A hot-Jupiter progenitor on a super-eccentric retrograde orbit.

Giant exoplanets orbiting close to their host stars are unlikely to have formed in their present configurations1. These 'hot Jupiter' planets are instead thought to have migrated inward from beyond the ice line and several viable migration channels have been proposed, including eccentricity excitation through angular-momentum exchange with a third body followed by tidally driven orbital circularization2,3. The discovery of the extremely eccentric (e = 0.93) giant exoplanet HD 80606 b (ref. 4) provided observational evidence that hot Jupiters may have formed through this high-eccentricity tidal-migration pathway5. However, no similar hot-Jupiter progenitors have been found and simulations predict that one factor affecting the efficacy of this mechanism is exoplanet mass, as low-mass planets are more likely to be tidally disrupted during periastron passage6-8. Here we present spectroscopic and photometric observations of TIC 241249530 b, a high-mass, transiting warm Jupiter with an extreme orbital eccentricity of e = 0.94. The orbit of TIC 241249530 b is consistent with a history of eccentricity oscillations and a future tidal circularization trajectory. Our analysis of the mass and eccentricity distributions of the transiting-warm-Jupiter population further reveals a correlation between high mass and high eccentricity.

Impact of kidney transplantation on sleep apnea severity: A prospective polysomnographic study.

Fluid overload has been associated with a high prevalence of sleep apnea (SA) in patients with end-stage kidney disease (ESKD). In this prospective study, we hypothesized that improvement in kidney function and hydration status after kidney transplantation (Tx) may result in an improvement in SA severity. A total of 196 patients on the kidney Tx waiting list were screened for SA using home nocturnal polysomnography (PSG) to measure the apnea-hypopnea index (AHI) and underwent bioimpedance to assess body composition. Of 88 participants (44.9%) with SA (AHI ≥ 15/h), 42 were reassessed 6 months post-Tx and were compared with 27 control patients. There was a significant, but small, post-Tx improvement in AHI (from 44.2 ± 24.3 to 34.7 ± 20.9/h, P = .02) that significantly correlated with a reduction in fluid overload (from 1.8 ± 2.0 to 1.2 ± 1.2 L, P = .02) and body water (from 54.9% to 51.6%, P = .003). A post-Tx increase in body fat mass (from 26% to 30%, P = .003) possibly blunted the beneficial impact of kidney Tx on SA. All parameters remained unchanged in the control group. In conclusion, SA is a frequent condition in ESKD patients and partially improved by kidney Tx. We suggest that SA should be systematically assessed before and after kidney Tx. ClinicalTrials.gov Identifier: NCT02020642.

Chemotherapy and plasma adipokines level in patients with colorectal cancer.

Adipokines are molecules produced and secreted by adipose tissue and are linked to multiple malignancies. Adipokines can suppress or promote particular cell behaviors in different types of cancer. The aim of this study was to investigate the impact of chemotherapy on select adipokines in patients with colorectal cancer (CRC). Blood samples were collected from 42 patients with pathologically documented advanced CRC, who required palliative chemotherapy. Leptin, adiponectin, resistin and visfatin levels were measured by ELISA before and 3 months after the administration of chemotherapy. Among the 42 patients evaluated, 18 achieved a partial response (PR), 16 achieved stable disease (SD) and 8 patients experienced disease progression (PD). We found that 5-fluorouracil-based chemotherapy regimens significantly increased plasma levels of leptin and adiponectin and decreased plasma levels of resistin and visfatin in PR and SD patients, whereas the plasma levels of these molecules were not affected in PD patients. Furthermore, the mean plasma levels of leptin were significantly lower, and the mean plasma levels of resistin and visfatin were significantly greater in patients with PD compared with PR and SD both before and after chemotherapy treatment. We conclude that palliative chemotherapy in CRC patients, in addition to providing clinical benefits, positively affects cytokine production and secretion in PR and SD patients. Specifically, we found that palliative chemotherapy increased plasma levels of the anti-inflammatory adipokine adiponectin and decreased the plasma levels of visfatin and resistin, molecules known to promote angiogenesis and cancer cell proliferation in PR and SD patients. Moreover, the baseline values of leptin, visfatin and resistin might serve as prognostic indicators of a poor response to chemotherapy.

