Low-dose radiotherapy for COVID-19 pneumonia treatment: case report, procedure, and literature review.

BACKGROUND: The COVID-19 pandemic outbreak has set the emergency services in developing countries on major alert, as the installed response capacities are easily overwhelmed by the constantly increasing high demand. The deficit of intensive care unit beds and ventilators in countries like Peru is forcing practitioners to seek preventive or early interventional strategies to prevent saturating these chronically neglected facilities. CASE PRESENTATION: A 64-year-old patient is reported after presenting with COVID-19 pneumonia and rapidly progressing to deteriorated ventilatory function. Compassionate treatment with a single 1­Gy dose to the bilateral whole-lung volume was administered, with gradual daily improvement of ventilatory function and decrease in serum inflammatory markers and oxygen support needs, including intubation. No treatment-related toxicity developed. Procedures of transport, disinfection, and treatment planning and delivery are described. CONCLUSION: Whole-lung low-dose radiotherapy seems to be a promising approach for avoiding or delaying invasive respiratory support. Delivered low doses are far from meeting toxicity ranges. On-going prospective trials will elucidate the effectiveness of this approach.

Memory T Cells Mediate Cardiac Allograft Vasculopathy and are Inactivated by Anti-OX40L Monoclonal Antibody.

PURPOSE: Cardiac allograft vasculopathy (CAV) is a major complication limiting the long-term survival of cardiac transplants. The role of memory T cells (Tmem) in the pathogenesis of CAV remains elusive. This study investigated the role of Tmem cells in the development of CAV and the therapeutic potential of targeting the OX40/OX40L pathway for heart transplant survival. METHODS: Tmem cells were generated in Rag-1(-/-) C57BL/6 (B6) mice by homeostatic proliferation (HP) of CD40L null CD3(+) T cells from B6 mice. Rag-1(-/-) B6 mice (H-2(b)) harboring Tmem cells received cardiac allografts from BALB/c mice (H-2(d)), and were either untreated or treated with anti-OX40L monoclonal antibody (mAb) (0.5 mg/mouse/day) for 10 days. RESULTS: Six weeks after HP, the majority of transferred CD40L(-/-) T cells in Rag-1(-/-) B6 mice were differentiated to CD44(high) and CD62L(low) Tmem cells. BALB/c heart allografts in Rag-1(-/-) B6 recipient mice in the presence of these Tmem cells developed a typical pathological feature of CAV; intimal thickening, 100 days after transplantation. However, functionally blocking the OX40/OX40L pathway with anti-OX40L mAb significantly prevented CAV development and reduced the Tmem cell population in recipient mice. Anti-OX40L mAb therapy also significantly decreased cellular infiltration and cytokine (IFN-γ, TNF-α and TGF-ß) expression in heart allografts. CONCLUSIONS: Tmem cells mediate CAV in heart transplants. Functionally blocking the OX40/OX40L pathway using anti-OX40L mAb therapy prevents Tmem cell-mediated CAV, suggesting therapeutic potential for disrupting OX40-OX40L signaling in order to prevent CAV in heart transplant patients.

[Modified cesarean-hysterectomy technique for management of placenta accreta]. / Técnica cesárea-histerectomía modificada para el tratamiento del acretismo placentario.

UNLABELLED: BAKGROUND: Obstetric hemorrhage is a major cause of maternal morbidity. The increasing number of births via cesarean has increased the incidence of placenta accreta worldwide. As new techniques aimed at reducing maternal mortality and morbidity have emerged with varying results. OBJECTIVES: To describe the surgical technique used in our hospital for management of placenta accreta. Report outcomes and maternal complications. METHODS: Descriptive study, data were obtained from clinical records of patients diagnosed with placenta accreta and whose management was by our modified technique cesarean-hysterectomy by a multidisciplinary team. We included patients who were treated at the Hospital Civil de Guadalajara Dr. Juan I. Menchaca in the period from April 1, 2008 to November 1, 2012. RESULTS: 23 patients were included. The mean gestational age at Doppler ultrasound diagnosis was 31 +/- 3 weeks and for termination of pregnancy was 34 +/- 1 weeks of gestation. Only 5 patients were admitted to intensive care, one patient suffer bladder injury noticed and repaired. CONCLUSIONS: Our modified technique cesarean-hysterectomy for management of placenta accreta has reduced mortality and morbidity in our hospital as well as injuries to nearby organs and hospital stay.

