[Clinical effects of free superficial circumflex iliac artery superficial branch perforator flap combined with full-thickness skin graft far from the flap donor site in repairing the large wounds in extremities]

Objective: To investigate the clinical effects of free superficial circumflex iliac artery (SCIA) superficial branch perforator flap combined with full-thickness skin graft far from the flap donor site in repairing the large wounds in extremities. Methods: The study was a retrospective observational study. From January 2020 to June 2022, 19 patients with large wounds in extremities who met the inclusion criteria were admitted to the First Affiliated Hospital of Bengbu Medical College, including 15 males and 4 females, aged 28-75 years. The debridement, fracture reduction and fixation, tendon, vessel, and nerve repair, and vacuum sealing drainage were performed in the first stage surgery. After debridement in the second stage surgery, the total wound area was 13.0 cm×8.0 cm-34.0 cm×15.0 cm. The tendon and bone exposed wound with area of 9.0 cm×6.0 cm-14.0 cm×7.0 cm was repaired with free SCIA superficial branch perforator flap with area of 10.0 cm×6.5 cm-15.0 cm×8.0 cm. The remaining granulation tissue wound with area of 5.0 cm×3.5 cm-13.0 cm×8.0 cm was repaired with full-thickness skin graft far from the flap donor site with area of 5.0 cm×3.5 cm-13.0 cm×8.0 cm. All the wounds in donor site were sutured. The operation time and amount of bleeding of patients during the surgery were recorded, the survival of flap and skin graft were observed after surgery. During follow-up, the flap and skin graft, scar in the donor site and its effect on donor site function were observed. At the last follow-up, the satisfaction of patients with the efficacy was evaluated by the efficacy satisfaction rating score. Results: The operation time of patients was 2.0-3.5 h. The amount of bleeding of patients during the surgery was 100-320 mL. One patient had ecchymosis and venous crisis in the edge of flap on the second day after surgery, and the flap survived after exploration. The flaps of the other patients survived smoothly. The skin grafts of patients all survived smoothly. Two patients had bloated flaps due to obesity in the later stage, and the expected results were achieved after flap thinning surgery 6 months after operation. During the follow-up of 6 to 24 months, the flaps had good elasticity and soft texture, and the skin grafts had no wear or ulceration; linear scars were left in all the donor sites but their functions were not affected. The patients were all satisfied with the efficacy. Conclusions: Free SCIA superficial perforator flap combined with full-thickness skin graft far from the donor site was used to repair the large wounds in extremities, which was safe, reliable, and less traumatic and short in operation time, and resulted in good postoperative appearance and function in the donor sites and recipient sites.

[A nomogram for predicting lymph node metastasis in early gastric cancer]

Objective: To explore the independent risk factors of lymph node metastasis (LNM) in early gastric cancer, and to use nomogram to construct a prediction model for above LNM. Methods: A retrospective cohort study was conducted. Inclusion criteria: (1) primary early gastric cancer as stage pT1 confirmed by postoperative pathology; (2) complete clinicopathological data. Exclusion criteria: (1) patients with advanced gastric cancer, stump gastric cancer or history of gastrectomy; (2) early gastric cancer patients confirmed by pathology after neoadjuvant chemotherapy; (3) other types of gastric tumors, such as lymphoma, neuroendocrine tumor, stromal tumor, etc.; (4) primary tumors of other organs with gastric metastasis. According to the above criteria, 1633 patients with early gastric cancer who underwent radical gastrectomy at the Department of General Surgery of the Chinese PLA General Hospital First Medical Center from December 2005 to December 2020 were enrolled as training set, meanwhile 239 patients with early gastric cancer who underwent gastrectomy at the Department of General Surgery of the Chinese PLA General Hospital Fourth Medical Center from December 2015 to December 2020 were enrolled as external validation set. Risk factors of LNM in early gastric cancer were identified by using univariate and multivariate logistic regression analyses. A nomogram prediction model was established with significant factors screened by multivariate analysis. Area under the receiver operating characteristic curve (AUC) was used for assessing the predictive value of the model. Calibration curve was drawn for external validation. Results: Among 1633 patients in training set, the mean number of retrieved lymph nodes was 20 (13-28), and 209 patients (12.8%) had lymph node metastasis. Univariate analysis showed that gender, resection range, tumor location, tumor morphology, lymph node clearance, vascular invasion, lymphatic cancer thrombus, tumor length, tumor differentiation, microscopic presence of signet ring cells and depth of tumor invasion were associated with LNM (all P<0.05). Multivariate analysis revealed that females, tumor morphology as ulcer type, vascular invasion, lymphatic cancer thrombus, tumor length≥3 cm, deeper invasion of mucosa, and poor differentiation were independent risk factors for LNM in early gastric cancers (all P<0.05). Receiver operating characteristic curve indicated that AUC of training set was 0.818 (95%CI: 0.790-0.847) and AUC of external validation set was 0.765 (95%CI: 0.688-0.843). The calibration curve showed that the LNM probability predicted by nomogram was consistent with the actual situation (C-index: 0.818 in training set and 0.765 in external validation set). Conclusions: Females, tumor morphology as ulcer type, vascular invasion, lymphatic cancer thrombus, tumor length≥3 cm, deeper invasion of mucosa and poor differentiation are independent risk factors for LNM of early gastric cancer. The establishment of a nomogram prediction model for LNM in early gastric cancer has great diagnostic value and can provide reference for treatment selection.

