Surgical strategies in the management of aggressive spinal haemangiomas: Retrospective case series with literature review and a practical treatment algorithm.

Purpose: We studied the clinico-radiological features and treatment outcomes of patients with aggressive spinal haemangiomas. Methods: We undertook a retrospective review of 24 patients with aggressive spinal haemangiomas managed at our centre from 2004 to 2016. The cohort was divided into two groups. Group1 included patients managed from 2004 to 2009 while Group 2 was those treated between 2010 and 2016. Clinicoradiological features and treatment outcomes were studied. Results: Back pain (24/24) and myelopathy (18/24) were the most common presenting complaints. Over 80% (20/24) of patients, had involvement of the thoracic spine and more than 50% (13/24) had severe spasticity, being Nurick grade 4&5 at presentation. The various treatment modalities used were laminectomy with or without instrumented posterior fusion (10/24), corpectomy with instrumented fusion (10/24) and alcohol injection alone (4/24). Patients who were treated with surgery had significant clinical improvement at follow-up in both groups. Patients who underwent alcohol injection did not have any improvement in symptoms at follow-up. There was a change in our strategy in the later part of the series from a two staged anterior and posterior approach to a single staged posterior-only approach to address vertebral body disease with preoperative angioembolization. Conclusion: Haemangiomas are benign lesions with locally aggressive behavior in some cases. Results of conservative approaches such as alcohol injection in management of these lesions are discouraging. Aggressive surgical decompression combined with preoperative adjuncts such as angioembolization with or without stabilization reduces intra operative blood loss and results in good neurological recovery even in patients with severe myelopathy.

Integrated transcriptome-proteome analyses of human stem cells reveal source-dependent differences in their regenerative signature.

Mesenchymal stem cells (MSCs) are gaining increasing prominence as an effective regenerative cellular therapy. However, ensuring consistent and reliable effects across clinical populations has proved to be challenging. In part, this can be attributed to heterogeneity in the intrinsic molecular and regenerative signature of MSCs, which is dependent on their source of origin. The present work uses integrated omics-based profiling, at different functional levels, to compare the anti-inflammatory, immunomodulatory, and angiogenic properties between MSCs from neonatal (umbilical cord MSC [UC-MSC]) and adult (adipose tissue MSC [AD-MSC], and bone marrow MSC [BM-MSC]) sources. Using multi-parametric analyses, we identified that UC-MSCs promote a more robust host innate immune response; in contrast, adult-MSCs appear to facilitate remodeling of the extracellular matrix (ECM) with stronger activation of angiogenic cascades. These data should help facilitate the standardization of source-specific MSCs, such that their regenerative signatures can be confidently used to target specific disease processes.

Umbilical cord mesenchymal stromal cells-from bench to bedside.

In recent years, mesenchymal stromal cells (MSCs) have generated a lot of attention due to their paracrine and immuno-modulatory properties. mesenchymal stromal cells derived from the umbilical cord (UC) are becoming increasingly recognized as having increased therapeutic potential when compared to mesenchymal stromal cells from other sources. The purpose of this review is to provide an overview of the various compartments of umbilical cord tissue from which mesenchymal stromal cells can be isolated, the differences and similarities with respect to their regenerative and immuno-modulatory properties, as well as the single cell transcriptomic profiles of in vitro expanded and freshly isolated umbilical cord-mesenchymal stromal cells. In addition, we discuss the therapeutic potential and biodistribution of umbilical cord-mesenchymal stromal cells following systemic administration while providing an overview of pre-clinical and clinical trials involving umbilical cord-mesenchymal stromal cells and their associated secretome and extracellular vesicles (EVs). The clinical applications of umbilical cord-mesenchymal stromal cells are also discussed, especially in relation to obstacles and potential solutions for their effective translation from bench to bedside.

Drivers of transcriptional variance in human intestinal epithelial organoids.