Carbon monoxide releasing molecules inhibit cell death resulting from renal transplantation related stress.

PURPOSE: Organ cold storage and subsequent transplantation are associated with significant ischemia-reperfusion injury, leading to cell death, graft inflammation and decreased graft function. MATERIALS AND METHODS: CORM-3s reduce oxidative stress and prevent inflammation in kidneys stored at 4C and subsequently transplanted. Graft survival and function are markedly improved compared to kidneys preserved and stored in University of Wisconsin solution alone. We determined whether CORM-3 has direct antiapoptotic effects on in vitro preparations of human HUVECs exposed to anoxic conditions. We also determined whether direct administration of CORM-3 to renal grafts before and/or after cold storage would prevent renal damage during the transplantation process. RESULTS: CORM-3 supplementation led to a significantly increased frequency of live cells (mean ± SD 72.3% ± 1.9%, p <0.01), reduced apoptosis (14.9% ± 6.1%, p <0.01) and decreased mitochondrial transmembrane potential (40.2% ± 7.2%, p <0.05) in HUVECs exposed to 20 hours of cold storage compared to controls (11.6% ± 3.5%, 82.2% ± 2.3% and 78.2% ± 3.2%, respectively). In keeping with this antiapoptotic effect CORM-3 supplementation led to a mean 7.4 ± 2.1-fold up-regulation in Bcl-2 gene expression. CORM-3 supplementation in standard preservation solution was most beneficial at initial ischemic injury and before cold storage exposure. However, additional reflushing before vascular reperfusion showed an additive benefit to graft survival and function after transplantation. This was confirmed by decreased glomerular and tubular necrosis, and apoptosis in double flushed grafts. CONCLUSIONS: CORM-3 supplementation in standard University of Wisconsin solution has a significant impact on decreasing cellular and graft injury, and improving survival through its antiapoptotic effects, which are likely mediated through mitochondrial membrane stabilization.

Effect of an angiogenesis inhibitor on hepatic tumor perfusion and the implications for adjuvant cytotoxic therapy.

PURPOSE: To determine whether dynamic contrast material-enhanced (DCE) computed tomography (CT) can help identify hepatic tumor perfusion response to vascular remodeling induced by antiangiogenesis treatment in a rabbit model. MATERIALS AND METHODS: The study was approved by the Animal Use Subcommittee of the University Council on Animal Care. DCE CT hepatic perfusion measurements were performed in the livers of 20 rabbits implanted with VX2 carcinoma. Vascular remodeling was induced with thalidomide dissolved in dimethyl sulfoxide and sterile water, starting at a tumor diameter of 0.7 cm±0.1 and continuing until metastatic lung nodules were observed. The control group (n=8) was given an equivalent volume of the vehicle. The therapy group was subdivided into animals that survived for more than 24 days without lung metastasis (responder group, n=5) or those that survived for less than 24 days (nonresponder group, n=7). Data were analyzed with the Kruskal-Wallis or Friedman rank test and reported as medians and interquartile ranges. RESULTS: DCE CT depicted differential perfusion change within the therapy group after treatment. By day 4, hepatic blood volume (HBV) in the responder group decreased by 29.2% (-32.5% to -11.8%) relative to that before treatment and was significantly different from that in the nonresponder (P=.048) and control (P=.011) groups, where HBV remained stable. By day 8, hepatic artery blood flow decreased by 50.0% (-59.08% to -21.05%) relative to that before treatment in the responder group and was significantly different from that in the nonresponder and control groups (P=.030 for both), which remained stable at -3.5% (-8.5% to 28.7%, P=.50) and -10.0% (-33.8% to 10.4%, P=.48), respectively. CONCLUSION: DCE CT can help differentiate responders from nonresponders by their early differential perfusion response to antiangiogenesis therapy.