SENTI-101, a Preparation of Mesenchymal Stromal Cells Engineered to Express IL12 and IL21, Induces Localized and Durable Antitumor Immunity in Preclinical Models of Peritoneal Solid Tumors

Advanced peritoneal carcinomatosis including high-grade ovarian cancer has poor prognoses and a poor response rate to current checkpoint inhibitor immunotherapies; thus, there is an unmet need for effective therapeutics that would provide benefit to these patients. Here we present the preclinical development of SENTI-101, a cell preparation of bone marrow-derived mesenchymal stromal (also known as stem) cells (MSC), which are engineered to express two potent immune-modulatory cytokines, IL12 and IL21. Intraperitoneal administration of SENTI-101 results in selective tumor-homing and localized and sustained cytokine production in murine models of peritoneal cancer. SENTI-101 has extended half-life, reduced systemic distribution, and improved antitumor activity when compared with recombinant cytokines, suggesting that it is more effective and has lower risk of systemic immunotoxicities. Treatment of tumor-bearing immune-competent mice with a murine surrogate of SENTI-101 (mSENTI-101) results in a potent and localized immune response consistent with increased number and activation of antigen presenting cells, T cells and B cells, which leads to antitumor response and memory-induced long-term immunity. Consistent with this mechanism of action, co-administration of mSENTI-101 with checkpoint inhibitors leads to synergistic improvement in antitumor response. Collectively, these data warrant potential clinical development of SENTI-101 for patients with peritoneal carcinomatosis and high-grade ovarian cancer.Graphical abstract: SENTI-101 schematic and mechanism of actionSENTI-101 is a novel cell-based immunotherapeutic consisting of bone marrow-derived mesenchymal stromal cells (BM-MSC) engineered to express IL12 and IL21 intended for the treatment of peritoneal carcinomatosis including high-grade serous ovarian cancer. Upon intraperitoneal administration, SENTI-101 homes to peritoneal solid tumors and secretes IL12 and IL21 in a localized and sustained fashion. The expression of these two potent cytokines drives tumor infiltration and engagement of multiple components of the immune system: antigen-presenting cells, T cells, and B cells, resulting in durable antitumor immunity in preclinical models of cancer.

Abstract 4246: SENTI-101, a novel genetically modified allogeneic cell product expressing IL12 and IL21, elicits a tumor-localized, robust, and multimodal immune response in preclinical models of solid tumors

While immunotherapies based on single recombinant cytokines such as IL12 and IL21 have shown great promise in preclinical models of solid tumors, clinical translation has proven challenging due to limited mechanisms of action, narrow therapeutic windows upon systemic administration, and short half-lives resulting in poor pharmacokinetics and distribution. Thus, there is a need for tumor-localized cytokine therapies capable of driving sustained efficacy with a wide therapeutic window.

SENTI-101 is a cell-based immunotherapy comprising allogeneic bone marrow-derived mesenchymal stromal cells (BM-MSCs) genetically modified to express IL12 and IL21. Consistent with prior studies, we demonstrated that SENTI-101 innately homes to disseminated tumors in the peritoneal cavity and induces durable anti-tumor responses and immune memory in various preclinical models of peritoneal tumors.

In this study, we investigated the mechanisms of action of SENTI-101. Our results demonstrate that the IL12 and IL21 combination elicits pleiotropic and complementary effects that drive a multi-modal immune response across various steps of the cancer immunity cycle.