Human intestinal epithelial organoids (enteroids and colonoids) are tissue cultures used for understanding the physiology of the human intestinal epithelium. Here, we explored the effect on the transcriptome of common variations in culture methods, including extracellular matrix substrate, format, tissue segment, differentiation status, and patient heterogeneity. RNA-sequencing datasets from 276 experiments performed on 37 human enteroid and colonoid lines from 29 patients were aggregated from several groups in the Texas Medical Center. DESeq2 and gene set enrichment analysis (GSEA) were used to identify differentially expressed genes and enriched pathways. PERMANOVA, Pearson's correlation, and dendrogram analysis of the data originally indicated three tiers of influence of culture methods on transcriptomic variation: substrate (collagen vs. Matrigel) and format (3-D, transwell, and monolayer) had the largest effect; segment of origin (duodenum, jejunum, ileum, colon) and differentiation status had a moderate effect; and patient heterogeneity and specific experimental manipulations (e.g., pathogen infection) had the smallest effect. GSEA identified hundreds of pathways that varied between culture methods, such as IL1 cytokine signaling enriched in transwell versus monolayer cultures and E2F target genes enriched in collagen versus Matrigel cultures. The transcriptional influence of the format was furthermore validated in a synchronized experiment performed with various format-substrate combinations. Surprisingly, large differences in organoid transcriptome were driven by variations in culture methods such as format, whereas experimental manipulations such as infection had modest effects. These results show that common variations in culture conditions can have large effects on intestinal organoids and should be accounted for when designing experiments and comparing results between laboratories. Our data constitute the largest RNA-seq dataset interrogating human intestinal epithelial organoids.

Effect of substrate stiffness on human intestinal enteroids' infectivity by enteroaggregative Escherichia coli.

Human intestinal enteroids (HIE) models have contributed significantly to our understanding of diarrheal diseases and other intestinal infections, but their routine culture conditions fail to mimic the mechanical environment of the native intestinal wall. Because the mechanical characteristics of the intestine significantly alter how pathogens interact with the intestinal epithelium, we used different concentrations of polyethylene glycol (PEG) to generate soft (~2 kPa), medium (~10 kPa), and stiff (~100 kPa) hydrogel biomaterial scaffolds. The height of HIEs cultured in monolayers atop these hydrogels was 18 µm whereas HIEs grown on rigid tissue culture surfaces (with stiffness in the GPa range) were 10 µm. Substrate stiffness also influenced the amount of enteroaggregative E. coli (EAEC strain 042) adhered to the HIEs. We quantified a striking difference in adherence pattern; on the medium and soft gels, the bacteria formed clusters of > 100 and even > 1000 on both duodenal and jejunal HIEs (such as would be found in biofilms), but did not on glass slides and stiff hydrogels. All hydrogel cultured HIEs showed significant enrichment for gene and signaling pathways related to epithelial differentiation, cell junctions and adhesions, extracellular matrix, mucins, and cell signaling compared to the HIEs cultured on rigid tissue culture surfaces. Collectively, these results indicate that the HIE monolayers cultured on the hydrogels are primed for a robust engagement with their mechanical environment, and that the soft hydrogels promote the formation of larger EAEC aggregates, likely through an indirect differential effect on mucus. STATEMENT OF SIGNIFICANCE: Enteroids are a form of in vitro experimental mini-guts created from intestinal stem cells. Enteroids are usually cultured in 3D within Matrigel atop rigid glass or plastic substrates, which fail to mimic the native intestinal mechanical environment. Because intestinal mechanics significantly alter how pathogens interact with the intestinal epithelium, we grew human intestinal enteroids in 2D atop polyethylene glycol (PEG) hydrogel scaffolds that were soft, medium, or stiff. Compared with enteroids grown in 2D atop glass or plastic, the enteroids grown on hydrogels were taller and more enriched in mechanobiology-related gene signaling pathways. Additionally, enteroids on the softest hydrogels supported adhesion of large aggregates of enteroaggregative E. coli. Thus, this platform offers a more biomimetic model for studying enteric diseases.

Protein-Functionalized Poly(ethylene glycol) Hydrogels as Scaffolds for Monolayer Organoid Culture.

