Human Thymus Gland in Young and Old Age; A Comparative Study

Aim: Research was undertaken to compare the findings between patients of different ages in terms of human thymus gland parameters. Study Design: Comparative/observational study Place and study: This study was conducted at anatomy department of Jinnah Hospital, Services Hospital and General Hospital Lahore during the period from November 2013 to October 2014. Methods: Total 70 specimens of human thymus of 54 patients were enrolled in this study. All specimens were divided in to two groups I and II, Group I contains 35 patients with ages < 30 years and group II with 35 patients having ages 45 to 60 years. All specimens were fixed in 10% formalin solution and then processed for paraffin embedding. Compare the different parameters such as thickness of interlobular connective tissue and thymic capsule, length and number of Hassal’s corpuscles between both groups. Data was analyzed by SPSS 23.0. Results: In group I mean age of the patient was 24.16±3.43 years with mean BMI 21.55±6.37 kg/m2 and in group II mean age was 52.11±2.87years with mean BMI 25.07±4.39 kg/m2. There was a significant difference observed between both groups regarding thickness of interlobular connective tissue and thymic capsule, quantity and length of Hassal’s corpuscles with p-value <0.05. Conclusion: As a result of this study, it can be inferred that younger patients had a substantially thinner thymic capsule and interlobular connective tissue, as well as more and smaller Hassal's corpuscles, than older patients. Keywords: Human Thymus Glands, Young Age, Old Age

Quantification of dendritic cell subsets in human thymus tissues of various ages

Background Dendritic cells (DCs) in the thymus are involved in central tolerance formation, but they also have other functions in the thymus, such as pathogen recognition. The density changes of human thymic DCs have been hardly investigated. In this study, human thymus samples of various ages were collected for tissue sectioning and staining. The thymic cortex and medulla area as well as the densities of various subsets of thymic DCs were calculated. Results All common DC subsets were found in the human thymus of various ages. Most DCs had accumulated in the human thymic epithelial space, especially the medulla. We also found that the human thymic cortex had atrophied relatively faster than the medulla, which led to a gradual increase of the area ratio of the medulla to cortex with the increase of age. The densities of DC subsets in the human thymus showed various changes with increasing age, which contributed to the composition changes of DC subsets. The density of plasmacytoid DCs (pDCs) in the human thymus had increased gradually with aging, which suggested that pDCs plays another essential role in the thymus in addition to central tolerance. Conclusions Inconsistent with the shrinking of the epithelial space in the thymus, the densities of DC subsets in the epithelial space of the thymus are maintained at a constant level with aging to preserve highly efficient autoreactive thymocyte screening. An increasing density of the thymic pDCs with aging implies an extra function of DCs in the thymus beyond central tolerance.

P03.07 Analysis of scRNAseq from the human thymus nominates genes potentially missing from central tolerance of cytotoxic T cells

BackgroundDuring thymic development, cytotoxic T cells that can bind to and attack self antigens undergo negative selection thus preventing damage to the self tissues. The sparse medullar thymic epithelial cells (mTECs) present in the thymus are responsible for presenting self antigens to T cells so that they can trigger apoptosis or differentiation into non-cytotoxic lineages if they bind too strongly.Materials and MethodsUnderstanding gene expression in mTECs is essential for understanding the shape of the human T cell receptor repertoire, which is key for current and emerging cancer immunotherapies. Recent availability of human thymus single cell RNAseq (scRNAseq) data provides an extremely high-resolution view into the pattern of expression within this critical cell type. To determine which epitopes have had to opportunity to be presented during T cell negative selection, we analyzed the human thymus scRNAseq dataset to establish which genes are expressed in mTECs and therefore subject to central tolerance.ResultsThe coverage of the whole transcriptome of a particular cell is generally sparse. It is therefore difficult to understand basic features of individual cells or cell types such as how many genes are expressed. We used cell- and read-level subsampling to estimate whether a sufficient number of cells and reads had been captured to support categorizing a gene as non-expressed in mTECs. We also examined the expression of the genes not expressed in mTECs in other healthy tissues, and found their expression was almost exclusively restricted to the testis (an immune-privileged site) and the liver (a site of peripheral tolerance)ConclusionsAltogether, these analyses establish a strategy for determining if a data set has sufficient depth to estimate the total number of genes expressed and secondly define a key list of genes that are not expressed during central tolerization of T cells, which represent a compelling list of possible cancer immunotherapy targets.Disclosure InformationL. Blumenberg: A. Employment (full or part-time); Significant; Regeneron Pharmaceuticals. G. Atwal: A. Employment (full or part-time); Significant; Regeneron Pharmaceuticals. A. Dhanik: A. Employment (full or part-time); Significant; Regeneron Pharmaceuticals.

