Superficial Tissue Layers Research Articles

Decellularized adipose-derived matrix from Superficial layers of abdominal adipose tissue exhibits superior capacity of adipogenesis compared to deep layers

The adipogenic property of decellularized adipose-derived matrix (DAM) varies widely across reports, making it difficult to make a horizontal comparison between reports and posing challenges for the stable clinical translation of DAM. It is possibly due to differences in donor characteristics, but the exact relationship remains unclear. Despite extensive research on the differences between superficial and deep layers of abdominal subcutaneous fat, a main donor of DAM, little is known about their extracellular matrix (ECM) which is promising in regenerative medicine. In this study, we first confirmed the distinct compositional profiles and adipogenic potential between superficial and deep DAM (S-DAM and D-DAM). Both in vitro and in vivo assays confirmed superior adipogenic induction potential in S-DAM over D-DAM. Total amounts of ECM proteins like collagen and laminin were similar, however, the predominant types differed, with collagen I dominating S-DAM and collagen XIV prevailing in D-DAM. S-DAM was enriched with mitochondrial and immunological proteins, whereas D-DAM featured more neuronal, vascular, muscular, and endocrine-related proteins. More proteins involved in mRNA processing were found in D-DAM, with Protein-Protein Interaction (PPI) analysis revealing HNRNPA2B1, HNRNPA1, and HNRNPC as the most tightly interacting members. These findings not only deepen our comprehension of the structural and functional heterogeneity of adipose tissues but also become one of the reason for the large variability between batches of DAM products, providing guidance for constructing more efficient and stable bio-scaffolds.

Etiology and epidemiology of digital dermatitis in Australian dairy herds

Bovine digital dermatitis (BDD) is an important cause of lameness in dairy cows worldwide. However, very little is known about this disease in Australian herds, which are predominantly managed on pasture. The primary objectives of this cross-sectional study were to describe the presence and prevalence of BDD in Australian dairy herds and to characterize the microbiota of healthy skin and M4 lesions of BDD-affected, pasture-managed cows. Cows from 71 dairy herds were examined at milking time to identify the presence of BDD lesions. True prevalence was estimated using Bayesian methods with informative priors for sensitivity and specificity. Biopsy samples (n = 60) were collected from cows with and without BDD lesions in 7 pasture-based herds. The microbiota in the superficial and deep strata of each tissue biopsy were characterized via sequencing of the V3-V4 region of the bacterial ribosomal RNA gene. Lesions were detected in 1,817 (11.5%) of 15,813 cows and in 68 of 71 (95.8%) herds. The median herd-level apparent and true prevalences of BDD were 8.5% and 18.1%, respectively, but prevalences varied considerably between farms. On farms with BDD, M4 lesions accounted for 70% to 100% of all lesions (interquartile range = 95.1%-100%, median = 100%); M2 lesions (i.e., large ulcerative lesions) were observed at low prevalence (<2.2%) in the few herds (7/71, 9.9%) where they were found. There was a significant difference in the composition of the microbiota between healthy skin and M4 lesions but not between superficial and deep tissue layers. Several gut- and effluent-associated bacterial taxa, including Lentimicrobium and Porphyromonas, which have previously been associated with BDD, were abundant in BDD lesions but not in control biopsies. Our study supports the idea that such taxa are involved in, although possibly not essential to, lesion development and persistence in pasture-managed cows in Australia. Our results also suggest that Dichelobacter may contribute to the disease process. We conclude that BDD is likely to occur in most Australian dairy farms, but that further studies are needed to identify its effect on cow welfare and productivity. Further investigation of the etiology of BDD in Australian dairy herds is also necessary to inform prevention and control strategies.

