The effects of necrostatin-1 on the in vitro development and function of young porcine islets over 14-day prolonged tissue culture.

BACKGROUND: Necrostatin-1 (Nec-1) supplementation to tissue culture media on day 3 has recently been shown to augment the insulin content, endocrine cellular composition, and insulin release of pre-weaned porcine islets (PPIs); however, its effects were only examined for the first 7 days of tissue culture. The present study examined whether the addition of Nec-1 on day 3 could further enhance the in vitro development and function of PPIs after 14 days of tissue culture. METHODS: PPIs were isolated from 8- to 15-day-old, pre-weaned Yorkshire piglets and cultured in an islet maturation media supplemented with Nec-1 on day 3. The recovery, viability, insulin content, endocrine cellular composition, GLUT2 expression in beta cells, differentiation and proliferation potential, and glucose-stimulated insulin secretion of PPIs were assessed on days 3, 7, and 14 of tissue culture (n = 5 on each day). RESULTS: Compared with day 7 of tissue culture, islets on day 14 had a lower recovery, GLUT2 expression in beta cells, proliferation capacity of endocrine cells, and glucose-induced insulin stimulation index. Prolonging the culture time to 14 days did not affect islet viability, insulin content, proportion of endocrine cells, and differentiation potential. CONCLUSION: The growth-inducing effects of Nec-1 on PPIs were most effective on day 7 of tissue culture when added on day 3. Our findings support existing evidence that the in vitro activities of Nec-1 are short-lived and encourage future studies to explore the use of other novel growth factors during prolonged islet tissue culture.

Necrostatin-1 Supplementation to Islet Tissue Culture Enhances the In-Vitro Development and Graft Function of Young Porcine Islets.

Pre-weaned porcine islets (PPIs) represent an unlimited source for islet transplantation but are functionally immature. We previously showed that necrostatin-1 (Nec-1) immediately after islet isolation enhanced the in vitro development of PPIs. Here, we examined the impact of Nec-1 on the in vivo function of PPIs after transplantation in diabetic mice. PPIs were isolated from pancreata of 8-15-day-old, pre-weaned pigs and cultured in media alone, or supplemented with Nec-1 (100 µM) on day 0 or on day 3 of culture (n = 5 for each group). On day 7, islet recovery, viability, oxygen consumption rate, insulin content, cellular composition, insulin secretion capacity, and transplant outcomes were evaluated. While islet viability and oxygen consumption rate remained high throughout 7-day tissue culture, Nec-1 supplementation on day 3 significantly improved islet recovery, insulin content, endocrine composition, GLUT2 expression, differentiation potential, proliferation capacity of endocrine cells, and insulin secretion. Adding Nec-1 on day 3 of tissue culture enhanced the islet recovery, proportion of delta cells, beta-cell differentiation and proliferation, and stimulation index. In vivo, this leads to shorter times to normoglycemia, better glycemic control, and higher circulating insulin. Our findings identify the novel time-dependent effects of Nec-1 supplementation on porcine islet quantity and quality prior to transplantation.

Exploring Insulin Production Following Alveolar Islet Transplantation (AIT).

Recent studies have demonstrated the feasibility of islet implantation into the alveoli. However, until today, there are no data on islet behavior and morphology at their transplant site. This study is the first to investigate islet distribution as well insulin production at the implant site. Using an ex vivo postmortem swine model, porcine pancreatic islets were isolated and aerosolized into the lung using an endoscopic spray-catheter. Lung tissue was explanted and bronchial airways were surgically isolated and connected to a perfusor. Correct implantation was confirmed via histology. The purpose of using this new lung perfusion model was to measure static as well as dynamic insulin excretions following glucose stimulation. Alveolar islet implantation was confirmed after aerosolization. Over 82% of islets were correctly implanted into the intra-alveolar space. The medium contact area to the alveolar surface was estimated at 60 +/- 3% of the total islet surface. The new constructed lung perfusion model was technically feasible. Following static glucose stimulation, insulin secretion was detected, and dynamic glucose stimulation revealed a biphasic insulin secretion capacity during perfusion. Our data indicate that islets secrete insulin following implantation into the alveoli and display an adapted response to dynamic changes in glucose. These preliminary results are encouraging and mark a first step toward endoscopically assisted islet implantation in the lung.

