2D and 3D microstructural analysis of the iliotibial tract.

The fascial system has gained recognition for its integral role in connecting skin, superficial and deep fasciae, and underlying muscles. However, consensus on its microstructure depending on its topography remains elusive as well as its implications in clinical practices, such as reconstructive surgery and physiotherapy techniques. This study focuses on the iliotibial tract (ITT) implicated in the iliotibial band syndrome. The goal is to describe microstructural characteristics using classical 2D histology and cryogenic contrast-enhanced microcomputed tomography (cryo-CECT) such as the total thickness, number of layers, layer thickness, fibre orientation and tortuosity, according to the specific topography. The total thickness of the ITT varied across topographic regions, with the superior part being on average thicker but non-significantly different from the other regions. The inferior part showed heterogeneity, with the anterior region (AI) being the thinnest and the posterior one (PI) the thickest. The ITT exhibited 1-3 layers, with no significant differences among regions. Most commonly, it consisted of two layers, except for the antero-superior (AS) and antero-middle (AM) regions, which sometimes had only one layer. The posterior regions frequently had 2 or 3 layers, with the PI region having the highest mean (2.7 layers). The intermediate layer was the thickest one, varying from the AI region (0.368 mm ± 0.114) to the PI region (0.640 mm ± 0.305). The superficial layer showed regional variability, with the AS region being the thinnest. The deep layer appeared thinner than the superficial one. Fibre orientation analysis indicated that the intermediate layer mainly consisted of oblique longitudinal fibres, orientated downward and forward, while the superficial and deep layers had transversal or oblique transversal fibres. Cryo-CECT 3D observations confirmed these findings, revealing distinct orientations for different layers. Fibre tortuosity exhibited differences based on orientation. Transversal fibres (>65°) were significantly less tortuous than longitudinal fibres (<25°) and oblique intermediate fibres (25°-65°), aligning with 3D plot observations. This quantitative study highlights various microstructural characteristics of the ITT, offering insights into its regional variations. The analysis accuracy is increased due to the novel technology of cryo-CECT which emerges as a valuable tool for precise assessment of 3D fibre orientation and tortuosity. These findings contribute to a deeper understanding of the ITT structure, useful in clinical practices, such as reconstructive surgery and physiotherapy, and future research endeavours.

Stromal cell-derived factor 1 (SDF-1) increases the number of telocytes in ex vivo and in vitro assays.

Telocytes are interstitial cells that are present in various tissues, have long cytoplasmic projections known as telopodes, and are classified as CD34+ cells. Telopodes form extensive networks that permeate the stroma, and there is evidence that these networks connect several stromal cell types, giving them an important role in intercellular communication and the maintenance of tissue organisation. Data have also shown that these networks can be impaired and the number of telocytes reduced in association with many pathological conditions such as cancer and fibrosis. Thus, techniques that promote telocyte proliferation have become an important therapeutic target. In this study, ex vivo and in vitro assays were conducted to evaluate the impact on prostatic telocytes of SDF-1, a factor involved in the proliferation and migration of CD34+ cells. SDF-1 caused an increase in the number of telocytes in explants, as well as morphological changes that were possibly related to the proliferation of these cells. These changes involved the fusion of telopode segments, linked to an increase in cell body volume. In vitro assays also showed that SDF-1 enriched prostate stromal cells with telocytes. Altogether, the data indicate that SDF-1 may offer promising uses in therapies that aim to increase the number of telocytes. However, further studies are needed to confirm the efficiency of this factor in different tissues/pathological conditions.

Emergent properties of a computational model of tumour growth.

While there have been enormous advances in our understanding of the genetic drivers and molecular pathways involved in cancer in recent decades, there also remain key areas of dispute with respect to fundamental theories of cancer. The accumulation of vast new datasets from genomics and other fields, in addition to detailed descriptions of molecular pathways, cloud the issues and lead to ever greater complexity. One strategy in dealing with such complexity is to develop models to replicate salient features of the system and therefore to generate hypotheses which reflect on the real system. A simple tumour growth model is outlined which displays emergent behaviours that correspond to a number of clinically relevant phenomena including tumour growth, intra-tumour heterogeneity, growth arrest and accelerated repopulation following cytotoxic insult. Analysis of model data suggests that the processes of cell competition and apoptosis are key drivers of these emergent behaviours. Questions are raised as to the role of cell competition and cell death in physical cancer growth and the relevance that these have to cancer research in general is discussed.