Absence of antibody responses to SARS-CoV-2 N protein in COVID-19 vaccine breakthrough cases

Understanding the risk factors for breakthrough coronavirus disease 2019 (COVID-19) (BC19) is critical to inform policy. Herein, we assessed Delta (Lineage B.1.617.2) variant-specific effectiveness of the BNT162b2 (Pfizer) vaccine and characterized Delta-driven BC19 cases (fully vaccinated individuals who get infected) with known-time-since-vaccination. In this longitudinal prospective study (January 21–October 30, 2021), 90 naïve and 15 convalescent individuals were enrolled at the initiation of vaccination. Samples from 27 unvaccinated individuals with previous laboratory-confirmed COVID-19 diagnosis were collected at a single time point. Longitudinal serology profile (antibodies against severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] S and N proteins) and live-virus-based neutralization capacities were assessed while controlling for age. Sex, age, history of reactions to the COVID-19 vaccine, and viral neutralization capacities were identified as significant risk factors for breakthrough COVID-19. At 8 months postvaccination, male sex, individuals ⩾65 years of age, and individuals who experienced noticeable side effects with the COVID-19 vaccine were at 5.47 (p-value = 0.0102), 4.33 (p-value = 0.0236), and 4.95 (p-value = 0.0159) fold greater risk of BC19 as compared to their peers, respectively. Importantly, every five-fold increase in viral neutralization capacities (by live-virus-based assays) was significantly associated with ~4-fold reduction in the risk occurrence of breakthrough COVID-19 (p-value = 0.045). Vaccine boosting remarkably increased these viral neutralization capacities by 16.22-fold (p- value = 0.0005), supporting the importance of the BNT162b2 booster in efforts to control the incursion of future variants into the population at large. Strikingly, BC19 cases exhibited a delayed/absent antibody response to the N protein, suggesting limited exposure to the virus. Since antibodies against N protein are widely used to evaluate the extent of virus spread in communities, our finding has important implications on the utility of existing serological diagnostic and surveillance for COVID-19.     

Revisiting the peripheral sink hypothesis: inhibiting BACE1 activity in the periphery does not alter β‐amyloid levels in the CNS

Aggregation of amyloid beta (Aβ) peptides and the subsequent neural plaque formation is a central aspect of Alzheimer's disease. Various strategies to reduce Aβ load in the brain are therefore intensely pursued. It has been hypothesized that reducing Aβ peptides in the periphery, that is in organs outside the brain, would be a way to diminish Aβ levels and plaque load in the brain. In this report, we put this peripheral sink hypothesis to test by investigating how selective inhibition of Aβ production in the periphery using a β‐secretase (BACE)1 inhibitor or reduced BACE1 gene dosage affects Aβ load in the brain. Selective inhibition of peripheral BACE1 activity in wild‐type mice or mice over‐expressing amyloid precursor protein (APPswe transgenic mice; Tg2576) reduced Aβ levels in the periphery but not in the brain, not even after chronic treatment over several months. In contrast, a BACE1 inhibitor with improved brain disposition reduced Aβ levels in both brain and periphery already after acute dosing. Mice heterozygous for BACE1, displayed a 62% reduction in plasma Aβ40, whereas brain Aβ40 was only lowered by 11%. These data suggest that reduction of Aβ in the periphery is not sufficient to reduce brain Aβ levels and that BACE1 is not the rate‐limiting enzyme for Aβ processing in the brain. This provides evidence against the peripheral sink hypothesis and suggests that a decrease in Aβ via BACE1 inhibition would need to be carried out in the brain.

     

Characterisation of human dental stem cells and buccal mucosa fibroblasts

Human craniofacial stem cells are recently discovered sources of putative mesenchymal stem cells that hold great promise for autogenic or allogenic cell therapy and tissue engineering. Prior to employing these cells in clinical applications, they must be thoroughly investigated and characterized. In this study, the surface marker expression was investigated on dental pulp stem cells (DPSCs), dental follicle cells (DFCs), periodontal ligament stem cells (PDLSCs), and buccal mucosa fibroblasts (BMFs) utilising surface markers for flow cytometry. The osteogenic potential was also examined by bone-associated markers alkaline phosphatase, Runx2, collagen type I, osteocalcin, and osteopontin. The results from our study demonstrate that the dental cell sources exhibit comparable surface marker and bone-associated marker profiles parallel to those of other mesenchymal stem cell sources, yet distinct from the buccal mucosa fibroblasts. Our data support evidence towards clinical applicability of dental stem cells in hard tissue regeneration.     

