The Role of Genetics in Managing Peripheral Arterial Disease.

BACKGROUND: Genome wide association studies (GWAS) have allowed for a rapid increase in our understanding of the underlying genetics and biology of many diseases. By capitalizing on common genetic variation between individuals, GWAS can identify DNA variants associated with diseases of interest. A variety of statistical methods can be applied to GWAS results which allows for risk factor identification, stratification, and to identify potential treatments. Peripheral artery disease (PAD) is a common vascular disease that has been shown to have a strong genetic component. This article provides a review of the modern literature and our current understanding of the role of genetics in PAD. METHODS: All available GWAS studies on PAD were reviewed. A literature search involving these studies was conducted and relevant articles applying the available GWAS data were summarized to provide a comprehensive review of our current understanding of the genetic component in PAD. RESULTS: The largest available GWAS on PAD has identified 19 genome wide significant loci, with factor V Leiden and genes responsible for circulating lipoproteins being implicated in the development of PAD. Mendelian randomization (MR) studies have identified risk factors and causal associations with smoking, diabetes, and obesity and many other traits; protein-based MR has also identified circulating lipid and clotting factor levels associated with the incidence of PAD. Polygenic risk scores may allow for improved prediction of disease incidence and allow for early identification of at-risk patients but more work needs to be done to validate this approach. CONCLUSIONS: Genetic epidemiology has allowed for an increased understanding of PAD in the past decade. Genome-wide association studies have led to improved detection of genetic contributions to PAD, and further genetic analyses have validated risk factors and may provide options for improved screening in at-risk populations. Ongoing biobank studies of chronic limb threatening ischemia patients and the increasing ancestral diversity in biobank enrollment will allow for even further exploration into the pathogenesis and progression of PAD.

Metabolomic profiling and genomic study of a marine sponge-associated Streptomyces sp.

Metabolomics and genomics are two complementary platforms for analyzing an organism as they provide information on the phenotype and genotype, respectively. These two techniques were applied in the dereplication and identification of bioactive compounds from a Streptomyces sp. (SM8) isolated from the sponge Haliclona simulans from Irish waters. Streptomyces strain SM8 extracts showed antibacterial and antifungal activity. NMR analysis of the active fractions proved that hydroxylated saturated fatty acids were the major components present in the antibacterial fractions. Antimycin compounds were initially putatively identified in the antifungal fractions using LC-Orbitrap. Their presence was later confirmed by comparison to a standard. Genomic analysis of Streptomyces sp. SM8 revealed the presence of multiple secondary metabolism gene clusters, including a gene cluster for the biosynthesis of the antifungal antimycin family of compounds. The antimycin gene cluster of Streptomyces sp. SM8 was inactivated by disruption of the antimycin biosynthesis gene antC. Extracts from this mutant strain showed loss of antimycin production and significantly less antifungal activity than the wild-type strain. Three butenolides, 4,10-dihydroxy-10-methyl-dodec-2-en-1,4-olide (1), 4,11-dihydroxy-10-methyl-dodec-2-en-1,4-olide (2), and 4-hydroxy-10-methyl-11-oxo-dodec-2-en-1,4-olide (3) that had previously been reported from marine Streptomyces species were also isolated from SM8. Comparison of the extracts of Streptomyces strain SM8 and its host sponge, H. simulans, using LC-Orbitrap revealed the presence of metabolites common to both extracts, providing direct evidence linking sponge metabolites to a specific microbial symbiont.

Differential Effects of HDAC6 Inhibition Versus Knockout During Hepatic Ischemia-Reperfusion Injury Highlight Importance of HDAC6 C-terminal Zinc-finger Ubiquitin-binding Domain.

