Skeletal muscle reprogramming enhances reinnervation after peripheral nerve injury

Peripheral Nerve Injuries (PNI) affect more than 20 million Americans and severely impact quality of life by causing long-term disability. The onset of PNI is characterized by nerve degeneration distal to the nerve injury resulting in long periods of skeletal muscle denervation. During this period, muscle fibers atrophy and frequently become incapable of "accepting" innervation because of the slow speed of axon regeneration post injury. We hypothesize that reprogramming the skeletal muscle to an embryonic-like state may preserve its reinnervation capability following PNI. To this end, we generated a mouse model in which NANOG, a pluripotency-associated transcription factor can be expressed locally upon delivery of doxycycline (Dox) in a polymeric vehicle. NANOG expression in the muscle upregulated the percentage of Pax7+ nuclei and expression of eMYHC along with other genes that are involved in muscle development. In a sciatic nerve transection model, NANOG expression led to upregulation of key genes associated with myogenesis, neurogenesis and neuromuscular junction (NMJ) formation, and downregulation of key muscle atrophy genes. Further, NANOG mice demonstrated extensive overlap between synaptic vesicles and NMJ acetylcholine receptors (AChRs) indicating restored innervation. Indeed, NANOG mice showed greater improvement in motor function as compared to wild-type (WT) animals, as evidenced by improved toe-spread reflex, EMG responses and isometric force production. In conclusion, we demonstrate that reprogramming the muscle can be an effective strategy to improve reinnervation and functional outcomes after PNI.

The intersection of video capsule endoscopy and artificial intelligence: addressing unique challenges using machine learning

Introduction

Technical burdens and time-intensive review processes limit the practical utility of video capsule endoscopy (VCE). Artificial intelligence (AI) is poised to address these limitations, but the intersection of AI and VCE reveals challenges that must first be overcome. We identified five challenges to address. Challenge #1: VCE data are stochastic and contains significant artifact. Challenge #2: VCE interpretation is cost-intensive. Challenge #3: VCE data are inherently imbalanced. Challenge #4: Existing VCE AIMLT are computationally cumbersome. Challenge #5: Clinicians are hesitant to accept AIMLT that cannot explain their process.

Methods

An anatomic landmark detection model was used to test the application of convolutional neural networks (CNNs) to the task of classifying VCE data. We also created a tool that assists in expert annotation of VCE data. We then created more elaborate models using different approaches including a multi-frame approach, a CNN based on graph representation, and a few-shot approach based on meta-learning.

Results

When used on full-length VCE footage, CNNs accurately identified anatomic landmarks (99.1%), with gradient weighted-class activation mapping showing the parts of each frame that the CNN used to make its decision. The graph CNN with weakly supervised learning (accuracy 89.9%, sensitivity of 91.1%), the few-shot model (accuracy 90.8%, precision 91.4%, sensitivity 90.9%), and the multi-frame model (accuracy 97.5%, precision 91.5%, sensitivity 94.8%) performed well.

Discussion

Each of these five challenges is addressed, in part, by one of our AI-based models. Our goal of producing high performance using lightweight models that aim to improve clinician confidence was achieved.

Deep Learning Methods for Anatomical Landmark Detection in Video Capsule Endoscopy Images

Video capsule endoscope (VCE) is an emerging technology that allows examination of the entire gastrointestinal (GI) tract with minimal invasion. While traditional endoscopy with biopsy procedures are the gold standard for diagnosis of most GI diseases, they are limited by how far the scope can be advanced in the tract and are also invasive. VCE allows gastroenterologists to investigate GI tract abnormalities in detail with visualization of all parts of the GI tract. It captures continuous real time images as it is propelled in the GI tract by gut motility. Even though VCE allows for thorough examination, reviewing and analyzing up to eight hours of images (compiled as videos) is tedious and not cost effective. In order to pave way for automation of VCE-based GI disease diagnosis, detecting the location of the capsule would allow for a more focused analysis as well as abnormality detection in each region of the GI tract. In this paper, we compared four deep Convolutional Neural Network models for feature extraction and detection of the anatomical part within the GI tract captured by VCE images. Our results showed that VGG-Net has superior performance with the highest average accuracy, precision, recall and, F1-score compared to other state of the art architectures: GoogLeNet, AlexNet and, ResNet.

