Eleven-month longitudinal study of antibodies in SARS-CoV-2 exposed and naïve primary health care workers upon COVID-19 vaccination

We evaluated the kinetics of antibody responses to Two years into the COVID-19 pandemic and 1 year after the start of vaccination rollout, the world faced a peak of cases associated with the highly contagious Omicron variant of concern (VoC) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) and nucleocapsid (N) antigens over five cross-sectional visits (January-November 2021), and the determinants of pre-booster immunoglobulin levels, in a prospective cohort of vaccinated primary health care workers in Catalonia, Spain. Antibodies against S antigens after a full primary vaccination course, mostly with BNT162b2, decreased steadily over time and were higher in pre-exposed (n = 247) than naive (n = 200) individuals, but seropositivity was maintained at 100% (100% IgG, 95.5% IgA, 30.6% IgM) up to 319 days after the first dose. Antibody binding to variants of concern was highly maintained for IgG compared to wild type but significantly reduced for IgA and IgM, particularly for Beta and Gamma. Factors significantly associated with longer-term antibodies included age, sex, occupation, smoking, adverse reaction to vaccination, levels of pre-vaccination SARS-CoV-2 antibodies, interval between disease onset and vaccination, hospitalization, oxygen supply, post COVID and symptomatology. Earlier morning vaccination hours were associated with higher IgG responses in pre-exposed participants. Symptomatic breakthroughs occurred in 9/447 (2.01%) individuals, all among naive (9/200, 4.5%) and generally boosted antibody responses. Additionally, an increase in IgA and/or IgM seropositivity to variants, and N seroconversion at later time points (6.54%), indicated asymptomatic breakthrough infections, even among pre-exposed. Seropositivity remained highly stable over almost a year after vaccination. However, gradually waning of anti-S IgGs that correlate with neutralizing activity, coupled to evidence of an increase in breakthrough infections during the Delta and Omicron predominance, provides a rationale for booster immunization

Adipose-derived stromal cells (ASCs)

Adipose-derived stromal cells (ASCs) are now emerging as a good alternative to bone marrow derived mesenchymal stromal cells (BM-MSC) for cellular therapy. Similarly to BM-MSC, ASCs can be easily isolated as adherent fibroblastoid cell population after processing lipoaspirate samples. Lipoaspiration provides a great number of cells, without extensive manipulation. ASCs express classical mesenchymal markers and only at early passages express CD34. ASCs can differentiate in cells of mesodermal lineages, such as adipocytes, osteocytes and condrocytes. ASCs share with BM-MSC the same ability to inhibit the proliferation of allogeneic, activated immune cells, thus affecting in vivo in animal models the onset and course of rheumatoid arthritis (RA), experimental autoimmune encephalomyelitis (EAE), Crohn\u2019s disease (CD), ulcerous colitis (UC) and graft-versus-host disease (GvHD). On the other hand, the main molecular pathway involved in this effect is still unclear. On the basis of this functional property, ASCs are used in different clinical trials to treat RA, CD, UC and GvHD. However, the most promising field of clinical application is represented by bone defect repair. Despite the ability to regenerate injured tissues and to block the progression of inflammatory disorders, some authors reported that ASCs can also induce, in in vivo animal models, the growth and vascularization of solid and hematological tumors. Conversely, ASCs have been shown to hamper tumor cell proliferation, reduce cell viability and induce necrosis. Thus, more accurate studies, collaborative protocols, high standardization of methods, and safety controls are required to exclude transformation of transplanted ASCs

Clinical-grade mesenchymal stromal cells produced under various GMP processes differ in their immunomodulatory properties: standardization of immune quality controls

Clinical-grade mesenchymal stromal cells (MSC) are usually expanded from bone marrow (BMMSC) or adipose tissue (ADSC) using processes mainly differing in the use of fetal calf serum (FCS) or human platelet lysate (PL). We aimed to compare immune modulatory properties of clinical-grade MSC using a combination of fully standardized in vitro assays. BMMSC expanded with FCS (BMMSC-FCS) or PL (BMMSC-PL), and ADSC-PL were analyzed in quantitative phenotypic and functional experiments including their capacity to inhibit the proliferation of T, B, and NK cells. The molecular mechanisms supporting T-cell inhibition were investigated. These parameters were also evaluated after pre-stimulation of MSC with inflammatory cytokines. BMMSC-FCS, BMMSC-PL, and ADSC-PL displayed significant differences in expression of immunosuppressive and adhesion molecules. Standardized functional assays revealed that resting MSC inhibited proliferation of T and NK cells, but not B cells. ADSC-PL were the most potent in inhibiting T-cell growth, a property ascribed to IFN-\u3b3-dependent indoleamine 2,3-dioxygenase activity. MSC did not stimulate allogeneic T cell proliferation but were efficiently lysed by activated NK cells. The systematic use of quantitative and reproducible validation techniques highlights differences in immunological properties of MSC produced using various clinical-grade processes. ADSC-PL emerge as a promising candidate for future clinical trial

The onset of PI3K-related vascular malformations occurs during angiogenesis and is prevented by the AKT inhibitor miransertib

Low-flow vascular malformations are congenital overgrowths composed of abnormal blood vessels potentially causing pain, bleeding and obstruction of different organs. These diseases are caused by oncogenic mutations in the endothelium, which result in overactivation of the PI3K/AKT pathway. Lack of robust in vivo preclinical data has prevented the development and translation into clinical trials of specific molecular therapies for these diseases. Here, we demonstrate that the Pik3caH1047R activating mutation in endothelial cells triggers a transcriptome rewiring that leads to enhanced cell proliferation. We describe a new reproducible preclinical in vivo model of PI3K-driven vascular malformations using the postnatal mouse retina. We show that active angiogenesis is required for the pathogenesis of vascular malformations caused by activating Pik3ca mutations. Using this model, we demonstrate that the AKT inhibitor miransertib both prevents and induces the regression of PI3K-driven vascular malformations. We confirmed the efficacy of miransertib in isolated human endothelial cells with genotypes spanning most of human low-flow vascular malformations.The research leading to these results has received funding by the Spanish Ministry of Science and Innovation MICINN (PID2020-116184RB-I00 /AEI/10.13038/501100011033). M.G. laboratory is supported by the research grants SAF2017-89116R-P (FEDER/EU) from MCIU (Spain) co-funded by European Regional Developmental Fund (ERDF), a Way to Build Europe and PID2020-116184RB-I00 from MCEI; PTEN RESEARCH Foundation (IJC-21-001); la Caixa Banking Foundation (LCF/PR/PR16/51110035 and LCF/PR/HR19/52160023; also to E.B. and J.M.); by la Asociación Española contra el Cancer (AECC)-Grupos Traslacionales (GCTRA18006CARR); by la Fundación BBVA (Ayuda Fundación BBVA a Equipos de Investigación Científica 2019); World Cancer Research (21-0159). The computations and data handling were enabled by resources in projects SNIC 2019/30-26 and SNIC 2019/8-129, provided by the Swedish National Infrastructure for Computing (SNIC) at UPPMAX, partially funded by the Swedish Research Council through grant agreement no. 2018-05973. Personal support was from Marie-Curie ITN Actions (P.K. and J.Z.) grant agreement 675392. L.G. is funded by the Swedish Research Council (2018-06591). S.D.C. is a recipient of a fellowship from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant agreement No 749731. S.D.C. is currently funded by la Caixa Banking Foundation Junior Leader project (LCF/BQ/PR20/11770002). E.B. is funded by the Agencia Estatal de Investigación (Proyectos de investigación en salud PI20/00102)