Hypoimmune induced pluripotent stem cells survive long term in fully immunocompetent, allogeneic rhesus macaques.

Genetic engineering of allogeneic cell therapeutics that fully prevents rejection by a recipient's immune system would abolish the requirement for immunosuppressive drugs or encapsulation and support large-scale manufacturing of off-the-shelf cell products. Previously, we generated mouse and human hypoimmune pluripotent (HIP) stem cells by depleting HLA class I and II molecules and overexpressing CD47 (B2M-/-CIITA-/-CD47+). To determine whether this strategy is successful in non-human primates, we engineered rhesus macaque HIP cells and transplanted them intramuscularly into four allogeneic rhesus macaques. The HIP cells survived unrestricted for 16 weeks in fully immunocompetent allogeneic recipients and differentiated into several lineages, whereas allogeneic wild-type cells were vigorously rejected. We also differentiated human HIP cells into endocrinologically active pancreatic islet cells and showed that they survived in immunocompetent, allogeneic diabetic humanized mice for 4 weeks and ameliorated diabetes. HIP-edited primary rhesus macaque islets survived for 40 weeks in an allogeneic rhesus macaque recipient without immunosuppression, whereas unedited islets were quickly rejected.

Hypoimmune anti-CD19 chimeric antigen receptor T cells provide lasting tumor control in fully immunocompetent allogeneic humanized mice.

Manufacturing autologous chimeric antigen receptor (CAR) T cell therapeutics is complex, and many patients experience treatment delays or cannot be treated at all. Although current allogeneic CAR products have the potential to overcome manufacturing bottlenecks, they are subject to immune rejection and failure to persist in the host, and thus do not provide the same level of efficacy as their autologous counterparts. Here, we aimed to develop universal allogeneic CAR T cells that evade the immune system and produce a durable response. We generated human hypoimmune (HIP) T cells with disrupted B2M, CIITA, and TRAC genes using CRISPR-Cas9 editing. In addition, CD47 and anti-CD19 CAR were expressed using lentiviral transduction. These allogeneic HIP CD19 CAR T cells were compared to allogeneic CD19 CAR T cells that only expressed the anti-CD19 CAR (allo CAR T). In vitro assays for cancer killing and exhaustion revealed no differences between allo CAR T and HIP CAR T cells, confirming that the HIP edits did not negatively affect T cell performance. Clearance of CD19+ tumors by HIP CAR T cells in immunodeficient NSG mice was comparable to that of allo CAR T cells. In fully immunocompetent humanized mice, HIP CAR T cells significantly outperformed allo CAR T cells, showed improved persistence and expansion, and provided lasting cancer clearance. Furthermore, CD47-targeting safety strategies reliably and specifically eliminated HIP CAR T cells. These findings suggest that universal allogeneic HIP CAR T cell-based therapeutics might overcome the limitations associated with poor persistence of allogeneic CAR T cells and exert durable anti-tumor responses.

Human hypoimmune primary pancreatic islets avoid rejection and autoimmunity and alleviate diabetes in allogeneic humanized mice.

Transplantation of allogeneic pancreatic donor islets has successfully been performed in selected patients with difficult-to-control insulin-dependent diabetes and impaired awareness of hypoglycemia (IAH). However, the required systemic immunosuppression associated with this procedure prevents this cell replacement therapy from more widespread adoption in larger patient populations. We report the editing of primary human islet cells to the hypoimmune HLA class I- and class II-negative and CD47-overexpressing phenotype and their reaggregation into human HIP pseudoislets (p-islets). Human HIP p-islets were shown to survive, engraft, and ameliorate diabetes in immunocompetent, allogeneic, diabetic humanized mice. HIP p-islet cells were further shown to avoid autoimmune killing in autologous, diabetic humanized autoimmune mice. The survival and endocrine function of HIP p-islet cells were not impaired by contamination of unedited or partially edited cells within the p-islets. HIP p-islet cells were eliminated quickly and reliably in this model using a CD47-targeting antibody, thus providing a safety strategy in case HIP cells exert toxicity in a future clinical setting. Transplantation of human HIP p-islets for which no immunosuppression is required has the potential to lead to wider adoption of this therapy and help more diabetes patients with IAH and history of severe hypoglycemic events to achieve insulin independence.

Mitral valve prosthesis choice for patients aged 65 years and over in the UK. Are the guidelines being followed and does it matter?