BACKGROUND: Ischemia-reperfusion injury (IRI) causes significant morbidity in liver transplantation among other medical conditions. IRI following liver transplantation contributes to poor outcomes and early graft loss. Histone/protein deacetylases (HDACs) regulate diverse cellular processes, play a role in mediating tissue responses to IRI, and may represent a novel therapeutic target in preventing IRI in liver transplantation. METHODS: Using a previously described standardized model of murine liver warm IRI, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were assessed at 24 and 48 h after reperfusion to determine the effect of different HDAC inhibitors. RESULTS: Broad HDAC inhibition with trichostatin-A (TSA) was protective against hepatocellular damage ( P  < 0.01 for AST and P  < 0.05 for ALT). Although HDAC class I inhibition with MS-275 provided statistically insignificant benefit, tubastatin-A (TubA), an HDAC6 inhibitor with additional activity against HDAC10, provided significant protection against liver IRI ( P  < 0.01 for AST and P  < 0.001 for ALT). Surprisingly genetic deletion of HDAC6 or -10 did not replicate the protective effects of HDAC6 inhibition with TubA, whereas treatment with an HDAC6 BUZ-domain inhibitor, LakZnFD, eliminated the protective effect of TubA treatment in liver ischemia ( P  < 0.01 for AST and P  < 0.01 for ALT). CONCLUSIONS: Our findings suggest TubA, a class IIb HDAC inhibitor, can mitigate hepatic IRI in a manner distinct from previously described class I HDAC inhibition and requires the HDAC6 BUZ-domain activity. Our data corroborate previous findings that HDAC targets for therapeutic intervention of IRI may be tissue-specific, and identify HDAC6 inhibition as a possible target in the treatment of liver IRI.

The Selective Estrogen Receptor Modulator, Raloxifene, Is Protective Against Renal Ischemia-reperfusion Injury.

BACKGROUND: There is increasing evidence that estrogen is responsible for improved outcomes in female kidney transplant recipients. Although the exact mechanism is not yet known, estrogen appears to exert its protective effects by ameliorating ischemia-reperfusion injury (IRI). In this study, we have examined whether the beneficial effects of exogenous estrogen in renal IRI are replicated by therapy with any one of several selective estrogen receptor modulators. METHODS: C57BL/6 adult mice underwent standardized warm renal ischemia for 28 min after being injected with the selective estrogen receptor modulators, raloxifene, lasofoxifene, tamoxifen, bazedoxifene, or control vehicle (dimethyl sulfoxide), at 16 and 1 h before IRI. Plasma concentrations of blood urea nitrogen and creatinine were assessed 24, 48, 72, and 96 h post-IRI. Tissue was collected 30 d postischemia for fibrosis analysis using Sirius Red staining. RESULTS: Raloxifene treatment in female mice resulted in significantly lower blood urea nitrogen and creatinine after IRI and significantly lower fibrosis 30 d following IRI. CONCLUSIONS: Raloxifene is protective against both acute kidney injury and fibrosis resulting from renal IRI in a mouse model.

An On-Chip Liquid Metal Plug Generator.

Gallium-based liquid metal nonspherical droplets (plugs) have seen increasing demand recently mainly because their high aspect ratios make them beneficial for a wide range of applications, including microelectromechanical systems (MEMS), microfluidics, sensor technology, radio-frequency devices, actuators, and switches. However, reproducibility of the generation of such plugs, as well as precise control over their size, is yet challenging. In this work, a simple on-chip liquid metal plug generator using a commercially available 3D microprinter is presented and the plug generator in poly(dimethylsiloxane) is replicated via soft lithography. Liquid metal plugs are generated via a combination of electrochemical oxidation, design of well-defined constrictions based on Laplace pressure, and the application of modulated voltage control signals. It is shown that plugs of various aspect ratios can be generated reproducibly for channel widths of 0.5, 0.8, and 1.5 mm with constriction widths of 0.1 mm at 6 V. Laplace-pressure-controlled plugs in constricted channels are compared to modulated-voltage-generated plugs in straight channels showing that this technique provides significantly enhanced reproducibility and control over the size and spacing between the plugs. This work paves the way to sub-millimeter liquid metal plugs generated directly on-chip for on-demand MEMS and microfluidic applications.