Failure in initial stage containment of global COVID-19 epicenters.

With multiple virus epicenters, COVID-19 has been declared a pandemic by the World Health Organization. Consequently, many countries have implemented different policies to manage this crisis including curfew and lockdown. However, the efficacy of individual policies remains unclear with respect to COVID-19 case development. We analyzed available data on COVID-19 cases of eight majorly affected countries, including China, Italy, Iran, Germany, France, Spain, South Korea, and Japan. Growth rates and doubling time of cases were calculated for the first 6 weeks after the initial cases were declared for each respective country and put into context with implemented policies. Although the growth rate of total confirmed COVID-19 cases in China has decreased, those for Japan have remained constant. For European countries, the growth rate of COVID-19 cases considerably increased during the second time interval. Interestingly, the rates for Germany, Spain, and France are the highest measured in the second interval and even surpass the numbers in Italy. Although the initial data in Asian countries are encouraging with respect to case development at the initial stage, the opposite is true for European countries. Based on our data, disease management in the 2 weeks following the first reported cases is of utmost importance.

Necrostatin-1 supplementation enhances young porcine islet maturation and in vitro function.

BACKGROUND: Necroptosis has been demonstrated to be a primary mechanism of islet cell death. This study evaluated whether the supplementation of necrostatin-1 (Nec-1), a potent inhibitor of necroptosis, to islet culture media could improve the recovery, maturation, and function of pre-weaned porcine islets (PPIs). METHODS: PPIs were isolated from pre-weaned Yorkshire piglets (8-15 days old) and either cultured in control islet culture media (n = 6) or supplemented with Nec-1 (100 µM, n = 5). On days 3 and 7 of culture, islets were assessed for recovery, insulin content, viability, cellular composition, GLUT2 expression in beta cells, differentiation of pancreatic endocrine progenitor cells, function, and oxygen consumption rate. RESULTS: Nec-1 supplementation induced a 2-fold increase in the insulin content of PPIs on day 7 of culture. When compared to untreated islets, Nec-1 treatment doubled the beta- and alpha-cell composition and accelerated the development of delta cells. Additionally, beta cells of Nec-1-treated islets had a significant upregulation in GLUT2 expression. The enhanced development of major endocrine cells and GLUT2 expression after Nec-1 treatment subsequently led to a significant increase in the amount of insulin secreted in response to in vitro glucose challenge. Islet recovery, viability, and oxygen consumption rate were unaffected by Nec-1. CONCLUSION: This study underlines the importance of necroptosis in islet cell death after isolation and demonstrates the novel effects of Nec-1 to increase islet insulin content, enhance pancreatic endocrine cell development, facilitate GLUT2 upregulation in beta cells, and augment insulin secretion. Nec-1 supplementation to culture media significantly improves islet quality prior to xenotransplantation.

Characterization of chelator-mediated recovery of pancreatic islets from barium-stabilized alginate microcapsules.

INTRODUCTION: Islet recovery from within alginate-based microcapsules is necessary for certain analytical assays like flow cytometry; however, this technology has not been widely characterized. In this study, we explore the ability of EDTA, EGTA, and sodium citrate to induce reverse alginate polymerization via chelation and assess the toxicity of each chelator on pancreatic islets. METHODS: EDTA, EGTA, and sodium citrate were used to dissolve single-layered Ba2+ alginate encapsulated islets and the rate of capsule breakdown calculated from analysis of imaging data. The effect of chelator exposure on islet viability and recovery was assessed using flow cytometry, while glucose-stimulated insulin release (GSIR) assay was used to measure effects on islet function. RESULTS: EGTA demonstrated the most rapid microcapsule dissolving rate followed by EDTA and sodium citrate. Islet recovery was significantly better when encapsulated islets were treated with EDTA than EGTA and Na+ citrate. A decrease in viability and increase in apoptotic cells were observed when encapsulated islets were treated with Na+ citrate compared to islets treated with EDTA and EGTA. Islets treated with EDTA and EGTA demonstrated comparable stimulation index values to non-treated control. Conversely, islets treated with Na+ citrate exhibited significantly decreased SI values compared to control. All chelator groups showed significantly lower insulin secretion than non-treated islets. CONCLUSION: Islet recovery from alginate microcapsule is possible using common chelators like Na+ citrate, EDTA, and EGTA. Chelation of encapsulated islets using EDTA demonstrated the most efficient dissolving capabilities with the least toxicity toward islet recovery and health.

