A multi-stem cell basis for craniosynostosis and calvarial mineralization

Craniosynostosis is a group of disorders of premature calvarial suture fusion. The identity of the calvarial stem cells (CSCs) that produce fusion-driving osteoblasts in craniosynostosis remains poorly understood. Here we show that both physiologic calvarial mineralization and pathologic calvarial fusion in craniosynostosis reflect the interaction of two separate stem cell lineages; a previously identified cathepsin K (CTSK) lineage CSC1 (CTSK+ CSC) and a separate discoidin domain-containing receptor 2 (DDR2) lineage stem cell (DDR2+ CSC) that we identified in this study. Deletion of Twist1, a gene associated with craniosynostosis in humans2,3, solely in CTSK+ CSCs is sufficient to drive craniosynostosis in mice, but the sites that are destined to fuse exhibit an unexpected depletion of CTSK+ CSCs and a corresponding expansion of DDR2+ CSCs, with DDR2+ CSC expansion being a direct maladaptive response to CTSK+ CSC depletion. DDR2+ CSCs display full stemness features, and our results establish the presence of two distinct stem cell lineages in the sutures, with both populations contributing to physiologic calvarial mineralization. DDR2+ CSCs mediate a distinct form of endochondral ossification without the typical haematopoietic marrow formation. Implantation of DDR2+ CSCs into suture sites is sufficient to induce fusion, and this phenotype was prevented by co-transplantation of CTSK+ CSCs. Finally, the human counterparts of DDR2+ CSCs and CTSK+ CSCs display conserved functional properties in xenograft assays. The interaction between these two stem cell populations provides a new biologic interface for the modulation of calvarial mineralization and suture patency.

A vertebral skeletal stem cell lineage driving metastasis

Vertebral bone is subject to a distinct set of disease processes from long bones, including a much higher rate of solid tumour metastases1-4. The basis for this distinct biology of vertebral bone has so far remained unknown. Here we identify a vertebral skeletal stem cell (vSSC) that co-expresses ZIC1 and PAX1 together with additional cell surface markers. vSSCs display formal evidence of stemness, including self-renewal, label retention and sitting at the apex of their differentiation hierarchy. vSSCs are physiologic mediators of vertebral bone formation, as genetic blockade of the ability of vSSCs to generate osteoblasts results in defects in the vertebral neural arch and body. Human counterparts of vSSCs can be identified in vertebral endplate specimens and display a conserved differentiation hierarchy and stemness features. Multiple lines of evidence indicate that vSSCs contribute to the high rates of vertebral metastatic tropism observed in breast cancer, owing in part to increased secretion of the novel metastatic trophic factor MFGE8. Together, our results indicate that vSSCs are distinct from other skeletal stem cells and mediate the unique physiology and pathology of vertebrae, including contributing to the high rate of vertebral metastasis.

Identification of a stem cell mediating osteoblast versus adipocyte lineage selection

Most skeletal fragility disorders are characterized by bone loss with a concurrent gain in marrow adipocytes 1-8. This suggests that a cell that forms adipocytes at the expense of osteoblasts is central to the pathogenesis of skeletal disorders. However, this cellular point of bifurcation between adipocyte and osteoblast differentiation pathways remains unknown. Here, we identify a new cell type defined by co-expression of skeletal stem cell and adipocyte precursor markers, 9-13 (CD24+CD29+ skeletal stem cells (SSCs)), that serves as a key cellular point of bifurcation between the osteoblast and adipocyte differentiation pathways, giving rise to closely related osteoblast and adipocyte lineage-restricted precursors. CD24+CD29+SSCs comprise a small fraction of SSCs, and only this fraction displays full stemness features, including the ability to undergo serial transplantation. In line with serving as the osteoblast/adipocyte bipotent cell, the "bone to fat" tissue remodeling occurring in models of postmenopausal osteoporosis or after high fat diet exposure occur in part by reprogramming these CD24+CD29+SSCs to change their output of lineage-restricted precursors. Lastly, as subcutaneous white adipose tissue displays a similar set of CD24+CD29+ stem cells and related lineage-restricted progenitors, these findings provide a new schema explaining the stem cell basis of bone versus adipose tissue production that unifies multiple mesenchymal tissues.