HDAC2 targeting stabilizes the CoREST complex in renal tubular cells and protects against renal ischemia/reperfusion injury.

Histone/protein deacetylases (HDAC) 1 and 2 are typically viewed as structurally and functionally similar enzymes present within various co-regulatory complexes. We tested differential effects of these isoforms in renal ischemia reperfusion injury (IRI) using inducible knockout mice and found no significant change in ischemic tolerance with HDAC1 deletion, but mitigation of ischemic injury with HDAC2 deletion. Restriction of HDAC2 deletion to the kidney via transplantation or PAX8-controlled proximal renal tubule-specific Cre resulted in renal IRI protection. Pharmacologic inhibition of HDAC2 increased histone acetylation in the kidney but did not extend renal protection. Protein analysis demonstrated increased HDAC1-associated CoREST protein in HDAC2-/- versus WT cells, suggesting that in the absence of HDAC2, increased CoREST complex occupancy of HDAC1 can stabilize this complex. In vivo administration of a CoREST inhibitor exacerbated renal injury in WT mice and eliminated the benefit of HDAC2 deletion. Gene expression analysis of endothelin showed decreased endothelin levels in HDAC2 deletion. These data demonstrate that contrasting effects of HDAC1 and 2 on CoREST complex stability within renal tubules can affect outcomes of renal IRI and implicate endothelin as a potential downstream mediator.

Accessibility of Primary, Specialist, and Allied Health Services for Aboriginal People Living in Rural and Remote Communities: Protocol for a Mixed-Methods Study.

BACKGROUND: Primary, specialist, and allied health services can assist in providing equitable access in rural and remote areas, where higher proportions of Aboriginal and Torres Strait Islander people (Aboriginal Australians) reside, to overcome the high rates of chronic diseases experienced by this population group. Little is currently known about the location and frequency of services and the extent to which providers believe delivery is occurring in a sustained and coordinated manner. OBJECTIVE: The objective of this study will be to determine the availability, accessibility, and level of coordination of a range of community-based health care services to Aboriginal people and identify potential barriers in accessing health care services from the perspectives of the health service providers. METHODS: This mixed-methods study will take place in 3 deidentified communities in New South Wales selected for their high population of Aboriginal people and geographical representation of location type (coastal, rural, and border). The study is designed and will be conducted in collaboration with the communities, Aboriginal Community Controlled Health Services (ACCHSs), and other local health services. Data collection will involve face-to-face and telephone interviews with participants who are health and community professionals and stakeholders. Participants will be recruited through snowball sampling and will answer structured, quantitative questions about the availability and accessibility of primary health care, specialist medical and allied health services and qualitative questions about accessing services. Quantitative data analysis will determine the frequency and accessibility of specific services across each community. Thematic and content analysis will identify issues relating to availability, accessibility, and coordination arising from the qualitative data. We will then combine the quantitative and qualitative data using a health ecosystems approach. RESULTS: We identified 28 stakeholder participants across the ACCHSs for recruitment through snowball sampling (coastal, n=4; rural, n=12; and border, n=12) for data collection. The project was funded in 2017, and enrolment was completed in 2017. Data analysis is currently under way, and the first results are expected to be submitted for publication in 2019. CONCLUSIONS: The study will give an indication of the scope and level of coordination of primary, specialist, and allied health services in rural communities with high Aboriginal populations from the perspectives of service providers from those communities. Identification of factors affecting the availability, accessibility, and coordination of services can assist ways of developing and implementing culturally sensitive service delivery. These findings could inform recommendations for the provision of health services for Aboriginal people in rural and remote settings. The study will also contribute to the broader literature of rural and remote health service provision. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/11471.

Data linkage in medical science using the resource description framework: the AVERT model.