Giant congenital malformation of the perirectal plexus in computed tomography imaging - case report.

BACKGROUND: Congenital arteriovenous malformation (AVM) in the pelvic area is uncommon in males. CASE REPORT: The described case is of a giant lesion of this type that caused recurrent hemorrhaging in the lower part of the gastrointestinal tract. Preliminary diagnosis of vascular pathology was made on the basis of an endoscopic examination that revealed numerous pulsating protuberances of the rectal wall, in which blood flow was identified by means of transrectal ultrasonography. Complementing the diagnostics with a CT revealed a considerable extent of malformation, as well as its morphology and anatomical relations with the surrounding tissues. RESULTS: Following a two-year follow-up period, the malformation did not progress or demonstrate any intensification of clinical symptoms, therefore the patient continues to undergo conservative treatment.

Nanostars in Highly Si-Doped GaN.

Understanding the relation between surface morphology during epitaxy of GaN:Si and its electrical properties is important from both the fundamental and application perspectives. This work evidences the formation of nanostars in highly doped GaN:Si layers with doping level ranging from 5 × 1019 to 1 × 1020 cm-3 grown by plasma-assisted molecular beam epitaxy (PAMBE). Nanostars are 50-nm-wide platelets arranged in six-fold symmetry around the [0001] axis and have different electrical properties from the surrounding layer. Nanostars are formed in highly doped GaN:Si layers due to the enhanced growth rate along the a-direction ⟨112̅0⟩. Then, the hexagonal-shaped growth spirals, typically observed in GaN grown on GaN/sapphire templates, develop distinct arms that extend in the a-direction ⟨112̅0⟩. The nanostar surface morphology is reflected in the inhomogeneity of electrical properties at the nanoscale as evidenced in this work. Complementary techniques such as electrochemical etching (ECE), atomic force microscopy (AFM), and scanning spreading resistance microscopy (SSRM) are used to link the morphology and conductivity variations across the surface. Additionally, transmission electron microscopy (TEM) studies with high spatial resolution composition mapping by energy-dispersive X-ray spectroscopy (EDX) confirmed about 10% lower incorporation of Si in the hillock arms than in the layer. However, the lower Si content in the nanostars cannot solely be responsible for the fact that they are not etched in ECE. The compensation mechanism in the nanostars observed in GaN:Si is discussed to be an additional contribution to the local decrease in conductivity at the nanoscale.

Fine-tuned continuous renal replacement therapy with calcium-free dialysate to manage severe hypercalcemia refractory to medical and intermittent hemodialysis.

Malignancy-related hypercalcemia is a leading cause of hypercalcemia among hospitalized patients that carries poor prognosis. Parathyroid carcinoma is a rare form of primary hyperparathyroidism that may be associated with PTH dependent hypercalcemia. Severe hypercalcemia is life-threatening and may require management in an intensive care unit by means of medical therapy consisting of volume expansion, loop diuretics, cinacalcet, calcitonin and bisphosphonates. Renal replacement therapy such as intermittent hemodialysis has been successfully used among patients with severe hypercalcemia who become refractory to medical treatment. However, little data are available for cases of severe refractory hypercalcemia that fail to respond to both optimal medical therapy and hemodialysis. Our present case illustrates the successful use of continuous veno-venous hemodiafiltration (CVVHDF) with calcium-free dialysate calcium and markedly increased dialysate flow rate, to restore normal calcemia in a patient with metastatic parathyroid carcinoma with severe refractory hypercalcemia.

Single-Sensor Vibration-Scanning Method for Assessing the Mechanical Properties of 3D Printed Elements.

