Vortex disaggregation for flow cytometry allows direct histologic correlation: a novel approach for small biopsies and inaspirable bone marrows

Automated–Mechanical Procedure Compared to Gentle Enzymatic Tissue Dissociation in Cell Function Studies

The first step to obtain a cellular suspension from tissues is the disaggregation procedure. The cell suspension method has to provide a representative sample of the different cellular subpopulations and to maximize the number of viable functional cells. Here, we analyzed specific cell functions in cell suspensions from several rat tissues obtained by two different methods, automated–mechanical and enzymatic disaggregation. Flow cytometric, confocal, and ultrastructural (TEM) analyses were applied to the spleen, testis, liver and other tissues. Samples were treated by an enzymatic trypsin solution or processed by the Medimachine II (MMII). The automated–mechanical and enzymatic disaggregation procedures have shown to work similarly in some tissues, which displayed comparable amounts of apoptotic/necrotic cells. However, cells obtained by the enzyme-free Medimachine II protocols show a better preservation lysosome and mitochondria labeling, whereas the enzymatic gentle dissociation appears to constantly induce a lower amount of intracellular ROS; nevertheless, lightly increased ROS can be recognized as a complimentary signal to promote cell survival. Therefore, MMII represents a simple, fast, and standardized method for tissue processing, which allows to minimize bias arising from the operator’s ability. Our study points out technical issues to be adopted for specific organs and tissues to obtain functional cells.

Single Cell Gene Expression Analysis in a 3D Microtissue Liver Model Reveals Cell Type-Specific Responses to Pro-Fibrotic TGF-β1 Stimulation

3D cell culture systems are widely used to study disease mechanisms and therapeutic interventions. Multicellular liver microtissues (MTs) comprising HepaRG, hTERT-HSC and THP-1 maintain multicellular interactions and physiological properties required to mimic liver fibrosis. However, the inherent complexity of multicellular 3D-systems often hinders the discrimination of cell type specific responses. Here, we aimed at applying single cell sequencing (scRNA-seq) to discern the molecular responses of cells involved in the development of fibrosis elicited by TGF-β1. To obtain single cell suspensions from the MTs, an enzymatic dissociation method was optimized. Isolated cells showed good viability, could be re-plated and cultured in 2D, and expressed specific markers determined by scRNA-seq, qRT-PCR, ELISA and immunostaining. The three cell populations were successfully clustered using supervised and unsupervised methods based on scRNA-seq data. TGF-β1 led to a fibrotic phenotype in the MTs, detected as decreased albumin and increased αSMA expression. Cell-type specific responses to the treatment were identified for each of the three cell types. They included HepaRG damage characterized by a decrease in cellular metabolism, prototypical inflammatory responses in THP-1s and extracellular matrix remodeling in hTERT-HSCs. Furthermore, we identified novel cell-specific putative fibrosis markers in hTERT-HSC (COL15A1), and THP-1 (ALOX5AP and LAPTM5).

Rinsing sampling of core needle biopsy for flow cytometric analysis: A favorable method for lymphoma diagnosis

BACKGROUND

Conventional protocols utilize core needle biopsy (CNB) or fine needle aspiration (FNA) to produce cell suspension for flow cytometry (FCM) is a diagnostic challenge for lymphoid malignancies. We aim to develop an alternative CNB rinsing technique (RT) to produce cell suspension for FCM during this mini-invasive procedure of CNB for lymphoma diagnosis.

METHODS

FNA and CNB specimens from the same lesion of 93 patients with suspected lymphoma were collected under the guidance of B-ultrasound simultaneously. The fresh CNB samples were prepared to cell suspension by RT for FCM immunophenotyping analysis (Group CNB-RT). Then, the CNB tissues after performing the RT process and the fresh FNA tissues were processed by conventional tissue cell suspension (TCS) technique to obtain the cell suspensions (Groups of CNB-TCS & FNA-TCS), respectively, as comparison. The diagnostic efficacies, as well as the concordances of the FCM results with reference to the morphologic diagnoses were compared in these three groups.

RESULTS

RT could yield sufficient cells for FCM immunophenotyping analysis, though a lower cell numbers compared to TCS technique. The diagnostic concordance was comparable in group CNB-RT (91.1%) to the group CNB-TCS (88.9%) and group FNA-TCS (88.4%) (p = 0.819). The diagnostic sensitivity and specificity of CNB-RT (91.1%; 100%) was not inferior to that of CNB-TCS (88.9%; 100%) and FNA-TCS (88.4%; 98.8%).

CONCLUSIONS

This study shows the CNB-RT presented non-inferior diagnostic concordance and efficacy as compared to the TCS technique. CNB-RT has the potential to produce cell suspension for FCM immunophenotyping while preserving tissue for lymphoma diagnosis and research.

A Simple and Effective Method for Flow Cytometric Study of Lymphoid Malignancies Using Needle Core Biopsy Specimens

OBJECTIVES

We developed a simple and effective rinsing technique (RT) of needle biopsies to produce cell suspensions for flow cytometry (FCM) and evaluated whether the RT is comparable to the conventional tissue cell suspension (TCS) technique.

METHODS

We retrieved 93 needle core biopsy cases employing the RT for FCM and 25 needle biopsy cases using TCS for FCM.

RESULTS

The diagnostic concordance between the FCM results and the morphologic diagnoses of both groups was compared. The diagnostic concordance was comparable in the RT group (92.6%) to the TCS group (71.4%). Furthermore, the diagnostic concordance in the RT group was associated with number of isolated cells. The diagnostic accuracy increased significantly when the cell number was above 30,000 in the RT group.