Discovery of a Vertebral Skeletal Stem Cell Driving Spinal Metastases

Vertebral bone is subject to a distinct set of disease processes from those of long bones, notably including a much higher rate of solid tumor metastases that cannot be explained by passive blood flow distribution alone. The basis for this distinct biology of vertebral bone has remained elusive. Here we identify a vertebral skeletal stem cell (vSSC), co-expressing the transcription factors ZIC1 and PAX1 together with additional cell surface markers, whose expression profile and function are markedly distinct from those of long bone skeletal stem cells (lbSSCs). vSSCs display formal evidence of stemness, including self-renewal, label retention and sitting at the apex of their differentiation hierarchy. Lineage tracing of vSSCs confirms that they make a persistent contribution to multiple mature cell lineages in the native vertebrae. vSSCs are physiologic mediators of spine mineralization, as genetic blockade of the ability of vSSCs to generate osteoblasts results in defects in the vertebral neural arch and body. Human counterparts of vSSCs can be identified in vertebral endplate specimens and display a conserved differentiation hierarchy and stemness. Multiple lines of evidence indicate that vSSCs contribute to the high rates of vertebral metastatic tropism observed clinically in breast cancer. Specifically, when an organoid system is used to place both vSSCs and lbSSCs in an identical anatomic context, vSSC-lineage cells are more efficient than lbSSC-lineage cells at recruiting metastases, a phenotype that is due in part to increased secretion of the novel metastatic trophic factor MFGE8. Similarly, genetically targeting loss-of-function to the vSSC lineage results in reduced metastasis rates in the native vertebral environment. Taken together, vSSCs are distinct from other skeletal stem cells and mediate the unique physiology and pathology of vertebrae, including contributing to the high rate of metastatic seeding of the vertebrae.

Addressing high cervical cancer rates in the Rio Grande Valley along the Texas-Mexico border: a community-based initiative focused on education, patient navigation, and medical provider training/telementoring

AIMS

Cervical cancer incidence and mortality rates are approximately 55% higher in the Rio Grande Valley (RGV) along the Texas-Mexico border compared with the average rates in the US. Our aim was to improve cervical cancer prevention efforts in the RGV through a comprehensive multilevel intervention initiative focused on community education, patient navigation, and training of local providers.

METHODS

We initiated a program in the RGV which consisted of (1) community education, (2) patient navigation, and (3) a training/mentoring program for local medical providers including hands-on training courses coupled with telementoring using Project ECHO® (Extension for Community Health Outcomes). We assessed the number of women undergoing cervical cancer screening, diagnosis, and treatment at three participating clinics caring for underserved women in the region.

RESULTS

From November 2014 to October 2018, 14,846 women underwent cervical cancer screening. A total of 2030 (13.7%) women underwent colposcopy for abnormal results (179% increase over baseline) and 453 women underwent loop electrosurgical excision procedures (LEEPs) for treatment of cervical dysplasia. Invasive cancer was diagnosed in 39 women who were navigated to a gynecologic oncologist for treatment. Seven local medical providers were trained to perform colposcopy and/or LEEP. Project ECHO telementoring videoconferences were held every 2 weeks for a total 101 sessions with an average of 22 participants per session and a total of 180 patient cases presented and discussed.

CONCLUSIONS

Our program led to a large number of women undergoing diagnosis and treatment of cervical dysplasia in the RGV. If sustained, we anticipate these efforts will decrease cervical cancer rates in the region. The program is currently being expanded to additional underserved areas of Texas and globally to low- and middle-income countries.

Schistosoma mansoni Infection Is Associated With Increased Monocytes and Fewer Natural Killer T Cells in the Female Genital Tract

Schistosoma mansoni infection may impair genital mucosal antiviral immunity, but immune cell populations have not been well characterized. We characterized mononuclear cells from cervical brushings of women with and without S mansoni infection. We observed lower frequencies of natural killer T cells and higher frequencies of CD14⁺ monocytes in infected women.