How do morphotypes and chemotypes relate to genotypes? The colonial ascidian Cystodytes (Polycitoridae)

Intraspecies variability is widespread in marine invertebrates. Size, colour, texture, general shape and secondary chemistry can differ quite drastically from one individual to another. Cystodytes dellechiajei (Polycitoridae) is a cosmopolitan colonial ascidian with several morphotypes, most of which differ in colour and spicular composition. New molecular tools enable us to assess the taxonomic status of these morphotypes. To determine whether variation observed in Mediterranean Cystodytes has a genetic basis, we sequenced 45 specimens from eight locations of the western Mediterranean and one from Mayotte (Indian Ocean), and obtained a 617 bp fragment of the mitochondrial gene COI. Fifteen different colour morphs were recorded and four kinds of spicules were found: disk-shaped, sphere-shaped, star-shaped and discoidal, thick spicules with a toothed margin. Zooid morphology was remarkably uniform in the whole sample set. Different tree construction methods (distance-based, parsimony-based, and maximum-likelihood-based) yielded consistent results, and recognized six major clades, which had no correspondence with spicule shape and were only partially consistent with colour morphs. Results are discussed in the light of previous knowledge of the chemistry of blue, green, brown and purple colour morphs. In spite of the different colour patterns and spicular variability we concluded, on the basis of chemical and genetic data, that the morphological traits analysed were not consistent enough to be used to differentiate between Cystodytes species. We point out the importance of genetics and chemistry in assessing the taxonomic status of species with variable morphology.     

Lipid Peroxidation in Hyperlipidaemic Patients. A Study of Plasma using an HPLC-Based Thiobarbituric Acid Test

The question of “increased lipid peroxidation” in plasma from hyperlipidaemic patients was investigated using an improved HPLC-based assay for thiobarbituric acid-reactive material. Levels of TBARS in healthy human controls were at or close to zero, provided that butylated hydroxytoluene was added to the sample with the TBA reagents. Levels of plasma TBARS in hyperlipidaemic patients were elevated, although the absolute levels were much lower than those reported previously in the literature.     

Characterising deviation from treat-to-target strategies for early rheumatoid arthritis: the first three years

IntroductionTreat-to-target (T2T) strategies using a protocol of pre-defined adjustments of disease-modifying anti-rheumatic drugs (DMARDs) according to disease activity improve outcomes for patients with rheumatoid arthritis (RA). However, successful implementation may be limited by deviations from the protocol. The aim of this study was to determine the prevalence of protocol deviation, explore the reasons and identify subsets of patients in whom treatment protocols are more difficult to follow.MethodsIn this retrospective cohort study, treatment-naïve patients with RA of less than one year’s duration, attending a dedicated early arthritis clinic between 2001 and 2013, were followed for three years from initiation of combination therapy with conventional DMARDs which was subsequently modified according to a T2T protocol. At each clinic visit, whether deviation from the protocol occurred, the type of deviation and the reasons for deviation were assessed. The relationship between protocol deviations and baseline variables was determined using linear regression analysis.ResultsIn total, 198 patients contributed 3,654 clinic visits. The prevalence of protocol deviations was 24.5% and deviation in at least at one clinic visit was experienced by 90.4% of patients. The median time to first deviation was 30 weeks. Continuing existing treatment rather than intensifying therapy was the most common type of deviation (59.9%). Patient and physician related factors were the most common reasons for deviation, each accounting for 24.7% of deviations, followed by toxicities (23.3%) and comorbidities (20.0%). The prevalence of protocol deviations was lower among patients who achieved remission after three years (13.1%; 162 deviations out of 1,228 visits) compared with those who were not in remission (30.9%; 523/1692) (P <0.0001). On multivariate analysis, only body mass index (P = 0.003) and helplessness score (P = 0.04) were independent predictors of protocol deviations although the predictive power of the model was not strong (R² = 0.17).ConclusionsDeviation from a T2T protocol occurred in one quarter of visits, indicating that applying the T2T approach is feasible in clinical practice. Failure to escalate dose when indicated was commonly encountered, and just under half of the observed deviations were related to either toxicities or comorbidities and were therefore justifiable on clinical grounds.     

Ionic cross‐linking of water‐soluble polyurethane improves protein encapsulation and release

Polymer nanoparticles (NPs) are promising systems for the delivery of protein drugs, as they enhance circulation half‐life, reduce degradation, and increase selectivity of the encapsulated agent. Among the different methods for the preparation of protein‐loaded NPs, ionotropic gelation—which exploits cross‐linking between charged groups in the polymer and counterions in the protein solution—has been extensively investigated for chitosan NPs. The present study aims at exploring the possibility to apply the method to prepare BSA‐loaded polyurethane NPs. A poly(ε‐caprolactone)/poly(ethyleneglicol)‐based polyurethane bearing tert‐butyloxycarbonyl‐protected amino groups was synthesized by a two‐step synthesis procedure. Amino functionalities were exposed under acidic conditions, as confirmed by ninhydrin assay, and then exploited to obtain ionic cross‐linking with sodium tripolyphosphate counterions. The effect of polymer and sodium tripolyphosphate concentration on particles size and BSA encapsulation has been investigated, showing that the PUR concentration plays a major role. Small particles, at 300 nm, with high BSA loading (90%) have been obtained. Sustained BSA release and low burst effect (20%) have been observed, indicating good interaction between the protein and the polymer matrix. The study highlights the possibility of introducing alternative polymers to improve loading and release of proteins from NPs obtained through the ionotropic gelation method.