Percutaneous Transsplenic Balloon-Assisted Transjugular Intrahepatic Portosystemic Shunt Placement in Patients with Portal Vein Obliteration for Portal Vein Recanalization: Feasibility, Safety and Effectiveness.

PURPOSE: To assess the feasibility, safety and effectiveness of portal vein recanalization (PVR)-transjugular portosystemic shunt (TIPS) placement via splenic access using a balloon puncture technique. MATERIALS AND METHODS: In a single-center retrospective study from March 2017 to February 2021, 14 consecutive patients with portal hypertension, chronic liver disease and portal vein occlusion or near-complete (> 95%) occlusion were referred for PVR-TIPS placement. Feasibility, safety and effectiveness including procedural characteristics such as technical success, complication profile and splenic access time (SAT), balloon positioning time (BPT), conventional portal vein entry time (CPVET), overall procedure time (OPT), fluoroscopy time (FT), dose-area product (DAP) and air kerma (AK) were evaluated. RESULTS: Transsplenic PVR-TIPS using balloon puncture technique was technically feasible in 12 of 14 patients (8 men, 49 ± 13 years). In two patients without detectable intrahepatic portal vein branches, TIPS placement was not feasible and both patients were referred for further treatment with nonselective beta blockers and endoscopic variceal ligation. No complications grade > 3 of the Cardiovascular and Interventional Radiological Society of Europe classification system occurred. The SAT was 25 ± 21 min, CPVET was 33 ± 26 min, the OPT was 158 ± 54 min, the FT was 42 ± 22 min, the DAP was 167.84 ± 129.23 Gy*cm2 and the AK was 1150.70 ± 910.73 mGy. CONCLUSIONS: Transsplenic PVR-TIPS using a balloon puncture technique is feasible and appears to be safe in our series of patients with obliteration of the portal vein. It expands the interventional options in patients with chronic PVT.

[Autoimmune hepatitis-standard and second-line therapy]. / Autoimmunhepatitis ­ Standard- und Zweitlinientherapie.

BACKGROUND: Autoimmune hepatitis (AIH) is a rare chronic inflammatory liver disease. Like other autoimmune diseases, the incidence continues to rise and, if left untreated, it has a detrimental natural course. AIM: Description of the current etiology, diagnosis and management of AIH. MATERIALS AND METHODS: Summary of current national as well as international guidelines and highlighting recently published studies. RESULTS AND CONCLUSION: In addition to autoantibody testing and liver histology, the diagnosis of AIH is based on the exclusion of other relevant liver diseases. The standard of care with prednisolone ± azathioprine, which has been well established for decades, significantly improves long-term survival. The therapeutic aim is the complete normalization of aminotransferases and immunoglobulin G. Budesonide, an alternative topical steroid with fewer systemic side effects, was approved for AIH therapy in non-cirrhotic patients in 2011. The therapeutic goal of complete biochemical remission is achieved in about 80% of patients and liver transplantation is rarely necessary. The majority of patients require life-long immunosuppressive therapy because of high relapse rates after discontinuation of immunosuppressants. Currently used second-line therapies are based on uncontrolled monocentric studies with single substances. Therefore, clear recommendations from international expert groups are lacking. These second-line therapies are not approved by the regulatory authorities such as the Food and Drug Administration or the European Medicines Agency.

Prevention of Allograft Rejection by Use of Regulatory T Cells With an MHC-Specific Chimeric Antigen Receptor.

CD4+ CD25high FOXP3+ regulatory T cells (Tregs) are involved in graft-specific tolerance after solid organ transplantation. However, adoptive transfer of polyspecific Tregs alone is insufficient to prevent graft rejection even in rodent models, indicating that graft-specific Tregs are required. We developed a highly specific chimeric antigen receptor that recognizes the HLA molecule A*02 (referred to as A2-CAR). Transduction into natural regulatory T cells (nTregs) changes the specificity of the nTregs without alteration of their regulatory phenotype and epigenetic stability. Activation of nTregs via the A2-CAR induced proliferation and enhanced the suppressor function of modified nTregs. Compared with nTregs, A2-CAR Tregs exhibited superior control of strong allospecific immune responses in vitro and in humanized mouse models. A2-CAR Tregs completely prevented rejection of allogeneic target cells and tissues in immune reconstituted humanized mice in the absence of any immunosuppression. Therefore, these modified cells have great potential for incorporation into clinical trials of Treg-supported weaning after allogeneic transplantation.

