A protective role of ABCA5 in response to elevated sphingomyelin levels in Parkinson's disease

Parkinson's disease (PD) is a chronic neurodegenerative disorder that affects the motor system. Increasing evidence indicates that lysosomal dysfunction is pivotal in the pathogenesis of PD, typically characterized by dysregulation of sphingolipids in lysosomes. ATP-binding cassette subfamily A member 5 (ABCA5) is a lysosomal transporter that mediates the removal of excess sphingomyelin from lysosomes. We therefore investigated whether the expression levels of ABCA5 are associated with sphingomyelin levels and α-synuclein pathology in PD. Firstly, we undertook a comprehensive assessment of the six sphingolipid classes that are part of the lysosomal salvage pathway in the disease-affected amygdala and disease-unaffected visual cortex using liquid chromatography-mass spectrometry. We found that sphingomyelin levels were significantly increased in PD compared to controls and correlated with disease duration only in the amygdala, whereas, the five other sphingolipid classes were slightly altered or unaltered. Concomitantly, the expression of ABCA5 was upregulated in the PD amygdala compared to controls and correlated strongly with sphingomyelin levels. Using neuronal cells, we further verified that the expression of ABCA5 was dependent on cellular levels of sphingomyelin. Interestingly, sphingomyelin levels were strongly associated with α-synuclein in the amygdala and were related to α-synuclein expression. Finally, we revealed that sphingomyelin levels were also increased in PD plasma compared to controls, and that five identical sphingomyelin species were increased in both the brain and the plasma. When put together, these results suggest that in regions accumulating α-synuclein in PD, ABCA5 is upregulated to reduce lysosomal sphingomyelin levels potentially as a protective measure. This process may provide new targets for therapeutic intervention and biomarker development for PD.

Arterial stiffness for the early prediction of pre-eclampsia compared with blood pressure, uterine artery Doppler and angiogenic biomarkers: a prospective cohort study

OBJECTIVE

Our aim was to evaluate the ability of arterial stiffness parameters to predict pre-eclampsia early compared with peripheral blood pressure, uterine artery Doppler and established angiogenic biomarkers.

DESIGN

Prospective cohort study.

SETTING

Tertiary care antenatal clinics in Montreal, Canada.

POPULATION

Women with singleton high-risk pregnancies.

METHODS

In the first trimester, arterial stiffness was measured by applanation tonometry, along with peripheral blood pressure and serum/plasma angiogenic biomarkers; uterine artery Doppler was measured in the second trimester. The predictive ability of different metrics was assessed through multivariate logistic regression.

MAIN OUTCOME MEASURES

Arterial stiffness (carotid-femoral pulse wave velocity, carotid-radial pulse wave velocity) and wave reflection (augmentation index, reflected wave start time), peripheral blood pressure, ultrasound indices of velocimetry and circulating angiogenic biomarker concentrations.

RESULTS

In this prospective study, among 191 high-risk pregnant women, 14 (7.3%) developed pre-eclampsia. A first-trimester 1 m/s increase in carotid-femoral pulse wave velocity was associated with 64% increased odds (P < 0.05), and a 1-millisecond increase in time to wave reflection with 11% decreased odds for pre-eclampsia (P < 0.01). The area under the curve of arterial stiffness, blood pressure, ultrasound indices and angiogenic biomarkers was 0.83 (95% confidence interval [CI] 0.74-0.92), 0.71 (95% CI 0.57-0.86), 0.58 (95% CI 0.39-0.77), and 0.64 (95% CI 0.44-0.83), respectively. With a 5% false-positive rate, blood pressure had a sensitivity of 14% for pre-eclampsia and arterial stiffness a sensitivity of 36%.

CONCLUSIONS

Arterial stiffness predicted pre-eclampsia earlier and with greater ability than blood pressure, ultrasound indices or angiogenic biomarkers.