Supplemental hydrogen sulphide protects transplant kidney function and prolongs recipient survival after prolonged cold ischaemia-reperfusion injury by mitigating renal graft apoptosis and inflammation.

UNLABELLED: What's known on the subject? and What does the study add? Hydrogen sulphide (H(2) S) has recently been classified as a member of the family of small gaseous molecules called gasotransmitters and has been found to have many important physiological functions. Several recent studies have elucidated the protective effects of H(2) S in many models of tissue ischaemia-reperfusion injury (IRI), including hepatic, myocardial, pulmonary, cerebral and renal IRI. It has previously been shown that H(2) S has a number of properties that may contribute to its protection against IRI, including vasodilatory, anti-apoptotic, anti-inflammatory and anti-oxidant effects, although the specific actions appear to vary between tissues. The few studies investigating the effects of H(2) S against renal IRI have only involved clamping of the renal pedicle to induce warm IRI. This study investigated the protective effects of H(2) S in the context of renal transplantation (RTx), which generally involves a more severe period of prolonged cold IRI. A previous study investigated the actions of H(2) S in RTx, but it was performed ex vivo and did not involve actual transplantation of donor kidneys. To our knowledge, this is the first study using a clinically relevant model of RTx to show that treatment of donor kidneys with H(2) S during preservation is protective against prolonged cold IRI. These findings suggest that H(2) S has potential utility in improving clinical organ preservation techniques and increasing the overall success of organ transplantation. OBJECTIVE: • To characterize the effects of hydrogen sulphide (H(2) S), an endogenously produced molecule recently described to have protective effects against warm ischaemic tissue injury, in mitigating transplantation-associated prolonged cold ischaemia-reperfusion injury (IRI) in a clinically applicable in vivo model of renal transplantation (RTx). MATERIALS AND METHODS: • After undergoing bilateral native nephrectomy, Lewis rats underwent RTx with kidneys that were flushed with either cold (4 °C) standard University of Wisconsin preservation solution (UW) or cold UW + 150 µM NaHS (H(2) S) solution and stored for 24 h at 4 °C in the same solution. • Recipient rats were monitored for a 14-day time course using metabolic cages to assess various characteristics of renal graft function. • Renal grafts were removed at time of death or after the rats were killed for histological, immunohistochemical and quantitative PCR analysis. RESULTS: • H(2) S-treated rats exhibited immediate and significant (P < 0.05) decreases in serum creatinine levels, increased urine output and increased survival compared with UW-treated rats. • H(2) S-treated grafts showed significantly reduced glomerular and tubular necrosis and apoptosis, diminished graft neutrophil and macrophage infiltrates and a trend towards improved inflammatory and anti-apoptotic cytokine profiles. CONCLUSION: • Our results provide the first evidence that supplemental H(2) S can mitigate renal graft IRI incurred during transplantation and prolonged cold storage, improving early graft function and recipient survival in a clinically applicable model of RTx.

Costimulation blockade in pig artery patch xenotransplantation - a simple model to monitor the adaptive immune response in nonhuman primates.

BACKGROUND: CD154 blockade-based immunosuppression successfully prevents both humoral and cellular adaptive immune responses in baboons receiving α1,3-galactosyltransferase gene-knockout (GTKO) pig organs. Using a GTKO pig artery transplantation model in baboons, we evaluated the efficacy of CD28/B7 costimulatory pathway blockade in comparison with CD154 blockade. METHODS: Baboons received artery patch grafts from GTKO pigs, with no (Group1), anti-CD154mAb-based (Group2), or CTLA4-Ig-based (Group3) immunosuppressive therapy. Anti-pig IgM and IgG antibody and cellular responses were monitored. Xenografts were immunohistologically evaluated for antibody and complement deposition, and cellular infiltration. RESULTS: Group1 baboons developed increased IgM and IgG antibody and cellular responses against GTKO antigens. In Group2, anti-CD154mAb alone prevented the development of both IgM and IgG antibody and cellular responses,but not cellular infiltration of the graft. In the single baboon that received anti-thymocyte globulin (ATG) + mycophenolate mofetil (MMF) + anti-CD154mAb, cellular infiltration of the graft was not seen. In Group3, CTLA4-Ig with ATG + MMF inhibited the cellular proliferative response to pig antigens but did not prevent the IgG response or cellular infiltration. CONCLUSIONS: (i) Artery patch transplantation is a simple model to monitor the adaptive immune response to xenografts; (ii) anti-CD154mAb prevents sensitization but not cellular infiltration (but, without anticoagulation, may result in early thrombosis of a pig xenograft); (iii) although in only one baboon, the addition of ATG and MMF prevents cellular infiltration and (iv) replacement of anti-CD154mAb by CTLA4-Ig (at the doses used), even in combination with ATG and MMF, prevents the cellular proliferative response to GTKO pig antigens but is insufficient to prevent the development of anti-pig antibodies.