Clinical characteristics with inflammation profiling of long COVID and association with 1-year recovery following hospitalisation in the UK: a prospective observational study

BACKGROUND

No effective pharmacological or non-pharmacological interventions exist for patients with long COVID. We aimed to describe recovery 1 year after hospital discharge for COVID-19, identify factors associated with patient-perceived recovery, and identify potential therapeutic targets by describing the underlying inflammatory profiles of the previously described recovery clusters at 5 months after hospital discharge.

METHODS

The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a prospective, longitudinal cohort study recruiting adults (aged ≥18 years) discharged from hospital with COVID-19 across the UK. Recovery was assessed using patient-reported outcome measures, physical performance, and organ function at 5 months and 1 year after hospital discharge, and stratified by both patient-perceived recovery and recovery cluster. Hierarchical logistic regression modelling was performed for patient-perceived recovery at 1 year. Cluster analysis was done using the clustering large applications k-medoids approach using clinical outcomes at 5 months. Inflammatory protein profiling was analysed from plasma at the 5-month visit. This study is registered on the ISRCTN Registry, ISRCTN10980107, and recruitment is ongoing.

FINDINGS

2320 participants discharged from hospital between March 7, 2020, and April 18, 2021, were assessed at 5 months after discharge and 807 (32·7%) participants completed both the 5-month and 1-year visits. 279 (35·6%) of these 807 patients were women and 505 (64·4%) were men, with a mean age of 58·7 (SD 12·5) years, and 224 (27·8%) had received invasive mechanical ventilation (WHO class 7-9). The proportion of patients reporting full recovery was unchanged between 5 months (501 [25·5%] of 1965) and 1 year (232 [28·9%] of 804). Factors associated with being less likely to report full recovery at 1 year were female sex (odds ratio 0·68 [95% CI 0·46-0·99]), obesity (0·50 [0·34-0·74]) and invasive mechanical ventilation (0·42 [0·23-0·76]). Cluster analysis (n=1636) corroborated the previously reported four clusters: very severe, severe, moderate with cognitive impairment, and mild, relating to the severity of physical health, mental health, and cognitive impairment at 5 months. We found increased inflammatory mediators of tissue damage and repair in both the very severe and the moderate with cognitive impairment clusters compared with the mild cluster, including IL-6 concentration, which was increased in both comparisons (n=626 participants). We found a substantial deficit in median EQ-5D-5L utility index from before COVID-19 (retrospective assessment; 0·88 [IQR 0·74-1·00]), at 5 months (0·74 [0·64-0·88]) to 1 year (0·75 [0·62-0·88]), with minimal improvements across all outcome measures at 1 year after discharge in the whole cohort and within each of the four clusters.

INTERPRETATION

The sequelae of a hospital admission with COVID-19 were substantial 1 year after discharge across a range of health domains, with the minority in our cohort feeling fully recovered. Patient-perceived health-related quality of life was reduced at 1 year compared with before hospital admission. Systematic inflammation and obesity are potential treatable traits that warrant further investigation in clinical trials.

FUNDING

UK Research and Innovation and National Institute for Health Research.

Robotic transanal minimally invasive surgery - technical, oncological and patient outcomes from a single institution

AIM

Robotic transanal minimally invasive surgery (R-TAMIS) is gaining traction around the globe as an alternative to laparoscopic conventional TAMIS for local excision of benign and early malignant rectal lesions. The aim was to analyse patient and oncological outcomes of R-TAMIS for consecutive cases in a single centre.

METHODS

A prospective analysis of consecutive R-TAMIS procedures over a 12-month period was performed. Data were collated from hospital databases and theatre registers.

RESULTS

Eleven patients (six men, five women), mean age 69.81 years (51-92 years), underwent R-TAMIS over 12 months utilizing a da Vinci Xi platform. The mean lesion size was 36 mm (20-60 mm) with a mean distance from the anal verge of 7.5 cm (3-14 cm). Five lesions were posterior in anatomical location, four anterior, one right lateral and one left lateral. All procedures were performed in the lithotomy position using a GelPOINT Path Platform. Mean operative time was 64 min (40-100 min). Complete resection was achieved in 10/11 patients with two patients being upgraded to a diagnosis of adenocarcinoma. Nine patients were diagnosed with dysplastic lesions. Four patients had a false positive diagnosis of an invasive tumour on MRI. Six patients required suturing for full-thickness resections. One patient had a postoperative bleed requiring repeat endoscopy and clipping. One patient (full-thickness resection of T3 tumour) proceeded to a formal resection without difficulty with no residual disease (T0N0, 0/22). One patient with a fully resected T2 tumour is undergoing a surveillance protocol. The mean length of stay was 1 day with two patients having a length of stay of 2 days and one patient of 4 days.