Multiple pathways of lipid dysregulation in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a rapidly progressing neurodegenerative disease characterized by the degeneration of motor neurons and loss of various muscular functions. Dyslipidaemia is prevalent in amyotrophic lateral sclerosis with aberrant changes mainly in cholesterol ester and triglyceride. Despite this, little is known about global lipid changes in amyotrophic lateral sclerosis or in relation to disease progression. The present study incorporated a longitudinal lipidomic analysis of amyotrophic lateral sclerosis serum with a comparison with healthy controls using advanced liquid chromatography-mass spectrometry. The results established that diglyceride, the precursor of triglyceride, was enriched the most, while ceramide was depleted the most in amyotrophic lateral sclerosis compared with controls, with the diglyceride species (18:1/18:1) correlating significantly to neurofilament light levels. The prenol lipid CoQ₈ was also decreased in amyotrophic lateral sclerosis and correlated to neurofilament light levels. Most interestingly, the phospholipid phosphatidylethanolamine and its three derivatives decreased with disease progression, in contrast to changes with normal ageing. Unsaturated lipids that are prone to lipid peroxidation were elevated with disease progression with increases in the formation of toxic lipid products. Furthermore, in vitro studies revealed that phosphatidylethanolamine synthesis modulated TARDBP expression in SH-SY5Y neuronal cells. Finally, diglyceride, cholesterol ester and ceramide were identified as potential lipid biomarkers for amyotrophic lateral sclerosis diagnosis and monitoring disease progression. In summary, this study represents a longitudinal lipidomics analysis of amyotrophic lateral sclerosis serum and has provided new insights into multiple pathways of lipid dysregulation in amyotrophic lateral sclerosis.

Increased unsaturated lipids underlie lipid peroxidation in synucleinopathy brain

Lipid peroxidation is a process of oxidative degradation of cellular lipids that is increasingly recognized as an important factor in the pathogenesis of neurodegenerative diseases. We were therefore interested in the manifestation of lipid peroxidation in synucleinopathies, a group of neurodegenerative diseases characterized by the central pathology of α-synuclein aggregates, including Parkinson’s disease, multiple system atrophy, dementia with Lewy bodies and Alzheimer’s disease with Lewy bodies. We assessed lipid peroxidation products, lipid aldehydes, in the amygdala, a common disease-affected region in synucleinopathies, and in the visual cortex, a disease-unaffected region. We found that the levels of lipid aldehydes were significantly increased in the amygdala, but not in the visual cortex. We hypothesized that these increases are due to increases in the abundance of unsaturated lipids, since lipid aldehydes are formed from unsaturated lipids. We undertook a comprehensive analysis of membrane lipids using liquid chromatography-mass spectrometry and found that unsaturated phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine and sphingomyelin were specifically elevated in the amygdala and correlated with increases in lipid aldehydes. Furthermore, unsaturated phosphatidylethanolamine levels were associated with soluble α-synuclein. Put together, these results suggest that manifestation of lipid peroxidation is prevalent in synucleinopathies and is likely to be due to increases in unsaturated membrane lipids. Our findings underscore the importance of lipid peroxidation in α-synuclein pathology and in membrane structure maintenance.

Sex-specific lipid dysregulation in the Abca7 knockout mouse brain

Alzheimer’s disease is a devastating neurodegenerative disease that affects more women than men. The pathomechanism underlying the sex disparity, especially in the brain, is unclear. ABCA7 is one of the strongest susceptibility genes for Alzheimer’s disease. It mediates the transport of lipids across membranes and is associated with pathways related to amyloid-β neuropathology. However, the role of ABCA7 in the regulation of brain lipids is largely unknown. Sex-specific differences in the pathological link between brain lipid dysregulation and amyloid-β are also unknown. Here, we undertook quantitative discovery lipidomics of male and female Abca7 knockout (n = 52) and wild type (n = 35) mouse brain using sophisticated liquid chromatography/mass spectrometry. We identified 61 lipid subclasses in the mouse brain and found sex-specific differences in lipids that were altered with Abca7 deletion. The altered lipids belong to cellular pathways that control cell signalling, sterol metabolism, mitochondrial function and neuroprotection. We also investigated the relationship between lipids and amyloid-β levels in the Abca7 knockout mice and found elevated free cholesterol only in female mice that was significantly correlated with amyloid-β42 levels. In male Abca7 knockout mice, the neuroprotective ganglioside GD1a levels were elevated and inversely correlated with amyloid-β42 levels. Collectively, these results demonstrate that Abca7 deletion leads to sex-specific lipid dysregulation in the brain, providing insight into the underlying sex disparity in the aetiology of Alzheimer’s disease.

