Neurointestinal diseases cause significant morbidity and effective treatments are lacking. This study aimes to test the feasibility of transplanting autologous enteric neural stem cells (ENSCs) to ...rescue the enteric nervous system (ENS) in a model of colonic aganglionosis. ENSCs are isolated from a segment of small intestine from Wnt1::Cre;R26iDTR mice in which focal colonic aganglionosis is simultaneously created by diphtheria toxin injection. Autologous ENSCs are isolated, expanded, labeled with lentiviral-GFP, and transplanted into the aganglionic segment in vivo. ENSCs differentiate into neurons and glia, cluster to form neo-ganglia, and restore colonic contractile activity as shown by electrical field stimulation and optogenetics. Using a non-lethal model of colonic aganglionosis, our results demonstrate the potential of autologous ENSC therapy to improve functional outcomes in neurointestinal disease, laying the groundwork for clinical application of this regenerative cell-based approach.
The enteric nervous system (ENS) is an extensive network of neurons and glia within the wall of the gastrointestinal (GI) tract that regulates many essential GI functions. Consequently, disorders of ...the ENS due to developmental defects, inflammation, infection, or age-associated neurodegeneration lead to serious neurointestinal diseases. Despite the prevalence and severity of these diseases, effective treatments are lacking as they fail to directly address the underlying pathology. Neuronal stem cell therapy represents a promising approach to treating diseases of the ENS by replacing the absent or injured neurons, and an autologous source of stem cells would be optimal by obviating the need for immunosuppression. We utilized the swine model to address key questions concerning cell isolation, delivery, engraftment, and fate in a large animal relevant to human therapy. We successfully isolated neural stem cells from a segment of small intestine resected from 1-month-old swine. Enteric neuronal stem cells (ENSCs) were expanded as neurospheres that grew optimally in low-oxygen (5%) culture conditions. Enteric neuronal stem cells were labeled by lentiviral green fluorescent protein (GFP) transduction, then transplanted into the same swine from which they had been harvested. Endoscopic ultrasound was then utilized to deliver the ENSCs (10,000-30,000 neurospheres per animal) into the rectal wall. At 10 and 28 days following injection, autologously derived ENSCs were found to have engrafted within rectal wall, with neuroglial differentiation and no evidence of ectopic spreading. These findings strongly support the feasibility of autologous cell isolation and delivery using a clinically useful and minimally invasive technique, bringing us closer to first-in-human ENSC therapy for neurointestinal diseases.
Over the last 20 years, there has been increasing focus on the development of novel stem cell based therapies for the treatment of disorders and diseases affecting the enteric nervous system (ENS) of ...the gastrointestinal tract (so-called enteric neuropathies). Here, the idea is that ENS progenitor/stem cells could be transplanted into the gut wall to replace the damaged or absent neurons and glia of the ENS. This White Paper sets out experts’ views on the commonly used methods and approaches to identify, isolate, purify, expand and optimize ENS stem cells, transplant them into the bowel, and assess transplant success, including restoration of gut function. We also highlight obstacles that must be overcome in order to progress from successful preclinical studies in animal models to ENS stem cell therapies in the clinic.
