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Pitsalidis, C.

Publications and source records attributed to Pitsalidis, C..

2 recordsLinked to original sources

In Silico Investigation of the Role of Local and Global Inflammation-Driven Feedback in Myelopoiesis and Clonal Cell Expansion

Chronic inflammation perturbs hematopoietic homeostasis, promoting aberrant myelopoiesis and clonal expansion of mutated stem cells. Here, we develop a mathematical model that integrates both local (bone marrow-intrinsic) and global (systemic/peripheral) inflammation-driven feedback mechanisms to investigate their roles in hematopoietic regulation and disease progression. Our model captures the nonlinear interplay between self-renewal, progenitor proliferation, and inflammatory cues, enabling classification of healthy, myelodysplastic, and leukemic states based on stem cell population dynamics. We show that global inflammatory feedback enhances the resilience of hematopoiesis, while excessive feedback on progenitor cells under chronic inflammation drives instability and clonal dominance. Using sensitivity analysis and parameter space mapping, we identify critical feedback thresholds governing transitions between hematopoietic states and reveal how mutated clones exploit inflammation to outcompete wild-type cells. This systems-level framework offers mechanistic insights into the emergence of myeloid malignancies and provides a computational platform for exploring potential anti-inflammatory therapeutic strategies.

systems biology↗

3D Organic Bioelectronics for Monitoring In Vitro Stem Cell Cultures

Three-dimensional in vitro stem cell models has enabled a fundamental understanding of cues that direct stem cell fate and be used to develop novel stem cell treatments. While sophisticated 3D tissues can be generated, technology that can accurately monitor these complex models in a high-throughput and non-invasive manner is not well adapted. Here we show the development of 3D bioelectronic devices based on the electroactive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) - PEDOT:PSS and their use for non-invasive, electrical monitoring of stem cell growth. We show that the electrical, mechanical and wetting properties as well as the pore size/architecture of 3D PEDOT:PSS scaffolds can be fine-tuned simply by changing the processing crosslinker additive. We present a comprehensive characterization of both 2D PEDOT:PSS thin films of controlled thicknesses, and 3D porous PEDOT:PSS structures made by the freeze-drying technique. By slicing the bulky scaffolds we show that homogeneous, porous 250 um thick PEDOT:PSS slices are produced, generating biocompatible 3D constructs able to support stem cell cultures. These multifunctional membranes are attached on Indium-Tin oxide substrates (ITO) with the help of an adhesion layer that is used to minimize the interface charge resistance. The optimum electrical contact result in 3D devices with a characteristic and reproducible, frequency dependent impedance response. This response changes drastically when human adipose derived stem cells grow within the porous PEDOT:PSS network as revealed by fluorescence microscopy. The increase of these stem cell population within the PEDOT:PSS porous network impedes the charge flow at the interface between PEDOT:PSS and ITO, enabling the interface resistance to be extracted by equivalent circuit modelling, used here as a figure of merit to monitor the proliferation of stem cells. The strategy of controlling important properties of 3D PEDOT:PSS structures simply by altering processing parameters can be applied for development of a number of stem cell in vitro models. We believe the results presented here will advance 3D bioelectronic technology for both fundamental understanding of in vitro stem cell cultures as well as the development of personalized therapies.

bioengineering↗