Human Thymus single cell dissociation protocol - Teichmann Lab v1

This Protocol is intended for human Thymus single cell dissociation. It includes tissue preservation and handling, Enzymatic dissociation, FACS an MACS enrichments. Developed In the Teichmann lab at the Sanger institute, Wellcome Gemone Campus, UK VK, CS and JP contributed equally

Lipidomic Typing of Colorectal Cancer Tissue Containing Tumour-Infiltrating Lymphocytes by MALDI Mass Spectrometry Imaging

Predicting the prognosis of colorectal cancer (CRC) patients remains challenging and a characterisation of the tumour immune environment represents one of the most crucial avenues when attempting to do so. For this reason, molecular approaches which are capable of classifying the immune environments associated with tumour infiltrating lymphocytes (TILs) are being readily investigated. In this proof of concept study, we aim to explore the feasibility of using spatial lipidomics by MALDI-MSI to distinguish CRC tissue based upon their TIL content. Formalin-fixed paraffin-embedded tissue from human thymus and tonsil was first analysed by MALDI-MSI to obtain a curated mass list from a pool of single positive T lymphocytes, whose putative identities were annotated using an LC-MS-based lipidomic approach. A CRC tissue microarray (TMA, n = 30) was then investigated to determine whether these cases could be distinguished based upon their TIL content in the tumour and its microenvironment. MALDI-MSI from the pool of mature T lymphocytes resulted in the generation of a curated mass list containing 18 annotated m/z features. Initially, subsets of T lymphocytes were then distinguished based on their state of maturation and differentiation in the human thymus and tonsil tissue. Then, when applied to a CRC TMA containing differing amounts of T lymphocyte infiltration, those cases with a high TIL content were distinguishable from those with a lower TIL content, especially within the tumour microenvironment, with three lipid signals being shown to have the greatest impact on this separation (p < 0.05). On the whole, this preliminary study represents a promising starting point and suggests that a lipidomics MALDI-MSI approach could be a promising tool for subtyping the diverse immune environments in CRC.

Comparison of Human Thymus Gland between Young and Old Age

Aim: Study was conducted to examine the different parameters of human thymus glands of young and old patients and compare the findings between both age groups. Study Design: Comparative/observational study Place and Study: Study was conducted at Anatomy department of Nishtar Medical University Hospital, Multan for duration of six months from 15th January 2020 to 15th July 2020. Methods: Total 54 specimens of human thymus of 54 patients were enrolled in this study. All specimens were divided in to two groups I and II, Group I contains 27 patients with ages <30 years and group II with 27 patients having ages 45 to 60 years. All specimens were fixed in 10% formalin solution and then processed for paraffin embedding. Compare the different parameters such as thickness of interlobular connective tissue and thymic capsule, length and number of Hassal’s corpuscles between both groups. Data was analyzed by SPSS 24.0. Results: In group I 12 (44.44%) patients were ages <15 years and 15 (55.56%) patients were ages >15 years. In group 13 (48.15%) and 14 (51.85%) patients were ages <50 years and >50 years. There was a significant difference observed between both groups regarding thickness of interlobular connective tissue and thymic capsule, quantity and length of Hassal’s corpuscles with p-value <0.05. Conclusion: It is to be concluded that patients with young age had significantly less thickness of thymic capsule and interlobular connective tissue with more in number and decreasing size of Hassal’s corpuscles as compared to old age patients. Keywords: Human Thymus Glands, Young Age, Old Age

Mouse Surgery – Transplantation of human thymus into the kidney capsule of NSG mice v1

This protocol details our minimally invasive approach for implanting human thymus tissue under the kidney capsule of NSG mice. In contrast to our open abdominal approach, this approach is from the dorsal aspect of the mouse and requires only two interrupted sutures and 1-2 staples to close the incision. The technique can be applied to other strains of mice, though we have found the NSG kidney capsule to be more delicate, and thus more challenging to manipulate during surgery.