Epigenetic control of epilepsy target genes contributes to a cellular memory of epileptogenesis in cultured rat hippocampal neurons

Hypersynchronous neuronal excitation manifests clinically as seizure (ictogenesis), and may recur spontaneously and repetitively after a variable latency period (epileptogenesis). Despite tremendous research efforts to describe molecular pathways and signatures of epileptogenesis, molecular pathomechanisms leading to chronic epilepsy remain to be clarified. We hypothesized that epigenetic modifications may form the basis for a cellular memory of epileptogenesis, and used a primary neuronal cell culture model of the rat hippocampus to study the translation of massive neuronal excitation into persisting changes of epigenetic signatures and pro-epileptogenic target gene expression. Increased spontaneous activation of cultured neurons was detected 3 and 7 days after stimulation with 10 μM glutamate when compared to sham-treated time-matched controls using calcium-imaging in vitro. Chromatin-immunoprecipitation experiments revealed short-term (3 h, 7 h, and 24 h) and long-term (3 d and 2 weeks) changes in histone modifications, which were directly linked to decreased expression of two selected epilepsy target genes, e.g. excitatory glutamate receptor genes Gria2 and Grin2a. Increased promoter methylation observed 4 weeks after glutamate stimulation at respective genes suggested long-term repression of Gria2 and Grin2a genes. Inhibition of glutamatergic activation or blocking the propagation of action potentials in cultured neurons rescued altered gene expression and regulatory epigenetic modifications. Our data support the concept of a cellular memory of epileptogenesis and persisting epigenetic modifications of epilepsy target genes, which are able to turn normal into pro-epileptic neurons and circuits.

Role of soluble gp130 in the tumour necrosis factor-alpha expression and its production by peripheral blood mononuclear cells

BACKGROUND

In our previous study we found that rhsIL-6R, along with recombinant human interleukin-6, plays a regulatory role in the immune response by modulating the tumour necrosis factor-alpha(TNF-alpha) expression and its production by peripheral blood mononuclear cells (PBMC). We also suggested that sIL-6R with IL-6 secreted by human PMN (neutrophils) influenced the TNF-alpha expression and its production by autologous PBMC.

AIMS

Since soluble gp130 (sgp130) is a natural inhibitor for sIL-6R/interleukin-6 responses, in the present study we estimated an effect of exogenous recombinant human sgp130 and sgp130 secreted by PMN on the TNF-alpha expression and its production by PBMC.

METHODS

Cells were isolated from whole blood of healthy persons. The PMN were cultured in 96-well plates for 1 h at 37 degrees C in a humidified incubator with 5% CO2. After the incubation, the culture supernatant of PMN was removed and added to the PBMC. PBMC were incubated for 1 h at 37 degrees C in the same conditions. Cytoplasmic protein fractions of PMN and, for comparative purpose of PBMC, were analysed for presence of sgp130 by western blotting with the use of monoclonal antibody capable of detecting this protein. In the culture supernatants of PMN we examined the concentrations of sgp130 by human enzyme-linked immunosorbent assay. TNF-alpha was measured at the protein levels as well as the mRNA levels.

RESULTS AND CONCLUSIONS

The present results revealed that exogenous recombinant human sgp130modulates the TNF-alpha expression and production by PBMC. In contrast, we did not find any effect of sgp130 secreted by PMN on the TNF-alpha expression and its production by autologous PBMC.

