One of the strategies used to improve the immunogenicity of purified protein antigens has relied on their association with synthetic nanocarriers, which, in general, have functioned as simple antigen ...containers. Here, we present a more advanced strategy based on the design of an antigen nanocarrier at the molecular level. The nanocarrier is composed of a vitamin E oily core, surrounded by two layers: a first layer of chitosan and a second of dextran sulphate. The selected antigen, IutA protein from Escherichia coli, was harboured between the two polymeric layers. The final bilayer nanocapsules had a nanometric size (≈ 200 nm), a negative zeta potential (< -40 mV) and a good antigen association efficiency (≈ 70%). The bilayer architecture led to an improvement on the formulation stability and the controlled release of the associated antigen. Remarkably, after being administered to mice, bilayer nanocapsules elicited higher IgG levels than those obtained with antigen precipitated with Alum. Moreover, freeze-dried nanocapsules were stable at room temperature for, at least, 3 months. These promising data, in addition to their contribution to the development of an uropathogenic E. coli vaccine, has allowed us to validate these novel bilayer nanocapsules as adequate platforms for the delivery of protein antigens.
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•Bilayer nanocapsules protect and control the delivery of their associated antigens.•Freeze-dried nanocapsules are stable for at least 3 months at room temperature.•Antigen-loaded bilayer nanocapsules elicit higher IgG levels in mice than Alum.
Abstract Background Comorbid elderly patients with non-ST-elevation myocardial infarction (non-STEMI) are underrepresented in randomized trials and undergo fewer cardiac catheterizations according to ...registries. Our aim was to compare the conservative and invasive strategies in these patients. Methods Randomized multicenter study, including 106 patients (January 2012–March 2014) with non-STEMI, over 70 years and with comorbidities defined by at least two of the following: peripheral artery disease, cerebral vascular disease, dementia, chronic pulmonary disease, chronic renal failure or anemia. Patients were randomized to invasive (routine coronary angiogram, n = 52) or conservative (coronary angiogram only if recurrent ischemia or heart failure, n = 54) strategy. Medical treatment was identical. The main endpoint was the composite of all-cause mortality, reinfarction and readmission for cardiac cause (postdischarge revascularization or heart failure), at long-term (2.5-year follow-up). Analysis of cumulative event rate (incidence rate ratio = IRR) and time to first event (hazard ratio = HR), were performed. Results Cardiac catheterization/revascularization rates were 100%/58% in the invasive versus 20%/9% in the conservative arm. There were no differences between groups in the main endpoint (invasive vs conservative: IRR = 0.946, 95% CI 0.466–1.918, p = 0.877) at long-term. The invasive strategy, however, tended to improve 3-month outcomes in terms of mortality (HR = 0.348, 95% CI 0.122–0.991, p = 0.048), and of mortality or ischemic events (reinfarction or postdischarge revascularization) (HR = 0.432, 95% CI 0.190–0.984, p = 0.046). This benefit declined during follow-up. Conclusions Invasive management did not modify long-term outcome in comorbid elderly patients with non-STEMI. The finding of a tendency towards an improvement in the short-term needs confirmation in larger studies ( clinicaltrials.gov NCT1645943).
The spectrum of COVID-19 infection includes acute respiratory distress syndrome (ARDS) and macrophage activation syndrome (MAS), although the histological basis for these disorders has not been ...thoroughly explored. Post-mortem pulmonary and bone marrow biopsies were performed in 33 patients. Samples were studied with a combination of morphological and immunohistochemical techniques. Bone marrow studies were also performed in three living patients. Bone marrow post-mortem studies showed striking lesions of histiocytic hyperplasia with hemophagocytosis (HHH) in most (16/17) cases. This was also observed in three alive patients, where it mimicked the changes observed in hemophagocytic histiocytosis. Pulmonary changes included a combination of diffuse alveolar damage with fibrinous microthrombi predominantly involving small vessels, in particular the alveolar capillary. These findings were associated with the analytical and clinical symptoms, which helps us understand the respiratory insufficiency and reveal the histological substrate for the macrophage activation syndrome-like exhibited by these patients. Our results confirm that COVID-19 infection triggers a systemic immune-inflammatory disease and allow specific therapies to be proposed.
