Management of Intracranial Incidental Findings on Brain MRI.

The wider use of MRI for imaging of the head in both research and clinical practice has led to an increasing number of intracranial incidental findings. Most of these findings have no immediate medical consequences. Nevertheless, knowledge of common intracranial incidental findings and their clinical relevance is necessary to adequately discuss the findings with the patient. Based on the author´s experiences from a large population-based study, the most common incidental MR findings in the brain will be presented, discussing their clinical relevance and giving recommendations for management according to the current literature and guidelines. Key points: • Intracranial incidental findings are common.• The majority of these findings have no immediate medical consequences.• Knowledge of common incidental findings is necessary for appropriate management. Citation Format: • Langner S, Buelow R, Fleck S et al. Management of Intracranial Incidental Findings on Brain MRI. Fortschr Röntgenstr 2016; 188: 1123 - 1133.

Improved long-term graft survival after HO-1 induction in brain-dead donors.

Brain death (BD) of the donor, a risk factor uniquely relevant for organs derived from cadaver donors, influences organ quality by induction of various inflammatory events. Consequently ischemia/reperfusion injury is deteriorated and acute and chronic rejections accelerated. Donor treatment might be an approach to improve the quality of the graft. The induction of heme oxygenase 1 (HO-1) has been shown to exert beneficial effects in living-donor transplantation models. Therefore, we examined the impact of donor treatment with the selective inducer of HO-1, cobalt protoporphyrin (CoPP), on organ quality and transplant outcome in a standardized BD model in a F344-->LEW kidney transplant rat model. Immediately after BD induction, donor animals were administered a single dose of CoPP (5 mg/kg) and in control groups, HO-1 activity was blocked with zinc protoporphyrin (ZnPP, 20 mg/kg). Recipients of organs from brain-dead donors treated with CoPP survived significantly better than those from untreated brain-dead donors (p < 0.05) and intra-graft analysis showed improved histology (p < 0.05). Blockade of HO-1 with ZnPP decreased the survival rates (p < 0.05) comparable to untreated brain-dead donors. Our results demonstrate that HO-1 induction by one single treatment of CoPP in brain-dead donors leads to enhanced allograft survival.

The future of antibody therapy.

Antibodies have been used successfully as therapeutics for over 100 years. The successful development of therapeutic human(ized) monoclonal antibodies (mAbs) in the last 20 years has demonstrated the potency of mAbs but also revealed some of their limitations. Studies in animals and humans demonstrated that it is possible to overcome some of these limitations using mixtures of mAbs or polyclonal antibody (pAb) preparations. pAbs from human and animal plasma are efficacious and safe therapeutics for the treatment of many diseases. Novel technologies are being developed for the production of human pAbs in genetically engineered animals. Immunization of such animals should allow the production of effective and safe high-titer antibody preparations for the treatment of infectious diseases, cancer, and autoimmunity.

Induction of carbon monoxide in the donor reduces graft immunogenicity and chronic graft deterioration.

Chronic allograft dysfunction remains the major obstacle for long-term successful transplantation. To date there is no effective treatment. Overexpression of protective genes has provided increased graft function and survival. This mechanism has been implicated in the process of graft accommodation. One of these genes that has been shown to mediate protective effects decodes the enzyme heme oxygenase-1 (HO-1), and an HO-1 downstream product, carbon monoxide (CO). Using an established model of kidney chronic allograft rejection in the rat, we investigated the impact of methylene chloride (MC), a CO donor, as a therapeutic tool to reduce chronic graft deterioration. We showed that donor and long-term recipient treatment with MC improved graft function and reduced histological signs of chronic rejection. Carbon monoxide may be a promising agent to improve graft quality and long-term graft function.

Sequence analysis of 0.4 megabases of the rabbit germline immunoglobulin kappa1 light chain locus.