Biomarker discovery and development for frontotemporal dementia and amyotrophic lateral sclerosis

Frontotemporal dementia refers to a group of neurodegenerative disorders characterized by behaviour and language alterations and focal brain atrophy. Amyotrophic lateral sclerosis is a rapidly progressing neurodegenerative disease characterized by loss of motor neurons resulting in muscle wasting and paralysis. Frontotemporal dementia and amyotrophic lateral sclerosis are considered to exist on a disease spectrum given substantial overlap of genetic and molecular signatures. The predominant genetic abnormality in both frontotemporal dementia and amyotrophic lateral sclerosis is an expanded hexanucleotide repeat sequence in the C9orf72 gene. In terms of brain pathology, abnormal aggregates of TAR-DNA-binding protein-43 are predominantly present in frontotemporal dementia and amyotrophic lateral sclerosis patients. Currently, sensitive and specific diagnostic and disease surveillance biomarkers are lacking for both diseases. This has impeded the capacity to monitor disease progression during life and the development of targeted drug therapies for the two diseases. The purpose of this review is to examine the status of current biofluid biomarker discovery and development in frontotemporal dementia and amyotrophic lateral sclerosis. The major pathogenic proteins implicated in different frontotemporal dementia and amyotrophic lateral sclerosis molecular subtypes and proteins associated with neurodegeneration and the immune system will be discussed. Furthermore, the use of mass spectrometry-based proteomics as an emerging tool to identify new biomarkers in frontotemporal dementia and amyotrophic lateral sclerosis will be summarized.

Pathological manifestation of human endogenous retrovirus K in frontotemporal dementia

BACKGROUND

Behavioral variant frontotemporal dementia (bvFTD) is a common form of younger-onset dementia with a proportion of cases overlapping pathologically and genetically with amyotrophic lateral sclerosis (ALS). Previous studies have identified that the human endogenous retrovirus K (HERV-K) is elevated in ALS serum and is associated with ALS TDP-43 pathology. In contrast, little is known about HERV-K changes in bvFTD. Here, we investigated the possible role of HERV-K in bvFTD.

METHODS

We measured the HERV-K env gene in sporadic bvFTD (N = 63), sporadic ALS (N = 89), and control (N = 21) serum by ddPCR. We also analyzed HERV-K env, by qPCR, and the HERV-K reverse transcriptase protein, by confocal immunofluorescence microscopy, in the disease-affected superior frontal cortex of bvFTD with TDP-43 pathology.

RESULTS

Here, we show that HERV-K env levels are significantly elevated (P = 3.5 × 10^-6) in bvFTD compared to control serum, differentiating cases with an AUC value of 0.867. HERV-K env levels are also specifically elevated in the superior frontal cortex of bvFTD with TDP-43 pathology, with the HERV-K reverse transcriptase protein and TDP-43 deposit localized to the neuronal cytoplasm. Furthermore, in a neuronal cell line overexpression of TDP-43 induces HERV-K env transcription.

CONCLUSIONS

These results suggest that manifestation of HERV-K is associated with bvFTD TDP-43 pathology. Analysis of HERV-K in bvFTD may provide insight into an unrecognized but targetable perturbed pathology.

Increased VLCFA-lipids and ELOVL4 underlie neurodegeneration in frontotemporal dementia

Rare, yet biologically critical, lipids that contain very long chain fatty acids (VLCFA-lipids) are synthesized in the brain by the enzyme ELOVL4. High levels of VLCFA-lipids are toxic to cells and excess VLCFA-lipids are actively removed by ABCD1 in an ATP-dependent manner. Virtually nothing is known about the impact of VLCFA-lipids in neurodegenerative diseases. Here, we investigated the possible role of VLCFA-lipids in frontotemporal dementia (FTD), which is a leading cause of younger-onset dementia. Using quantitative discovery lipidomics, we identified three VLCFA-lipid species that were significantly increased in FTD brain compared to controls, with strong correlations with ELOVL4. Increases in ELOVL4 expression correlated with significant decreases in the membrane-bound synaptophysin in FTD brain. Furthermore, increases in ABCD1 expression correlated with increases in VLCFA-lipids. We uncovered a new pathomechanism that is pertinent to understanding the pathogenesis of FTD.

846 Dysphagia Rates in Single- And Multiple-Level Anterior Cervical Discectomy and Fusion Surgery: A Meta-Analysis

Aim

To conduct a meta-analysis to assess dysphagia complicating single-level and multiple-level (≥2) anterior cervical discectomy and fusion (ACDF) surgery.

Method

Electronic searches were performed using four electronic databases from their inception to December 2017. Relevant studies reporting the rate of dysphagia as an endpoint for patients undergoing ACDF for degenerative disease, myelopathy, cervical canal stenosis or ossification of the posterior longitudinal ligament were identified according to prior inclusion and exclusion criteria. Statistical analysis was performed using a fixed effect model. P-scores were used to rank the levels of ACDF based on the rate of dysphagia. I2 was used to explore heterogeneity.