The Role of the Nrf2 Signaling in Obesity and Insulin Resistance.

Obesity, a metabolic disorder characterized by excessive accumulation of adipose tissue, has globally become an increasingly prevalent disease. Extensive studies have been conducted to elucidate the underlying mechanism of the development of obesity. In particular, the close association of inflammation and oxidative stress with obesity has become increasingly evident. Obesity has been shown to exhibit augmented levels of circulating proinflammatory cytokines, which have been associated with the activation of pathways linked with inflammation-induced insulin resistance, a major pathological component of obesity and several other metabolic disorders. Oxidative stress, in addition to its role in stimulating adipose differentiation, which directly triggers obesity, is considered to feed into this pathway, further aggravating insulin resistance. Nuclear factor E2 related factor 2 (Nrf2) is a basic leucine zipper transcription factor that is activated in response to inflammation and oxidative stress, and responds by increasing antioxidant transcription levels. Therefore, Nrf2 has emerged as a critical new target for combating insulin resistance and subsequently, obesity. However, the effects of Nrf2 on insulin resistance and obesity are controversial. This review focuses on the current state of research on the interplay of inflammation and oxidative stress in obesity, the role of the Nrf2 pathway in obesity and insulin resistance, and the potential use of Nrf2 activators for the treatment of insulin resistance.

Micro/nanobubbles: Improving Pancreatic Islet Cell Survival for Transplantation.

PURPOSE: The preservation of transplantable tissue is directly tied to and limited by the ischemia time. Micro/nanobubbles (MNBs) are miniature gaseous voids that allow for the oxygenation of tissue given their high oxygen-carrying capacity. One of the current limitations of islet cell transplantation for type 1 diabetes is poor islet survival, caused by hypoxia, after harvesting the cells from pancreata. As such, the purpose of this study was to elucidate whether MNBs, when added to standard culture medium, improve islet cell survival postharvest. MATERIALS AND METHODS: Islet cells were harvested from Sprague-Dawley rat pancreas tissue via a standard collagenase digestion and gradient purification. To create the MNB solution, a shear-based generation system was used to produce both air- and oxygen-filled MNBs in standard Connaught Medical Research Laboratories (CMRL) medium. Four groups, consisting of 500 islet equivalents, were cultured with either the standard CMRL medium, macrobubble-CMRL, MNB (air)-CMRL, or MNB (O2)-CMRL, and they were incubated at 37°C. Each treatment solution was replenished 24 hours postincubation, and after 48 hours of culture, dithizone staining was used to determine the islet cell counts, and the viability was assessed using Calcein AM/propidium iodide staining. RESULTS: Islet cells that were preserved in macrobubble-CMRL, MNB (air)-CMRL, and MNB (O2)-CMRL conditions showed an increased survival compared with those cultured with standard CMRL. The islet cells cultured in the MNB (air)-CMRL condition demonstrated the greatest cell survival compared with all other groups, including the pure oxygen-carrying MNBs. None of the MNB treatments significantly altered the viability of the islet cells compared to the control condition. CONCLUSIONS: The addition of MNBs to culture medium offers an innovative approach for the oxygenation of transplantable tissue, such as islet cells. This study demonstrated that MNBs filled with air provided the most optimal addition to the islet cell culture medium for improving islet cell survival amongst the treatment groups we tested. Given these findings, we hypothesize that MNBs may also improve the oxygenation and survival of a variety of other tissues, including fat grafts from lipoaspirate, chronic wounds, and solid organs.