CONCLUSION

R-TAMIS could potentially represent a safe novel approach for local resection of rectal lesions.

Discovery of a periosteal stem cell mediating intramembranous bone formation

Bone consists of separate inner endosteal and outer periosteal compartments, each with distinct contributions to bone physiology and each maintaining separate pools of cells owing to physical separation by the bone cortex. The skeletal stem cell that gives rise to endosteal osteoblasts has been extensively studied; however, the identity of periosteal stem cells remains unclear^1-5. Here we identify a periosteal stem cell (PSC) that is present in the long bones and calvarium of mice, displays clonal multipotency and self-renewal, and sits at the apex of a differentiation hierarchy. Single-cell and bulk transcriptional profiling show that PSCs display transcriptional signatures that are distinct from those of other skeletal stem cells and mature mesenchymal cells. Whereas other skeletal stem cells form bone via an initial cartilage template using the endochondral pathway⁴, PSCs form bone via a direct intramembranous route, providing a cellular basis for the divergence between intramembranous versus endochondral developmental pathways. However, there is plasticity in this division, as PSCs acquire endochondral bone formation capacity in response to injury. Genetic blockade of the ability of PSCs to give rise to bone-forming osteoblasts results in selective impairments in cortical bone architecture and defects in fracture healing. A cell analogous to mouse PSCs is present in the human periosteum, raising the possibility that PSCs are attractive targets for drug and cellular therapy for skeletal disorders. The identification of PSCs provides evidence that bone contains multiple pools of stem cells, each with distinct physiologic functions.

Liveweight gain and urinary nitrogen excretion of dairy heifers grazing perennial ryegrass-white clover pasture, canola, and wheat

This study was carried out to examine liveweight gain (LWG), urinary nitrogen (N) concentration, and urinary N excretion of dairy heifers grazing perennial ryegrass-white clover pasture, dual-purpose wheat and dual-purpose canola. A temporal replicate design with two replicates was used to conduct the study. A total of 24–30 Friesian × Jersey heifers, aged 9–11 months were allocated into three dietary treatment groups (pasture, canola, and wheat) according to their initial LW (184 ± 7.0 kg; mean ± s.d.) and breeding worth (NZ$142 ± 11.3; mean ± s.d.). Feed was allocated every 4 days with allowance calculated according to feed requirement for maintenance plus 0.8 kg LWG/day. The LWG over the 26–28-day experimental period was higher (P < 0.001) for heifers grazing wheat (0.66 kg/day) and canola (0.53 kg/day) than pasture (0.35 kg/day). After the experimental period, heifers were grazed together in one herd on pasture. The LWG over the 28–44-day carryover period was higher (P < 0.001) in canola (0.86 kg/day) than wheat (0.57 kg/day) and pasture (0.61 kg/day). The concentration of urinary N was lower (P = 0.017) in canola (0.21%) and wheat (0.24%) than pasture (0.35%). Estimated urinary N excretion was lower (P < 0.001) in canola (52.5 g/day) and wheat (59.1 g/day) than pasture (98.9 g/day). Data suggest that grazing canola and wheat compared with pasture may improve heifer LWG and potentially reduce N losses to the environment by reducing the N loading of urine patches.

