Clinical significance of platelet mononuclear cell aggregates in patients with sepsis and acute respiratory distress syndrome

BACKGROUND The diagnosis of sepsis combined with acute respiratory distress syndrome(ARDS)has increased owing to the enhanced awareness among medical profes-sionals and the continuous development of modern medical technologies,while early diagnosis of ARDS still lacks specific biomarkers.One of the main patho-genic mechanisms of sepsis-associated ARDS involves the actions of various pathological injuries and inflammatory factors,such as platelet and white blood cells activation,leading to an increase of surface adhesion molecules.These adhesion molecules further form platelet-white blood cell aggregates,including platelet-mononuclear cell aggregates(PMAs).PMAs has been identified as one of the markers of platelet activation,here we hypothesize that PMAs might play a potential biomarker for the early diagnosis of this complication.METHODS We selected 72 hospitalized patients diagnosed with sepsis as the study population between March 2019 and March 2022.Among them,30 patients with sepsis and ARDS formed the study group,while 42 sepsis patients without ARDS comprised the control group.After diagnosis,venous blood samples were imme-diately collected from all patients.Flow cytometry was employed to analyze the expression of PMAs,platelet neutrophil aggregates(PNAs),and platelet aggregates(PLyAs)in the serum.Additionally,the Acute Physiology and Chronic Health Evaluation(APACHE)II score was calculated for each patient,and receiver operating characteristic curves were generated to assess diagnostic value.RESULTS The study found that the levels of PNAs and PLyAs in the serum of the study group were higher than those in the control group,but the difference was not statistically significant(P>0.05).However,the expression of PMAs in the serum of the study group was significantly upregulated(P<0.05)and positively correlated with the APACHE II score(r=0.671,P<0.05).When using PMAs as a diagnostic indicator,the area under the curve value was 0.957,indicating a high diagnostic value(P<0.05).Furthermore,the optimal cutoff value was 8.418%,with a diagnostic sensitivity of 0.819 and specificity of 0.947.CONCLUSION In summary,the serum levels of PMAs significantly increase in patients with sepsis and ARDS.Therefore,serum PMAs have the potential to become a new biomarker for clinically diagnosing sepsis complicated by ARDS.

Abiotic factors in colony formation:effects of nutrition and light on extracellular polysaccharide production and cell aggregates of Microcystis aeruginosa

Colony morphology is important for Microcystis to sustain a competitive advantage in eutrophic lakes. The mechanism of colony formation in Microcystis is currently unclear. Extracellular polysaccharide （EPS） has been reported to play an important role in cell aggregate formation of some phytoplankton. Microcystis aeruginosa was cultivated under varied abiotic conditions, including different nutrient, light, and temperature conditions, to investigate their effects on EPS production and morphological change. The results show that nutrient concentration and light intensity have great effects on EPS production in M. aeruginosa. There was a considerable increase in EPS production after M. aeruginosa was cultivated in adjusted culture conditions similar to those present in the field （28.9 mg C/L, 1.98 mg N/L, 0.65 mg P/L, light intensity： 100 μtmol/（m2.s））. These results indicate that abiotic factors might be one of the triggers for colony formation in Microcystis.

ADVANCES IN EXPERIMENTAL APPROACHES FOR INVESTIGATING CELL AGGREGATE MECHANICS

Cells tend to form hierarchy structures in native tissues. Formation of cell aggregates in vitro such as cancer spheroids and embryonic bodies provides a unique means to study the mechanical properties and biological behaviors/functions of their counterparts in vivo. In this paper, we review state-of-the-art experimental approaches to assess the mechanical properties and mechanically-induced responses of cell aggregates in vitro. These approaches are classified into five categories according to loading modality, including micropipette aspiration, centrifugation, compression loading, substrate distention, and fluid shear loading. We discussed the advantages and disadvantages of each approach, and the potential biomedical applications. Understanding of the mechanical behavior of cell aggregates provides insights to physical interactions between cells and integrity of biological functions, which may enable mechanical intervention for diseases such as atheromatosis and cancer.