Plumbago scandens L. (Plumbaginaceae) occurs in all regions of Brazil. It has been described as toxic to cattle and goats. Caustic lesions in the upper digestive tract characterize poisoning. P. ...scandens contains a naphthoquinone named plumbagin, which presents high cytotoxic activity. Plumbago auriculata Lam., a widely used ornamental plant, is considered potentially toxic, but there is limited data about its toxicity. This work aimed to validate analytical methodologies for determining the levels of plumbagin in samples of leaves, stems, and rumen content to be used as an auxiliary chemical marker in the laboratory diagnosis of intoxication. One methodology used thin layer chromatography (TLC), and another used high-performance liquid chromatography (HPLC). The presence of palisade grass (Urochloa brizantha (Hochst. ex A.Rich.) R.D.Webster), Guinea grass (Megathyrsus maximus (Jacq.) B.K.Simon & S.W.L.Jacobs), corn silage, and rumen content did not interfere with plumbagin in the two methodologies. The TLC methodology generates qualitative results but is simple to implement and has a low cost. The HPLC methodology showed a limit of detection (LOD) of 0.01 μg/mL and a limit of quantification (LOQ) of 0.05 μg/mL. Leaf and stem samples of P. scandens evaluated showed high levels of plumbagin (0.261 ± 0.087 % and 0.327 ± 0.055 %, respectively). In contrast, leaves of P. auriculata did not show detectable levels of the toxin, and some stem samples showed low levels (up to 0.000114 %). Thus, these methodologies can be used to confirm or rule out the consumption of P. scandens in rumen content from animals suspected of poisoning.
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•TLC and HPLC methods for detecting plumbagin from Plumbago scandens in rumen and plant samples were validated.•The leaves and stem of Plumbago scandens showed high levels of plumbagin.•Plumbago auriculata showed no detectable levels in the leaves and low levels in the steams.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an enveloped positive stranded RNA virus which has caused the recent deadly pandemic called COVID-19. The SARS-CoV-2 virion is coated ...with a heavily glycosylated Spike glycoprotein which is responsible for attachment and entry into target cells. One, as yet unexploited strategy for preventing SARS-CoV-2 infections, is the targeting of the glycans on Spike. Lectins are carbohydrate-binding proteins produced by plants, algae, and cyanobacteria. Some lectins can neutralize enveloped viruses displaying external glycoproteins, offering an alternative therapeutic approach for the prevention of infection with virulent β-coronaviruses, such as SARS-CoV-2. Here we show that the cyanobacterial lectin cyanovirin-N (CV-N) can selectively target SARS-CoV-2 Spike oligosaccharides and inhibit SARS-CoV-2 infection in vitro and in vivo. CV-N neutralizes Delta and Omicron variants in vitro better than earlier circulating viral variants. CV-N binds selectively to Spike with a Kd as low as 15 nM and a stoichiometry of 2 CV-N: 1 Spike but does not bind to the receptor binding domain (RBD). Further mapping of CV-N binding sites on Spike shows that select high-mannose oligosaccharides in the S1 domain of Spike are targeted by CV-N. CV-N also reduced viral loads in the nares and lungs in vivo to protect hamsters against a lethal viral challenge. In summary, we present an anti-coronavirus agent that works by an unexploited mechanism and prevents infection by a broad range of SARS-CoV-2 strains.
Bovine besnoitiosis is continuing to spread in Europe. Therefore, the development of ruminant animal models of infection is urgently needed to evaluate therapeutic and prophylactic tools. Herein, we ...studied the effect of parasite dose and host age on the infection dynamics with Besnoitia besnoiti tachyzoites in cattle in two independent experimental infections. In experiment A, twelve 3‐month‐old male calves were inoculated intravenously with either three different doses of tachyzoites (G1: 108; G2: 107; G3: 106) or with PBS (G4). In experiment B, six 14‐month‐old bulls were inoculated with 106 tachyzoites based on results obtained in experiment A. In both trials, clinical signs compatible with acute and chronic besnoitiosis were monitored daily; blood and skin samples were collected regularly for 70–115 days post‐infection (pi). Finally, animals were killed, and tissues were collected for lesion and parasite detections. Infected animals developed mild–moderate signs compatible with acute besnoitiosis. Lymphadenopathy and fever were observed in both calves (from 12 hr until 7 days pi) and bulls (from 6 days until 9 days pi). Seroconversion was detected at 16–19 days pi, and antibody levels remained high. Infected animals did not developed characteristic clinical signs and macroscopic lesions of chronic besnoitiosis. However, successfully, parasite‐DNA was detected in a reduced number of target tissues: conjunctiva, ocular sclera, epididymis, skin of the scrotum and carpus in calves (n = 10, 6 of which belonged to G3), and pampiniform plexus and testicular parenchyma in bulls. Remarkably, one tissue cyst and mild microscopic lesions were also detected. In summary, inoculated animals developed the acute besnoitiosis and chronic infection was evidenced by microscopic findings. However, our results suggest that tachyzoite dose and host age are not key variables for inducing clinical signs and macroscopic lesions characteristic of chronic besnoitiosis. Thus, a further refinement of this model should evaluate other parasite‐ and host‐dependent variables.
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•MCPyV sequences grouped according to the geographic origin of human populations.•MCPyV diversification following human spread across the globe is suggested.•Specific MCPyV and HPyV6 ...lineages associated with South America.