Two rabbit germline bacterial artificial chromosome (BAC) libraries from animals with the b5 and b4 allotype were screened with probes specific for the immunoglobulin kappa1 light chain locus. Two partially overlapping BAC clones containing Vkappa elements of b5 allotype were isolated from the b5 library and one BAC clone containing Jkappa1, Ckappa and Vkappa was isolated from the b4 library. These three BAC clones were sequenced. They span about 0.4 MB of the rabbit Ig kappa1 light chain locus including 36 Vkappa elements, five J elements and the coding region of Ckappa1. The organization of the locus and the potential function of newly identified functional and structural elements are discussed.

Induction of long-term cardiac allograft survival by heme oxygenase-1 gene transfer.

Elevated expression of heme oxygenase-1 (HO-1), an intracellular enzyme that degrades heme into carbon monoxide (CO), biliverdine and free iron, has anti-inflammatory and antiapoptotic effects in diverse models. Here, we analyzed the effects of specific overexpression of HO-1 following adenovirus-mediated (AdHO-1) gene transfer in an acute cardiac allograft rejection model. The intragraft (i.g.) injection of AdHO-1 into cardiac allografts, as well as intramuscular (i.m.) or intravenous (i.v.) administration, prolonged allograft survival with, respectively, 13.3, 62.5 and 80% of the grafts surviving long term (>100 days), whereas control grafts were rejected with acute kinetics. HO-1 overexpression was associated with inhibited allogeneic responses in MLRs using graft-infiltrating leukocytes and splenocytes, but not with lymph node cells. The inhibition of splenocyte proliferation was mediated by soluble factors and was dependent on the presence of APCs, since purified T cells proliferated normally. i.v. but not i.g. AdHO-1 administration decreased the number of graft-infiltrating leukocytes, cytokine mRNA accumulation and apoptosis in transplanted hearts, whereas i.v. and i.g. AdHO-1 did not modify normal immune responses against cognate antigens, indicating that there was no general immunosuppression. These results indicate that HO-1 overexpression prolongs the survival of vascularized allografts by promoting tolerogenic mechanisms acting on allogeneic cellular immune responses.

RDP58, a novel immunomodulatory peptide with anti-inflammatory effects. A pharmacological study in trinitrobenzene sulphonic acid colitis and Crohn disease.

BACKGROUND: Tumour necrosis factor (TNF) plays a key role in the pathogenesis of Crohn disease (CD). RDP58 is a novel anti-inflammatory decapeptide which was developed using a novel rational design strategy. Recently, RDP58 has proved to be a potent inhibitor of TNF production at a post-transcriptional step. The aims of this study were to investigate the anti-inflammatory properties of RDP58 ex vivo in human CD and in vivo in an experimental model colitis. METHODS: Biopsies and lamina propria mononuclear cells from inflamed colonic mucosa of 18 CD patients were cultured for 24 h in the presence or absence of RDP58. TNF was quantified in a bioassay: interferon (IFN)-gamma and interleukin (IL)-1beta levels were measured by enzyme-linked immunosorbent assays. Colitis was induced by intra-rectal administration of 2, 4, 6 trinitrobenzene sulphonic acid (TNBS) in rats. Inflammation was assessed following 7 days of oral therapy with RDP58 or vehicle alone. RESULTS: RDP58 led to decreased TNF and IFN-gamma (but not IL-1beta) production by biopsies and lamina propria mononuclear cells from CD patients. In rats with TNBS-induced colitis, oral RDP58 therapy reduced weight loss and diarrhoea and improved macroscopic and histological inflammation scores. CONCLUSIONS: Our results suggest that RDP58 may be an effective therapy for CD with the clinical advantage of an oral administration.

Generation of heme oxygenase-1-transgenic rats.