TTYH2,a human homologue of the Drosophila melanogaster gene tweety,is up-regulated in colon carcinoma and involved in cell proliferation and cell aggregation

AIM: To investigate the expression patterns of TTYH2 in the human colon cancer and colon cancer cell lines and to evaluate the inhibitory effect of small interfering RNA (siRNA) on the expression of TTYH2 in colon cancer cell lines.METHODS: We investigated the expression patterns of TTYH2 in colon cancer, adjacent non-tumorous colon mucosa, and cancer cell lines (DLD-1, caco-2, and Lovo) by RT-PCR. Furthermore, a siRNA plasmid expression vector against TTYH2 was constructed and transfected into DLD-1 and Caco-2 with LipofectamineTM 2000. The down regulation of TTYH2 expression was detected by RT-PCR and the role of siRNA in inducing cell proliferation and cell aggregation was evaluated by MTT and aggregation assay.RESULTS: TTYH2 gene expression in colon cancer tissue was significantly up-regulated compared with normal colonic mucosa (1.23 ± 0.404 vs 0.655 ± 0.373, P = 0.0103). Colon cancer derived cell lines including DLD-1, Caco-2, and Lovo also expressed high levels of TTYH2. In contrast, transfection with siRNA-TTYH2 signifi cantly inhibited both proliferation and scattering of these cancer cell lines.CONCLUSION: The present work demonstrates, for the fi rst time, that the TTYH2 gene expression is signifi cantly up-regulated in colon cancer. The TTYH2 gene may play an important role in regulating both proliferating andmetastatic potentials of colorectal cancer.

Combined modeling of cell aggregation and adhesion mediated by receptor–ligand interactions under shear flow

Blood cell aggregation and adhesion to endothelial cells under shear flow are crucial to many biological processes such as thrombi formation, inflammatory cascade, and tumor metastasis, in which these cellular interactions are mainly mediated by the underlying receptor-ligand bindings. While theoretical modeling of aggregation dynamics and adhesion kinetics of interacting cells have been well studied separately, how to couple these two processes remains unclear. Here we develop a combined model that couples cellular aggregation dynamics and adhesion kinetics under shear flow. The impacts of shear rate （or shear stress） and molecular binding affinity were elucidated. This study provides a unified model where the action of a fluid flow drives cell aggregation and adhesion under the modulations of the mechanical shear flow and receptor-ligand interaction kinetics. It offers an insight into understanding the relevant biological processes and functions.

Modeling human hypertrophic scars with 3D preformed cellular aggregates bioprinting

The therapeutic interventions of human hypertrophic scars(HHS)remain puzzle largely due to the lack of accepted models.Current HHS models are limited by their inability to mimic native scar architecture and associated pathological microenvironments.Here,we create a 3D functional HHS model by preformed cellular aggregates(PCA)bioprinting,firstly developing bioink from scar decellularized extracellular matrix(ECM)and alginate-gelatin(Alg-Gel)hydrogel with suitable physical properties to mimic the microenvironmental factors,then pre-culturing patient-derived fibroblasts in this bioink to preform the topographic cellular aggregates for sequent printing.We confirm the cell aggregates preformed in bioink displayed well defined aligned structure and formed functional scar tissue self-organization after bioprinting,hence showing the potential of creating HHS models.Notably,these HHS models exhibit characteristics of early-stage HHS in gene and protein expression,which significantly activated signaling pathway related to inflammation and cell proliferation,and recapitulate in vivo tissue dynamics of scar forming.We also use the in vitro and in vivo models to define the clinically observed effects to treatment with concurrent anti-scarring drugs,and the data show that it can be used to evaluate the potential therapeutic target for drug testing.The ideal humanized scar models we present should prove useful for studying critical mechanisms underlying HHS and to rapidly test new drug targets and develop patient-specific optimal therapeutic strategies in the future.

Alternatives for large-scale production of cultured beef: A review

Cultured beef is a method where stem cells from skeletal muscle of cows are cultured in vitro to gain edible muscle tissue. For large-scale production of cultured beef, the culture technique needs to become more efficient than today＇s 2-dimensional（2D） standard technique that was used to make the first cultured hamburger. Options for efficient large-scale production of stem cells are to culture cells on microcarriers, either in suspension or in a packed bed bioreactor, or to culture aggregated cells in suspension. We discuss the pros and cons of these systems as well as the possibilities to use the systems for tissue culture. Either of the production systems needs to be optimized to achieve an efficient production of cultured beef. It is anticipated that the optimization of large-scale cell culture as performed for other stem cells can be translated into successful protocols for bovine satellite cells resulting in resource and cost efficient cultured beef.