Treatment of preclinical murine models of peritoneal tumors (e.g., CT26 and B16F10) with SENTI-101 significantly increased the local production of IFNg by more than 40-fold (p&lt;0.02). Concurrently, mice treated with SENTI-101 had significantly increased levels of cytokines and chemokines such as CXCL9 (p&lt;0.02), which have previously been associated with better prognosis and response to immunotherapy in multiple cancer types. We used flow cytometry and multiplexed IHC to characterize the immune landscape in response to SENTI-101. The number of antigen-presenting cells (F4/80negCD11c+MHC-II+CD103+) more than doubled in peritoneal lymph nodes 72 h after treatment with SENTI-101 (p=0.016). We also observed an increase in pSTAT1 positivity in the myeloid compartment, indicating a favorable immune phenotype. This change was accompanied by an increase in T-cell infiltrates into tumors (p=0.0003) that were in close proximity with B-cells and that were organized in tertiary lymphoid structures, which are known to correlate with improved prognosis in cancer patients. T-cell activation markers (CD38, CD25, IFNg, GranzymeB) also increased by more than 6 times (p=0.015) in the tumor microenvironment (TME) and peritoneal fluid after treatment with SENTI-101. In accordance with increased T-cell infiltration and activation in the TME, SENTI-101 showed a synergistic anti-tumor effect when combined with checkpoint inhibitor anti-PD1.

Overall, our preclinical studies show that SENTI-101 modulates the tumor immune landscape via multiple complementary modes of action, resulting in long-term anti-tumor immunity. Furthermore, this work demonstrates the therapeutic potential of tumor-localized cell therapies armed with gene circuits expressing combinatorial immune effectors to trigger a multi-factorial anti-tumor response.

Citation Format: Alba Gonzalez, Frances D. Liu, Archana Nagaraja, Alyssa Mullenix, Russell M. Gordley, Daniel O. Frimannsson, Anissa Benabbas, Chen-Ting Lee, Tiffany A. Truong, Allison Quach, Mengxi Tian, Rowena Martinez, Rishi Savur, Alyssa Perry-McNamara, Don-Hong Wang, Ori Maller, Dharini Iyer, Ashita Magal, Sravani Mangalampalli, Christina J. Huynh, Carmina C. Blanco, Jack T. Lin, Brian S. Garrison, Philip Lee, Timothy K. Lu, Gary Lee. SENTI-101, a novel genetically modified allogeneic cell product expressing IL12 and IL21, elicits a tumor-localized, robust, and multimodal immune response in preclinical models of solid tumors [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4246.

Improving hematopoietic recovery through modeling and modulation of the mesenchymal stromal cell secretome

BACKGROUND

Efficient and sustained hematopoietic recovery after hematopoietic stem cell or bone marrow transplantation is supported by paracrine signaling from specific subpopulations of mesenchymal stromal cells (MSCs). Here, we considered whether in vitro mechanopriming of human MSCs could be administered to predictively and significantly improve in vivo hematopoietic recovery after irradiation injury.

METHODS

First, we implemented regression modeling to identify eight MSC-secreted proteins that correlated strongly with improved rescue from radiation damage, including hematopoietic recovery, in a murine model of hematopoietic failure. Using these partial least squares regression (PLSR) model parameters, we then predicted recovery potential of MSC populations that were culture expanded on substrata of varying mechanical stiffness. Lastly, we experimentally validated these predictions using an in vitro co-culture model of hematopoiesis and using new in vivo experiments for the same irradiation injury model used to generate survival predictions.

RESULTS

MSCs grown on the least stiff (elastic moduli ~ 1 kPa) of these polydimethylsiloxane (PDMS) substrata secreted high concentrations of key proteins identified in regression modeling, at concentrations comparable to those secreted by minor subpopulations of MSCs shown previously to be effective in supporting such radiation rescue. We confirmed that these MSCs expanded on PDMS could promote hematopoiesis in an in vitro co-culture model with hematopoietic stem and progenitor cells (HSPCs). Further, MSCs cultured on PDMS of highest stiffness (elastic moduli ~ 100 kPa) promoted expression of CD123+ HSPCs, indicative of myeloid differentiation. Systemic administration of mechanoprimed MSCs resulted in improved mouse survival and weight recovery after bone marrow ablation, as compared with both standard MSC expansion on stiffer materials and with biophysically sorted MSC subpopulations. Additionally, we observed recovery of white blood cells, platelets, and red blood cells, indicative of complete recovery of all hematopoietic lineages.

CONCLUSIONS

These results demonstrate that computational techniques to identify MSC biomarkers can be leveraged to predict and engineer therapeutically effective MSC phenotypes defined by mechanoprimed secreted factors, for translational applications including hematopoietic recovery.

