Studying Closed Hydrodynamic Models of "In Vivo" DNA Perfusion in Pig Liver for Gene Therapy Translation to Humans

INTRODUCTION

Expressing exogenous genes after naked DNA delivery into hepatocytes might achieve sustained and high expression of human proteins. Tail vein DNA injection is an efficient procedure for gene transfer in murine liver. Hydrodynamic procedures in large animals require organ targeting, and improve with liver vascular exclusion. In the present study, two closed liver hydrofection models employing the human alpha-1-antitrypsin (hAAT) gene are compared to reference standards in order to evaluate their potential clinical interest.

MATERIAL AND METHODS

A solution of naked DNA bearing the hAAT gene was retrogradely injected in 7 pig livers using two different closed perfusion procedures: an endovascular catheterization-mediated procedure (n = 3) with infrahepatic inferior vena cava and portal vein blockage; and a surgery-mediated procedure (n = 4) with completely sealed liver. Gene transfer was performed through the suprahepatic inferior cava vein in the endovascular procedure and through the infrahepatic inferior vena cava in the surgical procedure. The efficiency of the procedures was evaluated 14 days after hydrofection by quantifying the hAAT protein copies per cell in tissue and in plasma. For comparison, samples from mice (n = 7) successfully hydrofected with hAAT and healthy human liver segments (n = 4) were evaluated.

RESULTS

Gene decoding occurs efficiently using both procedures, with liver vascular arrest improving its efficiency. The surgically closed procedure (sealed organ) reached higher tissue protein levels (4x10^5- copies/cell) than the endovascular procedure, though the levels were lower than in human liver (5x10^6- copies/cell) and hydrofected mouse liver (10^6- copies/cell). However, protein levels in plasma were lower (p<0.001) than the reference standards in all cases.

CONCLUSION

Hydrofection of hAAT DNA to "in vivo" isolated pig liver mediates highly efficient gene delivery and protein expression in tissue. Both endovascular and surgically closed models mediate high tissue protein expression. Impairment of protein secretion to plasma is observed and might be species-related. This study reinforces the potential application of closed liver hydrofection for therapeutic purposes, provided protein secretion improves.

Pharmacogenomics and the treatment of acute myeloid leukemia

Acute myeloid leukemia (AML) is a clinically and biologically heterogeneous malignancy that is primarily treated with combinations of cytarabine and anthracyclines. Although this scheme remains effective in most of the patients, variability of outcomes in patients has been partly related with their genetic variability. Several pharmacogenetic studies have analyzed the impact of polymorphisms in genes encoding transporters, metabolizers or molecular targets of chemotherapy agents. A systematic review on all eligible studies was carried out in order to estimate the effect of polymorphisms of anthracyclines and cytarabine pathways on efficacy and toxicity of AML treatment. Other emerging genes recently studied in AML, such as DNA repair genes, genes potentially related to chemotherapy response or AML prognosis, have also been included.

Impact of Single Nucleotide Polymorphisms (SNPs) on Immunosuppressive Therapy in Lung Transplantation

Lung transplant patients present important variability in immunosuppressant blood concentrations during the first months after transplantation. Pharmacogenetics could explain part of this interindividual variability. We evaluated SNPs in genes that have previously shown correlations in other kinds of solid organ transplantation, namely ABCB1 and CYP3A5 genes with tacrolimus (Tac) and ABCC2, UGT1A9 and SLCO1B1 genes with mycophenolic acid (MPA), during the first six months after lung transplantation (51 patients). The genotype was correlated to the trough blood drug concentrations corrected for dose and body weight (C0/Dc). The ABCB1 variant in rs1045642 was associated with significantly higher Tac concentration, at six months post-transplantation (CT vs. CC). In the MPA analysis, CT patients in ABCC2 rs3740066 presented significantly lower blood concentrations than CC or TT, three months after transplantation. Other tendencies, confirming previously expected results, were found associated with the rest of studied SNPs. An interesting trend was recorded for the incidence of acute rejection according to NOD2/CARD15 rs2066844 (CT: 27.9%; CC: 12.5%). Relevant SNPs related to Tac and MPA in other solid organ transplants also seem to be related to the efficacy and safety of treatment in the complex setting of lung transplantation.

SNPs and taxane toxicity in breast cancer patients

AIM

In order to identify genetic variants associated with taxanes toxicity, a panel with 47 SNPs in 20 genes involved in taxane pathways was designed.