Stem cell-derived, organotypic in vitro models, known as organoids, have emerged as superior alternatives to traditional cell culture models due to their unparalleled ability to recreate complex physiological and pathophysiological processes. For this reason, they are attractive targets of tissue-engineering efforts, as constructs that include organoid technology would be expected to better simulate the many functions of the desired tissue or organ. While the 3D spheroidal architecture that is the default architecture of most organoid models may be preferred for some applications, 2D monolayer arrangements remain the preferred organization for many applications in tissue engineering. Therefore, in this work, we present a method to create monolayer organoid cultures on poly(ethylene glycol) (PEG) hydrogel scaffolds, using intestinal epithelial organoids (IEOs) as a proof-of-concept. Our process involves two steps: the hydrogel is first functionalized with a layer of poly(D-lysine) (PDL), which then allows the adsorption of pristine, unmodified basement membrane proteins. This approach successfully mediates the formation of IEO monolayer unlike conventional approaches that rely on covalent modification of the hydrogel surface with cell-adhesive peptides and basement membrane proteins. We show that these IEO monolayers recreate important physiological functions of the native intestinal epithelium, including multilineage differentiation, apical-basal polarization, and the ability to model infections with human norovirus. We also show coating of a scaffold mimicking intestinal villous topography, resulting in a 3D IEO monolayer. We expect that this protocol will be useful to researchers attempting to leverage the increased physiological relevance of organoid models to elevate the potential of their tissue-engineered constructs. Impact statement While organoids are physiologically superior models of biological functions than traditional cell cultures, their 3D spheroidal architecture is an obstacle to their incorporation in many tissue-engineering applications, which often prefer 2D monolayer arrangements of cells. For this reason, we developed a protocol to establish monolayer cultures of organoids on poly(ethylene glycol) hydrogels and demonstrate its utility using intestinal epithelial organoids as a proof-of-concept. We expect that this protocol will be of use to researchers creating engineered tissues for both regenerative medicine applications, as well as advanced in vitro experimental models.

Elastin homeostasis is altered with pelvic organ prolapse in cultures of vaginal cells from a lysyl oxidase-like 1 knockout mouse model.

Pelvic organ prolapse (POP) decreases quality of life for many women, but its pathophysiology is poorly understood. We have previously shown that Lysyl oxidase-like 1 knockout (Loxl1 KO) mice reliably prolapse with age and increased parity, similar to women. Both this model and clinical studies also indicate that altered elastin metabolism in pelvic floor tissues plays a role in POP manifestation, although it is unknown if this is a cause or effect. Using Loxl1 KO mice, we investigated the effects of genetic absence of Loxl1, vaginal parity, and presence of POP on the expression of genes and proteins key to the production and regulation of elastic matrix. Cultured cells isolated from vaginal explants of mice were assayed with Fastin for elastic matrix, as well as RT-PCR and Western blot for expression of genes and proteins important for elastin homeostasis. Elastin synthesis significantly decreased with absence of LOXL1 and increased with parity (p < .001), but not with POP. Cells from prolapsed mice expressed significantly decreased MMP-2 (p < .05) and increased TIMP-4 (p < .05). The results suggest changes to elastin structure rather than amounts in prolapsed mice as well as poor postpartum elastin turnover, resulting in accumulation of damaged elastic fibers leading to abnormal tropoelastin deposition. POP may thus, be the result of an inability to initiate the molecular mechanisms necessary to clear and replace damaged elastic matrix in pelvic floor tissues after vaginal birth.

Accuracy of the freehand (fennell) technique using a uniform entry point and sagittal trajectory for insertion of thoracic pedicle screws: A computed tomography-based virtual simulation study.

BACKGROUND: Thoracic spine has complex pedicle anatomy with a narrow canal diameter which makes pedicle screw insertion challenging. Fennell et al. have described a simple freehand technique of thoracic pedicle screw placement. We have tested the accuracy of Fennell technique using computed tomography-based (CT-based) simulation model with pedicle screw simulator (PSS). METHODS: Normal CT thoracic spine obtained from CT thorax data of five patients were used in the 3D slicer environment using PSS for simulation. Entry points and axial trajectory as described by Fennell et al. and a sagittal trajectory parallel to the superior endplate were used for simulating the freehand technique using EA (entry angle) mode in the PSS. An ideal trajectory through the midsection of the pedicle from the same entry point and a sagittal trajectory parallel to the superior endplate were simulated using the ET (Entry Target) mode. Angle predicted by the software for an ideal axial trajectory was compared with the Fennell technique and this angle difference was noted at all the levels. Presence of pedicle breach was noted while simulating the Fennell technique. RESULTS: A total of 240 thoracic pedicle screw insertions were simulated, 120 screws by each technique. A sagittal trajectory parallel to the superior endplate caused no pedicle breach in the cranial-caudal direction at any level. No medial or lateral breach was noted while using an axial trajectory of 30° at T1-T2 and 20° from T3-T10. A 20° axial trajectory at T11 and T12 resulted in a breach of the medial cortex and the ideal mean axial angles at T11 and T12 were 2.8° and 6.5°, respectively. CONCLUSIONS: Fennell technique was effectively simulated using PSS. A uniform entry point and sagittal trajectory parallel to the superior endplate serves as a useful guide for freehand insertion of thoracic pedicle screws. At T11 and 12, ideal axial trajectories are less than 10°.