VEGF in the culture of PMN and the serum in oral cavity cancer patients

Vascular endothelial growth factor (VEGF) is a multifunctional cytokine that plays a pivotal role in angiogenesis in vivo. In the present study we examined the ability of polymorphonuclear neutrophils (PMN) to secrete VEGF confronted with the serum levels in oral cavity cancer patients. To investigate whether VEGF may have a prognostic importance, its value in the serum and the culture supernatants was related to the clinical course of patients. The levels of VEGF in the culture supernatant of PMN from patients were significantly higher than those from control. Increased VEGF production by PMN according to clinical progression disease, observed in the present study, seems to suggest a stimulating role of tumour cells in VEGF production by PMN. Additionally, a decrease in the ability of PMN to VEGF release after surgery may be caused by a removal of the tumour mass and then the lack the effects of tumour cells on PMN function. Results obtained appear to suggest that PMN can contribute significantly to the initiation and amplification of tumour angiogenesis and metastasis in oral cavity cancer patients. Increased values of VEGF with progression of disease and decreased values after surgery treatment clearly suggest that VEGF can play a role as a tumour marker in oral cavity cancer patients.

Effect of IL-18 on the release of IL-6 and its soluble receptors: sIL-6Ralpha and sgp130 by human neutrophils

The biological activities of IL-18 include its ability to induce the production of inflammatory cytokines such as IL-1 or IL-8 by immunocompetent cells. Our previous study demonstrated that rhIL-18 induces IL-1beta and, to a lesser exted, the secretion of IL-1beta regulatory proteins involving interleukin-1 receptor antagonist (IL-IRa) and soluble interleukin-1 receptor II (sIL-1RII) by neutrophils (PMN), suggesting a significant role of IL-18 in the reactions mediated by IL-1beta. In this study, we estimated the effect of rhIL-18 on the induction of IL-6 and its soluble receptors - sIL-6Ralpha and sgp130 by these cells. Results obtained indicate that IL-18 is a promising candidate for the enhanced secretion of IL-6 by human neutrophils. In contrast, we have not found a significant effect of IL-18 on the release of both soluble receptors of IL-6. The influence of IL-18 on the IL-6 production by PMN appears to indicate a potential role of IL-18 in the early steps of the inflammatory cascade and other immune reactions mediated by IL-6.

Effect of IL-15 on the secretion of IL-1beta, IL-1Ra and sIL-1RII by PMN from cancer patients

In the present study, we demonstrate an effect of rhIL-15 on the simultaneous secretion of IL-1beta and its natural inhibitors IL-1Ra and sIL-1RII by human neutrophils isolated from normal and tumour-bearing hosts (oral cavity cancer and melanoma patients) compared with serum IL-15 levels. We found an rhIL-15 influence on IL-beta and IL-1Ra secreted by PMN from healthy controls. In contrast, the PMNs from cancer patients were not sensitive to rhIL-15 stimulation. However, we found a priming effect of rhIL-15 on IL-1beta production by LPS-stimulated cells in oral cavity cancer. We also found no effect on sIL-1RII release by PMN from cancer patients.

IL-1beta, IL-1Ra and sIL-1RII in the culture supernatants of PMN and PBMC and the serum levels in patients with inflammation and patients with cancer disease of the same location

An inflammation or an other malignant process may create a microenvironment that modulates the production and activity of cytokines and their regulators. In the present study we compared the secretion of IL-1beta and its regulatory proteins: IL-IRa and sIL-1RII by PMN and PBMC derived from patients with inflammation and patients with cancer disease of the same location. We also examined the serum levels of these mediators in groups of patients. The results obtained revealed changes in the secretion of IL-1beta and IL-1Ra which are more characteristic of PMN and PBMC from cancer patients than of the cells from patients with inflammation. In contrast, the secretion of sIL-1RII is more characteristic of PMN and PBMC derived from patients with inflammation. Furthermore, PMN appear to play more significant role in the secretion of IL-1Ra into the circulation of cancer patients than PBMC. In contrast, PBMC affect to a large extent the secretion of IL-1beta and sIL-1RII into the circulation of patients with inflammation than PMN. Concluding, the secretion of IL-1beta and its regulatory proteins may depend on the type of immune cells and the type of the disease.

