and have the potential to be disseminated for mass exposure, for example, if effectively formulated, via inhalation or ingestion. As in many other chemical incidents, the health consequences of a deliberate release of synthetic opioid would manifest quickly, within minutes. Such an incident is unlikely, but the consequences could be grave. Awareness of the risk of this type of incident and preparedness to respond are required to save lives and reduce illness. Coordinated planning across the entire local community emergency response system is also critical. The ability to rapidly recognize the opioid toxidrome, education on personal protective actions, and training in medical management of individuals experiencing an opioid overdose are key components of preparedness for an opioid mass casualty incident.

Real-world comparison of the last generation balloon-expandable and self-expanding valves in patients undergoing TAVI

Background/Introduction

The balloon expandable (BE) Edwards Sapien-S3/Ultra, and the self-expanding (SE) Medtronic Evolut-Pro represent the main volume of transcatheter aortic valve implantation (TAVI) procedures conducted worldwide.

Purpose

The present study represents the largest real-world comparison of periprocedural and short-term outcome between the aforementioned last generation devices.

Methods

Consecutive patients who had undergone TAVI with either the BE (S3/Ultra) or SE (Evolut-Pro/R-34mm if 34mm valve was required) device, in five centers were retrospectively studied. Periprocedural and short-term outcomes were recorded and compared.

Results

In total, 1341 patients (58.5% male) were treated with contemporary BE and SE valves (574 and 767pts with BE and SE respectively) and followed up for a median of 18.7 (IQR 30) months. Baseline demographics were similar between the two groups apart from severe left ventricle (LV) systolic impairment and extensive aorta calcification, being more prevalent amongst BE and SE groups respectively. Patients treated with the Evolut-Pro/R34mm device had significantly lower peak (16±9mmHg for SE vs 23.9±6mmHg for the BE valves, p=0.001) and mean (8.6±6mmHg SE vs 11.2±5.2mmHg BE, p=0.001) gradients at discharge.

Conversely, the BE group demonstrated significantly lower rates of at least moderate residual aortic regurgitation (AR) post-operatively (0.7% vs 5.2% for BE and SE valves respectively, p<0.001). Interestingly, the rate of new permanent pacemaker (PPM) required after the implantation in initially pacemaker-free patients, was higher for the S3/Ultra cohort compared to the self-expanding valve group (14.4% vs 12.3% respectively, p=0.001). No statistical difference was recorded between valve groups regarding cerebrovascular events (3.4% vs. 2.7% for SE and BE respectively, p=0.466), major vascular complications (4.2% vs. 3.0% for SE and BE respectively, p=0.251) and death to hospital discharge (1.6% vs. 2.9% for SE and BE respectively, p=0.117).

One-year Kaplan-Meier estimated survival was similar between the two groups (88.7% for BE vs. 91.4% for SE valves, plog-rank=0.093). When adjusting for age, extensive calcification of the aorta and baseline LV function all caused mortality hazard ratios were similar between patients treated with BE vs SE valves (HR 1.39; 95% CI 0.97 to 1.98, p=0.07).

Conclusions

Real life comparison of the last generation balloon expandable and self-expanding devices demonstrates superiority of the former in terms of residual PVL, at the expense of higher transvalvular gradients and higher need of new PPM implantation. The latter however may represent differences in center practices with regards to thresholds for permanent pacing. Long-term follow-up and future larger trials are required to establish any potential long-term difference in clinical outcomes and prognosis.

Funding Acknowledgement

Type of funding sources: None.

Real-world comparison of the last generation main balloon-expandable and self-expanding valves in patients undergoing TAVI. Does the type matter?

Background/Introduction

The balloon expandable Edwards Sapien-S3 and Ultra, and the self-expanding Medtronic Evolut-Pro and Evolut-R 34mm represent the main volume of transcatheter aortic valve implantation (TAVI) procedures conducted worldwide.

Purpose

In the present study, we aim to compare the peri-procedural and one-year clinical outcomes between these last generation devices.

Methods

Consecutive patients from the ATLAS (Athens-Tokyo-London Aortic Stenosis) registry, who had undergone TAVI with either the S3/Ultra or Evolut-Pro/R 34mm device, in four centers were retrospectively studied. In-hospital procedural characteristics and outcomes were recorded and compared. Kaplan-Meier estimated 1-year all-cause mortality was compared between groups.

Results

In total, 692 patients (352pts treated with S3/Ultra and 340pts with Evolut-Pro/R34mm device) were included in the analysis. Baseline demographics (age, coronary artery disease risk factors, logistic Euroscore and aortic valve hemodynamics) were similar between the two groups.

In terms of peri-procedural and short-term outcomes, patients treated with the Evolut-Pro/R34mm device had significantly lower peak (25.4±3.6mmHg for S3/Ultra vs 14.9±0.6mmHg for the self-expanding valves, p=0.002) and mean (10.7±0.3mmHg S3/Ultra vs 7.9±0.4mmHg Evolut PRO/R34, p<0.001) gradients at discharge.

