Diagnosing pituitary adenoma in unstained sections based on multiphoton microscopy

Towards next-generation diagnostic pathology: AI-empowered label-free multiphoton microscopy

Diagnostic pathology, historically dependent on visual scrutiny by experts, is essential for disease detection. Advances in digital pathology and developments in computer vision technology have led to the application of artificial intelligence (AI) in this field. Despite these advancements, the variability in pathologists' subjective interpretations of diagnostic criteria can lead to inconsistent outcomes. To meet the need for precision in cancer therapies, there is an increasing demand for accurate pathological diagnoses. Consequently, traditional diagnostic pathology is evolving towards "next-generation diagnostic pathology", prioritizing on the development of a multi-dimensional, intelligent diagnostic approach. Using nonlinear optical effects arising from the interaction of light with biological tissues, multiphoton microscopy (MPM) enables high-resolution label-free imaging of multiple intrinsic components across various human pathological tissues. AI-empowered MPM further improves the accuracy and efficiency of diagnosis, holding promise for providing auxiliary pathology diagnostic methods based on multiphoton diagnostic criteria. In this review, we systematically outline the applications of MPM in pathological diagnosis across various human diseases, and summarize common multiphoton diagnostic features. Moreover, we examine the significant role of AI in enhancing multiphoton pathological diagnosis, including aspects such as image preprocessing, refined differential diagnosis, and the prognostication of outcomes. We also discuss the challenges and perspectives faced by the integration of MPM and AI, encompassing equipment, datasets, analytical models, and integration into the existing clinical pathways. Finally, the review explores the synergy between AI and label-free MPM to forge novel diagnostic frameworks, aiming to accelerate the adoption and implementation of intelligent multiphoton pathology systems in clinical settings.

Morpho-Molecular Metabolic Analysis and Classification of Human Pituitary Gland and Adenoma Biopsies Based on Multimodal Optical Imaging

Pituitary adenomas count among the most common intracranial tumors. During pituitary oncogenesis structural, textural, metabolic and molecular changes occur which can be revealed with our integrated ultrahigh-resolution multimodal imaging approach including optical coherence tomography (OCT), multiphoton microscopy (MPM) and line scan Raman microspectroscopy (LSRM) on an unprecedented cellular level in a label-free manner. We investigated 5 pituitary gland and 25 adenoma biopsies, including lactotroph, null cell, gonadotroph, somatotroph and mammosomatotroph as well as corticotroph. First-level binary classification for discrimination of pituitary gland and adenomas was performed by feature extraction via radiomic analysis on OCT and MPM images and achieved an accuracy of 88%. Second-level multi-class classification was performed based on molecular analysis of the specimen via LSRM to discriminate pituitary adenomas subtypes with accuracies of up to 99%. Chemical compounds such as lipids, proteins, collagen, DNA and carotenoids and their relation could be identified as relevant biomarkers, and their spatial distribution visualized to provide deeper insight into the chemical properties of pituitary adenomas. Thereby, the aim of the current work was to assess a unique label-free and non-invasive multimodal optical imaging platform for pituitary tissue imaging and to perform a multiparametric morpho-molecular metabolic analysis and classification.

LncRNA SNHG7 sponges miR-449a to promote pituitary adenomas progression

This study aimed to characterize the expression status and potentially mechanistic involvement of SNHG7 in pituitary adenoma. Relative expression of SNHG7 and miR-449a was analyzed by real-time PCR. Cell viability was measured with Cell Counting Kit-8 (CCK-8). Cell apoptosis was determined by PI/Annexin V double staining followed by flow cytometry analysis. Cell invasion and migration were analyzed by wound healing and transwell assays, respectively. The regulatory action of miR-449a on SNHG7 was interrogated by luciferase reporter assay. We also investigated the pro-tumor activity of SNHG7 with the MMQ xenograft tumor mouse model. We identified the aberrant up-regulation of SNHG7 in pituitary adenoma both in vivo and in vitro, which associated with poor survival outcome. siRNA-mediated SNHG7-knockdown decreased cell viability, increased apoptosis and compromised migration and invasion. We further predicted and validated that SNHG7 negatively regulated miR-449a via sponging. Concurrent inhibition of miR-449a restored cell viability, apoptosis, migration and invasion influenced by SNHG7-deficiency. Most importantly, we demonstrated that SNHG7-silencing delayed xenograft tumor progression, which was accompanied with increased miR-449a and decreased Ki67 intensity. Our study highlighted the essential oncogenic properties of the SNHG7/miR-449a axis in pituitary adenoma.

Multiphoton microscopy in surgical oncology- a systematic review and guide for clinical translatability

BACKGROUND

Multiphoton microscopy (MPM) facilitates three-dimensional, high-resolution functional imaging of unlabeled tissues in vivo and ex vivo. This systematic review discusses the diagnostic value, advantages and challenges in the practical use of MPM in surgical oncology.

METHOD AND FINDINGS

A Medline search was conducted in April 2019. Fifty-three original research papers investigating MPM compared to standard histology in human patients with solid tumors were identified. A qualitative synopsis and meta-analysis of 14 blinded studies was performed. Risk of bias and applicability were evaluated. MPM can image fresh, frozen or fixed tissues up to a depth 1000 μm in the z-plane. Best results including functional imaging and virtual histochemistry are obtained by in vivo imaging or scanning fresh tissue immediately after excision. Two-photon excited fluorescence by natural fluorophores of the cytoplasm and second harmonic generation signals by fluorophores of the extracellular matrix can be scanned simultaneously, providing high resolution optical histochemistry comparable to standard histology. Functional parameters like fluorescence lifetime imaging or optical redox ratio provide additional objective information. A major concern is inability to visualize the nucleus. However, in a subpopulation analysis of 440 specimens, MPM yielded a sensitivity of 94%, specificity of 96% and accuracy of 95% for the detection of malignant tissue.

CONCLUSION

MPM is a promising emerging technique in surgical oncology. Ex vivo imaging has high sensitivity, specificity and accuracy for the detection of tumor cells. For broad clinical application in vivo, technical challenges need to be resolved.

Label-free multiphoton imaging of β-amyloid plaques in Alzheimer's disease mouse models

β -Amyloid ( A β ) plaque, representing the progressive accumulation of the protein that mainly consists of A β , is one of the prominent pathological hallmarks of Alzheimer's disease (AD). Label-free imaging of A β plaques holds the potential to be a histological examination tool for diagnosing AD. We applied label-free multiphoton microscopy to identify extracellular A β plaque as well as intracellular A β accumulation for the first time from AD mouse models. We showed that a two-photon-excited fluorescence signal is a sensitive optical marker for revealing the spatial-temporal progression and the surrounding morphological changes of A β deposition, which demonstrated that both extracellular and intracellular A β accumulations play an important role in the progression of AD. Moreover, combined with a custom-developed image-processing program, we established a rapid method to visualize different degrees of A β deposition by color coding. These results provide an approach for investigating pathophysiology of AD that can complement traditional biomedical procedures.