Results

Ten studies were identified and included in the systematic review and meta-analysis, with a total of 4,018 patients identified; 2,362 patients underwent single-level ACDF, while 1,656 underwent multiple level (≥2 ACDF). The mean age ranged from 49.45 to 57.77 years. Mean follow-up time ranged from 2 days to 27.3 months. Overall, meta-analysis demonstrated a statistically significant higher dysphagia rate for multiple-level ACDF (6.6%) than for single-level ACDF (4%) (P heterogeneity =0.151, OR = 1.42, 95% CI: 1.05–1.91, I2=32%).

Conclusions

Dysphagia is a relatively common complication in the early postoperative period following ACDF and may cause patients significant discomfort and distress. This meta-analysis demonstrates a higher rate of dysphagia with multiple-level ACDF than with single-level ACDF at a period of 12–24 months.

843 Annular Closure Device for Disc Herniation: Meta-Analysis of Clinical Outcome and Complications

Aim

To assist surgeons to determine a potential approach to reduce incidences of recurrent lumbar disc herniation and assess the current devices regarding their outcomes and complications.

Method

Four electronic full-text databases were systematically searched through September 2017. All results were pooled utilising meta-analysis with weighted mean difference and odds ratio as summary statistics.

Results

Four studies met inclusion criteria. Three studies reported the use of Barricaid (ACD) while one study reported the use of Anulex (AR). A total of 24 symptomatic reherniation were reported among 811 discectomies with ACD/AR as compared to 51 out of 645 in the control group (OR: 0.34; 95% CI: 0.20,0.56; I2 = 0%; P &lt; 0.0001). Durotomies were lower among the ACD/AR patients with only 3 reported cases compared to 7 in the control group (OR: 0.54; 95% CI: 0.13, 2.23; I2 = 11%; P = 0.39). Similar outcomes for post-operative Oswestry Disability Index and visual analogue scale were obtained when both groups were compared.

Conclusions

Early results showed the use of Barricaid and Anulex devices are beneficial for short term outcomes demonstrating a reduction in symptomatic disc reherniation with low post-operative complication rates. Long-term studies are required to further investigate the efficacy of such devices.

Elective neck dissection versus observation for early-stage oral squamous cell carcinoma: Systematic review and meta-analysis

INTRODUCTION

Oral squamous cell carcinoma (OSCC) is the seventh most common cancer globally, and has been identified as a growing health concern. This study aims to evaluate the current literature comparing elective neck dissection to observation in the treatment of early-stage tongue SCC, focusing on nodal recurrence, overall survival, disease specific survival statistics from randomised controlled trials comparing the two interventions.

METHODS

Systematic review and meta-analysis was conducted according to PRISMA guidelines. The odds ratio (OR) was used as a summary statistic.

RESULTS

From 8 studies, there was a total of 372 cases of recurrence, 98 (15.1%) in END group and 274 (41.5%) in the Observation group. There was a significantly lower rate of recurrence in the END group compared to observation (OR 0.25, 95% CI 0.16-0.39, I² = 54%, P < 0.00001). END was associated with higher overall survival rates when compared with observation (OR 1.95, 95% CI 1.40-2.73, I² = 14%, P < 0.0001). END was also associated with higher disease-specific survival compared with observation (OR 1.88, 95% CI 1.21-2.93), I² = 47%, P = 0.005), with no significant heterogeneity noted.

CONCLUSIONS

END was associated with significantly lower recurrence rates and higher overall and disease-specific survival compared to a conservative observation approach in early-stage oral SCC with clinically N0 neck.

Uncovering pathophysiological changes in frontotemporal dementia using serum lipids

Blood serum is enriched in lipids and has provided a platform to understand the pathogenesis of a number of human diseases with improved diagnosis and development of biomarkers. Understanding lipid changes in neurodegenerative diseases is particularly important because of the fact that lipids make up >50% of brain tissues. Frontotemporal dementia (FTD) is a common cause of early onset dementia, characterized by brain atrophy in the frontal and temporal regions, concomitant loss of lipids and dyslipidemia. However, little is known about the link between dyslipidemia and FTD pathophysiology. Here, we utilized an innovative approach – lipidomics based on mass spectrometry – to investigate three key aspects of FTD pathophysiology – mitochondrial dysfunction, inflammation, and oxidative stress. We analyzed the lipids that are intrinsically linked to neurodegeneration in serum collected from FTD patients and controls. We found that cardiolipin, acylcarnitine, lysophosphatidylcholine, platelet-activating factor, o-acyl-ω-hydroxy fatty acid and acrolein were specifically altered in FTD with strong correlation between the lipids, signifying pathophysiological changes in FTD. The lipid changes were verified by measurement of the common disease markers (e.g. ATP, cytokine, calcium) using conventional assays. When put together, these results support the use of lipidomics technology to detect pathophysiological changes in FTD.