Identifying ADHD boys by very-low frequency prefrontal fNIRS fluctuations during a rhythmic mental arithmetic task

Objective. Computer-aided diagnosis of attention-deficit/hyperactivity disorder (ADHD) aims to provide useful adjunctive indicators to support more accurate and cost-effective clinical decisions. Deep- and machine-learning (ML) techniques are increasingly used to identify neuroimaging-based features for objective assessment of ADHD. Despite promising results in diagnostic prediction, substantial barriers still hamper the translation of the research into daily clinic. Few studies have focused on functional near-infrared spectroscopy (fNIRS) data to discriminate ADHD condition at the individual level. This work aims to develop an fNIRS-based methodological approach for effective identification of ADHD boys via technically feasible and explainable methods. Approach. fNIRS signals recorded from superficial and deep tissue layers of the forehead were collected from 15 clinically referred ADHD boys (average age 11.9 years) and 15 non-ADHD controls during the execution of a rhythmic mental arithmetic task. Synchronization measures in the time-frequency plane were computed to find frequency-specific oscillatory patterns maximally representative of the ADHD or control group. Time series distance-based features were fed into four popular ML linear models (support vector machine, logistic regression (LR), discriminant analysis and naïve Bayes) for binary classification. A ‘sequential forward floating selection’ wrapper algorithm was adapted to pick out the most discriminative features. Classifiers performance was evaluated through five-fold and leave-one-out cross-validation (CV) and statistical significance by non-parametric resampling procedures. Main results. LR and linear discriminant analysis achieved accuracy, sensitivity and specificity scores of near 100% (p <.001) for both CV schemes when trained with only three key wrapper-selected features, arising from surface and deep oscillatory components of very low frequency. Significance. We provide preliminary evidence that very-low frequency fNIRS fluctuations induced/modulated by a rhythmic mental task accurately differentiate ADHD boys from non-ADHD controls, outperforming other similar studies. The proposed approach holds promise for finding functional biomarkers reliable and interpretable enough to inform clinical practice.

Relationship between morphometric and mechanical properties of superficial lumbosacral soft tissue layers in healthy young adults.

Introduction: It is commonly considered that myotonometry is a non-invasive method capable of quantifying linear elastic and viscoelastic properties of the myofascial tissue through the application of a weak mechanical impulse to the surface of the skin. However, before the impulse can reach the myofascial tissue, it must cross more superficial tissues such as the skin and subcutaneous tissue (ST). All these superficial tissues have different distributions and organizations of structural components. Therefore, the study aimed to examine the potential relationships between the mechanical and morphometric properties of various superficial soft tissues surrounding the lumbar multifidus muscle (LM). Methods: Myotonometric measurements of dynamic stiffness, logarithmic decrement, and creep, and ultrasonographic measurements of thickness and echogenicity of cutaneous, subcutaneous, perimuscular tissue, and LM were obtained from 50 healthy individuals in the resting prone position and during contralateral arm lift. Results: The most important findings were that in both the relaxed and contracted LM state, the dynamic stiffness strongly negatively (r = -0.69; p < 0.001 in relaxation, r = -0.83; p < 0.001 in contraction) and creep strongly positively (r = 0.79; p < 0.001 in relaxation, r = 0.85; p < 0.001 in contraction) correlated with the thicknesses of the ST. Similar but weaker correlations were noticed between both these measures and the perimuscular tissue thickness. Elasticity was uncorrelated to the thicknesses of the tissues. With LM contraction (change from the relaxed to contracted state), the relative increase in dynamic stiffness was correlated with the relative decrease in dermis (r = -0.51; p < 0.001) and ST (r = -0.47; p = 0.001) thickness, and with the relative increase in LM (r = 0.36; p = 0.010) thickness. Moreover, the relative decrease (thinning) in the ST thickness was correlated with the relative increase in logarithmic decrement (i.e., decrease in soft tissue elasticity, r = -0.37, p = 0.011). The mechanical properties of the soft tissues were not related to their echogenicity. Discussion: In conclusion, the thicker the subcutaneous and perimuscular layers, the lesser the stiffness and the greater the time-dependent deformation to the external force of the tissues surrounding the LM during its relaxation and isometric contraction. Moreover, the greater the thinning of the ST and the thickening of the LM during its contraction, the higher the increase in lumbosacral tissue stiffness and the decrease in elasticity. Therefore, one should consider the thickness of the ST before planning or analyzing the outcomes of myotonometric or other external biomechanical measurements to avoid drawing the wrong conclusions about the mechanical properties of the myofascial tissue.