Effects of Periodic Intensive Insulin Therapy: An Updated Review.

BACKGROUND: Traditional insulin treatment for diabetes mellitus with insulin administered subcutaneously yields nonpulsatile plasma insulin concentrations that represent a fraction of normal portal vein levels. Oral hypoglycemic medications result in the same lack of pulsatile insulin response to blood glucose levels. Intensive treatments of significant complications of diabetes are not recommended due to complicated multidrug regimens, significant weight gain, and the high risk of hypoglycemic complications. Consequently, advanced complications of diabetes do not have an effective treatment option because conventional therapy is not sufficient. Intensive insulin therapy (IIT) simulates normal pancreatic function by closely matching the periodicity and amplitude of insulin secretion in healthy subjects; however, the mechanisms involved with the observed improvement are not clearly understood. OBJECTIVE: The current review aims to analyze the pathophysiology of insulin secretion, discuss current therapies for the management of diabetes, provides an updates on the recent advancements of IIT, and proposes its mechanism of action. METHODS: A literature search on PubMed, MEDLINE, Embase, and CrossRef databases was performed on multiple key words regarding the history and current variations of pulsatile and IIT for diabetes treatment. Articles reporting the physiology of insulin secretion, advantages of pulsatile insulin delivery in patients with diabetes patients, efficacy and adverse effects of current conventional insulin therapies for the management of diabetes, benefits and shortcomings of pancreas and islet transplantation, or clinical trials on patients with diabetes treated with pulsed insulin therapy or advanced IIT were included for a qualitative analysis and categorized into the following topics: mechanism of insulin secretion in normal subjects and patients with diabetes and current therapies for the management of diabetes, including oral hypoglycemic agents, insulin therapy, pancreas and islet transplantation, pulsed insulin therapy, and advances in IIT. RESULTS: Our review of the literature shows that IIT improves the resolution of diabetic ulcers, neuropathy, and nephropathy, and reduces emergency room visits. The likely mechanism responsible for this improvement is increased insulin sensitivity from adipocytes, as well as increased insulin receptor expression. CONCLUSIONS: Recent advancements show that IIT is an effective option for both type 1 diabetes mellitus and type 2 diabetes mellitus patient populations. This treatment resembles normal pancreatic function so closely that it has significantly reduced the effects of relatively common complications of diabetes in comparison to standard treatments. Thus, this new treatment is a promising advancement in the management of diabetes. (Curr Ther Res Clin Exp. 2019; 80:XXX-XXX).

Triple-Therapy of Peritoneal Metastasis-Partial-Dehydration under Hyperthermic Condition Combined with Chemotherapy: The First Preliminary In-Vitro Results.

A newly introduced combination of intraperitoneal dehydration and hyperthermia has recently been shown to be feasible and cytotoxic for colon cancer cells in vivo. For the first time, our study now aims to evaluate dehydration under hyperthermic conditions combined with chemotherapy for potential use in the clinical setting. In this study, in vitro colon cancer cells (HT-29) were subjected to single or several cycles of partial dehydration under hyperthermic conditions (45 °C), followed by chemotherapy (triple exposure) with oxaliplatin or doxorubicin in various configurations. The viability, cytotoxicity, and proliferation of cells after the proposed protocols were assessed. Intracellular doxorubicin uptake was measured via flow cytometry. After one cycle of triple exposure, the viability of HT-29 cells was significantly reduced versus the untreated control (65.11 ± 5%, p < 0.0001) and versus only chemotherapy (61.2 ± 7%, p < 0.0001). An increased chemotherapeutic inflow into the cells after triple exposure was detected (53.4 ± 11%) when compared to cells treated with chemotherapy alone (34.23 ± 10%) (p < 0.001). Partial dehydration in a hyperthermic condition combined with chemotherapy increases the overall cytotoxicity of colon cancer cells significantly compared to chemotherapy alone. This could possibly be related to enhanced intracellular uptake of chemotherapeutic agents after partial dehydration. Further studies are required for the further evaluation of this new concept.