PATIENTS & METHODS

Genomic DNA of 113 breast cancer patients was analyzed (70 taking docetaxel, 43 taking paclitaxel).

RESULTS

Two SNPs associated with docetaxel toxicity were identified: CYP3A4*1B with infusion-related reactions; and ERCC1 Gln504Lys with mucositis (p≤0.01). Regarding paclitaxel toxicity: CYP2C8 HapC and CYP2C8 rs1934951 were associated with anemia; and ERCC1 Gln504Lys with neuropathy (p≤0.01).

CONCLUSION

Genes involved in DNA repair mechanisms and reactive oxygen species levels influence taxane toxicity in cancer patients treated with chemotherapy schemes not containing platinum. These findings could lead to better treatment selection for breast cancer patients.

Association of SNPs with the efficacy and safety of immunosuppressant therapy after heart transplantation

Aim: Studying the possible influence of SNPs on efficacy and safety of calcineurin inhibitors upon heart transplantation. Materials & methods: In 60 heart transplant patients treated with tacrolimus or cyclosporine, we studied a panel of 36 SNPs correlated with a series of clinical parameters during the first post-transplantation year. Results: The presence of serious infections was correlated to ABCB1 rs1128503 (p = 0.012), CC genotype reduced the probability of infections being also associated with lower blood cyclosporine concentrations. Lower renal function levels were found in patients with rs9282564 AG (p = 0.003), related to higher blood cyclosporine blood levels. A tendency toward increased graft rejection (p = 0.05) was correlated to rs2066844 CC in NOD2/CARD15, a gene related to lymphocyte activation. Conclusion: Pharmacogenetics can help identify patients at increased risk of clinical complications.

Original submitted 30 January 2015; revision submitted 27 March 2015

Human AAT gene transfer to pig liver improved by using a perfusion isolated organ endovascular procedure

OBJECTIVE

The efficiency of endovascular liver gene transfer in pigs is evaluated by comparing two models of retrograde catheterization: single lobe catheterization with portal inflow (open procedure) versus whole liver isolation with portal and inferior vena cava blockage (close procedure).

METHODS

Percutaneous endovascular catheterization was performed in pigs. Open procedure (n = 3): 8Fr balloon catheter placement in a suprahepatic branch through the jugular vein. Closed procedure (n = 3): simultaneous catheterization of the intrahepatic portal vein (transhepatic catheterization, 10Fr balloon catheter), the supra- and infrahepatic cava veins (8Fr balloon catheters through the jugular and femoral veins). In both models, 200 ml of hAAT DNA solution (20 μg/ml) were retrogradely injected at 20 ml/s. Tissue samples (8 per liver) were obtained 14 days later and the exogenous DNA, RNA and protein per cell were quantified. Blood samples were collected periodically for transaminase determination in all the animals.

RESULTS

The open procedure achieved lower (approx. 1000-fold) DNA delivery, resulting in a significantly lower (p < 0.001) gene transcription (> 100-fold). The closed model also achieved a higher translation index, although differences were smaller (p < 0.001).

CONCLUSIONS

Portal inflow blockage increased the delivery, transcription and translation indexes, significantly improving the final procedure efficacy when compared with an open procedure.

KEY POINTS

Endovascular hydrodynamic pig liver gene transfer: open procedure versus closed procedure. Open procedure resulted in much lower DNA delivery than closed model. Open procedure reached significantly lower gene transcription index. Translation index with closed model was higher than with the open.

Low RNA translation activit limits the efficacy of hydrodynamic gene transfer to pig liver in vivo

BACKGROUND

Hydrodynamic gene delivery has proved an efficient strategy for nonviral gene therapy in the murine liver but it has been less efficient in pigs. The reason for such inefficiency remains unclear. The present study used a surgical strategy to seal the whole pig liver in vivo.

METHODS

A solution of enhanced green fluorescent protein (eGFP) DNA was injected under two different venous injection conditions (anterograde and retrograde), employing flow rates of 10 and 20 ml/s in each case, with the aim of identifying the best gene transfer conditions. The gene delivery and information decoding steps were evaluated by measuring the eGFP DNA, mRNA and protein copy number 24 h after transfection. In addition, gold nanoparticles (diameters of 4 and 15 nm) were retrogradely injected (10 ml/s) to observe, by electron microscopy, the ability of the particle to access the hepatocyte.