CONCLUSIONS

The RT for FCM not only maximizes the tissue utilization, but also is a simple and effective method to obtain cell suspension as compared to traditional cell suspension technique. © 2018 International Clinical Cytometry Society.

Vortex-dislodged cells from bone marrow trephine biopsy yield satisfactory results for flow cytometric immunophenotyping

INTRODUCTION

A good bone marrow (BM) sample is essential in evaluating many hematologic disorders. An unsuccessful BM aspiration (BMA) procedure precludes a successful flow cytometric immunophenotyping (FCI) in most hematologic malignancies. Apart from FCI, most ancillary diagnostic techniques in hematology are less informative. We describe the feasibility of FCI in vortex-dislodged cell preparation obtained from unfixed trephine biopsy (TB) specimens.

METHODS

In pancytopenic patients and dry tap cases, routine diagnostic BMA and TB samples were complemented by additional trephine biopsies. These supplementary cores were immediately transferred into sterile tubes filled with phosphate-buffered saline, vortexed, and centrifuged. The cell pellet obtained was used for flow cytometric immunophenotyping.

RESULTS

Of 7955 BMAs performed in 42 months, 34 dry tap cases were eligible for the study. Vortexing rendered a cell pellet in 94% of the cases (32 of 34), and FCI rendered a rapid diagnosis in 100% of the cases (32 of 32) where cell pellets were available.

CONCLUSION

We describe an efficient procedure which could be effectively utilized in resource-limited centers and reduce the frequency of repeat BMA procedures.

Tissue flow cytometry immunophenotyping in the diagnosis and classification of non-Hodgkin's lymphomas: a retrospective evaluation of 1,792 cases

A retrospective analysis of 1,792 solid tissues suggestive of lymphoma, submitted over a 12-year period, was carried out and flow cytometry (FC) results were compared with histologic findings. The final histologic diagnosis of cases documented in this report is as follows: 1,270 non-Hodgkin's lymphomas (NHL); 17 composite lymphomas; four NHL plus carcinomas; five post-transplant lymphoproliferative disorders; 105 Hodgkin's lymphomas (HL); eight acute leukemias; 42 tissue cancers; and 341 non-neoplastic diseases. A strong correlation between morphology and FC data was observed among hematological malignancies (1,268/1,304, 97.2%) with the exception of HL. Among B-NHL, FC detection of clonally restricted B-cell allowed the identification of lymphomas that were not histologically clear and the differential diagnosis between follicular lymphoma and reactive hyperplasia. A high correlation level (r = 0.83; P < 0.0001) was obtained in comparing proliferation results obtained by FC and immunohistochemistry. Among T-NHL, FC detection of an aberrant phenotype direct histologic diagnosis in cases having less than 20% of neoplastic cells. In nine cases, FC suggested the need to evaluate a neoplastic population, not morphologically evident. Results show that FC routinely performed on tissue samples suspected of lymphomas is a fundamental adjunct to morphology in the diagnosis of NHL and may enhance the performance of the histologic evaluation so as to achieve the final diagnosis. To the best of our knowledge, this is the first report in the literature of a wide series of tissues also studied by FC.

Phenotypic characterization and functional analysis of human tumor immune infiltration after mechanical and enzymatic disaggregation

Multi-parametric flow cytometry analysis is a reliable method for phenotypic and functional characterization of tumor infiltrating immune cells (TIIC). The isolation of infiltrating leukocytes from solid tumors can be achieved through various methods which can be both enzymatic and mechanical; however, these methods may alter cell biology. The aim of this study was to compare the effects of three tissue disaggregation techniques on TIIC biology in breast, kidney and lung tumor specimens. We therefore compared two enzymatic treatments using either collagenase type IA alone or in combination with collagenase type IV and DNase I type II, and one mechanical system (Medimachine™). We evaluated the impact of treatments on cell viability, surface marker integrity and proliferative capacity. We show that cell viability was not significantly altered by treatments. However, enzymatic treatments decreased cell proliferation; specifically collagenases and DNase provoked a significant decrease in detection of surface markers such as CD4, CD8, CD45RA and CD14, indicating that results of phenotypic studies employing these techniques could be affected. In conclusion, mechanical tissue disaggregation by Medimachine™ appears to be optimal to maintain phenotypic and functional TIIC features.

Failed or inadequate bone marrow aspiration: a fast, simple and cost-effective method to produce a cell suspension from a core biopsy specimen

Failure to aspirate bone marrow (BM) diminishes diagnostic accuracy and efficiency because BM cell suspensions are crucial for modern haematological diagnostic methods such as cytomorphology, flow cytometric immunophenotyping (FCI), cytogenetics or fluorescent in situ hybridization (FISH). We mechanically disaggregated unfixed BM core biopsies with the Dako Medimachine in 65 cases of macroscopically suspected dry taps. Cytospins, three-colour FCI and in some cases karyotyping and FISH were performed successfully. Most cytospins (34 of 50; 68.0%) were of good quality, while a further 18.0% showed moderate but still informative quality. FCI showed good quality in 36 of 60 (60.0%) cases; in 13.3% quality was moderate, but diagnostically useful results were obtained. Surprisingly, all four cases of formerly undiagnosed BM-carcinosis could be clearly detected on cytospins. Finally, five of seven (71.4%) attempts yielded analysable metaphases mostly in cases where no metaphases could be obtained from BM or peripheral blood. The described method of mechanical disaggregation of unfixed BM core biopsies compares favourably with other published approaches, allowing the application of all techniques where BM cell suspensions are needed. Thus, it can help to establish the underlying diagnosis in patients with abnormalities in peripheral blood and unsuccessful marrow aspirations.