This paper considers issues related to the assessment of the mechanical properties of elements made with 3D printing technology. To enable experimental testing, an automated test stand was built to perform amplitude and phase angle measurements of any point of the specimen. A contactless, optical measurement method was selected, as it is especially adequate when it comes to elements with small dimensions and masses. One innovative element of the test stand is the original method of phase angle measurement using a single vibration sensor fitted with a system forcing and ensuring full measurement synchronization and dynamic state repeatability. Additionally, numerical models of tested objects were produced and simulations of their oscillations were performed. Based on that, the properties of the tested material (PLA) were considered, with a special focus on the density, elastic modulus, and damping. The analyses were conducted for a few elements with different dimensions at different vibration frequencies.

Preoperative Neutrophil-lymphocyte Ratio as a Predictor of Overall Survival in Patients with Localized Renal Cell Carcinoma.

PURPOSE: The neutrophil-to-lymphocyte ratio (NLR), as an indicator of the systemic inflammatory response, predicts adverse outcomes in many malignancies. We investigated its prognostic significance in patients with non-metastatic renal cell carcinoma. MATERIALS AND METHODS: We retrospectively evaluated data of 196 consecutive non-metastatic RCC patients who underwent radical or partial nephrectomy between 2010 and 2012 at a single center. Overall survival (OS) was assessed using the Kaplan-Meier method and compared using the log-rank test. We applied univariate and multivariate Cox regression models to evaluate the prognostic value of dichotomized NLR for OS.   Results: At a median follow up of 68 months, high NLR (? 2,69) correlated with worse survival outcome (P = .006 in log-rank test) and higher tumor stage (P = .035). Univariate and multivariate analysis identified elevated NLR (P = .039), as well as age (P = .002), high Fuhrmann grade (P = .002) and high pathologic T stage (P < .001), as significantly associated with overall survival. CONCLUSION: In our cohort, an elevated neutrophil-to-lymphocyte ratio is significantly associated with worse OS on univariate and multivariate analysis. Consequently, the NLR is an easily acquired biomarker, which may be useful in pretreatment patient risk stratification.

Evidence for no relevance of anti-major histocompatibility complex class I-related chain a antibodies in liver transplantation.

The polymorphic major histocompatibility complex class I-related chain A (MICA) antigen is being increasingly recognized as a potential target molecule for immune cells during allograft rejection. Here we studied whether MICA is a target antigen for antibodies in liver transplant patients. Eighty-four patients were investigated for the presence of MICA antibodies before and after liver transplantation with MICA-transfected cells and flow cytometry. MICA typing was performed by polymerase chain reaction. Expression of MICA in liver cells was determined by reverse-transcription polymerase chain reaction, Western blotting, and flow cytometry. Liver biopsy specimens from liver transplant patients were examined for MICA expression. A total of 22 of 84 (26%) patients had MICA antibodies either pre-transplant (8/84, 9.5%) or post-transplant (14/84, 17%). No correlation between rejection frequencies (14/22, 63%) or other clinical parameters was observed in patients with MICA antibody versus those without MICA antibody (29/62, 47% P = not significant). We found weak messenger RNA expression for MICA in liver cells but no protein or cell surface expression. In addition, no MICA expression in liver biopsy sections from liver transplant patients was observed at any time point, including rejections. Thus, our preliminary results demonstrate no causal relationship between the presence of MICA antibodies and liver allograft rejections. Therefore, it is likely that MICA may not be an important target antigen during liver allograft rejections.

Expression of slow skeletal troponin I in hearts of phospholamban knockout mice alters the relaxant effect of beta-adrenergic stimulation.