Treatment of autoimmune arthritis using RNA interference-modulated dendritic cells.

Dendritic cells (DCs) have a dual ability to either stimulate or suppress immunity, which is primarily associated with the expression of costimulatory molecules. Ag-loaded DCs have shown encouraging clinical results for treating cancer and infectious diseases; however, the use of these cells as a means of suppressing immune responses is only recently being explored. Here, we describe the induction of RNA interference through administering short interfering RNA (siRNA) as a means of specifically generating tolerogenic DCs. Knockdown of CD40, CD80, and CD86, prior to loading DCs with the arthritogenic Ag collagen II, led to a population of cells that could effectively suppress onset of collagen-induced arthritis. Maximum benefits were observed when all three genes were concurrently silenced. Disease suppression was associated with inhibition of collagen II-specific Ab production and suppression of T cell recall responses. Downregulation of IL-2, IFN-gamma, TNF-alpha, and IL-17 and increased FoxP3(+) cells with regulatory activity were observed in collagen-induced arthritis mice treated with siRNA-transfected DCs. Collectively, these data support the use of ex vivo gene manipulation in DCs using siRNA to generate tailor-made tolerogenic vaccines for treating autoimmunity.

Osteopontin expressed in tubular epithelial cells regulates NK cell-mediated kidney ischemia reperfusion injury.

Renal ischemia reperfusion injury (IRI) occurs after reduced renal blood flow and is a major cause of acute injury in both native and transplanted kidneys. Studies have shown diverse cell types in both the innate and the adaptive immune systems participate in kidney IRI as dendritic cells, macrophages, neutrophils, B cells, CD4(+) NK(+) cells, and CD4(+) T cells all contribute to this form of injury. Recently, we have found that NK cells induce apoptosis in tubular epithelial cells (TECs) and also contribute to renal IRI. However, the mechanism of NK cell migration and activation during kidney IRI remains unknown. In this study, we have identified that kidney TECs express a high level of osteopontin (OPN) in vitro and in vivo. C57BL/6 OPN-deficient mice have reduced NK cell infiltration with less tissue damage compared with wild-type C57BL/6 mice after ischemia. OPN can directly activate NK cells to mediate TEC apoptotic death and can also regulate chemotaxis of NK cells to TECs. Taken together, our study's results indicate that OPN expression by TECs is an important factor in initial inflammatory responses that involves NK cells activity in kidney IRI. Inhibiting OPN expression at an early stage of IRI may be protective and preserve kidney function after transplantation.

Acute rejection is associated with antibodies to non-Gal antigens in baboons using Gal-knockout pig kidneys.

We transplanted kidneys from alpha1,3-galactosyltransferase knockout (GalT-KO) pigs into six baboons using two different immunosuppressive regimens, but most of the baboons died from severe acute humoral xenograft rejection. Circulating induced antibodies to non-Gal antigens were markedly elevated at rejection, which mediated strong complement-dependent cytotoxicity against GalT-KO porcine target cells. These data suggest that antibodies to non-Gal antigens will present an additional barrier to transplantation of organs from GalT-KO pigs to humans.

Carbon monoxide-releasing molecules protect against ischemia-reperfusion injury during kidney transplantation.