Heme oxygenase-1 (HO-1) expression protects cells from a variety of cellular insults and inhibits inflammation. However, its role in the regulation of immune responses has not yet been clearly established. We generated HO-1 transgenic rats to directly test the impact of HO-1 on the different immune mechanisms. To temporally control the expression of HO-1, we used a one-plasmid tetracycline (tet)-inducible system. This plasmid contains the H-2K(b) promoter, which transcribes the tet transactivator (tTA) and expression of a human HO-1 cDNA is obtained in the absence of tetracycline. The DNA construct was microinjected into one-cell rat embryos and mothers and pups were maintained with tetracycline. Eight transgenic founders were obtained. Analysis of transgene expression in the absence of tet showed that 2 lines (12.4 and 12.6) expressed HO-1 mRNA in several organs (as detected by reverse transcription polymerase chain reaction) and at the protein level only in the thymus. Expression levels of transgene-derived HO-1 increased after withdrawal of tet compared with transgenic rats maintained with tet, as detected by analysis of mRNA levels by quantitative real-time reverse transcription polymerase chain reaction. Gross examination and histopathological analysis of several organs in both lines showed no anomalies. Thymocytes and splenocytes of both lines showed normal cell subpopulations and allogeneic proliferation compared with controls. Systemic immune responses against cognate antigens were normal in both lines, as evaluated by the proliferation of lymph node cells and the production of antibodies against keyhole limpet hemocyanin after immunization. Animals from line 12.6 rejected transplanted allogeneic hearts with the same kinetics as controls. In conclusion, short-term induction of HO-1 overexpression did not modify immune responses compared to those of control non-transgenic animals.

RDP58, a Novel Immunomodulatory Peptide with Anti-Inflammatory Effects. A Pharmacological Study in Trinitrobenzene Sulphonic Acid Colitis and Crohn Disease.

BACKGROUND: Tumour necrosis factor (TNF) plays a key role in the pathogenesis of Crohn disease (CD). RDP58 is a novel anti-inflammatory decapeptide which was developed using a novel rational design strategy. Recently, RDP58 has proved to be a potent inhibitor of TNF production at a post-transcriptional step. The aims of this study were to investigate the anti-inflammatory properties of RDP58 ex vivo in human CD and in vivo in an experimental model colitis. METHODS: Biopsies and lamina propria mononuclear cells from inflamed colonic mucosa of 18 CD patients were cultured for 24 h in the presence or absence of RDP58. TNF was quantified in a bioassay; interferon (IFN)-γ and interleukin (IL)-1ß levels were measured by enzyme-linked immunosorbent assays. Colitis was induced by intra-rectal administration of 2, 4, 6 trinitrobenzene sulphonic acid (TNBS) in rats. Inflammation was assessed following 7 days of oral therapy with RDP58 or vehicle alone. RESULTS: RDP58 led to decreased TNF and IFN-γ (but not IL-1ß) production by biopsies and lamina propria mononuclear cells from CD patients. In rats with TNBS-induced colitis, oral RDP58 therapy reduced weight loss and diarrhoea and improved macroscopic and histological inflammation scores. CONCLUSIONS: Our results suggest that RDP58 may be an effective therapy for CD with the clinical advantage of an oral administration.

Orally administered RDP58 reduces the severity of dextran sodium sulphate induced colitis.

Oral administration of the novel anti-inflammatory peptide RDP58 markedly reduced the severity of dextran sulphate sodium (DSS) colitis as determined by clinical and quantitative histological criteria. The architecture of the colonic epithelium in DSS treated mice receiving RDP58 remained relatively normal compared with that of control DSS treated animals. 5-Bromo-2'-deoxyuridine (BrdU) labelling studies showed a pronounced inhibition of colonic epithelial cell proliferation during DSS treatment, which was partially reversed by RDP58 therapy. Remarkably, RDP58 almost completely prevented colonic epithelial cell death induced by DSS treatment. RDP58 therapy also inhibited the accumulation of neutrophils in the colon of DSS treated mice and effectively down regulated tumour necrosis factor (TNF) expression. Preservation of the intestinal mucosa by RDP58 may thus derive from its influence on TNF expression as well as additional anti-inflammatory properties. These findings indicate that RDP58 represents a new, orally available agent potentially useful in the treatment of inflammatory bowel disease.