Beta-adrenergic stimulation of the heart results in an enhanced relaxation rate in association with phosphorylation of both cardiac troponin I (cTnI) and phospholamban (PLB). We studied new lines of mice generated by crossbreeding mice that express slow skeletal troponin I (ssTnI) with PLB knockout (PLBKO) mice. This crossbreeding resulted in the generation of PLB/cTnI, PLB/ssTnI, PLBKO/cTnI, and PLBKO/ssTnI mice. Perfusion with isoproterenol (ISO) significantly increased the peak amplitude of fura-2 ratio in PLB/cTnI, PLBKO/cTnI, and PLBKO/ssTnI groups of mice. However, in the presence of ISO, there were no differences in the peak amplitude of fura-2 ratio among cells isolated from hearts of PLB/cTnI, PLBKO/cTnI, and PLBKO/ssTnI mice. In cells from PLB/cTnI mice, the extent of shortening was increased and the time of relaxation was significantly decreased during beta-adrenergic stimulation. In PLBKO/cTnI cells, stimulation with ISO resulted in an increased extent of shortening and no change in time of relaxation. However, stimulation with ISO in cells isolated from PLBKO/ssTnI mice not only significantly increased the extent of cell shortening but also increased the time of relaxation. We also determined the kinetics of relaxation of papillary muscles isolated from all four groups of animals in the presence and absence of ISO. Perfusion with ISO increased the rate of relaxation only in PLB/cTnI, PLB/ssTnI, and PLBKO/cTnI muscles. During ISO stimulation, the time of relaxation was unchanged in PLBKO/ssTnI muscles. Our data directly demonstrate that phosphorylation of both PLB and cTnI contributes to increased rate of relaxation during beta-adrenergic stimulation.

Extent of lymphadenectomy in patients with bladder cancer undergoing radical cystectomy - a multi-institutional analysis.

Lymph node dissection (LND) performed at radical cystectomy (RC) has therapeutic and staging significance. However, the extent of LND remains controversial. The aim of this study was to analyze surgical patterns and results of LND in a contemporary series of patients with bladder cancer. This is a retrospective analysis of 113 consecutive patients subjected to RC in seven urological centres in the year 2013. The mean age of the cohort was 66.6 years. There were 49 cases of organ confined and 64 cases of locally advanced disease. Study endpoints were: status and extent of LND, number of LNs removed, and number of positive LNs. LND was performed in 102 patients (90.3%). Detailed data on the anatomical extent of LND was available in 82 patients (80.4%). Limited (lLND) and extended LND (eLND) was performed in 68.3% (n = 56) and 31.7% (n = 26) of patients, respectively. Obturator fossa LNs were removed in 84.1%, external iliac in 72.0%, internal iliac in 40.2%, common iliac in 31.7%, and presacral in 15.9% of cases. The median number of LNs removed in the whole study cohort, in patients who underwent lLND, and eLND, was 8.5, 5, and 16.5, respectively. In 28 patients (27.5%), LN metastases were diagnosed, including 6 cases (12.5%) in the organ-confined cohort and 22 cases (34.4%) in the locally advanced disease cohort. LND is an integral part of radical cystectomy in patients with bladder cancer. However, in the majority of patients, the extent of the procedure was suboptimal, potentially negatively affecting the survival and adequacy of pathological staging.

Expression of vascular endothelial growth factor receptor-2 or Tie-2 on peripheral blood cells defines functionally competent cell populations capable of reendothelialization.

BACKGROUND: Receptor tyrosine kinases that include vascular endothelial growth factor (VEGFR)-1, VEGFR-2, and Tie-2 regulate cardiovascular development and physiological and pathological angiogenesis. We were interested in the phenotypic and functional characterization of peripheral blood cells expressing these receptors and their therapeutic potential in vascular injury. METHODS AND RESULTS: VEGFR-1+, VEGFR-2+, and Tie-2+ cells constituted approximately 3.0+/-0.2%, 0.8+/-0.5%, and 2.0+/-0.3%, respectively, of the total population of mononuclear cells in blood. Phenotypic analysis demonstrated that all 3 cell populations mainly expressed markers of monocytic/macrophage lineage. Only VEGFR-2+ and Tie-2+ cells phenotypically, morphologically, and functionally differentiated to endothelial cells after culture, whereas VEGFR-1+ cells did not. None of the cell types proliferated in vitro. Only freshly isolated VEGFR-2+ or Tie-2+ cells but not VEGFR-2- or Tie-2- cell populations significantly contributed to efficient endothelialization of balloon-injured femoral arteries of nude mice. Furthermore, these cells also differentiated into -actin-positive smooth muscle cells. Administration of bromodeoxyuridine to animals transplanted with human endothelial progenitor cells showed that VEGFR-2+ and Tie-2+ cells proliferated in vivo. CONCLUSIONS: These data demonstrate that expression of VEGFR-2 and/or Tie-2 on peripheral blood cells defines functionally competent cell populations that proliferate in vivo and that contribute to reendothelialization. These findings may have implications for a cell-based approach in vascular diseases.