Emerging Nano- and Micro-Technologies Used in the Treatment of Type-1 Diabetes.

Type-1 diabetes is characterized by high blood glucose levels due to a failure of insulin secretion from beta cells within pancreatic islets. Current treatment strategies consist of multiple, daily injections of insulin or transplantation of either the whole pancreas or isolated pancreatic islets. While there are different forms of insulin with tunable pharmacokinetics (fast, intermediate, and long-acting), improper dosing continues to be a major limitation often leading to complications resulting from hyper- or hypo-glycemia. Glucose-responsive insulin delivery systems, consisting of a glucose sensor connected to an insulin infusion pump, have improved dosing but they still suffer from inaccurate feedback, biofouling and poor patient compliance. Islet transplantation is a promising strategy but requires multiple donors per patient and post-transplantation islet survival is impaired by inflammation and suboptimal revascularization. This review discusses how nano- and micro-technologies, as well as tissue engineering approaches, can overcome many of these challenges and help contribute to an artificial pancreas-like system.

Pro-elastogenic effects of mesenchymal stem cell derived smooth muscle cells in a 3D collagenous milieu.

Intrinsically poor auto-regenerative repair of proteolytically-disrupted elastic matrix structures by resident SMCs in the wall of abdominal aortic aneurysms (AAAs) prevents growth arrest and regression of these wall expansions. Supporting their possible future use in a regenerative cell therapy for AAAs, in a prior study, we showed that bone marrow mesenchymal stem cell-derived Smooth Muscle Cells (BM-SMCs) secrete biological factors that have significant pro-elastogenic and anti-proteolytic effects on aneurysmal rat aortic SMCs (EaRASMCs) in non-contact co-cultures. We also identified one stable BM-SMC phenotype (cBM-SMC) generated by differentiating BM-MSCs on a 2D fibronectin substrate in the presence of PDGF (Platelet Derived Growth Factor) and TGF-ß1 (Transforming Growth Factor-ß1) that exhibited superior elastogenicity and pro-elastogenic/anti-proteolytic properties. In this study, we further investigated the ability of these cBM-SMCs to maintain these superior elastogenic properties in a 3D collagenous milieu alone and in co-culture with EaRASMC to evaluate their potential as an alternative cell source for cell therapy in AAA. Some of our key observations were higher contractility and greater amount of structurally intact elastin production in both standalone culture of cBM-SMCs as well as co-culture of cBM-SMCs with EaRASMCs as shown by VVG (Verhoeff-Van Gieson) staining and Pontamine Sky Blue labeling and lower MMP-9 protein expression in standalone culture in 3D collagenous environment. Our overall result indicates that cBM-SMCs possess the ability to provide elastogenic impetus in a 3D collagenous AAA milieu which is otherwise not conducive to elastogenesis. Therefore our study strongly suggest the utility of cBM-SMCs as a potential cell source for cell therapy to augment elastic matrix neo-assembly and fiber formation and attenuate proteolysis in a collagenous milieu that is evocative of the de-elasticized aneurysmal wall. STATEMENT OF SIGNIFICANCE: Abdominal aortic aneurysm (AAA) or ballooning of the aorta is one of the leading causes of cardiovascular disease (CVD) related death caused by significantly increased proteolytic activity in the aortic wall. Reversing pathophysiology of this condition is challenging due to intrinsically poor regeneration of elastin by aortic smooth muscle cells. Current management of AAA is limited to passive monitoring of the disease until it becomes large enough to receive surgical intervention and no drug based therapy currently exists. Cell based therapy can be a potential alternative treatment in this scenario because it provides elastogenic impetus to the aneurysmal SMCs, compensates for the dead SMCs and serves as a robust source of elastin while being delivered with minimal invasiveness. Hence this work will have significant impact in the field of tissue engineering and regenerative medicine.

Hypoxia Stimulates Synthesis of Neutrophil Gelatinase-Associated Lipocalin in Aortic Valve Disease.

