Arachidonic acid activates NLRP3 inflammasome in MDSCs via FATP2 to promote post-transplant tumour recurrence in steatotic liver grafts.

Background & Aims: The steatotic grafts have been applied in liver transplantation frequently owing to the high incidence of non-alcoholic fatty liver disease. However, fatty livers are vulnerable to graft injury. Myeloid-derived suppressor cell (MDSC) recruitment during liver graft injury promotes tumour recurrence. Lipid metabolism exerts the immunological influence on MDSCs in tumour progression. Here, we aimed to explore the role and mechanism of inflammasome activation in MDSCs induced by lipid metabolism during fatty liver graft injury and the subsequent effects on tumour recurrence. Methods: MDSC populations and nucleotide-binding oligomerisation domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome levels were investigated in a clinical cohort and a rat liver transplantation model. The mechanism of NLRP3 activation by specific fatty acids was explored in mouse hepatic ischaemia/reperfusion injury (IRI) with tumour recurrence model and in vitro studies. Results: MDSC populations and NLRP3 levels were increased with higher tumour recurrent rate in patients using steatotic grafts. NLRP3 was upregulated in MDSCs with lipid accumulation post mouse fatty liver IRI. Mechanistically, arachidonic acid was discovered to activate NLRP3 inflammasome in MDSCs through fatty acid transport protein 2 (FATP2), which was identified by screening lipid uptake receptors. The mitochondrial dysfunction with enhanced reactive oxygen species bridged arachidonic acid uptake and NLRP3 activation in MDSCs, which subsequently stimulated CD4+ T cells producing more IL-17 in fatty liver IRI. Blockade of FATP2 inhibited NLRP3 activation in MDSCs, IL-17 production in CD4+ T cells, and the tumour recurrence post fatty liver IRI. Conclusions: During fatty liver graft injury, arachidonic acid activated NLRP3 inflammasome in MDSCs through FATP2, which subsequently stimulated CD4+ T cells producing IL-17 to promote tumour recurrence post transplantation. Impact and implications: The high incidence of non-alcoholic fatty liver disease resulted in the frequent application of steatotic donors in liver transplantation. Our data showed that the patients who underwent liver transplantation using fatty grafts experienced higher tumour recurrence. We found that arachidonic acid activated NLRP3 inflammasome in MDSCs through FATP2 during fatty liver graft injury, which led to more IL-17 secretion of CD4+ T cells and promoted tumour recurrence post transplantation. The inflammasome activation by aberrant fatty acid metabolism in MDSCs bridged the acute-phase fatty liver graft injury and liver tumour recurrence.

Plasmacytoid dendritic cells recruited by HIF-1α/eADO/ADORA1 signaling induce immunosuppression in hepatocellular carcinoma.

Plasmacytoid dendritic cells (pDCs) play immunosuppressive roles in the tumor microenvironment (TME). However, the molecular mechanisms underlying the recruitment and dysfunction of pDCs in the TME remain largely elusive, especially in hepatocellular carcinoma (HCC). In this study, we observed the accumulation of pDCs in the blood, tumor tissue, and ascitic fluid of HCC patients. A high density of tumor-infiltrating pDCs was correlated with poor prognosis in patients with HCC. Hypoxia-induced extracellular adenosine (eADO) significantly enhanced pDC recruitment into tumors via the adenosine A1 receptor (ADORA1). Mechanistically, hypoxia-inducible factor 1-alpha (HIF-1α) transcriptionally upregulated the expression of the ectonucleotidases CD39 and CD73 in HCC cells, both of which are essential for the generation of eADO. Moreover, eADO-stimulated pDCs promoted the induction of regulatory T cells and suppressed proliferation and cytotoxicity of CD8+ T cells. Depletion of pDCs using a monoclonal antibody or an ADORA1 antagonist significantly improved antitumor immunity and suppressed HCC growth in the immunocompetent HCC mouse model. Thus, targeting pDC recruitment may serve as a potential adjuvant strategy for immunotherapies in HCC.

Monocytic MDSC mobilization promotes tumor recurrence after liver transplantation via CXCL10/TLR4/MMP14 signaling.