Flow-sorting and Exome Sequencing of the Reed-Sternberg Cells of Classical Hodgkin Lymphoma

The Hodgkin Reed-Sternberg cells of classical Hodgkin lymphoma are sparsely distributed within a background of inflammatory lymphocytes and typically comprise less than 1% of the tumor mass. Material derived from bulk tumor contains tumor content at a concentration insufficient for characterization. Therefore, fluorescence activated cell sorting using eight antibodies, as well as side- and forward-scatter, is described here as a method of rapidly separating and concentrating with high purity thousands of HRS cells from the tumor for subsequent study. At the same time, because standard protocols for exome sequencing typically require 100-1,000 ng of input DNA, which is often too high, even with flow sorting, we also provide an optimized, low-input library construction protocol capable of producing high-quality data from as little as 10 ng of input DNA. This combination is capable of producing next-generation libraries suitable for hybridization capture of whole-exome baits or more focused targeted panels, as desired. Exome sequencing of the HRS cells, when compared against healthy intratumor T or B cells, can identify somatic alterations, including mutations, insertions and deletions, and copy number alterations. These findings elucidate the molecular biology of HRS cells and may reveal avenues for targeted drug treatments.

Dysregulated bioenergetics: a key regulator of joint inflammation

Objectives

This study examines the relationship between synovial hypoxia and cellular bioenergetics with synovial inflammation.

Methods

Primary rheumatoid arthritis synovial fibroblasts (RASF) were cultured with hypoxia, dimethyloxalylglycine (DMOG) or metabolic intermediates. Mitochondrial respiration, mitochondrial DNA mutations, cell invasion, cytokines, glucose and lactate were quantified using specific functional assays. RASF metabolism was assessed by the XF24-Flux Analyzer. Mitochondrial structural morphology was assessed by transmission electron microscopy (TEM). In vivo synovial tissue oxygen (tpO₂ mmHg) was measured in patients with inflammatory arthritis (n=42) at arthroscopy, and markers of glycolysis/oxidative phosphorylation (glyceraldehyde 3-phosphate dehydrogenase (GAPDH), PKM2, GLUT1, ATP) were quantified by immunohistology. A subgroup of patients underwent contiguous MRI and positron emission tomography (PET)/CT imaging. RASF and human dermal microvascular endothelial cells (HMVEC) migration/angiogenesis, transcriptional activation (HIF1α, pSTAT3, Notch1-IC) and cytokines were examined in the presence of glycolytic inhibitor 3-(3-Pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO).

Results

DMOG significantly increased mtDNA mutations, mitochondrial membrane potential, mitochondrial mass, reactive oxygen species and glycolytic RASF activity with concomitant attenuation of mitochondrial respiration and ATP activity (all p<0.01). This was coupled with altered mitochondrial morphology. Hypoxia-induced lactate levels (p<0.01), which in turn induced basic fibroblast growth factor (bFGF) secretion and RASF invasiveness (all p<0.05). In vivo glycolytic markers were inversely associated with synovial tpO₂ levels <20 mm Hg, in contrast ATP was significantly reduced (all p<0.05). Decrease in GAPDH and GLUT1 was paralleled by an increase in in vivo tpO₂ in tumour necrosis factor alpha inhibitor (TNFi) responders. Novel PET/MRI hybrid imaging demonstrated close association between metabolic activity and inflammation. 3PO significantly inhibited RASF invasion/migration, angiogenic tube formation, secretion of proinflammatory mediators (all p<0.05), and activation of HIF1α, pSTAT3 and Notch-1IC under normoxic and hypoxic conditions.

Conclusions

Hypoxia alters cellular bioenergetics by inducing mitochondrial dysfunction and promoting a switch to glycolysis, supporting abnormal angiogenesis, cellular invasion and pannus formation.

Surface ligand-directed pair-wise hydrogenation for heterogeneous phase hyperpolarization

para-Hydrogen induced polarization is a technique of magnetic resonance hyperpolarization utilizing hydrogen's para-spin state for generating signal intensities at magnitudes far greater than state-of-the-art magnets. Platinum nanoparticle-catalysts with cysteine-capping are presented. The measured polarization is the highest reported to date in water, paving pathways for generating medical imaging contrast agents.

Tofacitinib regulates synovial inflammation in psoriatic arthritis, inhibiting STAT activation and induction of negative feedback inhibitors

BACKGROUND

Psoriatic arthritis (PsA) is a chronic inflammatory disease, characterised by synovitis and destruction of articular cartilage/bone. Janus-kinase and signal transducer and activator of transcription (JAK-STAT) signalling pathway is implicated in the pathogenesis of PsA.

OBJECTIVES

To examine the effect of tofacitinib (JAK inhibitor) on proinflammatory mechanisms in PsA.