Intraoperative parameters and postoperative follow-up of foam-based intraperitoneal chemotherapy (FBIC).

Background: For decades, intraperitoneal chemotherapy (IPC) has been delivered into the abdominal cavity as a liquid solution. Recently the concept of foam as a carrier-solution for IPC was suggested. This in-vivo swine study aims to evaluate the safety, intraoperative parameters, limitations and postoperative complications of foam-based intraperitoneal chemotherapy (FBIC). Methods: Three 65-day-old swine received FBIC with doxorubicin in a laparoscopy setting. Intraoperative parameters were monitored throughout the procedure and an extensive postoperative laboratory monitoring was conducted for 7 days. At day seven an autopsy was performed for further evaluation. Results: The insufflation of FBIC caused a temporary rise in blood pressure and a simultaneous drop in heart rate. Capnography detected a continuous increase in end-tital CO2 levels. A temporary drop of intraabdominal temperature was noted. Postoperative blood and serum laboratory results did not indicate any organ failure. No indication of intraperitoneal infections was noted and no structural tissue changes were visible in the autopsy. Discussion: The application of FBIC appears to be a feasible approach regarding intraoperative anesthesiology and postoperative surgical management. A lack of postoperative structural changes on the seventh day were a promising sign of safety and biocompatibility. Surgical reintervention would have been possible. To discuss a possible clinical application, further studies are required to investigate long-term safety, pharmacodynamics and the antitumoral potential of FBIC.

Drug Distribution and Penetration of Foam-Based Intraperitoneal Chemotherapy (FBIC).

For decades, intraperitoneal chemotherapy (IPC) was used as a liquid solution for the treatment of peritoneal metastasis. Due to its advantageous physical properties, foam-based intraperitoneal chemotherapy (FBIC) was recently proposed as a treatment for peritoneal metastasis. For the first time, this study intends to examine the feasibility, expansion, drug distribution, and penetration of FBIC in vivo. Three swine received contrast-enhanced FBIC doxorubicin delivered using a bicarbonate carrier system. During the procedure, intraoperative blood analyses and periumbilical diameter, as well as foam distribution, penetration, and expansion of the FBIC were analyzed. The swine received an abdominal CT scan to evaluate the contrast distribution. Furthermore, a hematoxylin-eosin (HE) staining of peritoneal samples was performed, and fluorescence microscopy was conducted. FBIC was performed without complications. The periumbilical diameter peaked after 5 min and then decreased. Blood analyses showed changes in blood parameters, with a reduction in the pH levels of serum calcium and potassium. CT scan detected contrast-enhanced FBIC throughout the abdominal cavity. Fluorescence microscopy confirmed that all areas were exposed to doxorubicin and no pathologies were detected in the HE histology. Our preliminary results are quite encouraging and indicate that FBIC is a feasible approach. However, in order to discuss possible clinical applications, further studies are required to investigate the pharmacologic, pharmacodynamic, and physical properties of FBIC.

First In Vivo Applicational Data of Foam-Based Intrathoracic Chemotherapy (FBiTC) in a Swine Model.

BACKGROUND: For decades, both intraperitoneal and pleural chemotherapy (IPC) have been delivered as a liquid solution. Recent studies suggest that foam carriers outperform liquid carriers for locoregional chemotherapy. For the first time, this study aims to evaluate the feasibility, safety, and characteristics of foam-based intrathoracic chemotherapy (FBiTC) in an in vivo setting. METHODS: In this study, contrast-enhanced FBiTC with doxorubicin was delivered via video-assisted thoracoscopy (VAT) in three swine under general anesthesia. Intraoperative and postoperative parameters, blood analyses, vital signs, and anesthesiologic data were collected. Additionally, an intraoperative computer tomography (CT) scan was performed, and histological tissue sections were collected and further analyzed using fluorescence microscopy. RESULTS: FBiTC was delivered without major complications. End-tidal capnometry detected increased CO2 levels with reduced peripheral oxygen saturation and increased blood pressure and heart rate. No major intra- or postoperative complications were observed. CT scans confirmed a multidirectional distribution pattern of foam. Postoperative laboratory workup did not reveal any critical changes in hemoglobin, white blood count, or platelets. There was no evidence of critical kidney impairment or liver function. Fluorescence microscopy of tissue specimen detected doxorubicin in pleural tissues. DISCUSSION: Our preliminary results are encouraging and indicate that FBiTC is feasible. However, to consider a possible clinical application, further studies are required to investigate the pharmacologic, pharmacodynamic, and physical properties of FBiTC and to ensure the safety of the overall procedure regarding oxygenation levels and capnography parameters.