Characterization of a new lectin involved in the protoplast regeneration of Bryopsis hypnoides

A group of coenocytic marine algae differs from higher plants,whose totipotency depends on an intact cell(or protoplast).Instead,this alga is able to aggregate its extruded protoplasm in sea water and generate new mature individuals.It is thought that lectins play a key role in the aggregation process.We purified a lectin associated with the aggregation of cell organelles in Bryopsis hypnoides.The lectin was ca.27 kDa with a pI between pH 5 and pH 6.The absence of carbohydrate suggested that the lectin was not a glycoprotein.The hemagglutinating activity(HA) of the lectin was not dependent on the presence of divalent cations and was inhibited by N-Acetylgalactosamine,N-Acetylglucosamine,and the glycoprotein bovine submaxillary mucin.The lectin preferentially agglutinated Gram-negative bacterium.The HA of this lectin was stable between pH 4 to pH 10.Cell organelles outside the cytoplasm were agglutinated by the addition of lectin solution(0.5 mg ml-1).Our results suggest that the regeneration of B.hypnoides is mediated by this lectin.We also demonstrated that the formation of cell organelle aggregates was inhibited by nigericin in natural seawater(pH 8.0).Given that nigericin dissipates proton gradients across the membrane,we hypothesize that the aggregation of cell organelles was proton-gradient dependent.

3D printed silk-gelatin hydrogel scaffold with different porous structure and cell seeding strategy for cartilage regeneration

Hydrogel scaffolds are attractive for tissue defect repair and reorganization because of their human tissue-like characteristics.However,most hydrogels offer limited cell growth and tissue formation ability due to their submicron-or nano-sized gel networks,which restrict the supply of oxygen,nutrients and inhibit the proliferation and differentiation of encapsulated cells.In recent years,3D printed hydrogels have shown great potential to overcome this problem by introducing macro-pores within scaffolds.In this study,we fabricated a macroporous hydrogel scaffold through horseradish peroxidase(HRP)-mediated crosslinking of silk fibroin(SF)and tyramine-substituted gelatin(GT)by extrusion-based low-temperature 3D printing.Through physicochemical characterization,we found that this hydrogel has excellent structural stability,suitable mechanical properties,and an adjustable degradation rate,thus satisfying the requirements for cartilage reconstruction.Cell suspension and aggregate seeding methods were developed to assess the inoculation efficiency of the hydrogel.Moreover,the chondrogenic differentiation of stem cells was explored.Stem cells in the hydrogel differentiated into hyaline cartilage when the cell aggregate seeding method was used and into fibrocartilage when the cell suspension was used.Finally,the effect of the hydrogel and stem cells were investigated in a rabbit cartilage defect model.After implantation for 12 and 16 weeks,histological evaluation of the sections was performed.We found that the enzymatic cross-linked and methanol treatment SF5GT15 hydrogel combined with cell aggregates promoted articular cartilage regeneration.In summary,this 3D printed macroporous SF-GT hydrogel combined with stem cell aggregates possesses excellent potential for application in cartilage tissue repair and regeneration.

Controlling molecular weight of naphthalenediimide-based polymer acceptor P(NDI2OD-T2)for high performance all-polymer solar cells

A widely-used naphthalenediimide （NDI） based electron acceptor P（NDI2OD-T2） with different number- average molecular weight （Mn） of 38 （N2200L）, 56 （N2200M）, 102 （N2200H） kDa were successfully prepared. The effect of molecular-weight on the performance of all-polymer solar cells based on Poly（5-（5-（4,8- bis（ 5-decylthiophen-2-yl ）-6-methylbenzo[1,2-b： 4,5-b＇]dithophen-2-yl ）thiophen-2-yl ）-6,7-difluoro-8- （5-methylthiophen-2-yl）-2,S-bis（3-（octyloxy）phenyl）quinoxaline） （P2F-DE）：N2200 was systematically investigated. The results reveal that N2200 with increased M. show enhanced intermolecular interac- tions, resulting in improved light absorption and electron mobility. However, the strong aggregation trend of N2200H can cause unfavorable morphology for exciton dissociation and carrier transport. The blend film using N2200 with moderate M. actually develops more ideal phase segregation for efficient charge separation and transport, leading to balanced electron/hole mobility and less carrier recombi- nation. Consequently, all-polymer solar cells employing P2F-DE as the electron donor and N2200M as the electron acceptor show the highest efficiency of 4.81%, outperforming those using N2200L （3,07~;） and N2200H （S,92%）. Thus, the Mn of the polymer acceptor plays an important role in all-polymer solar ceils, which allows it to be an effective parameter for the adjustment of the device morphology and efficiency.