OBJECTIVE: Current guidelines recommend that most patients aged ≥65 years should undergo mitral valve replacement (MVR) using a biological prosthesis. The objectives of this study were to assess whether these guidelines are being followed in UK practice, and to investigate whether the guidelines are appropriate based on in-hospital mortality and mid-term survival. METHODS: Data from the National Institute for Cardiovascular Outcomes Research Adult Cardiac Surgery Audit database from all National Health Service (NHS) hospitals and some private hospitals performing adult cardiac surgery in the UK between April 2001 and March 2011 were analysed. The overall cohort included 3862 patients aged ≥65 years who underwent first-time MVR. Propensity score matching and regression adjustment were used to compare outcomes between prosthesis groups. RESULTS: The mean age was 73.0 years (SD 4.9) with 50% of patients having surgery with a mechanical prosthesis. This proportion decreased over the study period and with increasing patient age with marked variation between hospitals. In the propensity-matched cohort, in-hospital mortality in the biological group was 6.9%, and in the mechanical group it was 5.9% giving an unadjusted OR of 1.17 (95% CI 0.84 to 1.63). There was no significant difference in mid-term survival between the matched groups with an unadjusted HR for biological prosthesis of 1.08 (95% CI 0.93 to 1.24). Similar results were found when using regression adjustment on unmatched data. CONCLUSIONS: Current guidelines concerning age and mitral valve prosthesis choice are not being followed for patients aged ≥65 years. With regards to in-hospital and mid-term mortality, this study demonstrates that there is no difference between prosthesis types.

Impact of transiently elevated diastolic pressure on cause of death: 29-year follow-up from the General Practice Hypertension Study Group.

OBJECTIVES: High blood pressure is known to be associated with higher cardiovascular risk. The emphasis has shifted over time from diastolic pressure to systolic pressure and variability in blood pressure. This study examined the impact of transient and sustained diastolic hypertension on later mortality. METHODS: In the early 1970s, the General Practice Hypertension Study Group screened more than 20,000 patients and selected those with diastolic hypertension, with a transiently elevated diastolic pressure and age-matched and sex-matched normotensive controls to be flagged for long-term death certificate follow-up. After a mean follow-up of 29 years, Cox proportional hazard regression was used to examine the relationship between diastolic hypertension and cause of death. RESULTS: Overall those with diastolic hypertension and transient diastolic hypertension were at increased risk of total and cardiovascular mortality. When men and women were examined separately, however, the relationships remained significant in women only, with transient diastolic hypertension showing the strongest association with cardiovascular and total mortality: hazard ratio 1.57 [95% confidence interval (CI) 1.11-2.23] and hazard ratio 1.39 (95% CI 1.10-1.76), respectively. CONCLUSION: Transient diastolic hypertension does not seem to be benign, particularly in women and may point to those at higher cardiovascular risk when seen in a general practice population.

Blood patch for persistent air leak: a review of the current literature.

PURPOSE OF REVIEW: Persistent air leak (PAL) poses a significant challenge to the thoracic surgeon. Of the numerous methods employed to manage this problem, autologous blood 'patch' pleurodesis (ABPP) remains one of the most controversial, seemingly due to a lack of robust data and consensus of opinion regarding its efficacy, technique of application and its role in clinical practice. Despite a lack of randomized control trials, the evidence to-date has shown ABPP to be an efficacious, cheap, simple, well tolerated and readily available treatment, with minimal side effects and broad range of applications, allowing for earlier chest drain removal, decreased complications and decreased hospital stay. A review is therefore required to assess the role for ABPP in contemporary clinical practice. RECENT FINDINGS: Recent studies have demonstrated that ABPP is an effective management for PAL in specific patient groups and there is an argument that it has the potential to be the gold-standard or first-line treatment in certain clinical scenarios such as for patients with interstitial lung disease or acute respiratory distress syndrome. SUMMARY: This review aims to discuss the relevance of recent findings and to suggest a firm role for ABPP in current practice. In addition, the evidence for the efficacy of ABPP will be assessed and compared with other established methods of pleurodesis. Finally, the review will include a summary of relevant research to-date in order to suggest an evidence-based standardized protocol for the application of ABPP.

A syllabus for research ethics committees: training needs and resources in different European countries.

This paper reports a European Forum for Good Clinical Practice workshop held in 2011 to consider a research ethics committee training syllabus, subsequent training needs and resources. The syllabus that was developed was divided into four competencies: committee working; scientific method; ethical analysis and the regulatory framework. Appropriate training needs for each, with possible resources, were discussed. Lack of funding for training was reported as a major problem but affordable alternatives were debated. Strengths and weaknesses of this approach were discussed and the resultant proposal will be disseminated through the European Forum for Good Clinical Practice and the research ethics committees of member states.

Anterolateral thigh free flap for complex composite central chest wall defect reconstruction with extrathoracic microvascular anastomoses.