Hepatic Infiltrates in Operational Tolerant Patients After Liver Transplantation Show Enrichment of Regulatory T Cells Before Proinflammatory Genes Are Downregulated.

Immunosuppression can be discontinued from selected and stable patients after liver transplantation resulting in spontaneous operational tolerance (SOT), although the underlying mechanisms remain elusive. Thus, we analyzed serial liver biopsy specimens from adult liver recipients enrolled in a prospective multicenter immunosuppression withdrawal trial that used immunophenotyping and transcriptional profiling. Liver specimens were collected before the initiation of weaning, at the time of rejection, or at 1 and 3 years after complete drug discontinuation. Unexpectedly, the tolerated grafts developed portal tract expansion with increased T cell infiltration after immunosuppression withdrawal. This was associated with transient and preferential accumulation of CD4(+) FOXP3(+) cells and a trend toward upregulation of immune activation and regulatory genes, without signs of rejection. At the same time, no markers of endothelial damage or activation were noted. Portal infiltrates persisted at 3 years but were characterized by decreased expression of genes associated with chronic immunological damage. Further, SOT was not associated with a progressive liver fibrosis up to 5 years. These data suggest that SOT involves several mechanisms: a long-lasting local immune cell persistence with a transient regulatory T cells accumulation followed by a downregulation of immune-activated genes over years. These results have important implications for designs and follow-up of weaning trials.

Humanized mouse models for type 1 diabetes including pancreatic islet transplantation.

We comment here on the suitability of available mouse models for type 1 diabetes research including research on therapeutic pancreatic islet transplantation. The major emphasis will be laid on models that require minimal invasive procedures. Most biological processes are too complex for a complete recapitulation in a test tube. The study of innate or even adaptive immune responses involves a number of different cell types and organs making in vitro studies unreliable but also providing extreme challenges for the use of surrogate model organisms. Studying these processes directly in humans is impossible due to ethical and technical constraints. To resolve this problem small animal models such as mice or rats are frequently used to study mechanisms of complex diseases. This has brought much insight into hematopoiesis and immune cell function including type 1 diabetes (T1D); however, 65 million years of evolution introduced striking differences between mice and humans 1. In fact, none of the many suggested therapies arising from studies using mice 2 3 that have promised prevention or even reversion of T1D made it into the clinic yet 4 5 6. The reason for this are major species-specific differences between rodents and humans regarding the immune system and beta cells.

Xenotransplantation of porcine islet cells as a potential option for the treatment of type 1 diabetes in the future.

Solid organ and cell transplantation, including pancreatic islets constitute the treatment of choice for chronic terminal diseases. However, the clinical use of allogeneic transplantation is limited by the growing shortage of human organs. This has prompted us to initiate a unique multi-center and multi-team effort to promote translational research in xenotransplantation to bring xenotransplantation to the clinical setting. Supported by the German Research Foundation, an interdisciplinary group of surgeons, internal medicine doctors, diabetologists, material sciences experts, immunologists, cell biologists, virologists, veterinarians, and geneticists have established a collaborative research center (CRC) focusing on the biology of xenogeneic cell, tissue, and organ transplantation. A major strength of this consortium is the inclusion of members of the regulatory bodies, including the Paul-Ehrlich Institute (PEI), infection specialists from the Robert Koch Institute and PEI, veterinarians from the German Primate Center, and representatives of influential ethical and religious institutions. A major goal of this consortium is to promote islet xenotransplantation, based on the extensive expertise and experience of the existing clinical islet transplantation program. Besides comprehensive approaches to understand and prevent inflammation-mediated islet xenotransplant dysfunction [immediate blood-mediated inflammatory reaction (IBMIR)], we also take advantage of the availability of and experience with islet macroencapsulation, with the goal to improve graft survival and function. This consortium harbors a unique group of scientists with complementary expertise under a cohesive program aiming at developing new therapeutic approaches for islet replacement and solid organ xenotransplantation.