Intraperitoneal microdialysis (IPM): a new technique for monitoring intestinal ischemia studied in a porcine model.

Acute mesenteric thrombosis, vascular complications of intestinal transplantation, sepsis, and multiple organ failure are all associated with intestinal ischemia. To improve the outcome of these patients, better monitoring devices are needed. A new technique, intraperitoneal microdialysis (IPM), was evaluated for detection of intestinal ischemia in a porcine model, with the intention of evaluating the technique for future use on humans. Fourteen pigs divided into two studies were used. In a total ischemia study a microdialysis catheter was placed intraperitoneally and the superior mesenteric artery was occluded for 1 h 40 min. In a local ischemia study, the arcus vessels supplying a 30-cm long small bowel segment were occluded for 3 h 20 min. One IPM catheter was placed next to the ischemic area and another IPM catheter 10 cm caudally as an intraperitoneal reference. In both studies reference catheters were placed subcutaneously. Glucose, lactate, pyruvate, and glycerol were analyzed every 20 min. In both studies vessel occlusion resulted in decreased glucose and increased lactate, glycerol, and lactate/pyruvate ratio. Significant changes were reached after 60 min of ischemia in most analytes, whereas the values from the reference catheter were stable. Our conclusion is that intestinal ischemia is detectable with IPM based on the analysis of well-documented markers of ischemia (increased lactate/pyruvate ratio) and cell membrane damage (elevated glycerol levels). It allows semi-continuous monitoring of the intestines with a minimally invasive procedure, which we believe will be possible to apply in human routine clinical use.

Surgical outcome in patients with spinal metastases in the period 1993-2002.

Background. Authors introduced ways and results of treatment operating patients with spinal metastases, treated in Orthopaedic Clinic of Central Military Hospital in years 1993-2002.
Material and methods. In introduced period in Clinic 54 patients was treated with spinal metastases. 37(68,6%) was treated surgical and 17(31,4%) conservatively. In Clinic following indications were established to operating treatments: pathological fracture of vertebrae, growing neurological symptoms, as well as uncompromising pain in conservative treatment. Advancement of neoplasmatic disease and very bad prognosis was most important contraindication to operating treatment. Following operating method treatments: posterior stabilization by Harrington method and stabilization by transpedicular screws. Percutaneous vertebroplasty was applied.
Results. In Frankel scale following results were noted down: in front of operation E-5, D-23, C-7, B-2, A-0, after operation E-8, D-24, C-5, B-0, A-0.
Conclusions. Authors affirm, that operation treatment in choose cases is only effective way of supply patients with spinal metastases.

Liver sinusoidal endothelial cell function in rejected and spontaneously accepted rat liver allografts.