Carbon monoxide (CO) can provide beneficial antiapoptotic and anti-inflammatory effects in the context of ischemia-reperfusion injury (IRI). Here we tested the ability of pretreating the kidney donor with carbon monoxide-releasing molecules (CORM) to prevent IRI in a transplant model. Isogeneic Brown Norway donor rats were pretreated with CORM-2 18 h before kidney retrieval. The kidneys were then cold-preserved for 26 h and transplanted into Lewis rat recipients that had undergone bilateral nephrectomy. Allografts from Brown Norway to Lewis rats were also performed after 6 h of cold ischemic time with low-dose tacrolimus treatment. All recipients receiving CORM-2-treated isografts survived the transplant process and had near-normal serum creatinine levels, whereas all control animals died of uremia by the third post-operative day. This beneficial effect was also seen in isografted Lewis recipients receiving kidneys perfused with CORM-3, indicating that CORMs have direct effects on the kidney. Pretreatment of human umbilical vein endothelial cells in culture with CORM-2 for 1 h significantly reduced cytokine-induced nicotinamide adenine dinucleotide phosphate-dependent production of superoxide, activation of the inflammation-relevant transcription factor nuclear factor-κB, upregulated expression of E-selectin and intercellular adhesion molecule-1 adhesion proteins, and leukocyte adhesion to the endothelial cells. Thus, CORM-2-derived CO protects renal transplants from IRI by modulating inflammation.

A novel in vivo siRNA delivery system specifically targeting dendritic cells and silencing CD40 genes for immunomodulation.

Translation of small interfering RNA (siRNA)-based approaches into practical therapeutics is limited because of lack of an effective and cell-specific delivery system. Herein, we present a new method of selectively delivering siRNA to dendritic cells (DCs) in vivo using CD40 siRNA-containing immunoliposomes (siILs) that were decorated with DC-specific DEC-205 mAb. Administration of CD40 siILs resulted in DC-specific cell targeting in vitro and in vivo. On treatment with CD40 siILs, the expression of CD40 in DCs, as well allostimulatory activity was inhibited. In vivo administration resulted in selective siRNA uptake into immune organs and functional immune modulation as assessed using a model antigen. In conclusion, this is the first demonstration of DC-specific siRNA delivery and gene silencing in vivo, which highlights the potential of DC-mediated immune modulation and the feasibility of siRNA-based clinical therapy.

Anti-IL-2 receptor antibody decreases cytokine-induced apoptosis of human renal tubular epithelial cells (TEC).

BACKGROUND: Transplant rejection is mediated by T-cell activation which is modulated by interleukin-2 (IL-2) binding to IL-2R (CD25). Monoclonal anti-IL-2 receptor antibody is used in renal transplantation to reduce rejection. Interestingly, proximal tubular epithelial cells (TEC) express CD25, similar to T cells. We have demonstrated that IL-2 induces murine TEC apoptosis through down-regulation of the caspase-8 inhibitor protein c-FLIP. Anti-CD25 antibody may be useful clinically to limit renal injury, but this has not been tested in human TEC. METHODS: Human PT-2 TEC were isolated and cloned from the urine of transplant patients. Apoptosis was determined by FACS with Annexin-V FITC. Protein expression was studied using western blot, and mRNA levels by quantitative real-time (PR-PCR). RESULTS: We demonstrated that the morphology of a human kidney cell line (PT-2) cloned from urine was consistent with proximal TEC and expresses alkaline phosphatase, cytokeratin, vimentin, CD13, CD26, and low levels of E-cadherin. Basal IL-2 receptor (CD25) was up-regulated by IL-2/IFN-γ stimulation, and cytokine exposure induced apoptosis in a dose-dependent manner. Apoptosis with IL-2/IFN-γ was associated with increased caspase-8 activity and decreased endogenous caspase-8 inhibitor c-FLIP mRNA and protein expression. IL-2/IFN-γ-induced apoptosis could be blocked by pre-treatment of PT-2 with anti IL-2R antibody (basiliximab) but not control IgG antibody. CONCLUSIONS: These data demonstrate for the first time in human TEC that IL-2 and IFN-γ can induce TEC apoptosis which can be blocked by CD25 blockade antibody. These data suggest that anti-CD25 mAb might similarly attenuate inflammation-induced TEC injury in vivo. Kidney-expressed CD25 may represent a clinically important new target for attenuating early inflammatory injury in donor kidneys and preserving renal function during anti-rejection therapy.

