Optical photothermal infrared spectroscopy can differentiate equine osteoarthritic plasma extracellular vesicles from healthy controls

Background Equine osteoarthritis is a chronic degenerative disease of the articular joint, characterised by cartilage degradation resulting in pain and reduced mobility and thus is a prominent equine welfare concern. Diagnosis is usually at a late stage through radiographic examination, whilst treatment is symptomatic not curative. Extracellular vesicles are small nanoparticles that are involved in intercellular communication. The objective of this study was to investigate the feasibility of Raman and optical photothermal infrared spectroscopy to detect osteoarthritis using plasma-derived extracellular vesicles. Methods Plasma samples were derived from thoroughbred racehorses. A total of 14 samples were selected (control; n= 6 and diseased; n=8). Extracellular vesicles were isolated using differential ultracentrifugation and characterised using nanoparticle tracking analysis, transmission electron microscopy, and human tetraspanin chips. Samples were then analysed using Raman and optical photothermal infrared spectroscopy. Results Infrared spectra were analysed between 950-1800 cm -1 . Raman spectra had bands between the wavelengths of 900-1800 cm -1 analysed. Bands below 900 cm -1 . Spectral data for both Raman and optical photothermal infrared spectroscopy was used to obtain a classification model and confusion matrices, characterising the techniques ability to distinguish diseased samples. Optical photothermal infrared spectroscopy could differentiate osteoarthritic extracellular vesicles from healthy with good classification (93.4%) whereas Raman displayed poor classification (64.3%). Plasma-derived extracellular vesicles from osteoarthritic horses contained increased signal for proteins, lipids and nucleic acids. Discussion/ conclusion For the first time we demonstrated the ability to use optical photothermal infrared spectroscopy to interrogate extracellular vesicles and osteoarthritis-related samples. Optical photothermal infrared spectroscopy was superior to Raman in this study, and could distinguish osteoarthritis samples, suggestive of its potential use diagnostically to identify osteoarthritis in equine patients. This study demonstrates the potential of Raman and optical photothermal infrared spectroscopy to be used as a diagnostic tool in clinical practice, with the capacity to detect changes in extracellular vesicles from clinically derived samples

Optical photothermal infrared spectroscopy can differentiate equine osteoarthritic plasma extracellular vesicles from healthy controls

Equine osteoarthritis is a chronic degenerative disease of the articular joint, characterised by cartilage degradation resulting in pain and reduced mobility and thus is a prominent equine welfare concern. Diagnosis is usually at a late stage through clinical examination and radiographic imaging, whilst treatment is symptomatic not curative. Extracellular vesicles are nanoparticles that are involved in intercellular communication. The objective of this study was to investigate the feasibility of Raman and Optical Photothermal Infrared Spectroscopies to detect osteoarthritis using plasma-derived extracellular vesicles, specifically differentiating extracellular vesicles in diseased and healthy controls within the parameters of the techniques used. Plasma samples were derived from thoroughbred racehorses. A total of 14 samples were selected (control; n = 6 and diseased; n = 8). Extracellular vesicles were isolated using differential ultracentrifugation and characterised using nanoparticle tracking analysis, transmission electron microscopy, and human tetraspanin chips. Samples were then analysed using combined Raman and Optical Photothermal Infrared Spectroscopies. Infrared spectra were collected between 950–1800 cm−1. Raman spectra had bands between the wavelengths of 900–1800 cm−1 analysed. Spectral data for both Raman and Optical Photothermal Infrared Spectroscopy were used to generate clustering via principal components analysis and classification models were generated using partial least squared discriminant analysis in order to characterize the techniques' ability to distinguish diseased samples. Optical Photothermal Infrared Spectroscopy could differentiate osteoarthritic extracellular vesicles from healthy with good classification (93.4% correct classification rate) whereas Raman displayed poor classification (correct classification rate = −64.3%). Inspection of the infrared spectra indicated that plasma-derived extracellular vesicles from osteoarthritic horses contained increased signal for proteins, lipids and nucleic acids. For the first time we demonstrated the ability to use optical photothermal infrared spectroscopy combined with Raman spectroscopy to interrogate extracellular vesicles and osteoarthritis-related samples. Optical Photothermal Infrared Spectroscopy was superior to Raman in this study, and could distinguish osteoarthritis samples, suggestive of its potential use diagnostically to identify osteoarthritis in equine patients. This study demonstrates the potential of Raman and Optical Photothermal Infrared Spectroscopy to be used as a future diagnostic tool in clinical practice, with the capacity to detect changes in extracellular vesicles from clinically derived samples

The Role of Heart Rate Variability in Mindfulness-Based Pain Relief

Mindfulness meditation is a self-regulatory practice premised on sustaining nonreactive awareness of arising sensory events that reliably reduces pain. Yet, the specific analgesic mechanisms supporting mindfulness have not been comprehensively disentangled from the potential nonspecific factors supporting this technique. Increased parasympathetic nervous system (PNS) activity is associated with pain relief corresponding to a number of cognitive manipulations. However, the relationship between the PNS and mindfulness-based pain attenuation remains unknown. The primary objective of the present study was to determine the role of high-frequency heart rate variability (HF HRV), a marker of PNS activity, during mindfulness-based pain relief as compared to a validated, sham-mindfulness meditation technique that served as a breathing-based control. Sixty-two healthy volunteers (31 females; 31 males) were randomized to a 4-session (25 min/session) mindfulness or sham-mindfulness training regimen. Before and after each group's respective training, participants were administered noxious (49°C) and innocuous (35°C) heat to the right calf. HF HRV and respiration rate were recorded during thermal stimulation and pain intensity and unpleasantness ratings were collected after each stimulation series. The primary analysis revealed that during mindfulness meditation, higher HF HRV was more strongly associated with lower pain unpleasantness ratings when compared to sham-mindfulness meditation (B = -.82, P = .04). This finding is in line with the prediction that mindfulness-based meditation engages distinct mechanisms from sham-mindfulness meditation to reduce pain. However, the same prediction was not confirmed for pain intensity ratings (B = -.41). Secondary analyses determined that mindfulness and sham-mindfulness meditation similarly reduced pain ratings, decreased respiration rate, and increased HF HRV (between group ps < .05). More mechanistic work is needed to reliably determine the role of parasympathetic activation in mindfulness-based pain relief as compared to other meditative techniques. Perspective: Mindfulness has been shown to engage multiple mechanisms to reduce pain. The present study extends on this work to show that higher HRV is associated with mindfulness-induced reductions in pain unpleasantness, but not pain intensity ratings, when compared to sham-mindfulness meditation. These findings warrant further investigation into the mechanisms engaged by mindfulness as compared to placebo