Lipid droplet occurrence in human leukocytes of peripheral blood is higher in males with recent-onset psychosis

Aberrant immune mechanisms in central and peripheral nervous system might underlie the heterogeneity of symptoms in schizophrenia. Lipid droplets (LDs) are implicated in inflammatory processes and immune response. Previous studies have successfully quantified LDs in cell lines by Nile Red staining.

Therefore, we hypothesized that LD abundance could be optimally quantified in leukocyte subpopulations and that LD occurrence in peripheral blood leukocytes could be altered in people with psychosis at early stages of the disorder. We optimized a method to detect and quantify LD occurrence in different leukocyte subpopulations using flow cytometry. We found that leukocyte subpopulations contain LDs, with lymphocytes showing the lowest LD content, followed by monocytes, neutrophils and eosinophils.

Leukocytes were able to modulate their LD abundance upon oleate exposure in in vitro blood culture from controls. Moreover, LD content was significantly higher in all leukocyte subpopulations in recent-onset psychosis (ROP) compared to controls. When stratified by sex, these differences were maintained in males but not in females.

Leukocyte subpopulations from males with ROP contain higher LD levels than controls, suggesting LD abundance as a potential male biomarker of a pro-inflammatory stage early in the disorder course. Further studies are required to confirm these findings in females. The authors sincerely thank the participants of this study for their generous contribution of time and for donating blood sample to support this research.

This work was supported by a Miguel Servet grant (MS16/00153, CP16/00153 to BR and CP20/00072 to MF-V) financed and integrated into the National R + D + I and funded by the Instituto de Salud Carlos III (Spanish Ministry of Health)—General Branch Evaluation and Promotion of Health Research—and the European Regional Development Fund (ERDF). This work was also supported by projects (PI18/00213 to BR and PI18/1535) of Instituto de Salud Carlos III and Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR; 2021SGR01380 and 2021SGR01475) This work was supported by a Miguel Servet grant (MS16/00153, CP16/00153 to BR and CP20/00072 to MF-V) financed and integrated into the National R + D + I and funded by the Instituto de Salud Carlos III (Spanish Ministry of Health)—General Branch Evaluation and Promotion of Health Research—and the European Regional Development Fund (ERDF). This work was also supported by projects (PI18/00213 to BR, PI24/00294 to SO and PI18/1535) of Instituto de Salud Carlos III and Agència de Gestió d’Ajuts Universitaris i de Recerca (AGAUR; 2021SGR01380 and 2021SGR01475).

The authors declare that all the sources of the funding has no role on conceptualization, design, collection, analyses, decision to publish or preparation of the manuscript. MERITT, Parc Sanitari Sant Joan de Déu, Institut de Recerca Sant Joan de Déu, Dr. Antoni Pujadas, 42, 08830, Sant Boi de Llobregat, Barcelona, Spain Francisco Vidal-Domènech, Marta Ferrer-Quintero, Susana Ochoa & Belén Ramos Departament de Bioquímica I Biologia Molecular, Facultat de Medicina, Universitat Autonoma de Barcelona, 08193, Bellaterra, Barcelona, Spain Francisco Vidal-Domènech & Enrique Claro Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Instituto de Salud Carlos III, Madrid, Spain Marta Ferrer-Quintero, Susana Ochoa, Carmen Almodóvar-Payá, Mar Fatjó-Vilas, Edith Pomarol-Clotet & Belén Ramos FIDMAG Germanes Hospitalàries Research Foundation, Dr Antoni Pujadas 38, 08830, Sant Boi de Llobregat, Barcelona, Spain Carmen Almodóvar-Payá, Mar Fatjó-Vilas & Edith Pomarol-Clotet Departament de Biologia Evolutiva, Ecologia I Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Av Diagonal, 648, 08028, Barcelona, Spain Leukemia and Pediatric Hematology Disorders, Developmental Tumors Biology Group, Institut de Recerca Sant Joan de Déu (IRSJD), Santa Rosa 39-57, 08950, Esplugues de Llobregat, Spain Hematology Laboratory, Hospital Sant Joan de Déu Barcelona, Passeig Sant Joan de Déu 2, 08950, Esplugues de Llobregat, Barcelona, Spain Centro de Investigación Biomédica en Red de Enfermedades Raras, Instituto de Salud Carlos III, 28029, Madrid, Spain Faculty of Medicine, University of Vic-Central University of Catalonia, UVic-UCC, Vic/Manresa, Catalonia, Spain The authors declare that they have no competing interests.