Free bone graft attenuates acute rejection and in combination with cyclosporin a leads to indefinite cardiac allograft survival.

We report on a novel approach aimed at preventing acute vascular rejection (AVR), one of the major unresolved hurdles of clinical transplantation. In a C3H-to-BALB/c heterotopic heart transplant model, we demonstrate that free bone transplantation combined with cyclosporin A suppresses antidonor Ab responses, induces indefinite cardiac allograft survival (>100 days), and preserves graft architecture. In contrast, untreated- or cyclosporin A alone-treated recipients rejected their cardiac grafts on days 7.7 +/- 0.6 and 15.5 +/- 1.1, respectively, with graft histology indicative of AVR. Splenic dendritic cells from nonrejecting recipients expressed low levels of MHC II, CD40, and CD86, reduced ability to stimulate donor cell proliferation, and augmented IL-10 production of responding T cells in vitro. Adoptive transfer of dendritic cells from long-term surviving recipients 1 day before cardiac grafting was able to confer hyporesponsiveness to naive BALB/c recipients of cardiac allografts. To determine whether graft survival was associated with hematopoietic or stromal elements of the transplanted free bone, we administered isolated bone marrow mononuclear cells or free bone that was irradiated to deplete hematopoietic elements. Although bone marrow mononuclear cells had no effect on cardiac graft survival, irradiated free bone transplantation was capable of prolonging graft survival. Most interestingly, the prolongation effect was Ag nonspecific, because third party irradiated bone graft was also effective. Due to the fact that current immunosuppressive approaches are clinically ineffective at preventing AVR, this study provides promise for further investigations of BM components as a means of addressing a currently unmet medical need.

A novel allergen-specific therapy for allergy using CD40-silenced dendritic cells.

BACKGROUND: Induction of RNA interference with small interfering RNA (siRNA) has demonstrated therapeutic potential through the knockdown of target genes. We have previously reported that systemic administration of CD40 siRNA is capable of attenuating allergic symptoms but in an allergen-nonspecific fashion. However, siRNA-based allergen-specific therapy for allergy has not been developed. OBJECTIVE: We attempted to develop a new allergen-specific therapy for allergy using CD40-silenced and allergen-pulsed dendritic cells (DCs). METHODS: Bone marrow-derived DCs were silenced with CD40 siRNA and pulsed with ovalbumin (OVA). Mice had allergy after intraperitoneal sensitization with OVA and keyhole limpet hemocyanin, followed by intranasal challenge with the same allergens. The mice were treated with CD40-silenced and OVA-pulsed DCs (CD40-silenced OVA DCs) either before allergic sensitization or after establishing allergic rhinitis. RESULTS: Mice receiving CD40-silenced OVA DCs either before or after the establishment of allergic rhinitis showed remarkable reductions in allergic symptoms caused by OVA challenge, as well as anti-OVA IgE levels in sera. Additionally, CD40-silenced OVA DCs suppressed eosinophil infiltration at the nasal septum, OVA-specific T-cell responses, T-cell production of IL-4 and IL-5 after stimulation with OVA, and CD4(+)CD25(-) effector T-cell responses. Furthermore, CD40-silenced OVA DCs facilitated the generation of CD4(+)CD25(+) forkhead box protein 3-positive OVA-specific regulatory T cells, which inhibit allergic responses in vivo. However, CD40-silenced OVA DCs suppressed only OVA-specific allergy but did not inhibit keyhole limpet hemocyanin-induced allergy, suggesting that CD40-silenced OVA DCs induce allergen-specific tolerance. CONCLUSIONS: This study is the first to demonstrate a novel allergen-specific therapy for allergy through DC-mediated immune modulation after gene silencing of CD40.

Novel small interfering RNA-containing solution protecting donor organs in heart transplantation.