New human polyomaviruses have been described in the last years, including the Merkel-cell polyomavirus (MCPyV; Human polyomavirus 5) and the Human polyomavirus 6 (HPyV6). Although their infection is usually asymptomatic, in immunocompromised host can cause life-threatening pathologies, such as the Merkel cell carcinoma, an aggressive skin neoplasia associated to the MCPyV. Despite being prevalent viruses in population, epidemiological data from South America are scarce, as well as the characterization of the viral types circulating and their origin. The aims of this work were to describe MCPyV and HPyV6 from environmental samples with different geographical origin and to analyze their phylogenetic and evolutionary histories, particularly for MCPyV.
Partial and complete genome sequences were obtained from sewage samples from Argentina, Uruguay and Spain. A total number of 87 sequences were obtained for MCPyV and 33 for HPyV6. Phylogenetic analysis showed that MCPyV sequences distributed according to their geographic origin in Europe/North America, Africa, Asia, South America and Oceania groups, suggesting that viral diversification might have followed human migrations across the globe. In particular, viruses from Argentina associated with Europe/North America and South America genotypes, whereas those from Uruguay and Spain also grouped with Africa genotype, reflecting the origin of the current population in each country, which could arrive not only during ancient human migration but also during recent migratory events. In addition, the South American group presented a high level of clusterization, showing internal clusters that could be related to specific locations, such as French Guiana and Brazil or the Southern region into South America, such as Argentina and Uruguay, suggesting a long term evolutionary process in the region.
Additionally, in this work, we carried out the first analysis about the evolutionary history of MCPyV trough the integration of phylogenetic, epidemiological and historical data. Since a strong association is observed between the phylogenetic relationships and the origin of the sampled population, this analysis was based on the hypothesis of co-divergence between the virus and human populations. This analysis resulted in a substitution rate of 5.1 × 10−8 s/s/y (∼5.1% of divergence per million years) for the complete genome of MCPyV, which is in the range of those estimated for other double-stranded DNA viruses.
Regarding HPyV6, a South American group with clusterization was observed (sequences from Uruguay). Meanwhile, sequences from Argentina grouped with European ones (France and Spain) and remained separated from those isolated in China, USA or Australia.
The analysis of viruses from the environment allowed us to deep characterize prevalent infections in different geographic regions, reveling that viruses circulating in each population reflected its origin and that there are specific lineages associated with South America.
Background
Despite notable advances in the support and treatment of patients admitted to the intensive care unit (ICU), the management of those who develop a systemic inflammatory response syndrome ...(SIRS) still constitutes an unmet medical need.
Main body
Both the initial injury (trauma, pancreatitis, infections) and the derived uncontrolled response promote a hyperinflammatory status that leads to systemic hypotension, tissue hypoperfusion and multiple organ failure. Mesenchymal stromal/stem cells (MSCs) are emerging as a potential therapy for severe ICU patients due to their potent immunomodulatory, anti‐inflammatory, regenerative and systemic homeostasis‐regulating properties. MSCs have demonstrated clinical benefits in several inflammatory‐based diseases, but their role in SIRS needs to be further explored.
Conclusion
In the current review, after briefly overviewing SIRS physiopathology, we explore the potential mechanisms why MSC therapy could aid in the recovery of this condition and the pre‐clinical and early clinical evidence generated to date.
Mesenchymal stromal/stem cells therapeutic potential for SIRS.
MSCs may control the exacerbated immune reaction after a critical insult (e.g. polytrauma, severe infections, burns and pancreatitis) at local and systemic levels.
MSCs can exert organ protection and tissue regeneration properties through direct and remote mechanisms.
MSCs are able to promote homeostasis recovery.
Most COVID-19 vaccines are based on the SARS-CoV-2 Spike glycoprotein (S) or their subunits. However, S shows some structural instability that limits its immunogenicity and production, hampering the ...development of recombinant S-based vaccines. The introduction of the K986P and V987P (S-2P) mutations increases the production and immunogenicity of the recombinant S trimer, suggesting that these two parameters are related. Nevertheless, S-2P still shows some molecular instability and it is produced with low yield. Here we described a novel set of mutations identified by molecular modeling and located in the S2 region of the S-2P that increase its production up to five-fold. Besides their immunogenicity, the efficacy of two representative S-2P-based mutants, S-29 and S-21, protecting from a heterologous SARS-CoV-2 Beta variant challenge was assayed in K18-hACE2 mice (an animal model of severe SARS-CoV-2 disease) and golden Syrian hamsters (GSH) (a moderate disease model). S-21 induced higher level of WH1 and Delta variants neutralizing antibodies than S-2P in K18-hACE2 mice three days after challenge. Viral load in nasal turbinate and oropharyngeal samples were reduced in S-21 and S-29 vaccinated mice. Despite that, only the S-29 protein protected 100% of K18-hACE2 mice from severe disease. When GSH were analyzed, all immunized animals were protected from disease development irrespectively of the immunogen they received. Therefore, the higher yield of S-29, as well as its improved immunogenicity and efficacy protecting from the highly pathogenic SARS-CoV-2 Beta variant, pinpoint the S-29 mutant as an alternative to the S-2P protein for future SARS-CoV-2 vaccine development.
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