Introduction: Indocyanine green (ICG) is a near infrared (NIR) dye which has been used clinically for over 50 years and has recently been utilised for fluorescence guided surgery in a number of cancer types, including sarcoma. ICG is taken up and retained by sarcoma tumours to a greater extent than normal tissue, demonstrating its potential to aid in visualisation of tumour margins. However, the mechanisms surrounding preferential ICG uptake in tumours are poorly understood. Methods: In vitro ICG cellular uptake studies were performed across a panel of four sarcoma cell lines and one breast cancer cell line, exhibiting varying proliferation rates and phenotypes. The effects of ICG concentration, incubation time, inhibition of clathrin mediated endocytosis and cell line proliferation rate on the cellular uptake of ICG were investigated, using fluorescence microscopy and flow cytometry. The spatial orientation of ICG was also assessed in a patient specimen. Results: The level of ICG cellular uptake was dependent on ICG concentration and incubation time. Cell line proliferation rate correlated significantly to ICG uptake within 30 minutes (Rs = 1, p<0.001), whilst retention of ICG after 24hrs did not (Rs = 0.3, p=0.624). From our data, the primary mechanism of ICG uptake in sarcoma cells is via clathrin mediated endocytosis. Following the resection of a grade 3 leiomyosarcoma, ICG signal was detectable macroscopically and on 3um sections, whilst being negative on the muscle control. Conclusions: The use of ICG for tumour detection in sarcoma surgery may demonstrate higher utility in high grade tumours compared to low grade tumours, due to the observation of higher ICG uptake in more proliferative cell lines. It is likely that the enhanced permeability and retention (EPR) effect plays a significant role in the retention of ICG within tumours. Future work on the detection of ICG at the cellular level within human tissue sections is required, with the aid of purpose built NIR microscopes.

Context Depression is prevalent among Asian Americans (AsA) during the COVID-19 pandemic, and depression often leads to sleep disturbance in this population. The gut microbiota (GM) plays a critical role in mental health and sleep quality, and the composition of the GM is largely unknown among AsA. Objectives Examine associations of the GM with depressive symptoms and sleep disturbance among Chinese and Korean American immigrants. Methods Depressive symptoms (PROMIS Short Form-Depression) and sleep quality (Pittsburgh Sleep Quality Index [PSQI]) were collected via surveys. PROMIS measure T-score > 55 indicates positive depressive symptoms, and a total PSQI score > 5 indicates sleep disturbance. 16S rRNA V3-V4 gene regions were sequenced from fecal specimens to measure GM. Permutational multivariate analysis of variance and linear discriminant analysis effect size were applied to examine associations of the GM with symptoms. Results Among 20 participants, 55% ( n = 11) reported depressive symptoms and 35% ( n = 7) reported sleep disturbance. A higher α-diversity was marginally associated with lower depressive symptoms: Chao1 (r = −0.39, p = 0.09) and Shannon index (r = −0.41, p = 0.08); β-diversity distinguished participants between categories of depressive symptoms (weighted UniFrac, p=0.04) or sleep disturbance (Jaccard, p=0.05). Those with depressive symptoms showed a higher abundance of Actinobacteria, while those without depressive symptoms had a higher abundance of Bacteroidetes. No significant taxa were identified for sleep disturbance. Conclusions Gut microbial diversity showed promising associations with depressive symptoms and sleep disturbance among Chinese and Korean immigrants. Specific taxa were identified as associated with depressive symptoms. Future studies with a larger sample size are warranted to confirm our findings.

BackgroundIt is critical to investigate the underlying pathophysiological mechanisms in the development of atopic dermatitis. The microbiota hypothesis suggested that the development of allergic diseases may be attributed to the gut microbiota of mother-offspring pairs. The purpose of this study was to investigate the relationship among maternal-offspring gut microbiota and the subsequent development of atopic dermatitis in infants and toddlers at 2 years old.MethodsA total of 36 maternal-offspring pairs were enrolled and followed up to 2 years postpartum in central China. Demographic information and stool samples were collected perinatally from pregnant mothers and again postpartum from their respective offspring at the following time intervals: time of birth, 6 months, 1 year and 2 years. Stool samples were sequenced with the 16S Illumina MiSeq platform. Logistic regression analysis was used to explore the differences in gut microbiota between the atopic dermatitis group and control group.ResultsOur results showed that mothers of infants and toddlers with atopic dermatitis had higher abundance of Candidatus_Stoquefichus and Pseudomonas in pregnancy and that infants and toddlers with atopic dermatitis had higher abundance of Eubacterium_xylanophilum_group at birth, Ruminococcus_gauvreauii_group at 1 year and UCG-002 at 2 years, and lower abundance of Gemella and Veillonella at 2 years. Additionally, the results demonstrated a lower abundance of Prevotella in mothers of infants and toddlers with atopic dermatitis compared to mothers of the control group, although no statistical difference was found in the subsequent analysis.ConclusionThe results of this study support that gut microbiota status among mother-offspring pairs appears to be associated with the pathophysiological development of pediatric atopic dermatitis.