Consensus summary report for CEPI/BC March 12–13, 2020 meeting: Assessment of risk of disease enhancement with COVID-19 vaccines

A novel coronavirus (CoV), Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in late 2019 in Wuhan, China and has since spread as a global pandemic. Safe and effective vaccines are thus urgently needed to reduce the significant morbidity and mortality of Coronavirus Disease 2019 (COVID-19) disease and ease the major economic impact. There has been an unprecedented rapid response by vaccine developers with now over one hundred vaccine candidates in development and at least six having reached clinical trials. However, a major challenge during rapid development is to avoid safety issues both by thoughtful vaccine design and by thorough evaluation in a timely manner. A syndrome of “disease enhancement” has been reported in the past for a few viral vaccines where those immunized suffered increased severity or death when they later encountered the virus or were found to have an increased frequency of infection. Animal models allowed scientists to determine the underlying mechanism for the former in the case of Respiratory syncytial virus (RSV) vaccine and have been utilized to design and screen new RSV vaccine candidates. Because some Middle East respiratory syndrome (MERS) and SARS-CoV-1 vaccines have shown evidence of disease enhancement in some animal models, this is a particular concern for SARS-CoV-2 vaccines. To address this challenge, the Coalition for Epidemic Preparedness Innovations (CEPI) and the Brighton Collaboration (BC) Safety Platform for Emergency vACcines (SPEAC) convened a scientific working meeting on March 12 and 13, 2020 of experts in the field of vaccine immunology and coronaviruses to consider what vaccine designs could reduce safety concerns and how animal models and immunological assessments in early clinical trials can help to assess the risk. This report summarizes the evidence presented and provides considerations for safety assessment of COVID-19 vaccine candidates in accelerated vaccine development.     

Aggregatibacter actinomycetemcomitans leukotoxin: From mechanism to targeted anti‐toxin therapeutics

Aggregatibacter actinomycetemcomitans is a Gram‐negative bacterium associated with localized aggressive periodontitis, as well as other systemic diseases. This organism produces a number of virulence factors, all of which provide some advantage to the bacterium. Several studies have demonstrated that clinical isolates from diseased patients, particularly those of African descent, frequently belong to specific clones of A. actinomycetemcomitans that produce significantly higher amounts of a protein exotoxin belonging to the repeats‐in‐toxin (RTX) family, leukotoxin (LtxA), whereas isolates from healthy patients harbor minimally leukotoxic strains. This finding suggests that LtxA might play a key role in A. actinomycetemcomitans pathogenicity. Because of this correlation, much work over the past 30 years has been focused on understanding the mechanisms by which LtxA interacts with and kills host cells. In this article, we review those findings, highlight the remaining open questions, and demonstrate how knowledge of these mechanisms, particularly the toxin's interactions with lymphocyte function‐associated antigen‐1 (LFA‐1) and cholesterol, enables the design of targeted anti‐LtxA strategies to prevent/treat disease.     

Evidence-based tailored nutrition educational intervention improves adherence to dietary guidelines,anthropometric measures and serum metabolic biomarkers in early-stage breast cancer patients: A prospective interventional study

PurposeThe impact of the adherence to dietary guidelines of early-stage breast cancer (EBC) patients on body composition changes during treatment is not entirely defined. This study aimed to evaluate the role of an evidence-based nutrition educational intervention, according to adherence to dietary guidelines, in EBC patients.MethodsThis prospective study included EBC patients, candidates for neoadjuvant/adjuvant therapy. Patients received an evidence-based tailored nutrition educational intervention. The adherence to dietary guidelines, anthropometric and dietary assessments, and blood glucose and lipid profile tests were evaluated at baseline and after a 12-months nutritional intervention.ResultsTwo hundred and forty-three patients were enrolled. At baseline, 38.3% and 23.9% of patients were overweight and obese, weight gain ≥5% (compared to 6-months before enrollment) and central obesity were observed in 47.3% and 52.7% of patients, respectively. Adherence to dietary guidelines was low (median Med-Diet score: 6 [IQR 4–8]). After the nutritional intervention (median follow-up: 22 months [range 12–45]), adherence to dietary guidelines significantly increased (median Med-Diet score: 12 [IQR 8–13]), p < 0.0001). High adherence to dietary guidelines (defines as Med-Diet score ≥10) significantly correlated with: 1) overall weight loss ≥5% (21.8% vs. 2.5%, p = 0.003); 2) median BMI drop (from 25.6 kg/m² to 24.4 kg/m², p = 0.003); 3) lower prevalence of central obesity (38.2% vs. 7.2%, p = 0.01); 4) improvement in blood glucose levels and lipid profile.ConclusionThis study suggests that an evidence-based tailored nutrition educational intervention during treatment for EBC significantly increases overall adherence to dietary guidelines, and it improves both anthropometric measures and serum metabolic biomarkers in patients with high adherence.     