[Daytime flexible application of Insulin degludec in patients with type 1 diabetes or type 2 diabetes]. / Tageszeitlich flexible Gabe von Insulin degludec bei Patienten mit Typ-1-Diabetes oderTyp-2-Diabetes.

BACKGROUND: Insulin degludec (IDeg) is a basal insulin with a stable, flat action profile and an even distribution of the blood glucose lowering effect over 24 hou rs. The terminal half-life of IDeg is about 25 hours, which reflects a mean prolongation by factor 2 compared to Insulin glargin (lGlar).This may enable for a more flexible daytime dosing versus up to now available basal insulins. METHOD: Two open, randomized, treat-to-target studies enrolled patients with type 1 diabetes (n =493) or type 2 diabetes (n = 687). Both phase 3 studies compared a daytime flexible dosing of IDeg (IDeg-flex) with IDeg at the evening meal (IDeg-evening) and IDler at a fixed daytime. In the IDeg-flex-group dosing intervals were predefined with variations between 8 and 40 hours. RESULTS: In patients with type 1 diabetes IDeg-flex proved to be non-inferior with respect to reduction of HbA1C (-0.40%) versus IDeg-evening (-0.41%) and IGlar (-0.58%) after 26 weeks. In addition, nocturnal hypoglycemic events were reduced by 40% (p < 0.01) with IDeg-flex versus IGlar. In patients with type 2 diabetes reduction of HbA1C with ID)eg-flex (-1.28%) was non-inferior to IDeg-evening (-1.07%) and IGlar (-1.26%), respectively, whereas rates for hypoglycemia were comparable. CONCLUSION: Patients with diabetes mellitus are enabled to dose a basal insulin flexibly when needed (minimum interval of 8 hours afterthe last injection is necessary). Impacts of this treatment option on quality of life and adherence and outcomes should be examined in observational trials.

Clinical value and safety of liver biopsies in patients transplanted for hepatitis C virus-related end-stage liver disease.

BACKGROUND: Hepatitis C is the leading indication for liver transplantation. Differentiation between recurrent graft hepatitis C (RGH-C) and graft rejection (GR) is challenging. Liver biopsy is standard to diagnose both conditions; however, little information is available regarding this procedure in hepatitis C virus (HCV)-infected liver transplant recipients. METHODS: Liver biopsies (n = 211) from all consecutive patients (n = 138) transplanted for hepatitis C at Hannover Medical School between January 2000 and October 2011 were screened, and a final cohort of 96 patients with 196 biopsies was included. Indications, histopathological findings, and biopsy-related complications were documented. Modifications in the treatment based on the biopsy result and the biochemical outcome were analyzed. RESULTS: Most biopsies (196/211, 93%) were representative. Five patients (2.5%) developed non-fatal biopsy-related complications. Biopsy results were GR (35%), RGH-C (31%), and other diagnoses (34%). GR was independently associated with lower albumin (P = 0.025) and higher bilirubin levels (P = 0.011). Treatment was modified based on the biopsy result in 25% of cases. Alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), and bilirubin levels improved in 41%, 25%, and 31% of cases 4 weeks post biopsy respectively. ALT improvements were more significant in patients with GR than in those with RGH-C. CONCLUSION: Liver biopsy in HCV-infected liver transplant recipients is safe and representative in >90% of cases. GR is independently associated with lower albumin and higher bilirubin levels.

[Daytime flexible application of Insulin degludec in patients with type 1 diabetes or type 2 diabetes]. / Tageszeitlich flexible Gabe von Insulin degludec bei Patienten mit Typ-1-Diabetes oderTyp-2-Diabetes.