Effect of 0.35 T and 1.5 T magnetic fields on superficial dose in MR-guided radiotherapy of laryngeal cancer

BackgroundTreatment of head and neck cancer on linear accelerators with on-board magnetic resonance imaging (MR-linac) might be beneficial to reduce side effects and increase accuracy. For many head and neck cancer patients, dose coverage of the often superficially located planning target volumes (PTVs) is required. This study examines the impact of the electron return effect (ERE) on the surface dose in MR-guided radiotherapy (MRgRT) compared to conventional radiotherapy. Materials and methodsFor this bicentric dosimetric study, 14 cases of laryngeal carcinomas with PTVs reaching up to the skin surface were included. For each patient, five different plans were compared, two VMAT plans (with and without a 5 mm bolus) and three IMRT MRgRT plans (0.35 T, 1.5 T and 0 T, each without bolus). Dose distributions were also validated with film measurements. ResultsA similar coverage on the most superficial 3–5 mm of the PTV was achieved in the VMAT plans with bolus and the MRgRT plans for both 0.35 T and 1.5 T. However, coverage on this region was usually not achieved for VMAT without bolus and the 0 T plans. The film measurements on phantoms confirmed the results with the relative error never exceeding the calculated differences between the plans. ConclusionThe present study could demonstrate that the ERE for both commercially available MR-linac variants provides sufficient coverage of the superficial tissue layers in MRgRT-plans for laryngeal carcinoma.

Tissue-Mimicking Materials for Ultrasound-Guided Needle Intervention Phantoms: A Comprehensive Review.

Ultrasound-guided needle interventions are common procedures in medicine, and tissue-mimicking phantoms are widely used for simulation training to bridge the gap between theory and clinical practice in a controlled environment. This review assesses tissue-mimicking materials from 24 studies as candidates for a high-fidelity ultrasound phantom, including methods for evaluating relevant acoustic and mechanical properties and to what extent the reported materials mimic the superficial layers of biological tissue. Speed of sound, acoustic attenuation, Young's modulus, hardness, needle interaction forces, training efficiency and material limitations were systematically evaluated. Although gelatin and agar have the closest acoustic values to tissue, mechanical properties are limited, and strict storage protocols must be employed to counteract dehydration and microbial growth. Polyvinyl chloride (PVC) has superior mechanical properties and is a suitable alternative if durability is desired and some ultrasound realism to human tissue may be sacrificed. Polyvinyl alcohol (PVA), while also requiring hydration, performs well across all categories. Furthermore, we propose a framework for the evaluation of future ultrasound-guided needle intervention tissue phantoms to increase the fidelity of training programs and thereby improve clinical performance.

Retrograde dye perfusion of the proximal aorta – A postmortem technical study

IntroductionMultiple cardiovascular conditions can lead to unexpected fatality, which is defined as sudden cardiac death. One of these potentially underlying conditions is aortic regurgitation, which can be caused by discrete changes of the geometry of the proximal aorta. To analyze aortic valve competency and furthermore to elucidate underlying pathological alterations of the coronary arteries and the vasa vasorum a perfusion method to simulate a diastolic state was designed. Material and methodsA postmortem approach with retrograde perfusion of the ascending aorta with methylene blue was applied to three bodies. The procedure comprised cannulation of the brachiocephalic trunk, clamping of the aortic arch between brachiocephalic trunk and left carotid artery, infusion of 250 ml of methylene blue, and optical clearing of the superficial tissue layers after perfusion. Organs were examined directly following perfusion and after optical clearing. ResultsAssessment and visualization of aortic valve competency and the vasa vasorum were possible in all three instances. Visualization of the coronary perfusion was impaired by postmortem thrombus formation. Optical clearing did not provide additional information. DiscussionThe method presented here is a time- and cost-efficient way of visualizing aortic valve competency and the vasa vasorum. The visualization of the vasa vasorum highlights the potential of this method in basic research on diseases of the great arteries and coronaries. However, for a time-efficient functional analysis of the coronaries, other methods must be applied.