Conversely, the S3 demonstrated significantly lower rates of at least moderate residual aortic regurgitation (AR) post-operatively (0.3% vs 4.8% for S3 and Evolut-Pro/R34mm respectively, p=0.001). Interestingly, the rate of new permanent pacemaker (PPM) required after the implantation in pacemaker-free patients on baseline, was higher for the S3/Ultra cohort compared to the self-expanding valve group (17.6% vs 11.7% respectively, p=0.054), however not reaching statistical significance yet. As expected, the need for balloon post dilatation of the implanted prosthesis was less among the S3/Ultra patients (5.5% vs 26.1%, p=0.001).

One-year Kaplan-Meier estimated survival was similar between the two groups (85.9% for S3 vs. 90% for Evolut-Pro/R34mm, plog-rank=0.071). Hazard ratio for all-cause mortality (Pro/R34 vs. S3/Ultra) after adjustment for gender and previous MI was similar between the groups (HR=0.73; 95% CI 0.47 to 1.14, p=0.165).

Conclusions

Real life comparison of the last generation balloon expandable and self-expanding devices demonstrates similar 1-year all-cause mortality. The S3/Ultra platforms, as compared to the Evolut-Pro/R34mm, demonstrate less paravalvular leak, at the expense of higher transvalvular gradients. Long-term follow-up and future larger trials are required to establish any potential long-term difference in clinical outcomes and prognosis.

Funding Acknowledgement

Type of funding source: None

P5385Development and preclinical testing of upscaled engineered heart tissue for use in translational studies

Introduction

The lack of efficacy of stem cell therapy for the treatment of heart failure may be related to the poor retention rates offered by existing delivery methods (intra-coronary/ intramyocardial). Tissue engineering strategies improve cell retention in small animal models but data regarding engineered heart tissue (EHT) patches large enough for human studies are lacking.

Purpose

To upscale EHT to a clinically relevant size and mature the patch in-vitro. Once matured to undergo preclinical testing in a rabbit model of myocardial infarction.

Methods

We developed an upscaled EHT patch (3cm x 2cm x 1.5mm) able to contain up to 50 million human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CM; Fig A/B). Myocardial infarction model was performed by permanent ligation.

Results

The patches began to beat spontaneously within 3 days of fabrication and after 28 days of dynamic culture (Late EHTs) showed the development of several mature characteristics when compared to early patches (<14 days from fabrication). For example, late EHTs contained hiPSC-CMs which were more aligned (hiPSC-CM accumulative angle change: early 2702±778 degrees [n=4] vs late 922±186 [n=5], p=0.042); showed better contraction kinetics (early peak contraction amplitude 87.9±5.8a.u. versus late 952±304a.u.; p<0.001) and faster calcium transients (time to peak: early 200.8±8.8ms [n=5] vs late 147.7±10.2ms [n=6], p=0.004; time to 75% decay: early 274±9.7ms vs late 219.9±2.7ms, p=0.0003).

We then tested the EHT patch in-vivo using a rabbit model (Fig C). Patches were applied to normal (n=5) or infarcted hearts (n=8). Sham operations used non-cellular fibrin patches (n=5). The mean fraction of troponin positive cells in the graft was 27.8±10.3% at 25.2±1.7 days relative to day 0 [n=5] and KU80 (human specific marker) staining confirmed that this was of human origin. CD31 (Fig D) and KU80 staining revealed that the grafts were well vascularized and that the vasculature was not human in origin (therefore were originating from the host). Ex-vivo optical mapping revealed evidence of electrical coupling between the graft and host at 2 weeks and preliminary experiments indicated that the patch improved left ventricular function when grafted onto infarcted hearts. Telemetry recordings in vivo and arrhythmia provocation protocols (ex vivo) indicated that the patch was not proarrhythmic.

Figure 1. A/B) EHT Images; C) 20x troponin T (brown) of rabbit myocardium/EHT (2 weeks after grafting), blue counterstain = haematoxylin, red lines = EHT borders; D) 63x CD31 staining (brown) rabbit/EHT border zone (2 weeks after grafting), blue stain = haematoxylin, red lines = graft/host border zones.

Conclusion

We successfully upscaled hiPSC-CM derived EHT to a clinically relevant size and demonstrated feasibility and integration using a rabbit model of myocardial infarction. Tissue engineering strategies may be the preferred modality of cell delivery for future cardiac regenerative medicine studies.