Cross-examining candidate genes implicated in multiple system atrophy

Multiple system atrophy (MSA) is a devastating neurodegenerative disease characterized by the clinical triad of parkinsonism, cerebellar ataxia and autonomic failure, impacting on striatonigral, olivopontocerebellar and autonomic systems. At early stage of the disease, the clinical symptoms of MSA can overlap with those of Parkinson's disease (PD). The key pathological hallmark of MSA is the presence of glial cytoplasmic inclusions (GCI) in oligodendrocytes. GCI comprise insoluble proteinaceous filaments composed chiefly of α-synuclein aggregates, and therefore MSA is regarded as an α-synucleinopathy along with PD and dementia with Lewy bodies. The etiology of MSA is unknown, and the pathogenesis of MSA is still largely speculative. Much data suggests that MSA is a sporadic disease, although some emerging evidence suggests rare genetic variants increase susceptibility. Currently, there is no general consensus on the susceptibility genes as there have been differences due to geographical distribution or ethnicity. Furthermore, many of the reported studies have been conducted on patients that were only clinically diagnosed without pathological verification. The purpose of this review is to bring together available evidence to cross-examine the susceptibility genes and genetic pathomechanisms implicated in MSA. We explore the possible involvement of the SNCA, COQ2, MAPT, GBA1, LRRK2 and C9orf72 genes in MSA pathogenesis, highlight the under-explored areas of MSA genetics, and discuss future directions of research in MSA.

JAK inhibitors for alopecia areata: a systematic review and meta-analysis

There have been a number of case reports and small clinical trials reporting promising outcomes of Janus Kinase (JAK) inhibitors tofacitinib, ruxolitinib and baricitinib for alopecia areata (AA). The majority of the literature to date is based on small volume data, with a lack of definitive evidence or guidelines. To determine the expected response of AA to JAK inhibitor therapy and factors which influence response and recurrence rates. A systematic review and meta-analysis was performed according to PRISMA guidelines. From 30 studies and 289 cases, there were 72.4% responders, good responders 45.7% and partial responders 21.4%. Mean time to initial hair growth was 2.2 ± 6.7 months, and time to complete hair regrowth was 6.7 ± 2.2 months. All 37 recurrences occurred when treatment was ceased after 2.7 months. Oral route was significantly associated with response to treatment compared to topical therapy. No difference was found between paediatric and adult cases in proportion of responses. There is promising low-quality evidence regarding the effectiveness of JAK inhibitors in AA. Future large-sized randomized studies are required to confirm findings.

On Flow Diversion: The Changing Landscape of Intracerebral Aneurysm Management

Uptake of flow-diverting technology is rapidly outpacing the availability of clinical evidence. Most current usage is off-label, and the endovascular community is nearer the beginning than the end of the learning curve, given the number of devices in development. A comprehensive overview of technical specifications alongside key outcome data is essential both for clinical decision-making and to direct further investigations. Most-studied has been the Pipeline Embolization Device, which has undergone a transition to the Pipeline Flex for which outcome data are sparse or heterogeneous. Alternative endoluminal devices do not appear to be outperforming the Pipeline Embolization Device to date, though prospective studies and long-term data mostly are lacking, and between-study comparisons must be treated with caution. Nominal technical specifications may be unrelated to in situ performance, emphasizing the importance of correct radiologic sizing and device placement. Devices designed specifically for bifurcation aneurysms also lack long-term outcome data or have only recently become available for clinical use. There are no major studies directly comparing a flow-diverting device with standard coiling or microsurgical clipping. Data on flow-diverting stents are too limited in terms of long-term outcomes to reliably inform clinical decision-making. The best available evidence supports using a single endoluminal device for most indications. Recommendations on the suitability and choice of a device for bifurcation or ruptured aneurysms or for anatomically complex lesions cannot be made on the basis of current evidence. The appropriateness of flow-diverting treatment must be decided on a case-by-case basis, considering experience and the relative risks against standard approaches or observation.