P31. How positive cultures affected clinical outcomes in patients undergoing primary lumbar fusion

<h3>BACKGROUND CONTEXT</h3> Occult bacteria have been linked to deep and chronic infections in spine surgery. These organisms are commensal to dermal and deeper tissue layers, including the intervertebral disc and bone. We hypothesize that standard surgical skin preparation nor preoperative antibiotics properly access and eradicate these organisms prior to primary spine surgery. These organisms can potentially adhere to the biofilm surrounding the hardware and limit bone formation. <h3>PURPOSE</h3> To determine the colonization rate of occult bacteria in the superficial and deep tissue layers of healthy patients undergoing primary instrumented lumbar spine surgery. <h3>STUDY DESIGN/SETTING</h3> This prospective, consecutive cohort of patients undergoing primary lumbar spine surgery at a single tertiary center. All patients met the inclusion/exclusion criteria which included between the ages of 18 and 80, undergoing a posterior approach with pedicle screw instrumentation with no evidence of a prior or current fracture, trauma, tumor, or an active systemic or local infection. Patients were also excluded if they were immunosuppressed or had received prior surgery at any lumbar level with hardware. This study was approved by our institutional review board and ethics review panel. <h3>PATIENT SAMPLE</h3> Fifty-four patients. <h3>OUTCOME MEASURES</h3> Culture swabs, fusion rates, revision rates. <h3>METHODS</h3> All patients received preoperative antibiotics and skin preparation. Culture samples were subsequently obtained from the superficial skin, dermal wound-edge following incision, hypodermis and the vertebral pedicle prior to instrumentation implantation. Control culture samples were taken from scalpel, tap and suction prior to incision. The primary outcome was the rate of positive culture samples from the various layers traversed during standard surgical spine exposure. Clinical outcomes of fusion status and revision rate were collected. <h3>RESULTS</h3> A total of 525 culture samples were obtained, and samples were positive in 33.3% of patients (18/54). Culture-positive patients had on average 3.1 positive samples per case. Superficial skin samples were positive in 13.0% (n=7), dermal layer samples in 16.7% (n=9), hypodermis samples in 13.0% (n=7), and vertebral samples in 20.4% (n=11) of cases. All control samples taken were culture-negative. C. acnes was the most common organism isolated, in 83.3% of culture-positive cases. Significantly more males were culture-positive than females. Patients with positive cultures were treated with antibiotics. At one-year postoperative, patients in culture-positive group had similar fusion rates to culture-negative groups. However, delayed fusion was observed at a higher rate in the culture-positive group. <h3>CONCLUSIONS</h3> Occult bacteria was detected in one-third of patients undergoing primary instrumented posterior spine surgery. Deep culture samples of the vertebral pedicle were more often positive than dermal layer samples. The data collected supports our hypothesis that occult bacteria persist in the skin and deeper tissue layers regardless of the efforts made by preoperative skin preparation and prophylactic antibiotics. The clinical sequela for culture-positive patients, although addressed perioperatively, was a higher incidence of delayed fusion. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Hyperspectral Imaging as a Tool for Viability Assessment During Normothermic Machine Perfusion of Human Livers: A Proof of Concept Pilot Study.

Normothermic machine perfusion (NMP) allows for ex vivo viability and functional assessment prior to liver transplantation (LT). Hyperspectral imaging represents a suitable, non-invasive method to evaluate tissue morphology and organ perfusion during NMP. Liver allografts were subjected to NMP prior to LT. Serial image acquisition of oxygen saturation levels (StO2), organ hemoglobin (THI), near-infrared perfusion (NIR) and tissue water indices (TWI) through hyperspectral imaging was performed during static cold storage, at 1h, 6h, 12h and at the end of NMP. The readouts were correlated with perfusate parameters at equivalent time points. Twenty-one deceased donor livers were included in the study. Seven (33.0%) were discarded due to poor organ function during NMP. StO2 (p < 0.001), THI (p < 0.001) and NIR (p = 0.002) significantly augmented, from static cold storage (pre-NMP) to NMP end, while TWI dropped (p = 0.005) during the observational period. At 12–24h, a significantly higher hemoglobin concentration (THI) in the superficial tissue layers was seen in discarded, compared to transplanted livers (p = 0.036). Lactate values at 12h NMP correlated negatively with NIR perfusion index between 12 and 24h NMP and with the delta NIR perfusion index between 1 and 24h (rs = −0.883, p = 0.008 for both). Furthermore, NIR and TWI correlated with lactate clearance and pH. This study provides first evidence of feasibility of hyperspectral imaging as a potentially helpful contact-free organ viability assessment tool during liver NMP.