Objective: Aortic valve disease is commonly found in the elderly population. It is characterized by dysregulated extracellular matrix remodeling followed by extensive microcalcification of the aortic valve and activation of valve interstitial cells. The mechanism behind these events are largely unknown. Studies have reported expression of hypoxia inducible factor-1 alpha (HIF1α) in calcific nodules in aortic valve disease, therefore we investigated the effect of hypoxia on extracellular matrix remodeling in aged aortic valves. Approach and Results: Western blotting revealed elevated expression of HIF1α and the complex of matrix metalloprotease 9 (MMP9) and neutrophil gelatinase-associated lipocalin (NGAL) in aged porcine aortic valves cultured under hypoxic conditions. Consistently, immunofluorescence staining showed co-expression of MMP9 and NGAL in the fibrosa layer of these porcine hypoxic aortic valves. Gelatinase zymography demonstrated that the activity of MMP9-NGAL complex was significantly increased in aortic valves in 13% O2 compared to 20% O2. Importantly, the presence of ectopic elastic fibers in the fibrosa of hypoxic aortic valves, also detected in human diseased aortic valves, suggests altered elastin homeostasis due to hypoxia. Conclusion: This study demonstrates that hypoxia stimulates pathological extracellular matrix remodeling via expression of NGAL and MMP9 by valve interstitial cells.

Patient-specific interactive software module for virtual preoperative planning and visualization of pedicle screw entry point and trajectories in spine surgery.

BACKGROUND: Lumbar pedicle screw insertion involves a steep learning curve for novice spine surgeons and requires image guidance or navigation. Small volume centers may be handicapped by the lack of cost-effective user-friendly tools for preoperative planning, guidance, and decision making. OBJECTIVE: We describe a patient-specific interactive software module, pedicle screw simulator (PSS), for virtual preoperative planning to determine the entry point and visualize the trajectories of pedicle screws. MATERIALS AND METHODS: The PSS was coded in Python for use in an open source image processing software, 3D Slicer. Preoperative computed tomography (CT) data of each subject was loaded into this module. The entry-target (ET) mode calculates the ideal angle from the entry point through the widest section of the pedicle to the desired target in the vertebral body. The entry-angle (EA) mode projects the screw trajectory from the desired entry point at a desired angle. The performance of this software was tested using CT data from four subjects. RESULTS: PSS provided a quantitative and qualitative feedback preoperatively to the surgeon about the entry point and trajectories of pedicle screws. It also enabled the surgeons to visualize and predict the pedicle breach with various trajectories. CONCLUSION: This interactive software module aids in understanding and correcting the orientation of each vertebra in three-dimensions, to identify the ideal entry points, angles of insertion and trajectories for pedicle screw insertion to suit the local anatomy.

Temporal changes in peritoneal cell phenotype and neoelastic matrix induction with hyaluronan oligomers and TGF-ß1 after implantation of engineered conduits.

The neoassembly and maturation of elastic matrix is an important challenge for engineering small-diameter grafts for patients with peripheral artery disease. We have previously shown that hyaluronan oligomers and transforming growth factor-ß (elastogenic factors or EFs) promote elastogenesis in smooth muscle cell (SMC) culture. However, their combined effects on macrophages and inflammatory cells in vivo are unknown. This information is needed to use the body (e.g., peritoneal cavity) as an "in vivo bioreactor" to recruit autologous cells to implanted EF-functionalized scaffolds. In this study, we determined if peritoneal fluid cells respond to EFs like smooth muscle cells and if these responses differ between cells sourced during different stages of inflammation triggered by scaffold implantation. Electrospun poly(ε-caprolactone)/collagen conduits were implanted in the peritoneal cavity prior to peritoneal fluid collection at 3-42 days postimplantation. Cells from the fluid were cultured in vitro with and without EFs to determine their response. Their phenotype/behaviour was assessed with a DNA assay, quantitative real-time PCR, and immunofluorescence. The EFs reduced peritoneal cell proliferation, maintained cell contractility, and unexpectedly did not exhibit proelastic effects, which we attributed to differences in cell density. We found the greatest elastin deposition in regions containing a high cell density. Further, we found that cells isolated from the peritoneal cavity at longer times after conduit implantation responded better to the EFs and exhibited more CD31 expression than cells at an earlier time point. Overall, this study provides information about the potential use of EFs in vivo and can guide the design of future tissue-engineered vascular grafts.

