Biology subjects

Leszczynski, B.

Publications and source records attributed to Leszczynski, B..

4 recordsLinked to original sources

bioRxiv2025

Small extracellular vesicles reflect senescence progression in human bone marrow-derived mesenchymal stem cells during hollow fiber bioreactor culture

Prolonged three-dimensional culture exposes stem cells to sustained microenvironmental and mechanical stresses that can promote aging- and senescence-associated phenotypic alterations. This study examined how long-term expansion of human bone marrow-derived mesenchymal stem cells (BMSCs) in a hollow fiber bioreactor (HFB) influences cellular senescence and the molecular composition of secreted small extracellular vesicles (sEVs). During extended HFB culture, BMSCs exhibited progressive morphological flattening and cytoskeletal disorganization, accompanied by increased senescence-associated {beta}-galactosidase activity and immunophenotypic remodeling characterized by reduced fluorescence intensity and spatial redistribution of canonical MSC markers, consistent with a stress-adapted, early senescence-associated cellular state. In parallel, sEVs were collected longitudinally over 40 days and characterized by nanoparticle tracking analysis, immunoblotting, and quantitative proteomics. While vesicle size, marker expression, and yield remained stable throughout culture, proteomic profiling revealed pronounced, phase-dependent remodeling of sEV cargo, including coordinated alterations in oxidative stress-related processes, lysosomal and extracellular matrix-associated pathways, and relative depletion of cytoskeletal and translational components. Notably, these vesicular signatures closely mirrored senescence-associated changes observed at the cellular level. The strong correspondence between cellular phenotypes and sEV proteomic profiles establishes vesicle analysis as a convergent and noninvasive readout of BMSC aging, enabling sensitive monitoring of senescence progression while reducing reliance on parallel, labor-intensive cellular assays. Collectively, these findings indicate that prolonged HFB culture promotes a controlled, stress-associated senescence program in BMSCs and position sEV proteomic profiling as a robust approach for assessing stem cell aging dynamics during long-term three-dimensional bioreactor culture.

molecular biology↗

bioRxiv2025

Fresh Paraformaldehyde Preserves Thrombus Biochemistry - An ATR-FTIR and PCA Investigation of Pulmonary Artery Thrombi

BackgroundBiochemical analyses of pulmonary embolism derived thrombi depend critically on fixative quality. ObjectiveTo quantify the impact of paraformaldehyde (PFA) shelf life on thrombus molecular integrity using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and time-of-flight secondary ion mass spectroscopy (SIMS) combined with principal component analysis. MethodsTen pulmonary artery thrombi were fixed in either aged PFA (6 months; n = 6) or freshly prepared 4% PFA (n = 4); an in-vitro plasma clot control received the same fresh PFA. Triplicate ATR-FTIR spectra (400-4000 cm-1) were collected and vector-normalized to the Amide I band. ToF-SIMS measurements were performed using a 30 keV Bi primary ion beam Fixative chemistry was assessed by the carbonyl absorbance at 1700 cm-1. ResultsFreshly fixed thrombi displayed narrow Amide I (~1650 cm-1) and Amide II (~1540 cm-1) bands with a higher signal-to-noise ratio (SNR; median 41.8) than aged-PFA samples (18.2; P < .01). Carbonyl absorbance at 1700 cm-1 was markedly higher in fresh PFA. Aged PFA introduces chemical variances of biological samples in low-mass molecule fragments. PCA showed clear separation of fresh versus aged specimens and alignment of fresh thrombi with plasma controls across spectral windows. ConclusionsPFA solutions older than three months markedly deteriorate thrombus biochemical fidelity. ATR-FTIR and ToF-SIMS offer a rapid quality-control assay prior to molecular analyses. Key pointsO_LIPFA stored [≥]3 months loses >70% of reactive aldehydes, yielding broad Amide envelopes, attenuated lipid bands and a two fold SNR drop. C_LIO_LIAged PFA introduces chemical variances of biological samples in low-mass molecule fragments. C_LIO_LIPCA of fingerprint, protein or lipid windows cleanly separates aged from fresh fixations (PC1 up to 80% variance). C_LIO_LIA rapid QC workflow (carbonyl absorbance [≥]0.25 a.u. plus PCA verification) safeguards molecular integrity irrespective of patient age, DVT history or clinical severity. C_LIO_LIAdopting this workflow will harmonise multi centre clot biorepositories and enhance the reproducibility of proteomic, lipidomic and imaging studies. C_LI

biophysics↗

bioRxiv2023

Cardiopulmonary structural, functional and immune-alterations in a Down syndrome mouse model and upon modulation of EGCG

In individuals with Down syndrome (DS), cardiovascular and pulmonary diseases are the most common health problem and result in increased mortality and morbidity. Although these clinical comorbidities are well described, no preclinical models for DS are fully characterized for cardiopulmonary alterations, preventing research to understanding the development and pharmacological modulation of lungs, heart and immune system. Our objective is to characterize the cardiopulmonary and immunological phenotype in Ts65Dn mice and investigate the modulatory effects green tea extract enriched in epigallocatechin 3 gallate (GTE-EGCG). GTE-EGCG administration started at embryonic day 9 and was discontinued at postnatal day (PD) 180. Newborns were longitudinally monitored until PD210 using micro-computed tomography. At endpoint, we characterized the structural, functional and immunological alterations and persistent effects of GTE-EGCG administration. This study revealed normal lung development in the Ts65Dn mice and highlighted RV hypertrophy and immunological alterations. GTE-EGCG administration resulted in genotype-specific and genotype-independent alterations resulting in lung immaturation and airway hyperreactivity. Our results highlight the cardiovascular and immunological phenotype of Ts65Dn mice and potential use for safety studies of therapeutic agents in a DS-specific context. Summary statementThis study longitudinally follows respiratory and cardiac alterations in the Ts65Dn mouse model and describes the impact of prenatal EGCG modulation on the euploid and trisomic phenotype

systems biology↗

bioRxiv2021

Developing a Novel Positronium Biomarker for Cardiac Myxoma Imaging

Here, positronium imaging is presented to determine cardiac myxoma (CM) extracted from patients undergoing urgent cardiac surgery due to unexpected atrial masses. Positronium is an atom build from an electron and a positron, produced copiously in intra-molecular voids during the PET imaging. CM, the most common cardiac tumor in adults, accounts for 50-75% of benign cardiac tumors. We aimed to assess if positronium serves as a biomarker for diagnosing CM. Perioperative examinations and histopathology staining in six patients confirmed the primary diagnosis of CM. We observed significant differences in the mean positronium lifetime between tumor and normal tissues, with an average value of 1.92(02) ns and 2.72(05) ns for CM and the adipose tissue, respectively. Our findings, combined with positronium lifetime imaging, reveals the novel emerging positronium biomarker for cardiovascular imaging. One-Sentence SummaryPositronium may serve as an imaging biomarker for cancer diagnostics.

biophysics↗