•New treatments are sought for diseases affecting the enteric nervous system.•Stem cells could be transplanted into the gut to repair the enteric nervous system.•Experts give views on optimal stem cell therapy approaches for enteric neuropathies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The natural reservoir of Influenza A is waterfowl. Normally, waterfowl viruses are not adapted to infect and spread in the human population. Sometimes, through reassortment or through whole host ...shift events, genetic material from waterfowl viruses is introduced into the human population causing worldwide pandemics. Identifying which mutations allow viruses from avian origin to spread successfully in the human population is of great importance in predicting and controlling influenza pandemics. Here we describe a novel approach to identify such mutations. We use a sitewise non-homogeneous phylogenetic model that explicitly takes into account differences in the equilibrium frequencies of amino acids in different hosts and locations. We identify 172 amino acid sites with strong support and 518 sites with moderate support of different selection constraints in human and avian viruses. The sites that we identify provide an invaluable resource to experimental virologists studying adaptation of avian flu viruses to the human host. Identification of the sequence changes necessary for host shifts would help us predict the pandemic potential of various strains. The method is of broad applicability to investigating changes in selective constraints when the timing of the changes is known.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The rapid evolution of influenza viruses presents difficulties in maintaining the optimal efficiency of vaccines. Amino acid substitutions result in antigenic drift, a process whereby antisera raised ...in response to one virus have reduced effectiveness against future viruses. Interestingly, while amino acid substitutions occur at a relatively constant rate, the antigenic properties of H3 move in a discontinuous, step-wise manner. It is not clear why this punctuated evolution occurs, whether this represents simply the fact that some substitutions affect these properties more than others, or if this is indicative of a changing relationship between the virus and the host. In addition, the role of changing glycosylation of the haemagglutinin in these shifts in antigenic properties is unknown. We analysed the antigenic drift of HA1 from human influenza H3 using a model of sequence change that allows for variation in selective pressure at different locations in the sequence, as well as at different parts of the phylogenetic tree. We detect significant changes in selective pressure that occur preferentially during major changes in antigenic properties. Despite the large increase in glycosylation during the past 40 years, changes in glycosylation did not correlate either with changes in antigenic properties or with significantly more rapid changes in selective pressure. The locations that undergo changes in selective pressure are largely in places undergoing adaptive evolution, in antigenic locations, and in locations or near locations undergoing substitutions that characterise the change in antigenicity of the virus. Our results suggest that the relationship of the virus to the host changes with time, with the shifts in antigenic properties representing changes in this relationship. This suggests that the virus and host immune system are evolving different methods to counter each other. While we are able to characterise the rapid increase in glycosylation of the haemagglutinin during time in human influenza H3, an increase not present in influenza in birds, this increase seems unrelated to the observed changes in antigenic properties.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background Enteric neuropathies, which result from abnormalities of the enteric nervous system, are associated with significant morbidity and high health-care costs, but current treatments are ...unsatisfactory. Cell-based therapy offers an innovative approach to replace the absent or abnormal enteric neurons and thereby restore gut function. Methods Enteric neuronal stem cells (ENSCs) were isolated from the gastrointestinal tract of Wnt1-Cre;R26tdTomato mice and generated neurospheres (NS). NS transplants were performed via injection into the mid-colon mesenchyme of nNOS.sup.-/- mouse, a model of colonic dysmotility, using either 1 (n = 12) or 3 (n = 12) injections (30 NS per injection) targeted longitudinally 1-2 mm apart. Functional outcomes were assessed up to 6 weeks later using electromyography (EMG), electrical field stimulation (EFS), optogenetics, and by measuring colorectal motility. Results Transplanted ENSCs formed nitrergic neurons in the nNOS.sup.-/- recipient colon. Multiple injections of ENSCs resulted in a significantly larger area of coverage compared to single injection alone and were associated with a marked improvement in colonic function, demonstrated by (1) increased colonic muscle activity by EMG recording, (2) faster rectal bead expulsion, and (3) increased fecal pellet output in vivo. Organ bath studies revealed direct neuromuscular communication by optogenetic stimulation of channelrhodopsin-expressing ENSCs and restoration of smooth muscle relaxation in response to EFS. Conclusions These results demonstrate that transplanted ENSCs can form effective neuromuscular connections and improve colonic motor function in a model of colonic dysmotility, and additionally reveal that multiple sites of cell delivery led to an improved response, paving the way for optimized clinical trial design. Keywords: Cell therapy, Enteric neuropathies, Nitric oxide synthase, Gastrointestinal motility, Optogenetics
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Diffuse intimal hyperplasia and graft irregularity adversely affect the long-term patency of saphenous vein grafts (SVGs) and clinical outcomes of patients undergoing coronary artery bypass grafting ...(CABG). The VEST trial evaluated the efficacy of external graft support in limiting the development of intimal hyperplasia (IH) at 1 year postsurgery. In the present secondary analysis, we explored the associations between graft disease and IH and clinical events. We also examined risk factors for early graft occlusion.