Inhibition of graft arteriosclerosis development in rat aortas following heme oxygenase-1 gene transfer.

Heme oxygenase 1 (HO-1) is an enzyme which degrades heme into tree end products: biliverdin, free iron and carbon monoxide. This enzyme has recently been shown to have anti-inflammatory and tissue protective effects. HO-1 expression is involved in organ protection in pathological situations, and immunosuppressive treatments resulting in indefinite graft survival without chronic rejection have been associated with HO-1 expression by cells of the vessel wall. The aim of this study was to analyze the effect of specific HO-1 overexpression. We used a recombinant adenovirus coding for human HO-1 cDNA in a rat aorta chronic rejection model, 30 days after transplantation. Control groups included rats non treated or treated with a non-coding adenovirus Addl324. We first demonstrated that AdHO-1 was efficiently expressed in endothelial cells in vitro, and in rat aortas ex vivo after adenovirus gene transfer. We found that intimal thickening in AdHO-1 treated aortas (10.8 +/- 3.8%, n=5) was significantly decreased compared to untreated (21.2 +/- 5.6%, n = 5) or Addl324-treated (21.1 +/- 1.2%, n = 4) aortas. Immunohistology showed that treatment with AdHO-1 resulted in a significant reduction in leukocyte infiltration and a decreasing number of VSMC in the intima, compared to Addl324-treated aortas. However, this effect of HO-1 on chronic rejection did not imply modifications on numbers of apoptotic cells in the graft or of alloantibody levels. We have demonstrated, for the first time, that specific HO-1 overexpression following gene transfer of HO-1 inhibited chronic rejection by reducing leukocyte and VSMC infiltration of the aorta intima.

RDP58, a locally active TNF inhibitor, is effective in the dextran sulphate mouse model of chronic colitis.

OBJECTIVE AND DESIGN: RDP58 is a novel anti-inflammatory peptide that inhibits TNF synthesis and upregulates heme oxygenase-1. RDP58 therapy was evaluated in the dextran sodium sulphate (DSS) model of chronic colitis. MATERIAL: Colitis was induced by giving DSS to mice (n = 8 animals/group). Toxicity studies were done in Rhesus monkeys (n = 5), dogs (n = 3) and mice (n = 10). TREATMENT: In colitis, mice were treated with p.o. vehicle (saline), RDP58 (5 and 10 mg/kg/day) or 5-ASA (50 mg/kg/day). METHODS: Disease activity index (DAI) was used as the endpoint of efficacy. RESULTS: RDP58 therapy significantly reduced DAI and histological scores in all animals. DAI scores in RDP58 treated animals declined faster than 5-ASA. RDP58 at 5 or 10 mg/ kg/day significantly reduced DAI compared to 5-ASA. RDP58 significantly reduced acute, chronic and total inflammation scores. It enhanced re-epithelialization by reducing crypt scores. RDP58 was not bioavailable and was well tolerated. CONCLUSIONS: Therapeutic efficacy of RDP58 combined with a lack of bioavailibility and toxicity suggest that RDP58 may be a promising new therapeutic for IBD.

Total and active thymoglobulin levels: effects of dose and sensitization on serum concentrations.