Exploring the potential of taurolidine in inducing mobilization and detachment of colon cancer cells: a preliminary in-vitro study.

BACKGROUND: Recently, taurolidine has been intensively studied on a variety of in-vitro cancer cell-lines and first data exhibit encouraging antitumoral effects. While the clinical use of taurolidine is considered, some studies with in-vivo experiments contradict this beneficial effect and even indicate advanced cancer growth. The aim of this study is to further investigate this paradox in-vivo effect by taurolidine and closely analyze the interaction of cancer cells with the surrounding environment following taurolidine exposure. METHODS: HT-29 (ATCC® HTB-38™) cells were treated with taurolidine at different concentrations and oxaliplatin using an in-vitro model. Morphological changes with respect to increasing taurolidine dosage were visualized and monitored using electron microscopy. Cytotoxicity of the agents as well as extent of cellular detachment by mechanical stress was measured for each substance using a colorimetric MTS assay. RESULTS: Both taurolidine and oxaliplatin exhibit cell toxicity on colon cancer cells. Taurolidine reshapes colon cancer cells from round into spheric cells and further induces cluster formation. When exposed to mechanical stress, taurolidine significantly enhances detachment of adherent colon carcinoma cells compared to the control (p < 0.05) and the oxaliplatin group (p < 0.05). This effect is dose dependent. CONCLUSIONS: Beside its cytotoxic effects, taurolidine could also change mechanical interactions of cancer cells with their environment. Local cancer cell conglomerates could be mechanically mobilized and may cause metastatic growth further downstream. The significance of changes in cellular morphology caused by taurolidine as well as its interaction with the microenvironment must be further addressed in clinical cancer therapies. Further clinical studies are needed to evaluate both the safety and efficacy of taurolidine for the treatment of peritoneal surface malignancies.

The Onset of In-Vivo Dehydration in Gas -Based Intraperitoneal Hyperthermia and Its Cytotoxic Effects on Colon Cancer Cells.

Background: Peritoneal metastasis (PM) is an ongoing challenge in surgical oncology. Current therapeutic options, including intravenous and intraperitoneal (i.p.) chemotherapies display limited clinical efficacy, resulting in an overall poor prognosis in affected patients. Combined hyperthermia and dehydration induced by a high-flow, gas-based i.p. hyperthermic procedure could be a novel approach in PM treatment. Our study is the first to evaluate the therapeutic potential of i.p. dehydration, hyperthermia, as well as the combination of both mechanisms in an in-vivo setting. Methods: For this study, three swine were subjected to diagnostic laparoscopy under a high-flow air stream at 48°, 49° and 50°Celsius (C). Hygrometry of the in- and outflow airstream was measured to calculate surface evaporation and i.p. dehydration. To analyze the effects of this concept, in vitro colon cancer cells (HT-29) were treated with hyperthermia and dehydration. Cytotoxicity and cell viability were measured at different time intervals. Additionally, structural changes of dehydrated cells were analyzed using scanning electron microscopy. Results: According to our results, both dehydration and hyperthermia were cytotoxic to HT-29 cells. However, while dehydration reduced cell viability, hyperthermia did not. However, dehydration effects on cell viability were significantly increased when combined with hyperthermia (p<0.01). Conclusions: Changes to the physiological milieu of the peritoneal cavity could significantly reduce PM. Therefore, limited dehydration of the abdominal cavity might be a feasible, additional tool in PM treatment. Further studies are required to investigate dehydration effects and their applicability in PM management.