Phosphoproteomic analysis reveals compensatory effects in the piriform cortex of VX nerve agent exposed rats

To gain insights into the toxicity induced by the nerve agent VX, an MS-based phosphoproteomic analysis was carried out on the piriform cortex region of brains from VX-treated rats. Using isobaric tag based TMT labeling followed by titanium dioxide enrichment strategy, we identified 9975 unique phosphosites derived from 3287 phosphoproteins. Temporal changes in the phosphorylation status of peptides were observed over a time period of 24 h in rats exposed to a 1× LD50, intravenous (i.v.) dose with the most notable changes occurring at the 1 h postexposure time point. Five major functional classes of proteins exhibited changes in their phosphorylation status: (i) ion channels/transporters, including ATPases, (ii) kinases/phosphatases, (iii) GTPases, (iv) structural proteins, and (v) transcriptional regulatory proteins. This study is the first quantitative phosphoproteomic analysis of VX toxicity in the brain. Understanding the toxicity and compensatory signaling mechanisms will improve the understanding of the complex toxicity of VX in the brain and aid in the elucidation of novel molecular targets that would be important for development of improved countermeasures. All MS data have been deposited in the ProteomeXchange with identifier PXD001184 (http://proteomecentral.proteomexchange.org/dataset/PXD001184).

Workplace injury data reported by occupational physicians and general practitioners

BACKGROUND

Accurate workplace injury data are useful in the prioritization of prevention strategies. In the UK, physicians report workplace ill-health data within The Health and Occupation Research (THOR) network, including injury case reports.

AIMS

To compare workplace injury data reported by occupational physicians (OPs) and general practitioners (GPs) to THOR.

METHODS

Injury cases reported by OPs and GPs, reported to THOR between 2006 and 2012 were analysed. Demographics, industrial groups, nature of injury, kind of accident and site of injury were compared. Data on sickness absence for workplace injuries reported by GPs were investigated.

RESULTS

In total, 2017 workplace injury cases were reported by OPs and GPs. Males were more likely to sustain a workplace accident than females. Sprains and strains were reported most often, with the upper limbs being affected most frequently. Slips, trips and falls were identified as important causal factors by both OPs and GPs. Psychological injuries also featured in THOR reporting, with a higher proportion reported by OPs (21%) than by GPs (3%). The proportion of people classified as 'unfit' by GPs reduced following the introduction of the 'fit' note.

CONCLUSIONS

THOR reports returned by OPs and GPs provide a valuable source of information of workplace injury data, and complement other sources of information, such as the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations and the Labour Force Survey.

LSN MS guidelines for the management of multiple sclerosis

OBJECTIVE

The prevalence of multiple sclerosis (MS) in Lebanon is unknown, as there are no available or reliable epidemiological studies to date. The circumstances of Middle East countries are different from those of Europe and North America in terms of differential diagnoses and disease management. The aim of the conference is to establish guidelines for diagnosis, treatment, follow-up and management of patients with MS in Lebanon. Another objective is to discuss and participate in research projects based on epidemiology, clinical trials and more fundamental aspects of the disease in the future.

METHODS

Under the authority of the Lebanese Society of Neurology (LSN), a group of neurologists took the initiative to participate in this LSN MS committee with the purpose of establishing a consensus for the management of patients with MS, and under the supervision of a Coordinator (A.T.) designed by the LSN board.

RESULTS

Diagnostic and therapeutic, follow-up and research recommendations were proposed with special emphasis on the specific needs and circumstances of Lebanon. The experts highlighted the importance of considering particular needs, the identification of patients at high risk of developing MS in order to maximize therapeutic opportunities, and cost-effective control of treatment efficacy, as well as global assessment of disability.

CONCLUSIONS

The experts established guidelines concerning diagnosis, treatment, and follow-up of patients with MS in Lebanon. Furthermore, they recommended some clinical and fundamental research projects.

Early neurologic complications following coronary bypass surgery

BACKGROUND

Coronary artery bypass surgery is associated with central and peripheral nervous system complications in the period following surgery. Recognising these complications may help in their prevention or early treatment.

METHODS

We reviewed medical records of all the patients who underwent coronary artery bypass surgery at our institution over a period of two years. We studied their risk factors, reasons for surgery, operative variables, and post operative neurologic complications.

RESULTS

Of the 587 coronary artery bypass surgeries performed at our centre over a two year period. We found that 2.04% of these patients developed neurologic complication in the two weeks following the surgery. Fifty percent of these patients suffered from cerebrovascular insults and 50% suffered from cognitive decline. No patients in this group developed seizures or peripheral nerve lesions. Patients with renal failure, carotid stenosis, history of cerebral strokes, and redo coronary bypass surgery were more predisposed to develop neurologic complications after bypass surgery. Furthermore, a longer stay in the coronary care unit and the development of arrhythmias predisposed patients to neurologic complications. Mortality for patients who developed neurologic complications post bypass surgery ranged between 16.7% and 33.4%.

CONCLUSIONS

Around 2% of patients who undergo coronary artery bypass surgery develop neurologic complications in the period directly after the surgery. Patients with previous history of cerebral, coronary, or carotid disease are more predisposed for such complications, as well as patients who spend more time in the intensive units after the surgery.