Short photoperiod restores ventral subicular lesion-induced deficits in affective and socio-cognitive behavior in male Wistar rats

Photoperiod (day-length) has enduring effects on an organism's physiological functions like metabolism and behavioral phenotypes including cognition and affect. Circadian rhythm manipulations are potentially effective non-pharmacological strategies in the management of central nervous system insults. In our previous study, we demonstrated the efficacy of short photoperiod regime (SPR; 06/18 hr light-dark cycle) in establishing functional recovery in ventral subicular lesion (VSL) rats. The present study further demonstrates the efficacy of SPR in mitigating anxiety and depression as well as facilitating socio-cognitive behavior in VSL rats. VSL elevated the basal plasma corticosterone levels, increased anxiety, anhedonia, and behavioral despair with decreased self-care. The VSL rats also exhibited a considerable degree of impaired social cognition, in terms of altered social preference and social novelty. Exposure to SPR for 21 days mitigated the anxiety- and depressive-like phenotypes as well as improved social cognition significantly. Thus, the study demonstrated the effectiveness of SPR strategy in reversing most of the behavioral deficits caused by VSL. SPR, perhaps, would have regulated the hypothalamo-pituitary-adrenal axis responsiveness as we observed a decrease in plasma corticosterone levels following SPR in VSL rats. The study implies the need for developing a task-dependent SPR strategy to achieve complete behavioral recovery as the functional demands of each behavior is distinct. In summary, the study highlights the efficacy of photoperiod manipulation as a novel, non-pharmacological approach in mitigating the affective and cognitive deficits associated with neuropsychiatric disorders such as bipolar disorder and Alzheimer's disease wherein circadian rhythm alterations are implicated.     

Genicular Artery Embolization for the Treatment of Knee Pain Secondary to Osteoarthritis

PurposeTo evaluate the efficacy and safety of embolization of hyperemic synovial tissue for the treatment of knee pain secondary to osteoarthritis (OA).Materials and MethodsTwenty patients with radiographic knee OA and moderate-to-severe pain refractory to conservative therapy were enrolled in a prospective, 2-site pilot study. Genicular artery embolization (GAE) was performed with 75- or 100-μm spherical particles. Patients were assessed with magnetic resonance imaging at baseline and at 1 month and with the Visual Analogue Scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at baseline and at 1, 3, and 6 months. Adverse events were recorded at all timepoints.ResultsEmbolization of at least 1 genicular artery was achieved in 20/20 (100%) patients. Mean VAS improved from 76 mm ± 14 at baseline to 29 mm ± 27 at 6-month follow-up (P < .01). Mean WOMAC score improved from 61 ± 12 at baseline to 29 ± 27 at 6-month follow-up (P < .01). Self-limiting skin discoloration occurred in 13/20 (65%) patients. Two of 20 (10%) patients developed plantar sensory paresthesia that resolved within 14 days.ConclusionsGAE to treat knee pain secondary to OA can be performed safely and demonstrates potential efficacy. Further randomized comparative studies are needed to determine true treatment effect versus placebo effect.     

Seeking the optimal schedule for chickenpox vaccination in Canada: Using an agent-based model to explore the impact of dose timing,coverage and waning of immunity on disease outcomes

Many countries continue to consider implementing a universal chickenpox vaccine program; however, there is no consensus on the most appropriate and effective timing between vaccine doses. The chickenpox vaccine schedule debate is highlighted in Canada, where there are currently eight different vaccine schedules across the country. The objective of this study was to test the overall effectiveness of chickenpox vaccination, as well as the specific impact of two different vaccine schedules, on chickenpox disease outcomes in Alberta over 75 years. Using an agent-based model of chickenpox disease, we tested the impact of three vaccination scenarios including: baseline (no vaccination), a long dosing interval-Schedule LDI (1^st dose – 12 months; 2^nd dose –  4-6 years) and a short dosing interval-Schedule SDI (1^st dose – 12 months; 2^nd dose – 18 months) on chickenpox and shingles disease outcomes. Chickenpox vaccination led to a substantial decrease in chickenpox incidence over 75 years post-vaccine implementation. Compared to Schedule LDI, Schedule SDI resulted in a significantly lower chickenpox incidence, a higher age of chickenpox infection, a lower chickenpox breakthrough rate and a higher shingles incidence rate. Our model findings suggest that the chickenpox vaccine is effective over a long period of time and the dose timing of the vaccine may impact disease outcomes and vaccine effectiveness. However, the effectiveness of the vaccine dose timing is only one consideration for policy-makers who are implementing a chickenpox vaccine program, with others including risk of adverse events, the impact of the schedule on other antigens in a combination vaccine, parental acceptance and the cost associated with different schedules.     

Differentiating autoimmune pancreatitis from pancreatic ductal adenocarcinoma with CT radiomics features

PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%.     

利用规律间隔成簇短回文重复序列/相关蛋白9系统敲减α2δ1对人肝癌细胞系Hep-12干性的影响

目的 通过规律间隔成簇短回文重复序列/相关蛋白9(CRISPR/Cas9)系统敲减人肝癌细胞系Hep12中电压依赖性钙离子通道 α2δ1的表达，观察α2δ1敲减后对肝癌细胞干性的影响。方法 设计3对靶向α2δ1的向导 (sgRNA)，长度为20 bp，构建到lenti CRISPRv2-puro载体上，然后在体外检测sgRNA切割活性，利用慢病毒包装系统包装含有sgRNA的重组质粒，将包装好的病毒感染Hep-12细胞，2 d后加入嘌呤霉素筛选。利用Western blotting验证α2δ1的敲减效果和干性相关基因的表达。通过成球实验检测其体外自我更新能力的变化。结果 测序结果显示，sgRNA成功插入载体质粒；体外切割实验显示，3条sgRNA均有切割活性；Western blotting结果显示，α2δ1基因的表达显著降低，干性相关基因B细胞特异性莫洛尼白血病病毒插入位点1(BMI1)和Nanog的表达显著被抑制；无血清培养基成球实验结果表明，敲减α2δ1导致Hep-12细胞的体外自我更新能力减弱。结论 利用CRISPR/Cas9技术成功构建敲除α2δ1基因的Hep-12细胞系；敲除α2δ1基因后能抑制Hep-12细胞肿瘤干细胞样特性。