METHODS

Primary PsA synovial fibroblasts (PsAFLS) and ex vivo PsA synovial explants were cultured with tofacitinib (1 µM). PhosphoSTAT3 (pSTAT3), phosphoSTAT1 (pSTAT1), suppressor of cytokine signaling-3 (SOCS3), protein inhibitor of activated Stat3 (PIAS3) and nuclear factor kappa B cells (NFκBp65) were quantified by western blot. The effect of tofacitinib on PsAFLS migration, invasion, Matrigel network formation and matrix metallopeptidase (MMP)2/9 was quantified by invasion/migration assays and zymography. Interleukin (IL)-6, IL-8, IFN-gamma-inducible protein 10 (IP-10) monocyte chemoattractant protein (MCP)-1, IL-17, IL-10, MMP3 and tissue inhibitor of metalloproteinases 3 (TIMP3) were assessed by ELISA.

RESULTS

Tofacitinib significantly decreased pSTAT3, pSTAT1, NFκBp65 and induced SOCS3 and PIAS3 expression in PsAFLS and synovial explant cultures (p<0.05). Functionally, PsAFLS invasion, network formation and migration were inhibited by tofacitinib (all p<0.05). In PsA explant, tofacitinib significantly decreased spontaneous secretion of IL-6, IL-8, MCP-1, MMP9/MMP2, MMP3 (all p<0.05) and decreased the MMP3/TIMP3 ratio (p<0.05), with no effect observed for IP-10 or IL-10.

CONCLUSIONS

This study further supports JAK-STAT inhibition as a therapeutic target for the treatment of PsA.

Exoplanet detection. A terrestrial planet in a ~1-AU orbit around one member of a ~15-AU binary

Using gravitational microlensing, we detected a cold terrestrial planet orbiting one member of a binary star system. The planet has low mass (twice Earth's) and lies projected at ~0.8 astronomical units (AU) from its host star, about the distance between Earth and the Sun. However, the planet's temperature is much lower, <60 Kelvin, because the host star is only 0.10 to 0.15 solar masses and therefore more than 400 times less luminous than the Sun. The host itself orbits a slightly more massive companion with projected separation of 10 to 15 AU. This detection is consistent with such systems being very common. Straightforward modification of current microlensing search strategies could increase sensitivity to planets in binary systems. With more detections, such binary-star planetary systems could constrain models of planet formation and evolution.

Qualitative evaluation of care plans for Canadian breast and head-and-neck cancer survivors

BACKGROUND

Survivorship care plans (scps) have been recommended as a way to ease the transition from active cancer treatment to follow-up care, to reduce uncertainty for survivors in the management of their ongoing health, and to improve continuity of care. The objective of the demonstration project reported here was to assess the value of scps for cancer survivors in western Canada.

METHODS

The Alberta CancerBridges team developed, implemented, and evaluated scps for 36 breast and 21 head-and-neck cancer survivors. For the evaluation, we interviewed 12 of the survivors, 9 nurses who delivered the scps, and 3 family physicians who received the scps (n = 24 in total). We asked about satisfaction, usefulness, emotional impact, and communication value. We collected written feedback from the three groups about positive aspects of the scps and possible improvements (n = 85). We analyzed the combined data using qualitative thematic analysis.

RESULTS

Survivors, nurses, and family physicians agreed that scps could ease the transition to survivorship partly by enhancing communication between survivors and care providers. Survivors appreciated the individualized attention and the comprehensiveness of the plans. They described positive emotional impacts, but wanted a way to ensure that their physicians received the scps. Nurses and physicians responded positively, but expressed concern about the time required to implement the plans. Suggestions for streamlining the process included providing survivors with scp templates in advance, auto-populating the templates for the nurses, and creating summary pages for physicians.

CONCLUSIONS

The results suggest ways in which scps could help to improve the transition to cancer survivorship and provide starting points for larger feasibility studies.