Studies have suggested that liver sinusoidal endothelial cells (LSEC) may play an important role in tolerance induction. In this study, we evaluated the functional difference of LSEC in rejection and spontaneous acceptance of liver allografts by using rat liver transplant model. LSEC function was determined by circulating hyaluronic acid (HA) levels and fluorescein isothiocyanate-labeled formaldehyde-treated serum albumin (FITC-FSA) uptake. Additional parameters include the number of circulating lymphocytes and LSEC apoptosis. In spontaneously accepted group, we found (i) significantly lower serum HA levels (P = 0.002), (ii) a more rapid uptake of FITC-FSA, and (iii) a reduced number of circulating CD8a+ cells when compared with the rejection group. Strikingly, HA levels in spontaneously accepted group are even lower than syngeneic control group. Further investigation revealed that interleukin-1beta, a cytokine that promotes LSEC function, was higher in DA than in Lewis rats. In summary, our study demonstrates that LSEC function is better preserved in spontaneously accepted rat liver allografts than in those which are rejected. These findings warrant further studies to verify if LSEC actively contributes to liver transplant outcome or just a target of different immunologic responses.

Correlations between alterations in length-dependent Ca2+ activation of cardiac myofilaments and the end-systolic pressure-volume relation.

We have tested the hypothesis that alterations in length dependent activation (LDA) of cardiac myofilaments represent an important regulatory mechanism affecting the Frank-Starling mechanism as determined by the slope (E(es)) of the relation between left ventricular (LV) volume and end-systolic pressure. We employed a transgenic (TG) mouse model in which the cardiac isoform of TnI (cTnI) has been completely replaced with slow skeletal TnI (ssTnI), the embryonic/neonatal isoform in the heart. Compared to non-transgenic (NTG) controls, myofilaments from TG-ssTnI hearts demonstrate an increase in Ca(2+) sensitivity and a substantially blunted LDA that is unaffected by PKA-dependent phosphorylation. We measured in situ LV pressure and volume relations during basal conditions and isoproterenol (ISO) stimulation. In the basal state in TG-ssTnI hearts there was significant increase in end-systolic pressure and slight decrease in heart rate. ISO stimulation resulted in a significant increase in heart rate, ejection fraction, maximum dP/dt, preload-recruitable stroke work, maximum dP/dt versus end diastolic volume and cardiac output in both groups. During basal conditions there was no difference in the E(es) relation between NTG and TG-ssTnI groups. However, during ISO stimulation the E(es) relation was significantly different between NTG and TG-ssTnI groups. Our study provides the first direct evidence that enhancement in differences in LDA between cardiac myofilaments from NTG and TG-ssTnI hearts induced by post-translational modifications of sarcomeric proteins are reflected in the in situ beating heart by a different change in E(es). Thus, changes in LDA should be considered in interpreting results from in situ experiments on inotropic effects associated with physiological and patho-physiological states of the heart.

Enteral donor pre-treatment with ursodeoxycholic acid protects the liver against ischaemia-reperfusion injury in rats.

Liver donor pre-treatment with ursodeoxycholic acid (UDCA) may protect against injury during transplantation. In the present study we evaluated whether enteral administration of UDCA has an effect on bile flow and protects the liver from injury related to transplantation. Wistar rats were used in liver perfusion (LP) and transplantation (LTx) models. Rats were enterally administered UDCA (800 mg/kg) 3 h before cold perfusion. In LP, bile flow and bile acid composition were analysed. In LTx, serum ALT and liver histology were analysed. LP showed biliary UDCA enrichment up to 36+/-13% in pre-treated rats, causing higher bile flow (P = 0.026) compared with control rats. LTx showed lower ALT and TUNEL positive hepatocytes in the UDCA group (P < 0.02 and P < 0.05). In conclusion, augmented bile salt-dependent bile flow is preserved in the liver after cold storage. Enteral donor pre-treatment with UDCA protects the liver against ischaemia-reperfusion injury.

Only a specific subset of human peripheral-blood monocytes has endothelial-like functional capacity.