Design of a Barometer-Based Pulse-Taking Device With In Vivo Validation Against High-Frequency Ultrasound Pulse Wave Imaging

Wrist-site pulse-sensing devices have drawn increasing attention for daily monitoring of human body conditions in the context of western medicine and modernization of traditional Chinese medicine (TCM) palpation. Existing tactile pulse sensors are deemed to only access the superficial tissue layer as surface detectors but have not been validated against medical imaging of the radial artery and its pulsation. We hereby proposed to employ high-frequency (15.6MHz) and high frame-rate (1000fps) ultrasound radial pulse wave imaging (US-rPWI) to substantiate human radial pulse-taking. We first presented an easy-to-fabricate, cost-effective pulse-sensing prototype based on a commercial off-the-shelf (COTS) barometer. The prototype performance was evaluated using a homemade pressurized vessel-mimicking phantom and 30 different <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vitro</i> pulses outputted from a TCM palpation training machine. Phantom experiments evidenced accurate portrayal of dynamic pressure waveforms (mean distortion ratio: 3.38±0.07%, compared with the ground truth). <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">In vivo</i> validation on human pre- and post- prandial pulses was further performed. US-rPWI revealed significantly diminished pulse amplitudes and gradual waveform deformation from the arterial wall to the skin layer. Nevertheless, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in vivo</i> pulse waveforms detected at the skin surface by the prototype were highly correlated (correlation coefficient: 0.926±0.07) with those obtained from the radial arterial wall by US-rPWI. Moreover, the changes in post-prandial pulse waveforms detected by both the prototype and US-rPWI were in excellent agreement with those in TCM literature, thus demonstrating the sensitivity of human pulse-taking in quantitative assessment of health conditions at the point of care and providing more clinical evidence for the modernization of TCM sphygmology.

Phenotypical Conversions of Dermal Adipocytes as Pathophysiological Steps in Inflammatory Cutaneous Disorders.

Adipocytes from the superficial layer of subcutaneous adipose tissue undergo cyclic de- and re-differentiation, which can significantly influence the development of skin inflammation under different cutaneous conditions. This inflammation can be connected with local loading of the reticular dermis with lipids released due to de-differentiation of adipocytes during the catagen phase of the hair follicle cycle. Alternatively, the inflammation parallels a widespread release of cathelicidin, which typically takes place in the anagen phase (especially in the presence of pathogens). Additionally, trans-differentiation of dermal adipocytes into myofibroblasts, which can occur under some pathological conditions, can be responsible for the development of collateral scarring in acne. Here, we provide an overview of such cellular conversions in the skin and discuss their possible involvement in the pathophysiology of inflammatory skin conditions, such as acne and psoriasis.

Measurement of Adult Human Brain Responses to Breath-Holding by Multi-Distance Hyperspectral Near-Infrared Spectroscopy

A major limitation of near-infrared spectroscopy (NIRS) is its high sensitivity to the scalp and low sensitivity to the brain of adult humans. In the present work we used multi-distance hyperspectral NIRS (hNIRS) to investigate the optimal source-detector distances, wavelength ranges, and analysis techniques to separate cerebral responses to 30 s breath-holds (BHs) from the responses in the superficial tissue layer in healthy adult humans. We observed significant responses to BHs in the scalp hemodynamics. Cerebral responses to BHs were detected in the cytochrome C oxidase redox (rCCO) at 4 cm without using data from the short-distance channel. Using the data from the 1 cm channel in the two-layer regression algorithm showed that cerebral hemodynamic and rCCO responses also occurred at 3 cm. We found that the waveband 700–900 nm was optimal for the detection of cerebral responses to BHs in adults.