In-vivo thermodynamic exploration of gas-based intraperitoneal hyperthermia.

Background: While hyperthermic intraperitoneal (i.p) applications are highly efficient in treating peritoneal metastases (PM), they are currently limited to temperatures of 41 - 43° Celsius (C). First data on gas-based i.p. hyperthermia is promising, as this novel method allows a significant temperature rise in superficial peritoneal layers without increasing core temperatures. Until now, key mechanisms of this novel tool, e.g. thermodynamic energy transfer, have not been investigated. This study aims to explore the volume of thermodynamic energy transfer during gas-based i.p. hyperthermia at 48-50°C and its peritoneal effects. Methods: For this study, three swine were subjected to gas-based i.p. hyperthermia at varying temperatures (48°, 49° and 50°C) in a diagnostic laparoscopy setting with a high-flow air stream. Temperatures of the i.p. cavity, in- and outflow airstream at the trocar were measured and the thermodynamic energy transfer was calculated. Tissue samples were collected on postoperative day 7 for histopathologic analyses. Results: According to our data, temperatures within the intraabdominal cavity and at the outflow site remain relatively stable at < 40°C. An increase in thermodynamic energy transfer is observed with increasing applied temperatures. Gas-based i.p. hyperthermia induced capillary coagulation and white blood cell infiltration within peritoneal layers. Conclusions: Gas-based i.p. hyperthermia is an innovative approach which enables the i.p. delivery of specific amounts of thermodynamic energy. Following this procedure, our data indicate remarkable histologic changes on the superficial peritoneal layer most likely attributable to the applied thermodynamic energy. Further studies are required to investigate how these findings can be applied in PM management.

Evaluating the concept of gas­based intraperitoneal hyperthermia beyond 43˚C in the treatment of peritoneal metastasis: A pilot study.

While hyperthermic intraperitoneal applications have demonstrated high efficacy in treating peritoneal metastases (PM), these applications are limited to temperatures of 41-43˚C to prevent a harmful increase in core temperature. However, since gaseous substances display low specific heat capacities, gas-based hyperthermia could potentially increase surface temperatures without affecting the body's core temperature. To the best of our knowledge, the present study is the first to explore the in vivo feasibility of gas-based hyperthermia via spatial and time-based distribution. In the present study, a temperature-isolated, abdominal box model was created with fresh peritoneal tissue exposed to continuous high-volume airflow temperatures ranging between 47 and 69˚C. Heat conduction within the peritoneal tissues was measured using temperature microsensors. Temperature build-up at different time points during the procedure was calculated and the safest option to perform gas-based intraperitoneal hyperthermia beyond 43˚C was identified using an in vivo swine model. In subsequent experiments, viability and cytotoxicity of HT-29 colon cancer cells were measured following short-term hyperthermia. The present study demonstrated that the application of gas-based intraperitoneal hyperthermia with temperatures up to 50˚C is possible without increasing the core temperature to harmful levels. Gas-based intraperitoneal hyperthermia can induce a histological reaction on the peritoneal surface, and it can also result in decreased viability and increased cytotoxicity of HT-29 cells. The concept of extreme hyperthermia may be of great clinical importance as it could significantly increase local cytotoxicity in PM without increasing the body's core temperature. Further studies are required to investigate the benefits, as well as the restrictions, of this novel concept.

Safety, feasibility, and application of intraperitoneal gas-based hyperthermia beyond 43°C in the treatment of peritoneal metastasis: An in-vivo pilot study.