Phenotype-based selection of bone marrow mesenchymal stem cell-derived smooth muscle cells for elastic matrix regenerative repair in abdominal aortic aneurysms.

Chronic proteolytic disruption of elastic fibres within the abdominal aortic wall results in wall vessel expansion to form rupture-prone abdominal aortic aneurysms (AAA). Arresting AAA growth is not possible as adult vascular smooth muscle cells (SMCs) poorly auto-regenerate and repair elastic fibres. Thus, there is a need to identify alternate cell sources capable of robust elastic matrix assembly to overcome elastolysis in the AAA wall. Previously, we demonstrated the superior elastogenic properties of rat bone marrow mesenchymal stem cell (BM-MSC)-derived SMCs (BM-SMCs) relative to aneurysmal and healthy rat aortic SMCs. In the present study, we investigate how phenotypic coordinates of the derived BM-SMCs, in turn dependent on conditions of BM-MSC differentiation, impact their elastic matrix synthesis abilities. More specifically, we investigated how glucose content, serum levels and the presence of transforming growth factor (TGF)-ß1 supplements alone or together with platelet-derived growth factor (PDGF-BB) in the differentiation medium influence phenotype of, and elastogenesis by derived rat BM-SMCs. BM-SMCs generated in low-glucose and 10% v/v serum conditions in the presence of TGF-ß1 with or without PDGF-BB exhibited a mature phenotype characterized by contractility and migrative tendencies similar to healthy rat aortic SMCs, and yet capable of robust tropoelastin (precursor) synthesis and assembly of a fibrous, highly crosslinked elastic matrix. Thus, we have identified metrics and conditions for selecting BM-SMCs with superior elastogenesis for in situ elastic matrix regeneration. Future studies will focus on characterizing these specific BM-SMC subtypes for their pro-elastogenic and anti-proteolytic effects on aneurysmal SMCs to confirm their preferred use for therapy aimed at AAA tissue regenerative repair. Copyright © 2016 John Wiley & Sons, Ltd.

Xanthogranulomatous colloid cyst of the third ventricle: Alter your surgical strategy.

Colloid cysts are the most common benign neoplasms of the anterior third ventricle, mostly located at the level of the foramen of Monro and can often manifest as sudden onset headache or loss of consciousness. These cysts often have a well-defined cyst wall, mucinous or watery intracystic fluid and have a fairly good plane with the surrounding parenchyma. Occasionally, intracystic haemorrhage can lead to xanthogranulomatous inflammatory changes within the cyst resulting in focal thickening of the cyst wall and adhesion to the surrounding structures. Here we describe a case of xanthogranulomatous colloid cyst which is a very rare variant of colloid cyst.

Hyponatremia in Traumatic Brain Injury: A Practical Management Protocol.

BACKGROUND: Hyponatremia (defined as serum sodium <135 mEq/L) is the most common electrolyte abnormality in traumatic brain injury (TBI) and is also an independent predictor of poor neurologic outcome. The reported incidence of hyponatremia varies widely in literature reports, and there is continuing difficulty in clearly differentiating between the 2 common causes of hyponatremia with natriuresis: the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and cerebral salt wasting (CSW). We encounter hyponatremia frequently in our practice, and we therefore decided to review data from our center to estimate the incidence of hyponatremia and the results of our management strategies, and attempt to formulate simple guidelines for the correction of hyponatremia in TBI. METHODS: A retrospective analysis of 1500 consecutively admitted patients with TBI was performed by the use of electronic records and radiographic review. Hyponatremia was defined as serum sodium <135 mEq/L, and natriuresis as a urine spot sodium of more than >40 mEq/L. The incidence of TBI, its management, and the effect of fludrocortisone were evaluated. RESULTS: The incidence of hyponatremia was 13.2%. Early therapy with fludrocortisone significantly reduced the duration of hospital stay (P < 0.05). Traumatic subarachnoid hemorrhage was the most common abnormality on the admission computed tomographic scan in patients who experienced hyponatremia. CONCLUSION: Early initiation of fludrocortisone in the setting of hyponatremia with natriuresis decreases the hospital stay. This protocol is probably safer in a tropical country where fluid restriction might be harmful. It also eliminates the need to differentiate between SIADH and CSW.