Hidradenitis suppurativa and diabetes mellitus: updated systematic review and adjusted meta-analysis

BACKGROUND

Hidradenitis suppurativa (HS) is a debilitating and distressing chronic inflammatory skin disease. There is also evolving evidence supporting the association between HS and cardiovascular risk factors, including smoking, obesity, hyperlipidaemia and metabolic syndrome. Notably, these are clinical features and risk factors that are closely associated with type 2 diabetes mellitus (DM).

AIMS

We performed a pooled adjusted meta-analysis of comparative studies to investigate the relationship between HS and DM.

METHODS

A systematic review and meta-analysis was performed according to recommended Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. OR was used as the summary effect size.

RESULTS

From pooled analysis of unadjusted data from 12 studies, we found a significantly higher proportion of DM in HS cases compared with non-HS healthy controls (16.1% vs. 15.7%; OR = 2.17; 95% CI 1.85-2.55; P < 0.001). Adjusted effect sizes from five studies were also pooled. A significantly higher proportion of DM was found for HS compared with healthy controls, although the effect size was attenuated compared with unadjusted analyses (OR 1.69; 95% CI 1.50-1.91; P < 0.001).

CONCLUSIONS

To our knowledge, our systematic review and meta-analysis is the first to pool adjusted effect sizes. We found that HS was associated with a 1.69-fold increased odds of diabetes; however, the absolute risk difference was small (16.1% vs. 15.7%) and is probably not clinically relevant. Treating clinicians should be aware of this association, but there may not be an urgent need to perform screening for impaired glucose tolerance or diabetes.

Eating peptides: biomarkers of neurodegeneration in amyotrophic lateral sclerosis and frontotemporal dementia

Objective

Physiological changes potentially influence disease progression and survival along the Amyotrophic Lateral Sclerosis (ALS)-Frontotemporal dementia (FTD) spectrum. The peripheral peptides that regulate eating and metabolism may provide diagnostic, metabolic, and progression biomarkers. The current study aimed to examine the relationships and biomarker potential of hormonal peptides.

Methods

One hundred and twenty-seven participants (36 ALS, 26 ALS- cognitive, patients with additional cognitive behavioral features, and 35 behavioral variant FTD (bvFTD) and 30 controls) underwent fasting blood analyses of leptin, ghrelin, neuropeptide Y (NPY), peptide YY (PYY), and insulin levels. Relationships between endocrine measures, cognition, eating behaviors, and body mass index (BMI) were investigated. Biomarker potential was evaluated using multinomial logistic regression for diagnosis and correlation to disease duration.

Results

Compared to controls, ALS and ALS-cognitive had higher NPY levels and bvFTD had lower NPY levels, while leptin levels were increased in all patient groups. All groups had increased insulin levels and a state of insulin resistance compared to controls. Lower NPY levels correlated with increasing eating behavioral change and BMI, while leptin levels correlated with BMI. On multinomial logistic regression, NPY and leptin levels were found to differentiate between diagnosis. Reduced Neuropeptide Y levels correlated with increasing disease duration, suggesting it may be useful as a potential marker of disease progression.

Interpretation

ALS-FTD is characterized by changes in NPY and leptin levels that may impact on the underlying regional neurodegeneration as they were predictive of diagnosis and disease duration, offering the potential as biomarkers and for the development of interventional treatments.

Laparoscopic vs. robotic rectal cancer surgery and the effect on conversion rates: a meta-analysis of randomized controlled trials and propensity-score-matched studies

BACKGROUND

The usage of robotic surgery in rectal cancer is increasing, but there is an ongoing debate as to whether it provides any benefit. The aim of the present study was to determine if robotic surgery results in less conversion to an open operation than laparoscopic rectal cancer surgery.

METHODS

A meta-analysis was performed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines using Ovid Medline, PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, ACP Journal Club and Database of Abstracts of Review of Effectiveness. Included were randomized controlled trials (RCTs) and propensity-score-matched (PSM) studies comparing a robotic vs. laparoscopic approach to rectal cancer surgery. The primary endpoint was conversion to open. All statistical analyses and data synthesis were conducted using STATA/IC version 14·2, Windows 64 bit (StataCorp LP, College Station, TX, USA) RESULTS: Six hundred and twenty-one studies were identified through electronic database search. After application of selection criteria as per PRISMA and MOOSE criteria, six RCTs and five PSM articles were analyzed. From the six RCTs, 512 robotic and 519 laparoscopic cases were evaluated. There was a significantly lower rate of conversion for the robotic surgery arm (4.1% vs. 8.1%, OR 0.28; 95% CI 0.00-0.57). Of the five PSM studies, 2097 robotic and 3053 laparoscopic cases were evaluated. There was a significantly lower conversion to open rate found in the robotic surgery cohort (7.4% vs. 15.6%; OR 0.39; 95% CI 0.30-0.47). Pooled RCT and PSM data demonstrated significantly lower conversion rates for robotic surgery (6.7% vs. 14.5%; OR 0.38; 95% CI 0.30-0.46).