BACKGROUND: Insulin degludec (IDeg) is a basal insulin with a stable, flat action profile and an even distribution of the blood glucose lowering effect over 24 hou rs. The terminal half-life of IDeg is about 25 hours, which reflects a mean prolongation by factor 2 compared to Insulin glargin (lGlar).This may enable for a more flexible daytime dosing versus up to now available basal insulins. METHOD: Two open, randomized, treat-to-target studies enrolled patients with type 1 diabetes (n =493) or type 2 diabetes (n = 687). Both phase 3 studies compared a daytime flexible dosing of IDeg (IDeg-flex) with IDeg at the evening meal (IDeg-evening) and IDler at a fixed daytime. In the IDeg-flex-group dosing intervals were predefined with variations between 8 and 40 hours. RESULTS: In patients with type 1 diabetes IDeg-flex proved to be non-inferior with respect to reduction of HbA1C (-0.40%) versus IDeg-evening (-0.41%) and IGlar (-0.58%) after 26 weeks. In addition, nocturnal hypoglycemic events were reduced by 40% (p < 0.01) with IDeg-flex versus IGlar. In patients with type 2 diabetes reduction of HbA1C with ID)eg-flex (-1.28%) was non-inferior to IDeg-evening (-1.07%) and IGlar (-1.26%), respectively, whereas rates for hypoglycemia were comparable. CONCLUSION: Patients with diabetes mellitus are enabled to dose a basal insulin flexibly when needed (minimum interval of 8 hours after the last injection is necessary). Impacts of this treatment option on quality of life and adherence and outcomes should be examined in observational trials.

Naive tumour-specific CD4+ T cells were efficiently primed in acute lymphoblastic leukaemia.

The recognition and neutralization of tumour cells is one of the big challenges in immunity. The immune system has to recognize syngeneic tumour cells and has to be primed and respond in an adequate manner. Priming of a leukaemia-specific immune response is a crucial step in tumour immunology that can mislead to tumour tolerance either by T cell ignorance, deletion or Treg induction. To resemble the situation of acute lymphoblastic leukaemia (ALL) in patients, we used the murine BALB/c model with syngeneic BM185 tumour cells. We established a tumour cell line that expresses the neo-antigen ovalbumin (BM185-OVA/GFP) to allow the application of T cell receptor transgenic, antigen-specific CD4(+) T cells. Here, we demonstrate that effective anti-ALL immunity can be established by in vivo priming of CD4(+) T cells that is sufficient to differentiate into effector cells. Yet they failed to control tumour alone, but initiated a Th1 response. An efficient tumour clearance was dependent on both antigen-specific CD4(+) T cells and CD8(+) effector T cells from the endogenous repertoire. The tolerogeneic milieu was characterized by increased Tregs numbers and elevated IL-10 level. Tregs hamper effective antitumour immune response, but their depletion did not result in reduced tumour growth. In contrast, neutralization of IL-10 improved median mouse survival. Future therapies should focus on establishing a strong CD4+ T cells response, either by adjuvant or by adoptive transfer.

Donor-specific regulatory T cells generated on donor B cells are superior to CD4+CD25high cells in controlling alloimmune responses in humanized mice.

CD4(+)CD25highFOXP3(+) regulatory T cells (Tregs) can control allospecific immune responses in vitro and in titrated lymphopenic transplantation models. However, under non-lymphopenic conditions, as seen in patients with autoimmune diseases or after organ transplantation, polyspecific Tregs so far have been largely ineffective to control immune responses in animal models. Yet currently polyspecific CD4(+)CD25high Tregs are being tested in clinical trials. Donor materials are usually limited for the generation of donor-specific Tregs. Herein we have developed a method to produce large quantities of activated donor B cells by stimulation of donor peripheral blood mononuclear cells with 3T3 fibroblasts expressing CD40L. These activated donor B cells are potent stimulators of CD4(+)CD25high Tregs, which were expanded efficiently to inhibit an allo-MLR in donor-specific fashion. They were far more potent in inhibiting alloimmune responses in humanized mice compared with the polyspecific CD4(+)CD25high Tregs. Generation of donor-specific Tregs could be performed under good manufacturing practice conditions. Donor-reactive Tregs may be a valuable tool to control immune responses after transplantation a setting in which polyspecific Tregs have failed to date.

Enrichment of regulatory T cells in acutely rejected human liver allografts.

