A Divergent Platelet Transcriptome in Patients with Lipedema and Lymphedema.

Lipedema and lymphedema are physically similar yet distinct diseases that are commonly misdiagnosed. We previously reported that lipedema and lymphedema are associated with increased risk for venous thromboembolism (VTE). The underlying etiology of the prothrombotic profile observed in lipedema and lymphedema is unclear, but may be related to alterations in platelets. Our objective was to analyze the platelet transcriptome to identify biological pathways that may provide insight into platelet activation and thrombosis. The platelet transcriptome was evaluated in patients with lymphedema and lipedema, then compared to control subjects with obesity. Patients with lipedema were found to have a divergent transcriptome from patients with lymphedema. The platelet transcriptome and impacted biological pathways in lipedema were surprisingly similar to weight-matched comparators, yet different when compared to overweight individuals with a lower body mass index (BMI). Differences in the platelet transcriptome for patients with lipedema and lymphedema were found in biological pathways required for protein synthesis and degradation, as well as metabolism. Key differences in the platelet transcriptome for patients with lipedema compared to BMI-matched subjects involved metabolism and glycosaminoglycan processing. These inherent differences in the platelet transcriptome warrant further investigation, and may contribute to the increased risk of thrombosis in patients with lipedema and lymphedema.

Preliminary Single-Cell RNA-Sequencing Analysis Uncovers Adipocyte Heterogeneity in Lipedema.

Background: Despite its increasing incidence and prevalence throughout Western countries, lipedema continues to be a very enigmatic disease, often misunderstood or misdiagnosed by the medical community and with an intrinsic pathology that is difficult to trace. The nature of lipedemic tissue is one of hypertrophic adipocytes and poor tissue turnover. So far, there are no identified pathways responsible, and little is known about the cell populations of lipedemic fat. Methods: Adipose tissue samples were collected from affected areas of both lipedema and healthy participants. For single-cell RNA sequencing analysis, the samples were dissociated into single-cell suspensions using enzymatic digestion and then encapsulated into nanoliter-sized droplets containing barcoded beads. Within each droplet, cellular mRNA was converted into complementary DNA. Complementary DNA molecules were then amplified for downstream analysis. Results: The single-cell RNA-sequencing analysis revealed three distinct adipocyte populations at play in lipedema. These populations have unique gene signatures which can be characterized as a lipid generating adipocyte, a disease catalyst adipocyte, and a lipedemic adipocyte. Conclusions: The single-cell RNA sequencing of lipedemic tissue samples highlights a triad of distinct adipocyte subpopulations, each characterized by unique gene signatures and functional roles. The interplay between these adipocyte subtypes offers promising insights into the complex pathophysiology of lipedema.

AKR1C1 and hormone metabolism in lipedema pathogenesis: a computational biology approach.

OBJECTIVE: Lipedema is an autosomal dominant genetic disease that mainly affects women. It is characterized by excess deposition of subcutaneous adipose tissue, pain, and anxiety. The genetic and environmental etiology of lipedema is still largely unknown. Although considered a rare disease, this pathology has been suggested to be underdiagnosed or misdiagnosed as obesity or lymphedema. Steroid hormones seem to be involved in the pathogenesis of lipedema. Indeed, aldo-keto reductase family 1 member C1 (AKR1C1), a gene coding for a protein involved in steroid hormones metabolism, was the first proposed to be correlated with lipedema. PATIENTS AND METHODS: In this study, we employed a molecular dynamics approach to assess the pathogenicity of AKR1C1 genetic variants found in patients with lipedema. Moreover, we combined information theory and structural bioinformatics to identify AKR1C1 polymorphisms from the gnomAD database that could predispose to the development of lipedema. RESULTS: Three genetic variants in AKR1C1 found in patients with lipedema were disruptive to the protein's function. Furthermore, eight AKR1C1  variants found in the general population could predispose to the development of lipedema. CONCLUSIONS: The results of this study provide evidence that AKR1C1 may be a key gene in lipedema pathogenesis, and that common polymorphisms could predispose to lipedema development.