CONCLUSIONS

Robotic surgery for rectal cancer is associated with reduced conversion to open surgery compared to a laparoscopic approach.

Altered High Density Lipoprotein Composition in Behavioral Variant Frontotemporal Dementia

Frontotemporal dementia (FTD) is a common cause of early onset dementia with behavioral variant FTD (bvFTD) being the most common form. bvFTD is characterized clinically by behavioral and personality changes, eating abnormalities, and pathologically, by systemic lipid dysregulation that impacts on survival. As lipoprotein metabolism is at the core of lipid dysregulation, here, we analyzed the composition, both proteins and lipids, of the two major lipoprotein classes in blood – high density lipoproteins (HDLs) and low density lipoproteins (LDLs). Fasted plasmas from bvFTD and Alzheimer’s disease (AD) patients and controls were fractionated using fast protein liquid chromatography (FPLC) and samples analyzed by lipid assays, ELISA and western blotting. We found that apolipoprotein A-I (apoA-I) and apolipoprotein A-II (apoA-II) levels in HDLs were decreased in bvFTD compared to controls, whereas apolipoprotein B (apoB) levels in LDLs were unaltered. We also found that cholesterol and triglyceride levels in FPLC fractions were altered in bvFTD compared to controls. The apoB:apoA-I ratio and the standard lipid ratios were significantly increased in bvFTD compared to AD and controls. Furthermore, we found that plasma apolipoprotein C-I and paraoxonase 1 levels were significantly altered in bvFTD and AD, respectively, compared controls. This study represents the first apolipoprotein analysis of bvFTD, and our results suggest altered HDL function and elevated cardiovascular disease risk in bvFTD.

The fitness costs and trade-off shapes associated with the exclusion of nine antibiotics by OmpF porin channels

The trade-off relationship between antibiotic exclusion and nutrient access across the Gram-negative outer membrane is determined by structural constraints in porin channels. The precise nutritional cost of exclusion is unknown for different antibiotics, as are the shapes of the nutrition-susceptibility trade-off. Using a library of 10 engineered isogenic Escherichia coli strains with structural modifications of OmpF porin expressed at a constant level, susceptibilities were measured for nine antibiotics and the nutritional fitness costs estimated by competitions in chemostats. Different antibiotics exhibited a remarkably varied range of geometries in the nutrition-susceptibility trade-off, including convex, concave and sigmoidal trade-off shapes. The trade-off patterns predict the possibility of adaptations in contributing to antibiotic resistance; exclusion of amoxicillin or trimethoprim in ompF mutants can occur with little loss of fitness whereas kanamycin and streptomycin exclusion has a high cost. Some individual OmpF changes even allow positive correlations (trade-ups), resulting in increased fitness and decreased susceptibility specifically to cephalexin or ciprofloxacin. The surprising plasticity of the nutrition-exclusion relationship means that there are no generalisable rules that apply to decreasing susceptibility for all antibiotics. The protein changes are exquisitely specific in determining nutritional fitness and adaptive outcomes in a structural constraint trade-off.

The constancy of global regulation across a species: the concentrations of ppGpp and RpoS are strain-specific in Escherichia coli

Background

Sigma factors and the alarmone ppGpp control the allocation of RNA polymerase to promoters under stressful conditions. Both ppGpp and the sigma factor σ^S (RpoS) are potentially subject to variability across the species Escherichia coli. To find out the extent of strain variation we measured the level of RpoS and ppGpp using 31 E. coli strains from the ECOR collection and one reference K-12 strain.

Results

Nine ECORs had highly deleterious mutations in rpoS, 12 had RpoS protein up to 7-fold above that of the reference strain MG1655 and the remainder had comparable or lower levels. Strain variation was also evident in ppGpp accumulation under carbon starvation and spoT mutations were present in several low-ppGpp strains. Three relationships between RpoS and ppGpp levels were found: isolates with zero RpoS but various ppGpp levels, strains where RpoS levels were proportional to ppGpp and a third unexpected class in which RpoS was present but not proportional to ppGpp concentration. High-RpoS and high-ppGpp strains accumulated rpoS mutations under nutrient limitation, providing a source of polymorphisms.