Acute cellular rejection (ACR) occurs frequently after liver transplantation and can usually be controlled. Triggering of allospecific immune responses and lack of immunoregulation are currently suggested as a cause of ACR, but there are no investigations of intrahepatic immune responses during ACR. Therefore we prospectively analyzed the intrahepatic T cell infiltration pattern in correlation to the severity of ACR in a cohort of patients with graft hepatitis (n = 151). While CD4(+) cells dominated the portal infiltrates in mild-moderate ACR, CD8(+) cells prevailed in severe ACR. Furthermore portal CD8(+) and not CD4(+) infiltration correlated with serum transaminases and with the likelihood of subsequent ACRs. Surprisingly, the rise of portal effector T cells density during ACR was surpassed by the increase in portal infiltration of regulatory T cells by a factor of two. Thus ACRs rather showed an increase and not a lack of regulation, as was suggested by analysis of peripheral blood mononuclear cells. Despite the pattern of enhanced immunoregulation, patients with severe ACR had a higher risk for subsequent rejections and showed a trend to a reduced survival. Thus, patients with severe rejections might need a modification of their immunosuppression to improve prognosis.

Treg-therapy allows mixed chimerism and transplantation tolerance without cytoreductive conditioning.

Establishment of mixed chimerism through transplantation of allogeneic donor bone marrow (BM) into sufficiently conditioned recipients is an effective experimental approach for the induction of transplantation tolerance. Clinical translation, however, is impeded by the lack of feasible protocols devoid of cytoreductive conditioning (i.e. irradiation and cytotoxic drugs/mAbs). The therapeutic application of regulatory T cells (Tregs) prolongs allograft survival in experimental models, but appears insufficient to induce robust tolerance on its own. We thus investigated whether mixed chimerism and tolerance could be realized without the need for cytoreductive treatment by combining Treg therapy with BM transplantation (BMT). Polyclonal recipient Tregs were cotransplanted with a moderate dose of fully mismatched allogeneic donor BM into recipients conditioned solely with short-course costimulation blockade and rapamycin. This combination treatment led to long-term multilineage chimerism and donor-specific skin graft tolerance. Chimeras also developed humoral and in vitro tolerance. Both deletional and nondeletional mechanisms contributed to maintenance of tolerance. All tested populations of polyclonal Tregs (FoxP3-transduced Tregs, natural Tregs and TGF-beta induced Tregs) were effective in this setting. Thus, Treg therapy achieves mixed chimerism and tolerance without cytoreductive recipient treatment, thereby eliminating a major toxic element impeding clinical translation of this approach.

[Pancreas and islet transplantation]. / Pankreas- und Inseltransplantation.

Pancreas transplantation is a successful and effective procedure resulting in tight glucose control. Due to the postoperative morbidity and the need for immunosuppression pancreas transplantation should be considered in patients with type I diabetes at the time of kidney transplantation. Besides this pancreas transplantation alone can be taken into consideration for patients with very poor metabolic control and quality of life despite optimal medical treatment. Recently, islet transplantation became a less invasive alternative to pancreas transplantation. Due to the lack of long-term follow-up and due to the need of multiple donor grafts for one recipient, islet transplantation should be performed under experimental settings in experienced centers. New developments in protecting transplanted islets and in the induction of donor-specific tolerance could increase the indication to perform the procedure. Therefore alternative sources of beta-cells have to be identified.

Role of regulatory T cells for the treatment of type 1 diabetes mellitus.

Beta-cell specific autoreactive T cells can be found in patients with type I diabetes (T1D) and in healthy controls. They are usually controlled by a network of regulatory mechanisms including CD4+CD25+Foxp3+ regulatory T cells (Tregs). It was suspected that defects in Treg number and activity are causally related to the development of T1D. Although there are hints that this concept might be true, it is neither proven in animal models nor in patients with T1D. However, increasing the number of Tregs by adoptive transfer can be used to prevent and treat even established T1D. It was demonstrated that Tregs recognizing beta-cell antigens are far more efficient in treating the disease than polyspecific Tregs. The use of beta-cell specific Tregs is also leading to a tissue specific immunotolerance without perturbing the general immunocompetence. Two sources for beta-cell specific Tregs are currently employed: First natural Tregs specific for beta-cells are expanded IN VITRO and reinfused into diabetic animals. Second naïve or activated T cells specific for beta-cell antigens are IN VITRO converted to Tregs by genetic manipulation or by specific cytokine combinations. Both approaches were successful in treating even established diabetes in animal models. Before such therapies can be used in patients safety measures regarding the fate and the effects of the transferred Tregs have to be studied. Besides this ethical considerations are important in regard to what risks we should take to treat a disease in young patients which can otherwise be treated medically. In the meantime the concept of Tregs for therapy of T1D is supported by successful clinical attempts to induce these cells IN VIVO by administration of monoclonal antibodies against CD3. If subsequent studies show that Tregs represent a safe and efficient source for therapy, they could become an important weapon in the fight against immune mediated pathology.