Tissue biomolecular and microstructure profiles in optical colorectal cancer delineation

Colorectal cancer (CRC) is the 3rd most common and the 2nd most deadly type of cancer worldwide. Understanding the biochemical and microstructural aspects of carcinogenesis is a critical step towards developing new technologies for accurate CRC detection. To date, optical detection through analyzing tissue chromophore concentrations and scattering parameters has been mostly limited to chromophores in the visible region and analytical light diffusion models. In this study, tissue parameters were extracted by fitting diffuse reflectance spectra (DRS) within the range 350–1900 nm based on reflectance values from a look-up table built using Monte Carlo simulations of light propagation in tissues. This analysis was combined with machine learning models to estimate parameter thresholds leading to best differentiation between mucosa and tumor tissues based on almost 3000 DRS recorded from fresh ex vivo tissue samples from 47 subjects. DRS spectra were measured with a probe for superficial tissue and another for slightly deeper tissue layers. By using the classification and regression tree algorithm, the most important parameters for CRC detection were the total lipid content (f lipid), the reduced scattering amplitude (α′), and the Mie scattering power (b Mie). Successful classification with an area under the receiver operating characteristic curve higher than 90% was achieved. To the best of our knowledge, this is the first study to evaluate the potential tissue biomolecule concentrations and scattering properties in superficial and deeper tissue layers for CRC detection in the luminal wall. This may have important clinical applications for the rapid diagnosis of colorectal neoplasia.

Novel Techniques to Improve Precise Cell Injection.

We noted recently that the injection of cells with a needle through a cystoscope in the urethral sphincter muscle of pigs failed to deposit them nearby or at the intended target position in about 50% of all animals investigated (n > 100). Increasing the chance for precise cell injection by shotgun approaches employing several circumferential injections into the sphincter muscle bears the risk of tissue injury. In this study, we developed and tested a novel needle-free technique to precisely inject cells in the urethral sphincter tissue, or other tissues, using a water-jet system. This system was designed to fit in the working channels of endoscopes and cystoscopes, allowing a wide range of minimally invasive applications. We analyze key features, including the physical parameters of the injector design, pressure ranges applicable for tissue penetration and cell injections and biochemical parameters, such as different compositions of injection media. Our results present settings that enable the high viability of cells post-injection. Lastly, the method is suitable to inject cells in the superficial tissue layer and in deeper layers, required when the submucosa or the sphincter muscle of the urethra is targeted.

Optoacoustic imaging of the skin.

Optoacoustic (OA, photoacoustic) imaging capitalizes on the synergistic combination of light excitation and ultrasound detection to empower biological and clinical investigations with rich optical contrast while effectively bridging the gap between micro and macroscopic imaging realms. State-of-the-art OA embodiments consistently provide images at micron-scale resolution through superficial tissue layers by means of focused illumination that can be smoothly exchanged for acoustic-resolution images at diffuse light depths of several millimetres to centimetres via ultrasound beamforming or tomographic reconstruction. Taken together, this unique multi-scale imaging capacity opens unprecedented capabilities for high-resolution in vivo interrogations of the skin at scalable depths. Moreover, diverse anatomical and functional information is retrieved via dynamic mapping of endogenous chromophores such as haemoglobin, melanin, lipids, collagen, water and others. This, along with the use of non-ionizing radiation, facilitates a clinical translation of the OA modalities. We review recent progress in OA imaging of the skin in preclinical and clinical studies exploiting the rich contrast provided by endogenous substances in tissues. The imaging capabilities of existing approaches are discussed in the context of initial translational studies on skin cancer, inflammatory skin diseases, wounds and other conditions.

Bowel adhesion and therapy with the stable gastric pentadecapeptide BPC 157, L-NAME and L-arginine in rats.