There is an ongoing challenge as to how best manage and understand 'big data' in precision medicine settings. This paper describes the potential for a Linked Data approach, using a Resource Description Framework (RDF) model, to combine multiple datasets with temporal and spatial elements of varying dimensionality. This "AVERT model" provides a framework for converting multiple standalone files of various formats, from both clinical and environmental settings, into a single data source. This data source can thereafter be queried effectively, shared with outside parties, more easily understood by multiple stakeholders using standardized vocabularies, incorporating provenance metadata and supporting temporo-spatial reasoning. The approach has further advantages in terms of data sharing, security and subsequent analysis. We use a case study relating to anti-Glomerular Basement Membrane (GBM) disease, a rare autoimmune condition, to illustrate a technical proof of concept for the AVERT model.

Centrifugal pumps and hemolysis in pediatric extracorporeal membrane oxygenation (ECMO) patients: An analysis of Extracorporeal Life Support Organization (ELSO) registry data.

PURPOSE: It is currently unclear whether centrifugal pumps cause more hemolysis than roller pumps in extracorporeal membrane oxygenation (ECMO) circuits. The aim of this study was to help answer that question in pediatric patients. METHODS: A limited deidentified data set was extracted from the international multicenter Extracorporeal Life Support Organization (ELSO) registry comprising all reported ECMO runs for patients 18years or younger between 2010 and 2015. Logistic regression was used to evaluate a possible association between hemolysis and pump type, controlling for patient demographics, circuit factors, and complications. RESULTS: 14,776 ECMO runs for 14,026 patients had pump type recorded. Centrifugal pumps were employed in 60.4% of ECMO circuits. Hemolysis was a reported complication for 1272 (14%) centrifugal pump runs and for 291 (5%) roller pump runs. 1755 (20%) centrifugal pump runs reported kidney injury as compared to 797 (14%) roller pump runs. In the full logistic regression, the odds of hemolysis were significantly greater for runs using centrifugal pumps (OR 3.3, 95% CI 2.9-3.8, p<0.001). CONCLUSIONS: In this retrospective analysis of a large international data set, the use of centrifugal pumps was associated with increased rates of hemolysis, hyperbilirubinemia, and kidney injury. TYPE OF STUDY: Retrospective cohort study. LEVEL OF EVIDENCE: Level III.

Ganglioglioma with anaplastic recurrence of the neuronal element following radiotherapy.

Gangliogliomas are rare tumours in adults representing between 0.5% and 1% of all neuroepithelial tumours. They are of mixed cellularity comprised both of a neuronal and a glial population. Although malignant transformation is rare, and this mostly occurs in the glial element, we present a case of malignant neuroblastomatous transformation of a ganglioglioma. This is only the second ever case to our knowledge in the literature reporting the participation of the neuronal element in the malignant transformation of a ganglioglioma. In contrast with the previous published case, our patient has received post-operative therapeutic radiotherapy. The related literature is reviewed and the oncogenic role of therapeutic irradiation is discussed.

Evidence for plasmid-mediated salt tolerance in the human gut microbiome and potential mechanisms.

The human gut microbiome is critical to health and wellbeing. It hosts a complex ecosystem comprising a multitude of bacterial species, which contributes functionality that would otherwise be absent from the host. Transient and commensal bacteria in the gut must withstand many stresses. The influence of mobile genetic elements such as plasmids in stress adaptation within the ecosystem is poorly understood. Using a mobilomic approach we found evidence for plasmid-mediated osmotolerance as a phenotype amongst the Proteobacteria in healthy faecal slurries. A transconjugant carrying multiple plasmids acquired from healthy faecal slurry demonstrated increased osmotolerance in the presence of metal salts, particularly potassium chloride, which was not evident in the recipient. Pyrosequencing and analysis of the total plasmid DNA demonstrated the presence of plasmid-borne osmotolerance systems (including KdpD and H-NS) which may be linked to the observed phenotype. This is the first report of a transferable osmotolerance phenotype in gut commensals and may have implications for the transfer of osmotolerance in other niches.

Transferring the blues: Depression-associated gut microbiota induces neurobehavioural changes in the rat.