BACKGROUND: Ischemia/reperfusion injury is a major factor in graft quality and subsequent function in the transplantation setting. We hypothesize that the process of RNA interference may be used to "engineer" a graft to suppress expression of genes associated with inflammation, apoptosis, and complement, which are believed to cause ischemia/reperfusion injury. Such manipulation of pathological gene expression may be performed by treatment of the graft ex vivo with small interfering RNA (siRNA) as part of the preservation procedure. METHODS AND RESULTS: Heart grafts from BALB/c mice were preserved in UW solution (control) or UW solution containing siRNAs targeting tumor necrosis factor-alpha, C3, and Fas genes (siRNA solution) at 4 degrees C for 48 hours and subsequently transplanted into syngeneic recipients. Tumor necrosis factor-alpha, C3, and Fas genes were elevated by ischemia/reperfusion injury after 48 hours of preservation in UW solution. Preservation in siRNA solution knocked down gene expression at the level of messenger RNA and protein in the grafts after transplantation. All grafts preserved in siRNA solution showed strong contraction, whereas grafts preserved in control solution demonstrated no detectable contraction by high-frequency ultrasound scanning. siRNA solution-treated organs exhibited improved histology and diminished neutrophil and lymphocyte infiltration compared with control solution-treated organs. Furthermore, the treated heart grafts retained strong beating up to the end of the observation period (>100 days), whereas all control grafts lost function within 8 days. CONCLUSIONS: Incorporation of siRNA into organ storage solution is a feasible and effective method of attenuating ischemia/reperfusion injury, protecting cardiac function, and prolonging graft survival.

NK cells induce apoptosis in tubular epithelial cells and contribute to renal ischemia-reperfusion injury.

Renal ischemia-reperfusion injury (IRI) can result in acute renal failure with mortality rates of 50% in severe cases. NK cells are important participants in early-stage innate immune responses. However, their role in renal tubular epithelial cell (TEC) injury in IRI is currently unknown. Our data indicate that NK cells can kill syngeneic TEC in vitro. Apoptotic death of TEC in vitro is associated with TEC expression of the NK cell ligand Rae-1, as well as NKG2D on NK cells. In vivo following IRI, there was increased expression of Rae-1 on TEC. FACS analyses of kidney cell preparations indicated a quantitative increase in NKG2D-bearing NK cells within the kidney following IRI. NK cell depletion in wild-type C57BL/6 mice was protective, while adoptive transfer of NK cells worsened injury in NK, T, and B cell-null Rag2(-/-)gamma(c)(-/-) mice with IRI. NK cell-mediated kidney injury was perforin (PFN)-dependent as PFN(-/-) NK cells had minimal capacity to kill TEC in vitro compared with NK cells from wild-type, FasL-deficient (gld), or IFN-gamma(-/-) mice. Taken together, these results demonstrate for the first time that NK cells can directly kill TEC and that NK cells contribute substantially to kidney IRI. NK cell killing may represent an important underrecognized mechanism of kidney injury in diverse forms of inflammation, including transplantation.

Development of techniques for gastrojejunal bypass surgery in obese mice.

We have previously described a duodenojejunal bypass (DJB) surgical model in healthy C57BL/6 mice. However, our pilot study showed that the same surgical technique caused a high mortality rate in obese mice. In this study, to significantly improve animal survival rate following bariatric surgery and thereby providing a stable surgical model for the study of glucose homeostasis in obese mice, we have used modified techniques and developed the end-to-side gastrojejunal bypass (GJB) surgery in obese C57BL/6 with impaired glucose tolerance. The modification consisted of using the distal part of the jejunum for biliopancreatic diversion including: 1) ligation of the distal stomach at the level of the pylorus; 2) connection the jejunum to the anterior wall of stomach in an end-to-side fashion; and 3) diverting the biliopancreatic secretions through the blind limb into the distal jejunum through an end-to-side anastomosis. We found that by modifying the proximal end-to-end duodenojejunal anastomosis, described in our original model, to an end-to-side gastrojejunal anastomosis in these obese mice, we were able to significantly improve the postoperative mortality in this study. We have also demonstrated that performing the GJB surgery in obese mice resulted in significant weight loss, normalized blood glucose levels, and prevented acute pancreatitis. This newly developed GJB surgery in the obese mice offers a unique advantage to study the mechanisms of gastrointestinal surgery as treatment for type 2 diabetes.