A group of 79 renal transplant patients undergoing acute rejection episodes were treated with Thymoglobulin (rabbit anti-thymocyte globulin), 1.5 mg/kg/day for 6-14 days as part of a double-blinded trial comparing the efficacy of Thymoglobulin and Atgam (horse anti-thymocyte globulin). Serial serum samples from the patients were tested to determine the level of Thymoglobulin (i.e. rabbit IgG levels = total Thymoglobulin) and anti-Thymoglobulin using ELISAs. Antibodies binding to human lymphocytes (active Thymoglobulin), were determined by flow cytometry; no correlation was seen between treatment efficacy and either active or total Thymoglobulin concentrations; the overall treatment success rate was 86%. Pharmacokinetics of total and active Thymoglobulin were distinctly different; active Thymoglobulin disappeared much more rapidly: only 12% of patients had detectable active Thymoglobulin by day 90 compared to 81% of patients with detectable total Thymoglobulin; percent active Thymoglobulin decreased from a peak of 0.56-0.7% during treatment, to 0.07-0.35% by day 21, and less than 0.14% by day 30. Thymoglobulin and active Thymoglobulin concentrations were modeled by multiple regression. Using dose number and sensitization as independent variables, 47-76% of the variability seen in interpatient Thymoglobulin levels could be explained, while for active Thymoglobulin levels, the measured variables accounted for 13-48% of the observed interpatient variation. We conclude that: (1) for a group of patients receiving primary Thymoglobulin treatment (averaging nine full and one partial dose per patient), neither Thymoglobulin nor active Thymoglobulin levels are predictive of treatment outcome; (2) active Thymoglobulin disappears more rapidly from the circulation than total Thymoglobulin; and (3) patients that develop anti-rabbit IgG antibodies clear Thymoglobulin and active Thymoglobulin more rapidly than unsensitized patients.

Inhibition of cutaneous UV light-induced tumor necrosis factor-alpha protein production by Allotrap 1258, a novel immunomodulatory peptide.

Peptides derived from the heavy chain of the HLA Class-I molecules have been shown to modulate immune responses both in vivo and in vitro. Using a computer-aided rational drug design approach, novel immunomodulatory peptides were designed based on peptide 2702.75-85, derived from HLA-B2702. Several peptides were identified which had increased immunomodulatory activity, including peptides RDP1258 and its D-isomer the peptide Allotrap 1258. The present study using Skh/hr hairless mouse skin model evaluated the in vivo effects of Allotrap 1258 on acute UVB-induced skin inflammation. Here we demonstrate that intraperitoneal administration of Allotrap 1258 1 h prior to UV exposure resulted in significantly diminished levels of UV-induced tumor necrosis factor (TNF)-alpha protein production in the epidermis but had no effect on other parameters of the acute UV-induced inflammatory response. By virtue of its ability to suppress TNF-alpha protein production, Allotrap 1258 could prove to be an effective modulator of inflammatory responses.

Heme oxygenase-1 overexpression protects rat livers from ischemia/reperfusion injury with extended cold preservation.

This study analyzes the effects and mechanisms of heme oxygenase-1 (HO-1)-mediated cytoprotection in rat livers exposed to cold preservation. In the first series, rats were pretreated with cobalt protoporphyrin (CoPP) or zinc protoporphyrin (ZnPP), HO-1 inducer and antagonist, respectively. Livers were stored at 4 degrees C for 24 h, and then perfused ex vivo for 2 h. Livers pretreated with CoPP had significantly higher portal venous blood flow and increased total bile production, as compared with the ZnPP group. This correlated with histologic (Banff) criteria of hepatocyte injury/liver function. In the second series, rat livers were stored at 4 degrees C for 24 h or 40 h, and then transplanted into syngeneic recipients. After 24 h of preservation, 80% of rats bearing CoPP-pretreated liver grafts survived 21 days (vs. 50% in controls). After 40h of cold preservation, liver transplant survival at day 1, 7 and 21 for the CoPP group was: 100%, 71% and 57%, respectively (vs. 50%, 50% and 33% in controls). This correlated with improved hepatic function/histologic (Suzuki) criteria of hepatocyte injury after HO-1 overexpression (immunohistology/Western blots) by infiltrating macrophages. This study documents the potential utility of HO-1-inducing agents in preventing ischemia/reperfusion injury resulting from prolonged storage of liver transplants.