The gut microbiota interacts with the host via neuroimmune, neuroendocrine and neural pathways. These pathways are components of the brain-gut-microbiota axis and preclinical evidence suggests that the microbiota can recruit this bidirectional communication system to modulate brain development, function and behaviour. The pathophysiology of depression involves neuroimmune-neuroendocrine dysregulation. However, the extent to which changes in gut microbiota composition and function mediate the dysregulation of these pathways is unknown. Thirty four patients with major depression and 33 matched healthy controls were recruited. Cytokines, CRP, Salivary Cortisol and plasma Lipopolysaccharide binding protein were determined by ELISA. Plasma tryptophan and kynurenine were determined by HPLC. Fecal samples were collected for 16s rRNA sequencing. A Fecal Microbiota transplantation was prepared from a sub group of depressed patients and controls and transferred by oral gavage to a microbiota-deficient rat model. We demonstrate that depression is associated with decreased gut microbiota richness and diversity. Fecal microbiota transplantation from depressed patients to microbiota-depleted rats can induce behavioural and physiological features characteristic of depression in the recipient animals, including anhedonia and anxiety-like behaviours, as well as alterations in tryptophan metabolism. This suggests that the gut microbiota may play a causal role in the development of features of depression and may provide a tractable target in the treatment and prevention of this disorder.

Opportunistic screening to detect atrial fibrillation in Aboriginal adults in Australia.

INTRODUCTION: There is a 10-year gap in life expectancy between Aboriginal and non-Aboriginal Australians. The leading cause of death for Aboriginal Australians is cardiovascular disease, including myocardial infarction and stroke. Although atrial fibrillation (AF) is a known precursor to stroke there are no published studies about the prevalence of AF for Aboriginal people and limited evidence about AF in indigenous populations globally. METHODS AND ANALYSIS: This mixed methods study will recruit and train Aboriginal health workers to use an iECG device attached to a smartphone to consecutively screen 1500 Aboriginal people aged 45 years and older. The study will quantify the proportion of people who presented for follow-up assessment and/or treatment following a non-normal screening and then estimate the prevalence and age distribution of AF of the Australian Aboriginal population. The study includes semistructured interviews with the Aboriginal health workers about the effectiveness of the iECG device in their practice as well as their perceptions of the acceptability of the device for their patients. Thematic analysis will be undertaken on the qualitative data collected in the study. If the device and approach are acceptable to the Aboriginal people and widely adopted, it may help prevent the effects of untreated AF including ischaemic stroke and early deaths or impairment in Aboriginal people. ETHICS AND DISSEMINATION: This mixed methods study received ethics approval from the Aboriginal Health and Medical Research Council (1135/15) and the Australian Health Council of Western Australia (HREC706). Ethics approval is being sought in the Northern Territory. The findings of this study will be shared with Aboriginal communities, in peer reviewed publications and at conferences. There are Aboriginal investigators in each state/territory where the study is being conducted who have been actively involved in the study. They will also be involved in data analysis, dissemination and research translation. TRIAL REGISTRATION NUMBER: ACTRN12616000459426.

Submandibular schwannoma: is excision a 'gold standard treatment'?

A 58-year-old man was referred to ear, nose and throat (ENT) with an 8-week history of painless right submandibular swelling with no history of weight loss, dysphagia or difficulty with mastication. On examination, there was enlargement of the right submandibular gland, which was diffuse, nodular and firm; but no calcification of the duct or cervical lymphadenopathy. ENT examination including fibreoptic laryngoscopy was normal. Fine-needle aspiration of the lump was inconclusive. Neck ultrasound scan showed a well-defined 3 cm × 3.8 cm × 4.3 cm heterogeneous mass with significant internal vascularity, anterior to the right submandibular gland. MRI (T2-weighted MRI) revealed a neurogenic tumour or a non-sarcomatous soft tissue lesion. Complete excision of the lump was performed by intracapsular dissection and the specimen was submitted for histology, which confirmed the diagnosis of 'Ancient schwannoma' of the submandibular gland. The management resulted in complete resolution of symptoms with no cranial nerve deficits.

Eosinophilic granuloma: resolution of maxillofacial bony lesions following minimal intervention. Report of three cases and a review of the literature.