VEST is a within-patient randomized, multicenter trial that enrolled 224 patients with multivessel coronary disease undergoing CABG surgery, of whom 203 were evaluated by 1 year postsurgery. Intimal hyperplasia, lumen uniformity, graft stenosis, and graft perfusion were measured by intravascular ultrasound and angiography. Major cardiac and cerebrovascular events (MACCE; including death, myocardial infarction, stroke, and revascularization) were recorded over a median follow-up of 3 years.
Worse lumen uniformity, greater stenosis, and worse graft perfusion were associated with higher IH values and an increased incidence of clinical events. Consistent with previous findings, we identified endoscopic vein harvesting, female sex, and transit time flow measurement of pulsatility index and flow as risk factors for SVG occlusion during the first year postsurgery.
In this secondary analysis of the VEST trial, we observed an association between intimal hyperplasia area and clinical measures of SVG disease at 1 year postsurgery. More severe SVG disease and larger areas of IH were associated with a higher incidence of 3-year MACCE. Ongoing follow-up to 5 years will further elucidate the impact of SVG disease on long-term clinical outcomes of CABG.
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Functional neurological symptoms (FNS) are commonly encountered but have engendered remarkably little academic interest. 'UK-Functional Neurological Symptoms (UK-FNS)' was an informal inaugural ...meeting of UK based clinicians in March 2011 with a variety of research and clinical interests in the field. This narrative review reflects the content of the meeting, and our opinion of key findings in the field since the turn of the millennium.
To summarize the current world position on laparoscopic liver surgery.
Multiple series have reported on the safety and efficacy of laparoscopic liver surgery. Small and medium sized procedures have ...become commonplace in many centers, while major laparoscopic liver resections have been performed with efficacy and safety equaling open surgery in highly specialized centers. Although the field has begun to expand rapidly, no consensus meeting has been convened to discuss the evolving field of laparoscopic liver surgery.
On November 7 to 8, 2008, 45 experts in hepatobiliary surgery were invited to participate in a consensus conference convened in Louisville, KY, US. In addition, over 300 attendees were present from 5 continents. The conference was divided into sessions, with 2 moderators assigned to each, so as to stimulate discussion and highlight controversies. The format of the meeting varied from formal presentation of experiential data to expert opinion debates. Written and video records of the presentations were produced. Specific areas of discussion included indications for surgery, patient selection, surgical techniques, complications, patient safety, and surgeon training.
The consensus conference used the terms pure laparoscopy, hand-assisted laparoscopy, and the hybrid technique to define laparoscopic liver procedures. Currently acceptable indications for laparoscopic liver resection are patients with solitary lesions, 5 cm or less, located in liver segments 2 to 6. The laparoscopic approach to left lateral sectionectomy should be considered standard practice. Although all types of liver resection can be performed laparoscopically, major liver resections (eg, right or left hepatectomies) should be reserved for experienced surgeons facile with more advanced laparoscopic hepatic resections. Conversion should be performed for difficult resections requiring extended operating times, and for patient safety, and should be considered prudent surgical practice rather than failure. In emergent situations, efforts should be made to control bleeding before converting to a formal open approach. Utilization of a hand assist or hybrid technique may be faster, safer, and more efficacious. Indications for surgery for benign hepatic lesions should not be widened simply because the surgery can be done laparoscopically. Although data presented on colorectal metastases did not reveal an adverse effect of the laparoscopic approach on oncological outcomes in terms of margins or survival, adequacy of margins and ability to detect occult lesions are concerns. The pure laparoscopic technique of left lateral sectionectomy was used for adult to child donation while the hybrid approach has been the only one reported to date in the case of adult to adult right lobe donation. Laparoscopic liver surgery has not been tested by controlled trials for efficacy or safety. A prospective randomized trial appears to be logistically prohibitive; however, an international registry should be initiated to document the role and safety of laparoscopic liver resection.
Laparoscopic liver surgery is a safe and effective approach to the management of surgical liver disease in the hands of trained surgeons with experience in hepatobiliary and laparoscopic surgery. National and international societies, as well as governing boards, should become involved in the goal of establishing training standards and credentialing, to ensure consistent standards and clinical outcomes.
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