Tumor recurrence is the major obstacle for pushing the envelope of liver transplantation for hepatocellular carcinoma (HCC) patients. The inflammatory cascades activated by acute liver graft injury promote tumor recurrence. We aimed to explore the role and mechanism of myeloid-derived suppressor cell (MDSC) mobilization induced by liver graft injury on tumor recurrence. By analyzing 331 HCC patients who received liver transplantation, the patients with graft weight ratio (GWR, the weight of liver graft divided by the estimated standard liver weight of recipient) <60% had higher tumor recurrence than GWR ≥60% ones. MDSCs and CXCL10/TLR4 levels were significantly increased in patients with GWR <60% or tumor recurrence. These findings were further validated in our rat orthotopic liver transplantation model. In CXCL10-/- and TLR4-/- mice of hepatic ischemia/reperfusion injury plus major hepatectomy (IRH) model, monocytic MDSCs, instead of granulocytic MDSCs, were significantly decreased. Importantly, CXCL10 deficiency reduced the accumulation of TLR4+ monocytic MDSCs, and CXCL10 increased MDSC mobilization in the presence of TLR4. Moreover, MMP14 was identified as the key molecule bridging CXCL10/TLR4 signaling and MDSC mobilization. Knockout or inhibition of CXCL10/TLR4 signaling significantly reduced the tumor growth with decreased monocytic MDSCs and MMP14 in the mouse tumor recurrent model. Our data indicated that monocytic MDSCs were mobilized and recruited to liver graft during acute phase injury, and to promote HCC recurrence after transplantation. Targeting MDSC mobilization via CXCL10/TLR4/MMP14 signaling may represent the therapeutic potential in decreasing post-transplant liver tumor recurrence.

Development of cisplatin-loaded hydrogels for trans-portal vein chemoembolization in an orthotopic liver cancer mouse model.

Transarterial chemoembolization is a standard treatment for intermediate-stage hepatocellular carcinoma (HCC). This study evaluated the anti-tumor effect of the semi-interpenetrating network (IPN) hydrogel as a novel embolic material for trans-portal vein chemoembolization (TPVE) in vivo. A nude mice orthotopic HCC model was established, followed by TPVE using IPN hydrogel loaded with or without cisplatin. Portal vein blockade was visualized by MRI and the development of tumor was monitored by IVIS Spectrum Imaging. Tumor proliferation and angiogenesis were evaluated by Ki67 and CD34 staining respectively. Intra-tumor caspase 3, Akt, ERK1/2, and VEGF activation were detected by Western Blot. 18 F-FMISO uptake was evaluated by microPET-MRI scanning. IPN hydrogel first embolized the left branch of portal vein within 24 hours and further integrated into the intra-tumor vessels during 2 weeks after the treatment. Mice treated with cisplatin-loaded hydrogels exhibited a significant decrease in tumor growth, along with lower plasma AFP levels as compared to hydrogel-treated and untreated tumor-bearing mice. By Ki67 and CD34 staining, the TPVE with IPN hydrogel suppressed tumor proliferation and angiogenesis. In addition, increased tumor apoptosis shown by up-regulation of caspase 3 with decreased expressions of tumor cell survival indicators Akt and ERK1/2 were observed in the treatment groups. Consistent with the decreased expression of VEGF after TPVE, hypoxia level in the tumor was also reduced as indicated by 18 F-FMISO uptake level. IPN hydrogel-based TPVE significantly suppressed the tumor development by regulating intra-tumor angiogenesis and cell survival in an orthotopic HCC mouse model, suggesting a viable embolic agent for transarterial chemoembolization.

Neonatal Compartment Syndrome and Compound Presentation at Birth.

Neonatal compartment syndrome is a rare condition. Early diagnosis and timely surgical intervention are paramount to optimize outcome. Time to fasciotomy is the most important prognostic factor. The purposes of this study were to describe a case presentation of neonatal compartment syndrome associated with a compound birth presentation and to perform a literature review. In this case, the neonate's fingers were noted to be present on maternal cervical examination 24 hours before delivery. The patient then was noted to have a sentinel skin lesion. A diagnosis of neonatal compartment syndrome was suspected, and she underwent urgent fasciotomy. Literature review identified a total of 60 patients from 26 studies. Most patients were managed operatively. All patients presented with a sentinel skin lesion, emphasizing the importance of this clinical sign in diagnosis. Manometry is not routinely performed and no standards are available for acceptable pressure gradients.

Microsurgical Reconstruction of the Smile: A Critical Analysis of Outcomes.