Standard versus extended criteria graft procurement. Experience at the Hospital de Especialidades La Raza. / Procuración de injertos estándar frente a extendidos. Experiencia en el Hospital de Especialidades La Raza.

BACKGROUND: In Mexico, there are 23 158 patients waiting for an organ or tissue transplant. The increasing demand of grafts justifies the use of expanded criteria donors; however, not even all standard grafts have been procured. OBJECTIVE: To identify the associated factors to the decision of not procuring grafts from brain death donors whose donation was consented. METHOD: Retrospective cohort, univariate and multivariate analysis. 35 donation files with brain death were included from 2014 to 2019. Groups in which the heart wasn't procured versus those in which it was procured were compared; same comparisons were made for liver, kidney, skin, bone tissue and corneas. RESULTS: 20 women (57.1%), 15 men (42.9%) average age of 43.8 ± 16.4 years. High-dose of inotropic or norepinephrine use increased the probability of cardiac procurement (odds ratio [OR] 0.57; 95% confidence interval [95% CI]: 0.0-0.5). It was not detected a sensitive and specific variable for decision making at liver procurement. Implementation of two or more diagnostic methods for BD were associated with kidney loss (OR: 10; 95% CI: 1.2-78.1). Organs and tissues met standard criteria; however, 76 (41.5%) were not procured. CONCLUSIONS: Non-procurement associated factors were different from the standard donor established criteria. It is necessary to follow clear procurement criteria, in order to reduce viable grafts loss.

INTRODUCCIÓN: En México se registraron 23,158 personas en espera de un órgano o tejido para trasplante durante el año 2019. El constante aumento de la demanda sustenta el empleo de donantes con criterios extendidos; sin embargo, no todos los injertos estándar se procuran. OBJETIVO: Identificar los factores asociados a la decisión de no procurar injertos provenientes de donantes con muerte encefálica en quienes se consintió la donación. MÉTODO: Cohorte retrospectiva, análisis univariado y multivariado. Se incluyeron 35 expedientes de donación concretada con muerte encefálica de 2014 a 2019. Se compararon los grupos en los que no se procuró corazón, en los que sí, y para hígado, riñón, tejido óseo, piel y córneas. RESULTADOS: Se incluyeron 20 mujeres (57.1%) y 15 hombres (42.9%) con una edad media de 43.8 ± 16.4 años. El uso de inotrópico a dosis altas o norepinefrina aumentó la probabilidad de procuración cardiaca (razón de momios [RM]: 0.57; intervalo de confianza del 95% [IC95%]: 0.0-0.5). No se detectó ninguna variable sensible y específica para la toma de decisión en la procuración hepática. El empleo de dos o más métodos diagnósticos de muerte encefálica se asoció a pérdida del riñón (RM: 10; IC95%: 1.2-78.1). Cumplieron con criterios estándar 183 órganos y tejidos (74.6%); sin embargo, 76 (41.5%) no fueron procurados. CONCLUSIONES: Los factores asociados a la decisión de no procuración fueron distintos a los criterios de donante estándar establecidos. Es necesario seguir criterios claros de procuración para disminuir la pérdida de injertos viables.

Impact of a SBRT/SRS longitudinal telehealth training pilot course in Latin America.

PURPOSE: To assess the impact of longitudinal telehealth training in stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) for clinicians in Latin America. MATERIALS AND METHODS: Professionals from two Peruvian centers received an initial SBRT/SRS on-site training course and subsequently received follow-up telehealth training (interventional group) or not (negative control arm). Twelve live video conference sessions were scheduled. Surveys pre- and post-curriculum measured participants' confidence in seven practical domains of SBRT/SRS, based on Likert scales of 1-5, and post-curriculum surveys assessed educators' experiences. RESULTS: Sixty-one participants were registered, with an average of 24 attendees per session. Pre- and post- surveys were completed by 22 participants. For interventional and negative-control groups, mean changes in Likert scale were satisfactory for the former and remained unmodified for the latter. CONCLUSIONS: Conducting telehealth educational programs via virtual classroom sessions could be a reliable method to augment training for SBRT and SRS.