Structure-activity and immunochemical data provide evidence of developmental- and tissue-specific myosuppressin signaling

Myosuppressin peptides dramatically diminish contractions of the gut and heart. Thus, delineating mechanisms involved in myosuppressin signaling may provide insight into peptidergic control of muscle contractility. Drosophila myosuppressin (DMS, TDVDHVFLRFamide) structure-activity relationship (SAR) was investigated to identify an antagonist and explore signaling. Alanyl-substituted, N-terminal truncated, and modified amino acid analogs identified residues and peptide length required for activity. Immunochemistry independently provided insight into myosuppressin mechanisms. DMS decreased gut motility and cardiac contractility dose dependently; the different effective concentrations at half maximal-response were indicative of tissue-specific mechanisms. Replacement of aspartic acid 2 (D2) generated an analog with different developmental- and tissue-specific effects; [A2] DMS mimicked DMS in adult gut (100% inhibition), yet decreased larval gut contractions by only 32% with increased potency in pupal heart (126% inhibition). The DMS active core differed across development and in tissues; adult (DHVFLRFamide) and larval gut (TDVDHVFLRFamide), and adult (VFLRFamide) and pupal heart (VFLRFamide). Substitution of D2 and D4 with a modified amino acid, p-benzoyl-phenylalanine, produced developmental- and tissue-specific antagonists. In the presence of protease inhibitors, DMS and VFLRFamide were more effective in adult gut, but lower or unchanged in pupal heart compared to peptide or analog alone, respectively. DMS-specific antisera stained neurons that innervated the gut or heart. This study describes novel antagonists and data to identify developmental- and tissue-specific mechanisms underlying the pleotropic effects of myosuppressin in muscle physiology.

STAT1 deficiency in the heart protects against myocardial infarction by enhancing autophagy

Previous studies have shown that the transcription factor signal transducer and activator of transcription 1 (STAT1) activation is increased in primary cardiac myocytes exposed to simulated ischaemia/reperfusion injury. This promotes apoptotic cell death by enhancing the expression of pro-apoptotic proteins. Autophagy has been demonstrated to play a cardioprotective role in the heart following myocardial infarction (MI). We therefore investigated the role of STAT1 in the intact heart subjected to MI and examined the contribution of autophagy in modulating the protective effect of STAT1 after MI injury. STAT1-deficient hearts had significantly smaller infarcts than wild-type hearts and this correlated with increased levels of autophagy shown by light chain 3 (LC3)-I/LC3-II conversion, and up-regulation of Atg12 and Beclin 1. Moreover, pre-treatment with the autophagy inhibitor 3-methyladenine reversed the cardioprotection observed in the STAT1-deficient hearts. These results reveal a new function of STAT1 in the control of autophagy and indicate a cross-talk between the cardioprotective versus the damaging effects of STAT1 in the intact heart exposed to MI injury.

Venous drainage, a simple method to prevent the systemic consequences of ischaemia-reperfusion injury in acute lower limb ischaemia

BACKGROUND

Ischaemia-reperfusion injury (I-R injury) is a recognised and potentially fatal complication following revascularisation of an ischaemic limb. Prevention of reperfusion injury is the focus of much research, but effective drug regimens have yet to be established into clinical practice.

CASE REPORT

Here we present a man with prolonged, severe lower limb ischaemia, successfully treated with a novel surgical technique for preventing I-R injury. Prior to revascularisation, the common femoral vein was cannulated and the harmful venous effluent was drained. The patient made an excellent recovery, the limb was salvaged and no systemic complications were encountered.

Synovial tissue hypoxia and inflammation in vivo

INTRODUCTION

Hypoxia is a microenvironmental feature in the inflamed joint, which promotes survival advantage for cells. The aim of this study was to examine the relationship of partial oxygen pressure in the synovial tissue (tPO(2)) in patients with inflammatory arthritis with macroscopic/microscopic inflammation and local levels of proinflammatory mediators.

METHODS

Patients with inflammatory arthritis underwent full clinical assessment and video arthroscopy to quantify macroscopic synovitis and measure synovial tPO(2) under direct visualisation. Cell specific markers (CD3 (T cells), CD68 (macrophages), Ki67 (cell proliferation) and terminal deoxynucleotidyl transferase dUTP nick end labelling (cell apoptosis)) were quantified by immunohistology. In vitro migration was assessed in primary and normal synoviocytes (synovial fibroblast cells (SFCs)) using a wound repair scratch assay. Levels of tumour necrosis factor alpha (TNFalpha), interleukin 1beta (IL1beta), interferon gamma (IFNgamma), IL6, macrophage inflammatory protein 3alpha (MIP3alpha) and IL8 were quantified, in matched serum and synovial fluid, by multiplex cytokine assay and ELISA.