Background: 43°Celsius (C) is currently the highest temperature used in the treatment of peritoneal metastasis (PM). Despite sufficient data on water- based hyperthermic solutions in PM treatment, there is currently no information on gas-based hyperthermia extending beyond 43°C. This study is the first to provide in-vivo data on different organ systems during and after intraperitoneal gas-based hyperthermia beyond 43°C. The aim of this study is to explore in-vivo feasibility, safety, and efficacy of this novel concept from a biological perspective. Methods: For this study, three swine were subjected to laparoscopy and subsequent gas-based intraperitoneal hyperthermia at 48°, 49° and 50°C under a high-flow air stream. Intraoperative data from multiple temperature sensors were analysed. Additionally, intraoperative anaesthesiologic and gasometrical data was analysed. Postoperatively, swine were monitored for one week and laboratory work-up was performed on postoperative days 1, 3 and 7. Results: During gas-based intraperitoneal hyperthermia, anesthesiologic parameters did not exhibit critical values. No intra- or postoperative complications were observed. Distinct temperature measurements on the skin, cystohepatic triangle and esophagus did not display any temperature increase. Postoperative laboratory workup did not show any changes in hemoglobin, white blood cell count, platelets, or kidney function. Discussion: Based on our data, there are no safety concerns for the application of gas-based hyperthermia between 48 - 50°C. In fact, no critical systemic temperature increase was observed. With respect to possible limitations, further in-vivo studies are required to evaluate whether gas-based intraperitoneal hyperthermia may be a therapeutic option for PM patients.

Intraoperative Near-Infrared Spectroscopy Monitoring of Renal Allograft Reperfusion in Kidney Transplant Recipients: A Feasibility and Proof-of-Concept Study.

Conventional renal function markers are unable to measure renal allograft perfusion intraoperatively, leading to delayed recognition of initial allograft function. A handheld near-infrared spectroscopy (NIRS) device that can provide real-time assessment of renal allograft perfusion by quantifying regional tissue oxygen saturation levels (rSO2) was approved by the FDA. This pilot study evaluated the feasibility of intraoperative NIRS monitoring of allograft reperfusion in renal transplant recipients (RTR). Intraoperative renal allograft rSO2 and perfusion rates were measured in living (LDRT, n = 3) and deceased donor RTR (DDRT, n = 4) during the first 50 min post-reperfusion and correlated with renal function markers 30 days post-transplantation. Intraoperative renal allograft rSO2 for the DDRT group remained significantly lower than the LDRT group throughout the 50 min. Reperfusion rates were significantly faster in the LDRT group during the first 5 min post-reperfusion but remained stable thereafter in both groups. Intraoperative rSO2 were similar among the upper pole, renal hilum, and lower pole, and strongly correlated with allograft function and hemodynamic parameters up to 14 days post-transplantation. NIRS successfully detected differences in intraoperative renal allograft rSO2, warranting future studies to evaluate it as an objective method to measure ischemic injury and perfusion for the optimization of preservation/reperfusion protocols and early prediction of allograft function.

Exosome loaded immunomodulatory biomaterials alleviate local immune response in immunocompetent diabetic mice post islet xenotransplantation.

Foreign body response (FBR) to biomaterials compromises the function of implants and leads to medical complications. Here, we report a hybrid alginate microcapsule (AlgXO) that attenuated the immune response after implantation, through releasing exosomes derived from human Umbilical Cord Mesenchymal Stem Cells (XOs). Upon release, XOs suppress the local immune microenvironment, where xenotransplantation of rat islets encapsulated in AlgXO led to >170 days euglycemia in immunocompetent mouse model of Type 1 Diabetes. In vitro analyses revealed that XOs suppressed the proliferation of CD3/CD28 activated splenocytes and CD3+ T cells. Comparing suppressive potency of XOs in purified CD3+ T cells versus splenocytes, we found XOs more profoundly suppressed T cells in the splenocytes co-culture, where a heterogenous cell population is present. XOs also suppressed CD3/CD28 activated human peripheral blood mononuclear cells (PBMCs) and reduced their cytokine secretion including IL-2, IL-6, IL-12p70, IL-22, and TNFα. We further demonstrate that XOs mechanism of action is likely mediated via myeloid cells and XOs suppress both murine and human macrophages partly by interfering with NFκB pathway. We propose that through controlled release of XOs, AlgXO provide a promising new platform that could alleviate the local immune response to implantable biomaterials.