INTRODUCTION: Langerhans' cell histiocytosis is a collective term used to describe a group of enigmatic proliferative disorders. The natural history of the disease varies from a slow, benign, localized symptomatic bony or soft tissue lesion, to a rapidly progressive widespread multiple organ disorder which is often fatal. Eosinophilic granuloma accounts for 60-70% of all cases of Langerhans' cell histiocytosis and can present as solitary (50-75%) or multifocal defects in bone. It occasionally presents as a localized soft tissue lesion. There are multiple treatment options but the response is unpredictable. AIMS: We present three separate cases, of the maxillofacial skeleton where the lesions of eosinophilic granuloma resolved following incisional biopsy only. PATIENTS AND RESULTS: Three patients presented with solitary lesions of the maxillofacial skeleton. All were diagnosed as Langerhans' cell histiocytosis following open curettage, which also resulted in resolution of the lesions. Follow-up has thus far been disease free. CONCLUSION: For some solitary Langerhans' cell histiocytosis lesions, simple curettage is the only treatment required. The paper discusses the need to confirm the solitary nature of the disease and the need for follow-up. Reviewing the literature on the disease, the authors suggest that perhaps cellular immaturity holds the cells of the lesion in a disease state until pushed to maturity by the trauma of open curettage surgery, resulting in a complete resolution of the disease.

Effects of gastrogastric fistula repair on weight loss and gut hormone levels.

BACKGROUND: Weight regain after gastric bypass (GBP) can be associated with a gastrogastric fistula (GGF), in which a channel forms between the gastric pouch and gastric remnant, allowing nutrients to pass through the "old route" rather than bypassing the duodenum. To further understand the mechanisms by which GGF may lead to weight regain, we investigated gut hormone levels in GBP patients with a GGF, before and after repair. MATERIALS AND METHODS: Seven post-GBP subjects diagnosed with GGF were studied before and 4 months after GGF repair. Another cohort of 22 GBP control subjects without GGF complication were studied before and 1 year post-GBP. All subjects underwent a 50-g oral glucose tolerance test and blood was collected from 0-120 min for glucose, insulin, ghrelin, PYY3-36, GIP, and GLP-1 levels. RESULTS: Four months after GGF repair subjects lost 6.0 ± 3.9 kg and had significantly increased postprandial PYY3-36 levels. After GGF repair, fasting and postprandial ghrelin levels decreased and were strongly correlated with weight loss. The insulin response to glucose also tended to be increased after GGF repair, however no concomitant increase in GLP-1 was observed. Compared to the post-GBP group, GLP-1 and PYY3-36 levels were significantly lower before GGF repair; however, after GGF repair, PYY3-36 levels were no longer lower than the post-GBP group. CONCLUSIONS: These data utilize the GGF model to highlight the possible role of duodenal shunting as a mechanism of sustained weight loss after GBP, and lend support to the potential link between blunted satiety peptide release and weight regain.

The clinical impact of expert pathological review on lymphoma management: a regional experience.

The All Wales Lymphoma Panel (AWLP) was established in January 1998 to provide a central expert pathological review service for district general hospital pathologists. A discordance rate of 20% between the submitted and reviewed diagnosis has previously been identified. It has not been known whether this change in diagnosis affects clinical management. Ninety-nine patients whose diagnosis was changed as a result of central pathological review are presented. Between January 1998 and August 2000, 125 of 745 (17%) specimens submitted for AWLP review had a consequent change in pathological diagnosis. Of these 125 specimens, 99 (79%) complete case notes were recovered. In all 99 cases, a hypothetical management plan was generated using collected data, clinical protocols and the submitted pathological diagnosis. These plans were compared with the actual management patients received based on the reviewed diagnosis proffered by the AWLP. Forty-six of 99 (46%) cases had a change in management as a result of central pathological review. Overall, management was changed in 8% of cases referred for central pathological review. In conclusion, expert central pathological review has a direct effect on patient management.