Static mechanical strain induces capillary endothelial cell cycle re-entry and sprouting

Vascular endothelial cells are known to respond to a range of biochemical and time-varying mechanical cues that can promote blood vessel sprouting termed angiogenesis. It is less understood how these cells respond to sustained (i.e., static) mechanical cues such as the deformation generated by other contractile vascular cells, cues which can change with age and disease state. Here we demonstrate that static tensile strain of 10%, consistent with that exerted by contractile microvascular pericytes, can directly and rapidly induce cell cycle re-entry in growth-arrested microvascular endothelial cell monolayers. S-phase entry in response to this strain correlates with absence of nuclear p27, a cyclin-dependent kinase inhibitor. Furthermore, this modest strain promotes sprouting of endothelial cells, suggesting a novel mechanical 'angiogenic switch'. These findings suggest that static tensile strain can directly stimulate pathological angiogenesis, implying that pericyte absence or death is not necessarily required of endothelial cell re-activation.

Fluconazole susceptibility of 3,056 clinical isolates of Candida species from 2005 to 2009 in a tertiary-care hospital

In recent years, Candida infections have been increasing significantly. This study was to investigate the distribution and fluconazole susceptibility of such infections. Totally, 3,056 clinical isolates were analysed, C. albicans was the most prevalent species from respiratory and vaginal specimens. However, non-albicans species constituted the majority of isolates from blood, urine, intensive care unit (ICU), organ transplant and burned patients. Similarly, Candida spp. from different specimens and clinical services had different degrees of susceptibility to fluconazole. Isolates from vagina and burned patients had the highest resistance rate, while all of the isolates from ascites and dermatological services were susceptible to fluconazole.

Chemical transformations of nanosilver in biological environments

The widespread use of silver nanoparticles (Ag-NPs) in consumer and medical products provides strong motivation for a careful assessment of their environmental and human health risks. Recent studies have shown that Ag-NPs released to the natural environment undergo profound chemical transformations that can affect silver bioavailability, toxicity, and risk. Less is known about Ag-NP chemical transformations in biological systems, though the medical literature clearly reports that chronic silver ingestion produces argyrial deposits consisting of silver-, sulfur-, and selenium-containing particulate phases. Here we show that Ag-NPs undergo a rich set of biochemical transformations, including accelerated oxidative dissolution in gastric acid, thiol binding and exchange, photoreduction of thiol- or protein-bound silver to secondary zerovalent Ag-NPs, and rapid reactions between silver surfaces and reduced selenium species. Selenide is also observed to rapidly exchange with sulfide in preformed Ag(2)S solid phases. The combined results allow us to propose a conceptual model for Ag-NP transformation pathways in the human body. In this model, argyrial silver deposits are not translocated engineered Ag-NPs, but rather secondary particles formed by partial dissolution in the GI tract followed by ion uptake, systemic circulation as organo-Ag complexes, and immobilization as zerovalent Ag-NPs by photoreduction in light-affected skin regions. The secondary Ag-NPs then undergo detoxifying transformations into sulfides and further into selenides or Se/S mixed phases through exchange reactions. The formation of secondary particles in biological environments implies that Ag-NPs are not only a product of industrial nanotechnology but also have long been present in the human body following exposure to more traditional chemical forms of silver.

Histology of Kashin-Beck lesions

There are few papers in existence describing the histopathology of Kashin-Beck disease. The few existing papers mention chondronecrosis within the epiphyseal primodium and metaphyseal cartilage. In the present study, two series of samples were available for histology: supernumerary fingers removed from young subjects and intra-articular bodies collected in more advanced cases of the disease. The prevailing characteristic of the samples is the absence of vascularisation within the proximal cartilage end plate of the phalanx associated with an alteration of the epiphyseal bone formation. These observations suggest that Kashin-Beck disease could develop from an alteration of the angiogenesis of the metaphyseal cartilage resulting in degeneration with consequent joint dysplasia, which may be associated with a decrease in growth of the diaphyseal bones.

Osteotomy at the knee for advanced cases of Kashin-Beck disease

The results of 247 osteotomies at the knee were analysed in 195 patients with Kashin-Beck disease. Since 1983, 37 varus and 210 valgus deformities have been operated on. Supracondylar osteotomy was carried out so that there is a cortical spike in the distal metaphysis which is impacted into the femoral condyle. A U-shaped tibial osteotomy is made 0.5 cm below the growth plate and around the insertion of the patellar ligament. The mechanical axis is corrected and stability obtained by impacting the fragments; internal fixation is not used. Correction of the initial angular deformities was achieved after the osteotomies, and function was improved.