BACKGROUND: Complex central chest wall resection defects present a challenging management problem for both thoracic and reconstructive surgeons. Although most chest wall defects can be repaired using local and regional flaps, more complicated cases require increasingly sophisticated techniques such as microsurgical free tissue transfer. This study reviews a single plastic surgeon's experience over a 4-year period with complex chest wall reconstruction using the anterolateral thigh free flap. METHODS: Five female patients who underwent the above procedure between 2004 and 2007 were reviewed retrospectively. The clinicopathologic details recorded included histologic diagnosis, extent of resection, type of skeletal defect, flap size, receipt vessels, ischemia time, and flap/donor-site complications. Skeletal reconstruction used methylmethacrylate/polypropylene mesh sandwich prostheses. RESULTS: The indications for surgery were metastatic breast cancer (n=3), advanced primary fibrosarcoma (n=1), and extensive radionecrosis (n=1). The average surface area of the chest wall resection was 197 cm (range, 156 to 270 cm). The four patients who underwent partial sternectomy and rib resection required skeletal reconstruction and subsequent ventilatory support postoperatively in the intensive care unit. The mean anterolateral thigh flap size was 188 cm (range, 143 to 252 cm); none of the donor sites was skin grafted. There was 100 percent flap survival, and the prostheses remained fully covered in all cases after a mean follow-up of 16 months (range, 5 to 28 months). No major complications were observed. CONCLUSIONS: The anterolateral thigh free flap is a safe and reliable option for reconstructing complicated composite chest wall defects. It therefore provides a practical alternative when regional pedicled flap options are unavailable or inadequate.

Does preservation of the sub-valvular apparatus during mitral valve replacement affect long-term survival and quality of life? A Microsimulation Study.

BACKGROUND: Techniques to preserve the sub-valvular apparatus in order to reduce morbidity and mortality following mitral valve replacement have been frequently reported. However, it is uncertain what impact sub-valvular apparatus preservation techniques have on long-term outcomes following mitral valve replacement. This study investigated the effect of sub-valvular apparatus preservation on long-term survival and quality of life following mitral valve replacement. METHODS: A microsimulation model was used to compare long-term survival and quality-adjusted life years following mitral valve replacement after conventional valve replacement and sub-valvular apparatus preservation. Probabilistic sensitivity analysis and alternative analysis were performed to investigate uncertainty associated with the results. RESULTS: Our Analysis suggests that patients survive longer if the sub-valvular apparatus are preserved (65.7% SD 1.5%, compared with 58.1% SD 1.6% at 10 years). The quality adjusted life years gained over a 10 year period where also greater after sub-valvular apparatus preservation. (6.54 QALY SD 0.07 QALY, compared with 5.61 QALY, SD 0.07 QALY). The superiority of preservation techniques was insensitive to patient age, parameter or model uncertainty. CONCLUSION: This study suggests that long-term outcomes may be improved when the sub-valvular apparatus are preserved. Given the lack of empirical data further research is needed to investigate health-related quality of life after mitral valve replacement, and to establish whether outcomes differ between preservation techniques.

Reduction of persistent air leak with endoscopic valve implants.

The standard management of air leaks due to persistent bronchopleural fistula involves chest drainage and occasionally pleurodesis, with intractable cases requiring surgical decortication or surgical repair. However, some of these patients may be at high risk for surgery, particularly if they have already had thoracic surgery or have other medical problems; for this group there is a need for less invasive methods of stopping or reducing air leaks. Emphasys endobronchial valves (EBV) are occlusive devices designed primarily for endoscopic lung volume reduction in emphysema. Because the device is a one-way inspiratory airway blocker, it is possible that it could be used in controlling persistent air leaks while maintaining the drainage of secretions. Two cases are reported of persistent air leaks that were managed by endoscopic occlusion with EBV. In one case complete stoppage of the air leak was achieved with immediate clinical benefits. The second patient died 5 days after treatment from additional complications apparently not related to the procedure. Endobronchial blockage may be a useful salvage procedure for patients with persistent air leak for whom there is no other treatment available.

A multidisciplinary approach to recurrent cervicothoracic cystic hygroma in an adult.

Cystic hygroma is a benign congenital lymphatic malformation affecting mainly the head and neck region in children. Although mediastinal or multiorgan lymphangiomatosis is rare, it can present at any age. We report an unusual case of recurrent bilateral cystic hygroma in an adult affecting both neck and mediastinum. When the extensive lesion became symptomatic, a multidisciplinary approach was necessary to remove the expanding mass to achieve the optimal functional and cosmetic outcome.