Conclusions

The ppGpp and σ^S variance means that the expression of genes involved in translation, stress and other traits affected by ppGpp and/or RpoS are likely to be strain-specific and suggest that influential components of regulatory networks are frequently reset by microevolution. Different strains of E. coli have different relationships between ppGpp and RpoS levels and only some exhibit a proportionality between increasing ppGpp and RpoS levels as demonstrated for E. coli K-12.

Molecular and evolutionary bases of within-patient genotypic and phenotypic diversity in Escherichia coli extraintestinal infections

Although polymicrobial infections, caused by combinations of viruses, bacteria, fungi and parasites, are being recognised with increasing frequency, little is known about the occurrence of within-species diversity in bacterial infections and the molecular and evolutionary bases of this diversity. We used multiple approaches to study the genomic and phenotypic diversity among 226 Escherichia coli isolates from deep and closed visceral infections occurring in 19 patients. We observed genomic variability among isolates from the same site within 11 patients. This diversity was of two types, as patients were infected either by several distinct E. coli clones (4 patients) or by members of a single clone that exhibit micro-heterogeneity (11 patients); both types of diversity were present in 4 patients. A surprisingly wide continuum of antibiotic resistance, outer membrane permeability, growth rate, stress resistance, red dry and rough morphotype characteristics and virulence properties were present within the isolates of single clones in 8 of the 11 patients showing genomic micro-heterogeneity. Many of the observed phenotypic differences within clones affected the trade-off between self-preservation and nutritional competence (SPANC). We showed in 3 patients that this phenotypic variability was associated with distinct levels of RpoS in co-existing isolates. Genome mutational analysis and global proteomic comparisons in isolates from a patient revealed a star-like relationship of changes amongst clonally diverging isolates. A mathematical model demonstrated that multiple genotypes with distinct RpoS levels can co-exist as a result of the SPANC trade-off. In the cases involving infection by a single clone, we present several lines of evidence to suggest diversification during the infectious process rather than an infection by multiple isolates exhibiting a micro-heterogeneity. Our results suggest that bacteria are subject to trade-offs during an infectious process and that the observed diversity resembled results obtained in experimental evolution studies. Whatever the mechanisms leading to diversity, our results have strong medical implications in terms of the need for more extensive isolate testing before deciding on antibiotic therapies.

We investigated whether an infection is a site of pathogen within-species diversity. Our results indicate that there is indeed extensive diversity during human extraintestinal infections by Escherichia coli. This diversity was of two types, not mutually exclusive, as we found that patients were infected either by several distinct E. coli clones or by members of a single clone that exhibit micro-heterogeneity. The high degree of phenotypic diversity, including antibiotic resistance, suggests that there is no uniform selection pressure leading to a single fitter clone during an infection. We discuss a possible mechanism and a mathematical model that explains these unexpected results. Our data suggest that the evolution of diversity in the course of an infection and in in vitro experimental evolution in the absence of host immune selective pressure may have many parallels. Whatever the mechanisms leading to diversity, our results have strong medical implications in terms of the need for more extensive isolate testing before deciding on antibiotic therapies.

[Operative and follow-up treatment of rotator cuff tears--the current situation]

AIM

The aim of this study was to evaluate the current situation of rotator cuff repair and follow-up treatment in German hospitals.

METHODS

An evaluated survey, enquiring about the year 2006, was sent to all 777 German orthopaedic and/or trauma surgery departments. The hospitals were chosen using the official index of hospitals from the German Federal Statistical Office.

RESULTS

44 % of the surveys were sent back, whereby 40 % were of use. Within the 309 departments, 26 % of the total number of 59,957 shoulder operations were rotator cuff repairs. Mini-open was the operation method in 49 %, open in 29 % and arthroscopic in 22 % of cases. Regarding the operational methods, there were differences between the departments and level of care. The arthroscopic technique was used sometimes in 48 % of the departments, whereas 52 % never used it. Specialised shoulder departments employed the total arthroscopic procedure more often. A set follow-up treatment occurred in 79 % of departments.

CONCLUSION

Rotator cuff repair is mainly carried out using the mini-open method, which is nowadays regarded as gold standard.