RESULTS

The tPO(2) was 22.5 (range 3.2-54.1) mm Hg and correlated inversely with macroscopic synovitis (r=-0.421, p=0.02), sublining CD3 cells (-0.611, p<0.01) and sublining CD68 cells (r=-0.615, p<0.001). No relationship with cell proliferation or apoptosis was found. Primary and normal SFCs exposed to 1% and 3% oxygen (reflecting the median tPO(2) in vivo) induced cell migration. This was coupled with significantly higher levels of synovial fluid tumour necrosis factor alpha (TNFalpha), IL1beta, IFNgamma and MIP3alpha in patients with tPO(2) <20 mm Hg (all p values <0.05).

CONCLUSIONS

This is the first study to show a direct in vivo correlation between synovial tPO(2), inflammation and cell migration, thus it is proposed that hypoxia is a possible primary driver of inflammatory processes in the arthritic joint.

Abstract 1802: Correlating flow-cytometric and 19F-NMR changes in fluorodeoxyglucose signal in response to the Raf-inhibitor RAF265

FDG-PET (2-Deoxy-2-fluoro-D-glucose-Positron-Emission-Tomography) is an established tool in the management of cancer patients and is increasingly used as an early response marker. Interpreting the cellular basis of the FDG signal however, remains a challenge. The aim of this study was to explore changes in FDG signal by leveraging the quantitative and chemical specificity of 19F-NMR (nuclear magnetic resonance) and correlating these with flow-cytometric (FC) measurement of cell count, apoptosis and cell cycle in A375M melanoma cells treated with the investigational Raf-kinase inhibitor RAF265.

Cell culture and flow cytometry: A375M cells (melanoma cell line expressing B-RafV600E) were grown in Eagle's Minimal Essential Media with 10% HI FCS (Hyclone), penicillin 100U/ml and streptomycin 100μg/ml. Cells were incubated in the presence of 1μM RAF265 or a 1:1000 dilution of DMSO as a control. After 24 hours 1.5 mM FDG was added to the culture media followed two hours later by a perchloric acid extraction of trypsinized cells. The neutralized lysate was analyzed via 19F-NMR. FC measurements were performed on trypsinized cells using a B-D Canto II with Diva software and analyzed with FlowJo Analysis software and Dean-Jett-Fox cell cycle modeling software.

19F-NMR: All experiments were performed at room temperature on a Bruker 300 MHz DPX spectrometer equipped with a QNP probe. All samples were doped with D2O and 5-fluorouracil as the internal 19F-reference. A non-1H-decoupled sequence was used to collect and quantitate spectra. Spectral assignments were based on prior reports.

The spectra and FC results differed qualitatively and quantitatively between groups. Spectral 19F-NMR resonances consistent with phosphorylated FDG metabolites were identified. The mean quantity of FDG metabolites in the treated group was 113.8 nmol ± 3.06 (SD) and 281.3 nmol ± 1.34 (SD) in the untreated group, representing a significant (p&lt;0.001) 59.5% difference. FC results indicated that RAF265 treatment resulted in a mean increase of 32% in the G0/G1 population and a decrease of 41% and 40% in the percentage of cells in the S and G2/M phases respectively. Correspondingly, there was a 27% decrease in the cell count between the treated and untreated groups. There was a four-fold increase in the proportion of Annexin-V staining cells.

In summary, we have identified and quantified FDG metabolites in cell extracts using 19FNMR following treatment with the investigational Raf kinase inhibitor RAF265. There was a qualitative and quantitative drop in FDG metabolites suggesting a modulation in the metabolism of FDG. The corresponding changes in cell cycle and number in the drug-treated samples suggest a less metabolically active profile. By inference, FDG is expected to behave similarly in the clinic and therefore this technique, subject to validation, could provide a cellular basis for the interpretation of response.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1802.