The monocyte population in blood is considered a possible source of endothelial precursors. Because endothelial-specific receptor tyrosine kinases act as regulators of endothelial cell function, we investigated whether expression of the vascular endothelial growth factor receptor-2 (VEGFR-2) on monocytes is important for their endothelial-like functional capacity. Peripheral-blood monocytes expressing vascular endothelial growth factor receptor-2 (VEGFR-2), or CD14+/VEGFR-2+, were isolated, and their phenotypic, morphologic, and functional capacities were compared with those of monocytes negative for this marker (CD14+/VEGFR-2-). CD14+/VEGFR-2+ cells constituted approximately 2% +/- 0.5% of the total population of monocytes and 0.08% +/- 0.04% of mononuclear cells in blood. CD14+/VEGFR-2+ cells exhibited the potential to differentiate in vitro into cells with endothelial characteristics. The cells were efficiently transduced by a lentiviral vector driving expression of the green fluorescence protein (GFP). Transplantation of GFP-transduced cells into balloon-injured femoral arteries of nude mice significantly contributed to efficient reendothelialization. CD14+/VEGFR-2- did not exhibit any of these characteristics. These data demonstrate that the expression of VEGFR-2 on peripheral blood monocytes is essential for their endothelial-like functional capacity and support the notion of a common precursor for monocytic and endothelial cell lineage. Our results help clarify which subpopulations may restore damaged endothelium and may participate in the maintenance of vascular homeostasis.

The long-term impact of liver transplantation on kidney function in familial amyloidotic polyneuropathy patients.

The aim of the study is to evaluate the long-term kidney function after liver transplantation (LTx) in familial amyloidotic polyneuropathy (FAP) Portuguese type patients and compare the findings with patients transplanted for chronic liver disease of other origin. We analysed the medical records of 32 FAP patients who underwent transplantation between 1990 and 1999 with a follow-up of more than 1 year after LTx. The control group consisted of 61 patients who had undergone LTx for chronic liver disease. Kidney function was measured by the glomerular filtration rate (GFR), serum creatinine and urea. There were no differences between the groups in creatinine and urea levels during the follow-up. However, during the first year after transplantation, the increase in creatinine and urea was significantly higher in the control group (P < 0.01). The decline in GFR after transplantation was also more pronounced in the controls (P < 0.01). Initially after LTx, kidney function deteriorated in both FAP and control patients, but the deterioration was more pronounced in the controls. The decline of the FAP patients' kidney function after LTx was not more pronounced than that observed in control patients, although many FAP patients' kidney function was impaired before the procedure, suggesting that LTx may halt the progression of kidney damage caused by amyloid deposition.

Non-viral delivery of the porphobilinogen deaminase cDNA into a mouse model of acute intermittent porphyria.

Acute intermittent porphyria (AIP), an inborn error of metabolism, results from the deficient activity of the third enzyme in the heme biosynthetic pathway, porphobilinogen deaminase (PBGD). Clinical symptoms of this autosomal dominant hepatic porphyria include episodic acute attacks of abdominal pain, neuropathy, and psychiatric disturbances. Current therapy based on intravenous heme administration is palliative and there is no way to prevent the attacks. Thus, efforts are focused on methods to replace the deficient activity in the liver to prevent the acute attacks of this hepatic porphyria. Here we explore the efficiency of a non-viral gene delivery to obtain PBGD expression in the liver of AIP transgenic mice. Four vectors were evaluated: naked DNA and DNA complexed to liposomes, polyethylenimine (PEI), and PEI-galactose, using a luciferase construct as reporter gene. The vectors were administered intravenously or directly into the portal vein with transient blood flow blockage. After tail vein injection of the DNA complexes, the liposome vector had the highest luciferase expression in lung and less in liver. When injected into the portal vein, the naked DNA had considerably higher hepatic reporter gene expression; 100 microg of naked DNA had the highest hepatic luciferase expression 24h after portal vein injection. When these vectors were used to deliver the PBGD gene into the AIP mouse model no enhancement of the endogenous PBGD activity in liver was detectable, despite the presence of the PBGD-plasmids as verified by PCR. Thus, more efficient non-viral vectors are needed to express sufficient PBGD activity over the endogenous hepatic level (approximately 30% of normal) in this murine system.