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Abstract Background Vascularized composite tissue allotransplantation (VCA) to replace limbs or faces damaged beyond repair is now possible. The resulting clear benefit to quality of life is a compelling reason to attempt this complex procedure. Unfortunately, the high doses of immunosuppressive drugs required to protect this type of allograft result in significant morbidity and mortality giving rise to ethical concerns about performing this surgery in patients with non‐life‐threatening conditions. Here we tested whether we could suppress anti‐graft immune activity by using a safe β2‐adrenergic receptor (AR) agonist, terbutaline, to mimic the natural immune suppression generated by nervous system‐induced signalling through AR. Methods A heterotopic hind limb transplantation model was used with C57BL/6 (H‐2b) as recipients and BALB/c (H‐2d) mice as donors. To test the modulation of the immune response, graft survival was investigated after daily intraperitoneal injection of β2‐AR agonist with and without tacrolimus. Analyses of immune compositions and quantification of pro‐inflammatory cytokines were performed to gauge functional immunomodulation. The contributions to allograft survival of β2‐AR signalling in donor and recipient tissue were investigated with β2‐AR−/− strains. Results Treatment with the β2‐AR agonist delayed VCA rejection, even with a subtherapeutic dose of tacrolimus. β2‐AR agonist decreased T‐cell infiltration into the transplanted grafts and decreased memory T‐cell populations in recipient's circulation. In addition, decreased levels of inflammatory cytokines (IFN‐γ, IL‐6, TNF‐α, CXCL‐1/10 and CCL3/4/5/7) were detected following β2‐AR agonist treatment, and there was a decreased expression of ICAM‐1 and vascular cell adhesion molecule‐1 in donor stromal cells. Conclusions β2‐AR agonist can be used safely to mimic the natural suppression of immune responses, which occurs during adrenergic stress‐signalling and thereby can be used in combination regimens to reduce the dose needed of toxic immunosuppressive drugs such as tacrolimus. This strategy can be further evaluated for feasibility in the clinic.

Abstract Aberrancies in the tumor microvasculature limit the systemic delivery of anticancer agents, which impedes tumor response. Using human intravital microscopy (HIVM), we hypothesized that HIVM would be feasible in patients with peritoneal carcinomatosis (PC). During cytoreductive surgery with hyperthermic intraperitoneal chemotherapy for PC, HIVM was performed in both tumor and non-tumor areas. The primary outcome was HIVM feasibility to measure vessel characteristics. We secondarily evaluated associations between HIVM vessel characteristics and oncologic outcomes (RECIST response to neoadjuvant therapy and disease-specific survival). Thirty patients with PC were enrolled. Nineteen patients (63.3%) received neoadjuvant therapy. HIVM was feasible in all patients. Compared to non-tumor (control) areas, PC areas had a lower density of functional vessels, higher proportion of non-functional vessels, smaller lumenal diameters, and lower blood flow velocity. Qualitative differences in these vessel characteristics were observed among patients who had partial response, stable disease, or progressive disease after receiving neoadjuvant therapy. However, no statistically significant relationships were found between HIVM vessel characteristics and oncologic outcomes. These novel findings comprise the first-in-human, real-time evidence of the microscopic differences between normal and tumor-associated vessels and form the basis for our larger, ongoing clinical trial appropriately powered to determine the clinical utility of HIVM (NCT03823144).

Intravital microscopy has been used in laboratory animals to visualise the blood vessels in tumours. Here, the authors use this technique in melanoma patients undergoing surgery and show that vessels in situhave a larger diameter than excised tissue