[Autoimmune polyglandular syndromes]. / Autoimmun polyglanduläre Syndrome.

Autoimmune polyglandular syndromes are rare autoimmune endocrinopathies, which can be also associated with non endocrine autoimmune diseases. The autoimmune polyglandular syndrome type I (autoimmune polyendocrinopathy-candidiasis ectodermal dystrophy; APECED) is distinguished from autoimmune polyglandular syndrome type 2 (APS-2). Main symptoms of APECED are adrenal insufficiency, hypoparathyroidism and candidiasis. The diagnosis is established when two out of three of these symptoms are present. APECED is associated with mutations of the autoimmune regulator gene (AIRE) and predominantly affects juvenile patients with a family background from Sardinia, Finland and Iranian Jews. The APS-2 is not AIRE associated. It is characterized by the presence of autoimmune thyroid disease, adrenal insufficiency and/or diabetes mellitus type I. APS-2 is more common than APECED and mainly affects adult women without any preference of a certain ethnic group. Therapy consists of hormone replacement therapy and treatment of clinical symptoms. In some APECED patients immunosuppressive therapy seems to be promising.

[Organ transplantation in endocrinology. Islet cells and pancreas]. / Organtransplantation in der Endokrinologie. Inselzellen und Pankreas.

Pancreas transplantation is a successful and effective procedure resulting in tight glucose control. Due to the postoperative morbidity and the need for immunosuppression pancreas transplantation should be considered at the time of kidney transplantation. Besides this, pancreas transplantation alone should be considered for patients with unacceptably poor metabolic control and quality of life despite optimal medical treatment. Recently, islet transplantation became a less invasive alternative to pancreas transplantation. Due to the lack of long-term follow-up and due to the need of multiple donor grafts for one recipient, islet transplantation should be performed under experimental settings in experienced centers. New developments in protecting transplanted islets and in the induction of donor-specific tolerance could increase the indication to perform the procedure. Therefore alternative sources of beta-cells have to be identified.

Correlation of expression of cyclooxygenase-2, vascular endothelial growth factor, and peroxisome proliferator-activated receptor delta with head and neck squamous cell carcinoma.

Cyclooxygenase (COX) is the rate-limiting enzyme in the formation of prostaglandins from arachidonic acid. COX exists in 2 isoforms, COX-1 and COX-2. These isoforms are encoded by separate genes and demonstrate cell-specific expression and regulation. Peroxisome proliferator-activated receptor delta (PPARdelta) is a nuclear transcription factor that is activated by prostacyclin. Vascular endothelial growth factor (VEGF) is a proangiogenic factor that is up-regulated in various tumors. Vascular endothelial growth factor has been shown to interact with COX-derived prostaglandins in angiogenesis. To better understand the roles of these genes in head and neck squamous cell carcinoma (HNSCCA), we examined the differential expression of the COX1, COX2, VEGF, and PPARdelta genes in these tumors. Tissue samples from patients with HNSCCA were analyzed for COX-1, COX-2, VEGF, and PPARdelta messenger RNAs (mRNAs) by in situ hybridization. COX-1 and COX-2 mRNAs were also evaluated with Northern blot hybridization. Immunohistochemistry was used to analyze for COX-2 and PPARdelta proteins. Results showed focal areas of accumulation for COX-2, VEGF, and PPARdelta but not COX-1 in human HNSCCA. Northern blot hybridization showed higher levels of COX-2 mRNA in HNSCCA than in normal tissue. This suggests a supportive role of COX-2 in development and/or progression of HNSCCA. In addition, PPARdelta may be a receptor for COX-2-produced prostaglandins in HNSCCA. There is a potential role for selective COX-2 inhibitors in the treatment of these lesions.