BACKGROUND: Facial paralysis is a significant problem with functional, psychological, and esthetic consequences. Free muscle transfer for reanimation of the smile has been established as the preferred reconstructive method. However, little has been reported on the complications after this procedure. We sought to perform a critical analysis of these complications and their ultimate outcomes. METHODS: A retrospective review was performed on consecutive patients undergoing microsurgical reconstruction of the smile by the senior author from 2013 through 2017. Patient demographics including age, race, body mass index, and medical comorbidities were recorded. The cause of facial palsy and type of microsurgical reconstruction were assessed. Patient outcomes including complications and management of the complication were analyzed. All statistical analyses were performed using nonparametric analyses. RESULTS: We identified 17 patients who underwent microsurgical reconstruction of the smile, with 1 patient undergoing bilateral procedures, for a total of 18 microsurgical smile reanimation procedures performed. Sixteen of these were 1-stage reconstructions with the coaptation of the nerve to the masseter, whereas 2 were 2-stage reconstructions using cross-facial nerve grafts. The gracilis muscle was used as the donor muscle in all cases. The patients had a median age of 26.5 and a median follow-up of 1.04 years from surgery. There were no major early complications observed in our cohort. Eight (44.4%) reanimations developed a minor complication that required subsequent reoperation. The reoperations were performed at a median of 0.97 years after the microsurgical procedure. The most common indication for reoperation was lateral retraction of the insertion of the transplanted muscle, which occurred in 5 (62.5%) patients. One patient underwent surgical exploration for an abrupt loss of transplanted muscle function after trauma to the cheek. Another patient had less than expected transplanted muscle activity at 1 year postoperatively and underwent exploration of the cross-facial nerve graft and a neurorrhaphy revision. Lastly, 1 patient developed significant rhytids over the transplanted muscle secondary to tethering of the skin to the underlying muscle. This patient underwent 2 subsequent revisions, with placement of acellular dermal matrix between the muscle and skin and fat grafting. All patients had functional animation of the transplanted muscle postoperatively. CONCLUSIONS: Complications occurred in 44.4% of patients undergoing microsurgical reanimation of the smile. Most complications were minor in nature and were readily addressed with advancement of the transplanted muscle. All patients in our series had muscle function after the muscle transplantation.

Transverse tensor fascia lata myocutaneous flap for microvascular breast reconstruction: case report and review of the literature.

The transverse tensor fascia lata (TTFL) flap is an important alternative flap for autologous breast reconstruction. It is a horizontal variant of the tensor fascia lata myocutaneous flap and contains fat from the prominence of the upper lateral thigh (saddle bag). We present the surgical management of a woman with trochanteric lipodystrophy, who underwent staged bilateral mastectomy and autologous breast reconstruction with TTFL flaps. We discuss technical points in TTFL flap design and harvest. Breast reconstruction was successful and the thigh donor sites had excellent aesthetic contour. There were no complications at either recipient or donor sites. The TTFL flap is an important alternative flap for autologous breast reconstruction when other options are less optimal, and has a secondary benefit of thigh donor site closure with lateral thigh lift techniques. The TTFL flap should be presented as an option for autologous breast reconstruction in women with prominent trochanteric lipodystrophy of the upper lateral thighs.

Vertical island trapezius myocutaneous flap for cervical esophagoplasty: case report and review of the literature.

Reconstruction of the cervical esophagus can be fraught with a variety of complications, such as fistula formation or stricture. Additional complicating factors may include local tumor recurrence, failed prior reconstruction, partial or total flap necrosis, and compromised tissues in an irradiated field. Once complications occur, the chance of a successful reconstruction in subsequent operations is greatly reduced. We report a case of a patient who had local tumor recurrence despite chemoradiotherapy necessitating cervical esophagectomy. Reconstruction of the esophagus was initially performed with a tubed anterolateral thigh flap, which was complicated by partial flap necrosis and salivary fistula. Since the patient was elderly and already had a pectoralis flap used in a previous operation, we elected to perform a vertical island trapezius myocutaneous flap as a salvage procedure to restore esophageal continuity. Postoperatively, the patient had no evidence of further fistula and was able to tolerate a regular diet.

Free flap scalp reconstruction in a 91-year-old patient under local-regional anesthesia: case report and review of the literature.

In the elderly population with significant medical comorbidities, the safety of general anesthesia is often in question. In the head and neck, where regional and extradural anesthesia are not options, reconstruction of defects requiring free tissue transfer becomes a particular challenge for patients in whom general anesthesia is contraindicated. We present a case of a scalp reconstruction utilizing a latissimus dorsi free flap in a 91-year-old man performed entirely under local and regional anesthesia. General anesthesia was contraindicated secondary to the patient's multiple medical comorbidities. A paravertebral block was used for the harvest of the latissimus dorsi muscle and skin grafts. The microvascular portion of the procedure and the inset were performed under local anesthesia alone. The patient tolerated the procedure, and the operation was successful. This case is unique in that there are no published reports of head and neck free tissue transfer being performed entirely under local-regional anesthesia. We conclude that despite the medical challenges of performing complex reconstruction in elderly patients, expedient free tissue transfer can offer patients access to successful reconstruction.