The influence of very low doses of N-nitrosodimethylamine (NDMA) on the apoptosis of rat neutrophils in vivo. The role of reactive oxygen species

N-nitrosodimethylamine (NDMA) causes the apoptosis of neutrophils in vitro experiments. This compound also has the ability to stimulate neutrophils for the production of reactive oxygen species. It has been decided to examine more closely whether the apoptosis of neutrophils by NDMA is caused by the influence of the radicals produced by these cells and whether the stimulation to undergo apoptosis of neutrophils is caused by NDMA in either the original form or by its metabolites. The experiment was conducted on rats. The animals were administered a one-time dose of NDMA intragastrically, 1.5 mg/kg. The research was conducted 1,2,4,12 h consecutively following NDMA administration. The concentration of NDMA in blood was evaluated by means of the gas chromatography method. The neutrophils were isolated from blood by means of differential centrifugation. Respiratory burst was assessed in cells, by means of the cytochrome c reduction method. The percentage of cells revealing morphological properties of apoptosis was determined under the fluorescent microscope. It has been observed that the activation of the respiratory burst is caused mainly by non-metabolised NDMA. Probably the non-metabolised molecules of this compound also have a decisive role in the initiation of apoptosis of neutrophils. It can be assumed that the main factor responsible for the apoptosis of neutrophil rats following a one-time NDMA administration is the induction of respiratory burst in neutrophils by this compound.

Role of neutrophils in release of some cytokines and their soluble receptors

Available data suggest that cytokines and soluble cytokine receptors, which are being produced by immunological cells, can modulate the immune response of the host. Although the production of mediators such as TNF-alpha and IL-6 as well as that of their soluble receptors has been extensively studied in tissue cells and mononuclear cells, it has not been fully investigated in neutrophils (PMN). In the present study we examined the ability of PMN to simultaneously release TNF-alpha, IL-6 and their soluble receptors-sTNFRp55, sTNFRp75 and sIL-6R. Concentrations of soluble receptors were compared with expression of membrane-bound TNF and IL-6 receptors. For comparative purposes, similar examinations with autologous peripheral blood mononuclear cells (PBMC) were performed. We found that PMN and PBMC have the same ability to release IL-6 and sTNFRp75. In contrast, there were significant differences in the release of TNF-alpha, sTNFRp55 and sIL-6R between these cells. Reduction in membrane TNF receptor expression, observed in this study, was associated with increase secretion of soluble TNF receptors by PMN and PBMC. The results suggest that PMN can play an essential role in modulating the inflammatory response by affecting the balance between pro-inflammatory mediators, such as TNF-alpha, and anti-inflammatory mediators, such as soluble TNF receptors.

Evaluation of the influence of N-nitrosodimethyloamine (NDMA) on the apoptosis of neutrophils of peripheral blood (PMN) and the expression of the IL-6R membrane receptor--in vitro research

Evaluation of the influence of N-nitrosodimethyloamine (NDMA) on the apoptosis of neutrophils of peripheral blood (PMN) and the expression of the IL-6R membrane receptor - in vitro research. The aim of the present work was the evaluation of N-nitrosodimethyloamine (NDMA) on the induction of apoptosis in the neutrophils of peripheral blood as well as the evaluation of the surface receptors for IL-6. The isolated neutrophils were incubated for 1 and 3 hours with NDMA of a concentration of 2.5, 5, 7.5, and 10 mg/ml. In the samples incubated for 1 hour a significant, dose- dependent increase of apoptosis in the examined cells was observed. In the cells incubated for 3 hours, the increase of apoptosis was observed only at concentration of NDMA of 2.5 and 5 mg/ml. In case of higher concentration used, probably necrotic processes dominated in the cells. No influence of NDMA on the expression of IL-6R was observed.