Background. Vascularized composite tissue allotransplantation (VCA) from a cadaveric donor has now become a clinical reality and the treatment modality of choice for patients with devastating injuries, deformities, and complex tissue defects. However, many VCA patients experience severe toxicities due to the strong immunosuppression required secondary to high antigenicity of the grafts. To improve immunosuppressive protocols for VCA, feasible and reliable preclinical models are necessary. The purpose of this study was to introduce new techniques to an established preclinical VCA model to accelerate future investigations. Methods. C57BL/6 (H-2b) and BALB/c (H-2d) mice were used to perform VCA as recipients and donors, respectively. Surgery time, success rate, associated complications, and mortality were analyzed. Blood flow in grafts was interrogated with laser speckle image (LSI). Results. A nonsuture cuff technique was used with the abdominal aorta for end-to-end anastomosis. The cuff technique demonstrated efficiency for donor surgery (52 ± 10 minutes for donor vs. 45 ± 8 minutes for recipient surgery). Successful revascularization was achieved in 27 (90%) of 30 transplants. The majority of surgical complications occurred within 48 hours including artery occlusion, venous occlusion, cerebral stroke, and minor bleeding without mortality. LSI was useful in detecting intraoperative vascular complications with display patterns predictive of complication type. Conclusions. The described techniques may facilitate a more efficient heterotopic hind limb transplantation mouse model of VCA.

Gynecomastia-like hyperplasia of orthotopic female breast tissue is a rare entity. We present the singularly unique case of a 22-year-old female who presented with a small axillary mass subsequently discovered to be a discrete deposit of ectopic breast tissue with gynecomastia-like hyperplasia. This case highlights the etiology, variable presentation, and evaluation of ectopic breast tissue.

Myeloid-derived suppressor cells (MDSC) contribute to an immunosuppressive network that drives cancer escape by disabling T cell adaptive immunity. The prevailing view is that MDSC-mediated immunosuppression is restricted to tissues where MDSC co-mingle with T cells. Here we show that splenic or, unexpectedly, blood-borne MDSC execute far-reaching immune suppression by reducing expression of the L-selectin lymph node (LN) homing receptor on naïve T and B cells. MDSC-induced L-selectin loss occurs through a contact-dependent, post-transcriptional mechanism that is independent of the major L-selectin sheddase, ADAM17, but results in significant elevation of circulating L-selectin in tumor-bearing mice. Even moderate deficits in L-selectin expression disrupt T cell trafficking to distant LN. Furthermore, T cells preconditioned by MDSC have diminished responses to subsequent antigen exposure, which in conjunction with reduced trafficking, severely restricts antigen-driven expansion in widely-dispersed LN. These results establish novel mechanisms for MDSC-mediated immunosuppression that have unanticipated implications for systemic cancer immunity.

While surgical resection is a cornerstone of cancer treatment, local and distant recurrences continue to adversely affect outcome in a significant proportion of patients. Evidence that an alternative debulking strategy involving radiofrequency ablation (RFA) induces antitumor immunity prompted the current investigation of the efficacy of performing RFA prior to surgical resection (pre-resectional RFA) in a preclinical mouse model.Therapeutic efficacy and systemic immune responses were assessed following pre-resectional RFA treatment of murine CT26 colon adenocarcinoma.Treatment with pre-resectional RFA significantly delayed tumor growth and improved overall survival compared to sham surgery, RFA, or resection alone. Mice in the pre-resectional RFA group that achieved a complete response demonstrated durable antitumor immunity upon tumor re-challenge. Failure to achieve a therapeutic benefit in immunodeficient mice confirmed that tumor control by pre-resectional RFA depends on an intact adaptive immune response rather than changes in physical parameters that make ablated tumors more amenable to a complete surgical excision. RFA causes a marked increase in intratumoral CD8+ T lymphocyte infiltration, thus substantially enhancing the ratio of CD8+ effector T cells: FoxP3+ regulatory T cells. Importantly, pre-resectional RFA significantly increases the number of antigen-specific CD8+ T cells within the tumor microenvironment and tumor-draining lymph node but had no impact on infiltration by myeloid-derived suppressor cells, M1 macrophages or M2 macrophages at tumor sites or in peripheral lymphoid organs (i.e., spleen). Finally, pre-resectional RFA of primary tumors delayed growth of distant tumors through a mechanism that depends on systemic CD8+ T cell-mediated antitumor immunity.Improved survival and antitumor systemic immunity elicited by pre-resectional RFA support the translational potential of this neoadjuvant treatment for cancer patients with high-risk of local and systemic recurrence.