BACKGROUNDAfter parietal peritoneum excision with an underlying superficial layer of muscle tissue in rats, there is failed vasculature, and finally, increased adhesion formation. We hypothesized that unlike nitric oxide (NO)-agents, L-NAME and/or L-arginine, the application of the stable gastric pentadecapeptide BPC 157 with its most recent vascular effects (“vascular recruitment”) means attenuated bowel adhesion formation and NO- and malondialdehyde (MDA)-tissue values.AIMTo focused on the bowel adhesion and the therapy with the BPC 157, its most and application of NO-agents.METHODSAlong with defect creation, medication was (1) during surgery, once, at 1 min after defect creation as an abdominal bath (1 mL/rat), BPC 157 (10 µg/kg, 10 ng/kg, 1 mL/rat), an equivolume of saline, L-NAME (5 mg/kg), L-arginine (200 mg/kg) alone and/or combined. Alternatively, medication was (2) intraperitoneally once daily, first application at 30 min after surgery, last application 24 h before assessment at d 7 or d 14. As a postponed therapy to pre-existing adhesion (3), BPC 157 (10 µg/kg, 10 ng/kg intraperitoneally, 1 mL/rat) was given once daily since d 7.RESULTSThe recovery effect of the BPC 157 regimens goes with the presence of abundant vascular vessels in and near the defect, which occurs rapidly. Lastly, also applied as post-treatment, BPC 157 creates attenuated adhesions, minimal or no adhesion. Contrarily, NO-agents have diverse initial and final effects: The initial weakening of blood vessel disappearance and finally, severe worsening of adhesions (L-NAME) vs the initial weakening of blood vessel disappearance and finally, attenuation of adhesions formation (L-arginine), which counteract each other response given together. Importantly, BPC 157 maintains its beneficial effect also when given with NO-agents (L-NAME + BC 157; L-arginine + BPC 157; L-NAME + L-arginine + BPC 157). Finally, with respect to the increased NO- and MDA- values-adhesion tissue formation relation, unlike diverse effect of the NO-agents, the BPC 157 application effect regularly combines decrease on the increased NO- and MDA- values and the beneficial outcome (less adhesion formation).CONCLUSIONBPC 157 therapy can be suited for the realization of the peritoneal defect healing with minimal or no adhesion formation.

Efficacy of radiofrequency RDN may be significantly improved if the procedure is guided by impedance drop during the treatment

Abstract Background Experimental studies of radiofrequency renal denervation (RDN) have shown a strong relation of the depth of structural lesions and completeness of renal nerve injury to the relative drop in impedance during the treatment caused by the increased permeability of the cell membranes. Thus, the otherwise successful treatments but with low impedance drop may be, in fact, totally ineffective. Objective We assessed the relation between impedance drop during single radiofrequency treatments and local structural changes of vascular wall at the electrode positions using optical coherence tomography. Methods Optical coherence tomography of the treated segments was performed during radiofrequency RDN in 14 patients with resistant hypertension. The parameters of contrast injection depended on the position of the guiding catheter: for selective branch imaging 15 ml volume was injected at 8 ml/sec speed; otherwise 30 ml of contrast was injected at the speed 15 ml/sec to flush the whole renal artery. Automatic pullback of the sensor was done with the standard speed 20 mm/sec. In total, 423 mm of treated segments in 22 renal vessels (mostly distal branches) had sufficient quality of imaging and were studied for structural changes. Results There was almost no local structural changes of the arterial wall after the treatments with low impedance drop &amp;lt;10% reflecting a rather weak heating of even superficial tissue layers. No effect on the deeper tissue layers is expected in this case because these layers are heated almost exclusively by the heat transfer from superficial layer. In contrast, the treatments with the impedance drop 10% or greater were able to significantly affect the arterial structure causing local edema, small dissections, and local thrombi formation as a result of significant resistive heating of the superficial tissue, and, therefore, high potential for heating of the deep layers containing the renal nerves. Only approximately 40% of the point treatments had the impedance drop 10% or greater suggesting adequate lesion depth and sufficient completeness of renal nerve injury. This may indicate a rather low procedural efficacy of the current mode of radiofrequency RDN due to a large proportion of small-depth treatments marked by only a few percent decrease in impedance yet considered fully “successful”. Also, it means a potential for significant increase in the efficacy of radiofrequency RDN through controlling/guiding the treatment by the impedance drop. Conclusion Our study shows that variable efficacy of radiofrequency RDN may be explained by a significant proportion of the small-depth point treatments ineffective in terms of renal nerve injury, and, thereby, may be significantly improved if the procedure is guided by the impedance drop during the treatment. Funding Acknowledgement Type of funding source: None

Photodynamic therapy of oral lichen planus.