Tumor necrosis factor-alpha and soluble tumor necrosis factor receptors in the culture supernatants of polymorphonuclear cells and peripheral blood mononuclear cells from cancer patients

Recent clinical and experimental studies have focused on the measurement of cytokines and their regulators, produced by immunocompetent cells. Their estimation may be used as parameters for the immune potential of cancer patients. In the present study we studied the ability of unstimulated and lipopolysaccharide (LPS)-stimulated polymorphonuclear cells (PMN) and peripheral blood mononuclear cells (PBMC) from oral cavity cancer and breast cancer patients to release tumor necrosis factor alpha (TNF-alpha) and soluble tumor necrosis factor receptors (sTNFR). There were significant differences concerning the parameters examined for PMN and PBMC from cancer patients as compared with normal subjects. We found significantly higher concentrations of sTNF-R p75 than sTNF-R p55 in the cell-culture supernatants. The culture supernatants of cells from oral cavity cancer patients contained higher concentrations of TNF-alpha and lower concentrations of sTNF-R p55 and sTNF-R p75 in comparison with breast cancer cell supernatants. In contrast, cells from breast cancer patients secreted lower concentrations of TNF-alpha and higher concentrations of sTNF-R p55 and sTNF-R p75. Although PBMC secreted higher concentrations of mediators than PMN, the quantitative dominance of PMN in the peripheral blood suggests an essential role of these cells in the defense reactions controlled by TNF-alpha.

Design and characterization of hirulogs: a novel class of bivalent peptide inhibitors of thrombin

A novel class of synthetic peptides has been designed that inhibit the thrombin catalytic site and exhibit specificity for the anion-binding exosite (ABE) of alpha-thrombin. These peptides, called "hirulogs", consist of (i) an active-site specificity sequence with a restricted Arg-Pro scissile bond, (ii) a polymeric linker of glycyl residues from 6 to 18 A in length, and (iii) an ABE recognition sequence such as that in the hirudin C-terminus. Hirulog-1 ([D-Phe)-Pro-Arg-Pro-(Gly)4-Asn-Gly-Asp-Phe-Glu-Glu-Ile- Pro-Glu-Tyr-Leu] inhibits the thrombin-catalyzed hydrolysis of a tripeptide p-nitroanilide substrate with Ki = 2.3 nM. In contrast, the synthetic C-terminal hirudin peptide S-Hir53-64, which binds to the thrombin ABE, blocked the fibrinogen clotting activity of the enzyme with Ki = 144 nM but failed to inhibit the hydrolysis of p-nitroanilide substrates at concentrations as high as 1 mM. In addition, the pentapeptide (D-Phe)-Pro-Arg-Pro-Gly, which comprises the catalytic-site inhibitor moiety of hirulog-1, was determined to have a Ki for thrombin inhibition greater than 2 microM. Hirulog-1, but not S-Hir53-64, was found to inhibit the incorporation of [14C]diisopropyl fluorophosphate in thrombin. Hirulog-1 appears specific for thrombin as it lacks inhibitory activities toward human factor Xa, human plasmin, and bovine trypsin at inhibitor:enzyme concentrations 3 orders of magnitude higher than those required to inhibit thrombin. The optimal inhibitory activity of hirulog-1 depends upon all three components of its structure.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of the human gene that encodes the peptide core of secretory granule proteoglycans in promyelocytic leukemia HL-60 cells and analysis of the translated product

