Glycosphingolipid Levels in Urine Extracellular Vesicles Enhance Prediction of Therapeutic Response in Lupus Nephritis

Extracellular vesicles: Illuminating renal pathophysiology and therapeutic frontiers

Extracellular vesicles (EVs) are minute sacs released by cells into the extracellular milieu, harboring an array of biomolecules including proteins, nucleic acids, and lipids. Notably, a large number of studies have demonstrated the important involvement of EVs in both physiological and pathological aspects of renal function. EVs can facilitate communication between different renal cells, but it is important to recognize their dual role: they can either transmit beneficial information or lead to renal damage and worsening of existing conditions. The composition of EVs in the context of the kidneys offers valuable insights into the intricate mechanisms underlying specific renal functions or disease states. In addition, mesenchymal stem cell-derived EVs have the potential to alleviate acute and chronic kidney diseases. More importantly, the innate nanoparticle properties of EVs, coupled with their engineering potential, make them effective tools for drug delivery and therapeutic intervention. In this review, we focus on the intricate biological functions of EVs in the kidney. In addition, we explore the emerging role of EVs as diagnostic tools and innovative therapeutic agents in a range of renal diseases.

Metabolic Markers and Association of Biological Sex in Lupus Nephritis

Lupus nephritis (LN) is a serious complication for many patients who develop systemic lupus erythematosus, which primarily afflicts women. Our studies to identify biomarkers and the pathogenic mechanisms underlying LN will provide a better understanding of disease progression and sex bias, and lead to identification of additional potential therapeutic targets. The glycosphingolipid lactosylceramide (LacCer) and N-linked glycosylated proteins (N-glycans) were measured in urine and serum collected from LN and healthy control (HC) subjects (10 females and 10 males in each group). The sera from the LN and HC subjects were used to stimulate cytokine secretion and intracellular Ca2+ flux in female- and male-derived primary human renal mesangial cells (hRMCs). Significant differences were observed in the urine of LN patients compared to HCs. All major LacCers species were significantly elevated and differences between LN and HC were more pronounced in males. 72 individual N-glycans were altered in LN compared to HC and three N-glycans were significantly different between the sexes. In hRMCs, Ca2+ flux, but not cytokine secretion, was higher in response to LN sera compared to HC sera. Ca2+ flux, cytokine secretion, and glycosphingolipid levels were significantly higher in female-derived compared to male-derived hRMCs. Relative abundance of some LacCers and hexosylceramides were higher in female-derived compared to male-derived hRMCs. Urine LacCers and N-glycome could serve as definitive LN biomarkers and likely reflect renal disease activity. Despite higher sensitivity of female hRMCs, males may experience greater increases in LacCers, which may underscore worse disease in males. Elevated glycosphingolipid metabolism may poise renal cells to be more sensitive to external stimuli.

Biomarkers Associated with Drugs for the Treatment of Lupus Nephritis

The constant updating of lupus drug treatment guidelines has led to a question. How can the efficacy of treatment be more effectively monitored? Systemic lupus erythematosus (SLE) is a complex autoimmune disease that often presents clinically with multi-organ involvement, and approximately 30% of patients with SLE develop lupus nephritis (LN). Therefore, it is important to better track disease progression and drug efficacy. Now, kidney biopsy is still the gold standard for diagnosing and guiding the treatment of LN, but it is invasive and expensive. If simple, non-invasive and effective biomarkers can be found, drug intervention and prognosis can be better monitored and targeted. In this review, we focus on LN and explore biomarkers related to LN therapeutics, providing clinicians with more possibilities to track the therapeutic effect of drugs, improve treatment options and assess patient outcomes.

Glycosylation in extracellular vesicles: Isolation, characterization, composition, analysis and clinical applications

This review provides a comprehensive overview of our understanding of the role that glycans play in the formation, loading and release of extracellular vesicles (EVs). The capture of EVs (typically with a size of 100-200 nm) is described, including approaches based on glycan recognition with glycan-based analysis offering highly sensitive detection of EVs. Furthermore, detailed information is provided about the use of EV glycans and glycan processing enzymes as potential biomarkers, therapeutic targets or tools applied for regenerative medicine. The review also provides a short introduction into advanced methods for the characterization of EVs, new insights into the biomolecular corona covering EVs and bioanalytical tools available for glycan analysis.

Utility of the ACR-1997, SLICC-2012 and EULAR/ACR-2019 classification criteria for systemic lupus erythematosus: a single-centre retrospective study

Background and aims

Several different versions of classification criteria, including the American College of Rheumatology (ACR)-1997, Systemic Lupus International Collaborating Clinics (SLICC)-2012 and European Alliance of Associations for Rheumatology (EULAR)/ACR-2019 classification criteria, have been launched in the past decades. The current study aimed to investigate the performance of these three classification criteria for diagnosing patients with SLE in a Chinese cohort.

Methods

352 patients with SLE and 385 controls with other diseases who had the detection results of ANA were enrolled into the study. Various clinical parameters were estimated, such as demographics variables, clinical characteristics and other variables related to three criteria.

Results

The current study demonstrated great diagnostic ability of the three criteria; and the receiver operating characteristic curve and the area under curve (AUC) were used to evaluate the diagnostic ability of three criteria: ACR-1997 (AUC=0.972), SLICC-2012 (AUC=0.986) and EULAR/ACR-2019 (AUC=0.983). Despite lower specificity of the SLICC-2012 and EULAR/ACR-2019 classification criteria, their sensitivity is significantly improved than ACR-1997. Of note, we also compared the median time interval between the appearance of the earliest item and fulfilment of the three sets of criteria, suggesting the SLICC-2012 and EULAR/ACR-2019 could achieve earlier diagnosis. Adjusting the thresholds of the EULAR/ACR-2019 criteria from 10 to 12, the specificity and accuracy significantly increased.

Conclusion

The SLICC-2012 and EULAR/ACR-2019 performed well in Chinese patients with SLE and showed better early diagnosis ability. In addition, by adjusting the classification threshold, the accuracy of the EULAR/ACR-2019 classification criteria was improved.