Magnetically-responsive, multifunctional drug delivery nanoparticles for elastic matrix regenerative repair.

Arresting or regressing growth of abdominal aortic aneurysms (AAAs), localized expansions of the abdominal aorta are contingent on inhibiting chronically overexpressed matrix metalloproteases (MMPs)-2 and -9 that disrupt elastic matrix within the aortic wall, concurrent with providing a stimulus to augmenting inherently poor auto-regeneration of these matrix structures. In a recent study we demonstrated that localized, controlled and sustained delivery of doxycycline (DOX; a tetracycline-based antibiotic) from poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs), enhances elastic matrix deposition and MMP-inhibition at a fraction of the therapeutically effective oral dose. The surface functionalization of these NPs with cationic amphiphiles, which enhances their arterial uptake, was also shown to have pro-matrix regenerative and anti-MMP effects independent of the DOX. Based on the hypothesis that the incorporation of superparamagnetic iron oxide NPs (SPIONs) within these PLGA NPs would enhance their targetability to the AAA site under an applied external magnetic field, we sought to evaluate the functional effects of NPs co-encapsulating DOX and SPIONs (DOX-SPION NPs) on elastic matrix regeneration and MMP synthesis/activity in vitro within aneurysmal smooth muscle cell (EaRASMC) cultures. The DOX-SPION NPs were mobile under an applied external magnetic field, while enhancing elastic matrix deposition 1.5-2-fold and significantly inhibiting MMP-2 synthesis and MMP-2 and -9 activities, compared to NP-untreated control cultures. These results illustrate that the multifunctional benefits of NPs are maintained following SPION co-incorporation. Additionally, preliminary studies carried out demonstrated enhanced targetability of SPION-loaded NPs within proteolytically-disrupted porcine carotid arteries ex vivo, under the influence of an applied external magnetic field. Thus, this dual-agent loaded NP system proffers a potential non-surgical option for treating small growing AAAs, via controlled and sustained drug release from multifunctional, targetable nanocarriers. STATEMENT OF SIGNIFICANCE: Proactive screening of high risk elderly patients now enables early detection of abdominal aortic aneurysms (AAAs). There are no established drug-based therapeutic alternatives to surgery for AAAs, which is unsuitable for many elderly patients, and none which can achieve restore disrupted and lost elastic matrix in the AAA wall, which is essential to achieve growth arrest or regression. We have developed a first generation design of polymer nanoparticles (NPs) for AAA tissue localized delivery of doxycycline, a modified tetracycline drug at low micromolar doses at which it provides both pro-elastogenic and anti-proteolytic benefits that can augment elastic matrix regenerative repair. The nanocarriers themselves are also uniquely chemically functionalized on their surface to also provide them pro-elastin-regenerative & anti-matrix degradative properties. To provide an active driving force for efficient uptake of intra-lumenally infused NPs to the AAA wall, in this work, we have rendered our polymer NPs mobile in an applied magnetic field via co-incorporation of super-paramagnetic iron oxide NPs. We demonstrate that such modifications significantly improve wall uptake of the NPs with no significant changes to their physical properties and regenerative benefits. Such NPs can potentially stimulate structural repair in the AAA wall following one time infusion to delay or prevent AAA growth to rupture. The therapy can provide a non-surgical treatment option for high risk AAA patients.

Pro-elastogenic effects of bone marrow mesenchymal stem cell-derived smooth muscle cells on cultured aneurysmal smooth muscle cells.

Abdominal aortic aneurysms (AAAs) involve slow proteolysis and loss of structural matrix components (collagen and elastin), which lead to wall thinning, weakening and ultimate rupture. At this time, no established non-surgical therapy is available to slow or arrest AAA growth. Inhibiting matrix metalloproteases (MMPs; e.g. MMP2 and -9) overexpressed within AAAs is insufficient to arrest AAA growth, since resident smooth muscle cells (SMCs) are poorly elastogenic and cannot overcome elastolysis to reinstate a healthy elastic matrix. Towards overcoming this limitation, this first study sought to determine the utility of rat bone marrow mesenchymal stem cell (BM-MSC)-derived SMCs to stimulate elastin and elastic matrix synthesis and assembly by aneurysmal SMCs (EaRASMCs). BM-MSCs were successfully differentiated into cells of an SMC lineage (SMLCs). Our study indicates that BM-MSC-derived SMLCs secrete trophic factors, contained in conditioned medium (CM) from their cultures, that, when exposed to EaRASMC cultures in real time, stimulate elastin precursor and matrix deposition and crosslinking by these elastogenically deficient cells, with added benefits in terms of attenuating MMPs, specifically MMP9. The results thus lend support to a proposed cell therapy for AAAs, based on the use of BM-MSC-derived SMLCs. Although we observed no particular improvement in elastic fibre formation, no attenuation of MMP2 activity and increase in amounts of active MMP2 enzyme, we believe that this study justifies follow-up studies to improve upon these outcomes. Future studies will explore the effects of concentrated CM collected from long-term SMLC cultures on EaRASMCs and also investigate the elastogenic output of SMLCs themselves. Copyright © 2014 John Wiley & Sons, Ltd.