Based upon the deduced amino acid sequence of a cDNA (cDNA-H4) that had been proposed to encode the peptide core of an eosinophil and a HL-60 cell secretory granule proteoglycan, a 16-amino acid peptide was synthesized. This peptide was then used to elicit rabbit antibodies for study of the translation and post-translational modification of this gene product in hematopoietic cells. When HL-60 cells were radiolabeled for 2 min with [35S]methionine, a protein that migrated in a sodium dodecyl sulfate-polyacrylamide electrophoresis gel with a Mr of 20,000 was immunoprecipitated with the IgG fraction of the anti-peptide serum. Kinetic experiments revealed that within 10 min this radiolabeled precursor protein was converted in HL-60 cells into an Mr approximately 150,000 chondroitin sulfate proteoglycan intermediate. After a 20-min to 1-h chase, this [35S]methionine- or [35S]sulfate-labeled proteoglycan intermediate lost its antigenicity, presumably due to proteolysis of its N terminus. A human genomic library was probed under conditions of high stringency with cDNA-H4 to isolate genomic clones that contain the gene that encodes this proteoglycan peptide core. This gene spans approximately 15 kilobases and consists of three exons. The first exon encodes the 5'-untranslated region of the mRNA transcript, as well as the entire 27-amino acid signal peptide of the translated molecule. The second exon encodes a 49-amino acid region of the peptide core, predicted to be the N terminus of the molecule after its proteolytic processing in the endoplasmic reticulum. The third exon encodes the remainder of the molecule, including its glycosaminoglycan attachment, serine-glycine repeat region. As assessed by S1 nuclease mapping and primer extension analysis, the transcription-initiation site in HL-60 cells for this gene resides 53 base pairs upstream from the translation-initiation site.

Anticoagulant activity of synthetic hirudin peptides

Synthetic peptides based on the COOH-terminal 21 residues of hirudin were prepared in order to 1) evaluate the role of this segment in hirudin action toward thrombin, 2) define the shortest peptide derivative with anticoagulant activity, and 3) investigate the role of tyrosine sulfation in the peptides' inhibitory activities. A hirudin derivative of 20 amino acids, Hir45-64 (derived from residues 45-64 of the hirudin polypeptide), was found to effect a dose-dependent increase in the activated partial thromboplastin time (APTT) of normal human plasma but to have no measurable inhibitory activity toward thrombin cleavage of a tripeptidyl p-nitroanilide substrate. Anticoagulant activity in hirudin derivatives was comparable in peptides of 20, 16, and 12 residues truncated from the NH2 terminus. Additional truncated peptides prepared by synthesis and carboxypeptidase treatment reveal that the minimal sequence of a hirudin peptide fragment with maximal anticoagulant activity is contained within the sequence: NH2-Asn-Gly-Asp-Phe-Glu-Glu-Ile-Pro-Glu-Glu-Tyr-Leu-COOH. The 12-residue derivative thus identified was reacted with dicyclohexylcarbodiimide in the presence of sulfuric acid to yield a Tyr-sulfated peptide, S-Hir53-64. By comparison to unsulfated peptide, S-Hir53-64 was found to contain a specific inhibitory activity enhanced by one order of magnitude toward increase in APTT and to effect a dose-dependent increase in thrombin time of normal human plasma to yield a 4-fold increase in thrombin time with 2.5 micrograms/ml peptide using 0.8 units/ml alpha-thrombin. Comparison of S-Hir53-64 to hirudin in thrombin time and APTT assays reveals a 50-fold difference in molar specific activities toward inhibition of thrombin. Comparison of antithrombin activities of S-Hir53-64 using a variety of animal thrombins demonstrates greatest inhibitory activity toward murine, rat, and human enzymes and a 10-fold reduced activity toward bovine thrombin.

Relationship between arterial and peak expired carbon dioxide pressure during anesthesia and factors influencing the difference

To determine how closely peak expired PCO2 measured by mass spectrometry reflects arterial PCO2 during anesthesia and what variables contribute to a difference between the two measurements, peak expired CO2, arterial PCO2, and other physiologic variables were measured simultaneously. There was a significant correlation between peak expired and arterial PCO2 (p less than 0.001). The difference between temperature-corrected arterial and peak expired PCO2 was related to the presence or absence of lung disease, age, A.S.A. class, and systolic blood pressure. No significant relationship was seen between the temperature-corrected difference and duration of anesthesia, diastolic pressure, expired O2 concentration, or anesthetic agent. Mean temperature-corrected arterial PCO2 exceeded mean peak expired PCO2 by 1.7 torr in all patients, 0.8 torr in patients without lung disease, and 3.3 torr in patients with lung disease. In patients in whom more than one arterial sample was obtained, initial differences correlated significantly with subsequent differences (p less than 0.001).