Oral lichen planus (OLP) is a chronic inflammatory and immune-mediated disease affecting the oral mucosa. OLP presents with asymptomatic, lacelike white stripes and/or symptomatic red, ulcerated mucous membranes. Eating, drinking and oral hygiene procedures may be painful resulting in reduced quality of life (QOL). The histopathological picture is a zone of cellular infiltrate, mainly CD8+ cells, in the superficial layer of the connective tissue and signs of liquefaction degeneration of the basal membrane. Conventional treatment is corticosteroids. Local and systemic side effects are common, and patients may develop drug resistance. The intention with this article is to demonstrate the heterogeneity in photodynamic therapy (PDT) of OLP. A search in PubMed, Embase (Ovid) and Medline (Ovid) identified seventeen clinical studies investigating PDT of OLP. Only five were randomised controlled studies and the study groups varied from 5 to 50 patients. Five different photosensitisers or precursors were tested. Both broadband spectrum lamps, lasers and light-emitting-diodes (LEDs), with wavelengths from 420 nm to 682 nm, were used. The number of treatment sessions varied from one to ten. The patients were followed up for 0 to 48 months, but in thirteen studies the post treatment observation time was ≤6 months. Single arm studies demonstrated improvement of OLP except in one study. In all controlled studies except for one, PDT was superior or equal to conventional treatment. The majority of patients experienced a slight burning sensation during light activation, but no serious adverse events were reported. Only few studies examined the effect of PDT on a cellular level.

A composite hydrogel-3D printed thermoplast osteochondral anchor as example for a zonal approach to cartilage repair: in vivo performance in a long-term equine model

Recent research has been focusing on the generation of living personalized osteochondral constructs for joint repair. Native articular cartilage has a zonal structure, which is not reflected in current constructs and which may be a cause of the frequent failure of these repair attempts. Therefore, we investigated the performance of a composite implant that further reflects the zonal distribution of cellular component both in vitro and in vivo in a long-term equine model. Constructs constituted of a 3D-printed poly(ϵ-caprolactone) (PCL) bone anchor from which reinforcing fibers protruded into the chondral part of the construct over which two layers of a thiol-ene cross-linkable hyaluronic acid/poly(glycidol) hybrid hydrogel (HA-SH/P(AGE-co-G)) were fabricated. The top layer contained Articular Cartilage Progenitor Cells (ACPCs) derived from the superficial layer of native cartilage tissue, the bottom layer contained mesenchymal stromal cells (MSCs). The chondral part of control constructs were homogeneously filled with MSCs. After six months in vivo, microtomography revealed significant bone growth into the anchor. Histologically, there was only limited production of cartilage-like tissue (despite persistency of hydrogel) both in zonal and non-zonal constructs. There were no differences in histological scoring; however, the repair tissue was significantly stiffer in defects repaired with zonal constructs. The sub-optimal quality of the repair tissue may be related to several factors, including early loss of implanted cells, or inappropriate degradation rate of the hydrogel. Nonetheless, this approach may be promising and research into further tailoring of biomaterials and of construct characteristics seems warranted.

Polarization gating technique extracts depth resolved fluorescence redox ratio in oral cancer diagnostics.

Mortality of oral cancer is often due to late diagnosis. Effective non-invasive diagnostic techniques may increase the survival rate based on an earlier diagnosis.. We report on the application of the polarization gating technique for isolating weakly scattered and highly scattered components of fluorescence emission from the superficial and deeper layers of tissue due to intrinsic fluorophores NADH and FAD. The fluorescence polarization spectra were collected from 21 normal and 67 oral squamous cell carcinoma biopsy tissues. The tissues were excited at 350 nm and the fluorescence emission had two peaks corresponding to NADH, and FAD respectively. The spectra were analyzed using the polarization gating technique along with the spectral deconvolution method to derive the optical redox ratio from different layers of tissue. The fractional change in redox ratio between superficial and deeper layers of tissue exhibits excellent statistical significance (p<10-3) which may be due to a shift in the metabolic pathway from oxidative phosphorylation to glycolysis in the cancer cell. Further, variation in collagen intensity in deeper layers of tissue is observed which may be attributed to the breakdown of collagen fibers in the stroma. Linear discriminant analysis showed that oral cancer tissue is discriminated with a better accuracy using polarization gating technique than that of conventional fluorescence spectroscopy.