Distinct genetic architectures for syndromic and nonsyndromic congenital heart defects identified by exome sequencing.

Congenital heart defects (CHDs) have a neonatal incidence of 0.8-1% (refs. 1,2). Despite abundant examples of monogenic CHD in humans and mice, CHD has a low absolute sibling recurrence risk (∼2.7%), suggesting a considerable role for de novo mutations (DNMs) and/or incomplete penetrance. De novo protein-truncating variants (PTVs) have been shown to be enriched among the 10% of 'syndromic' patients with extra-cardiac manifestations. We exome sequenced 1,891 probands, including both syndromic CHD (S-CHD, n = 610) and nonsyndromic CHD (NS-CHD, n = 1,281). In S-CHD, we confirmed a significant enrichment of de novo PTVs but not inherited PTVs in known CHD-associated genes, consistent with recent findings. Conversely, in NS-CHD we observed significant enrichment of PTVs inherited from unaffected parents in CHD-associated genes. We identified three genome-wide significant S-CHD disorders caused by DNMs in CHD4, CDK13 and PRKD1. Our study finds evidence for distinct genetic architectures underlying the low sibling recurrence risk in S-CHD and NS-CHD.

Smooth Muscle Progenitor Cells Derived From Human Pluripotent Stem Cells Induce Histologic Changes in Injured Urethral Sphincter.

: Data suggest that myoblasts from various sources, including bone marrow, skeletal muscle, and adipose tissue, can restore muscle function in patients with urinary incontinence. Animal data have indicated that these progenitor cells exert mostly a paracrine effect on the native tissues rather than cell regeneration. Limited knowledge is available on the in vivo effect of human stem cells or muscle progenitors on injured muscles. We examined in vivo integration of smooth muscle progenitor cells (pSMCs) derived from human pluripotent stem cells (hPSCs). pSMCs were derived from a human embryonic stem cell line (H9-ESCs) and two induced pluripotent stem cell (iPSC) lines. pSMCs were injected periurethrally into urethral injury rat models (2 × 106 cells per rat) or intramuscularly into severe combined immunodeficiency mice. Histologic and quantitative image analysis revealed that the urethras in pSMC-treated rats contained abundant elastic fibers and thicker muscle layers compared with the control rats. Western blot confirmed increased elastin/collagen III content in the urethra and bladder of the H9-pSMC-treated rats compared with controls. iPSC-pSMC treatment also showed similar trends in elastin and collagen III. Human elastin gene expression was not detectable in rodent tissues, suggesting that the extracellular matrix synthesis resulted from the native rodent tissues rather than from the implanted human cells. Immunofluorescence staining and in vivo bioluminescence imaging confirmed long-term engraftment of pSMCs into the host urethra and the persistence of the smooth muscle phenotype. Taken together, the data suggest that hPSC-derived pSMCs facilitate restoration of urethral sphincter function by direct smooth muscle cell regeneration and by inducing native tissue elastin/collagen III remodeling. SIGNIFICANCE: The present study provides evidence that a pure population of human smooth muscle progenitor cells (pSMCs) derived from human pluripotent stem cells (hPSCs) (human embryonic stem cells and patient induced pluripotent stem cells) restores urethral sphincter function by two mechanisms: modulation of extracellular matrix protein metabolism in vivo and pSMC proliferation and differentiation into smooth muscle cells to regenerate the muscle layer in the lower urinary tract. These findings on the in vivo effects of human pSMCs should aid in optimizing regenerative therapies using human myoblasts.