RESULTS

The gene delivery level was higher with anterograde injection, whereas the efficacy of gene expression was better with retrograde injection, suggesting differences in the decoding processes. Thus, retrograde injection mediates gene transcription (mRNA copy/cell) equivalent to that of intermediate expression proteins but the mRNA translation was lower than that of rare proteins. Electron microscopy showed that nanoparticles within the hepatocyte were almost exclusively 4 nm in diameter.

CONCLUSIONS

The results suggest that the low activity of mRNA translation limits the final efficacy of the gene transfer procedure. On the other hand, the gold nanoparticles study suggests that elongated DNA conformation could offer advantages in that the access of 15-nm particles is very limited.

Comparative antitumor effect among GM-CSF, IL-12 and GM-CSF+IL-12 genetically modified tumor cell vaccines

Genetically modified cells have been shown to be one of the most effective cancer vaccine strategies. An evaluation is made of the efficacy of both preventive and therapeutic antitumor vaccines against murine melanoma, using C57BL/6 mice and irradiated B16 tumor cells expressing granulocyte and macrophage colony-stimulating factor (GM-CSF), interleukin-12 (IL-12) or both. Tumor was transplanted by the injection of wild-type B16 cells. Tumor growth and survival were measured to evaluate the efficacy of vaccination. Specific humoral response and immunoglobulin G (IgG) switch were evaluated measuring total IgG and IgG1 and IgG2a subtypes against tumor membrane proteins of B16 cells. In preventive vaccination, all treated groups showed delayed tumor growth. In addition, the group vaccinated to express only GM-CSF achieved 100% animal survival (P<0.005). Vaccination with GM-CSF+IL-12-producing B16 cells yielded lesser results (60% survival, P<0.005). Furthermore, all surviving animals remained disease-free after second tumor implantation 1 year later. The therapeutic vaccination strategies resulted in significantly delayed tumor growth, mainly using B16 cells producing GM-CSF+IL-12 cytokines, with 70% tumor growth inhibition (P<0.001)-although none of the animals reached overall survival. The results obtained suggest that the GM-CSF+IL-12 combination only increases the efficacy of therapeutic vaccines. No differences in classical regulatory T cells were found among the different groups.

Influence of pharmacogenetic polymorphisms in routine immunosuppression therapy after renal transplantation

Pharmacogenetics is the study of the cause of various individual responses to the same pharmacologic therapy. Genetic alterations in a single nucleotide in the genes responsible for transport and metabolism of an immunosuppression drug may modify patient response. Although pharmacogenetics is of interest, its clinical relevance remains to be demonstrated. The objective of the present study was to evaluate the effect of single-nucleotide polymorphisms (SNPs) in renal transplant recipients and their donors relative to blood concentrations of tacrolimus in the first 2 weeks posttransplantation. Seventy-one blood samples each from renal transplant recipients and their donors were analyzed using a genetic analysis system (MassARRAY; Sequenom, Inc, San Diego, California) in an attempt to characterize the more relevant SNPs of the ABCB1 and CYP3A5 genes for correlation with recipient trough concentrations of drug. Two-way analysis of variance and Bonferroni post hoc tests were used. In agreement with theoretical predictions, the wild-type genotype in ABCB1 SNPs (CC) tended to stabilize drug concentrations within the therapeutic range, whereas the T variant induced a mean increase in blood concentrations of more than 60%. These findings are in agreement with statistical tests that compared mean concentrations in various recipient-donor populations and found significant differences between them (P<.001) in CC vs TT, and P<.01 in CT vs TT). Donor genotype did not seem to be relevant. However, further studies are required to achieve more robust conclusions.

Naked DNA delivery to whole pig cardiac tissue by coronary sinus retrograde injection employing non-invasive catheterization

BACKGROUND

Hydrodynamic injection has demonstrated to be very efficient in the liver of small animals, although this procedure must be translated to the clinical practice in a milder but no less efficient way. The present study evaluates the capacity of non-invasive interventional catheterization as a procedure for naked DNA delivery to the heart in large animals.

METHODS

Two catheters were placed in the coronary sinus: one of them to block blood circulation and the other to retrogradely inject 50 ml of a saline solution of DNA (20 µg/ml) containing the enhanced green fluorescent protein (EGFP) gene, at a flow rate of 5 ml/s.

RESULTS

The results obtained show that EGFP protein, identified by immunohistochemistry, was present and widely distributed throughout the atrial and ventricular cardiac tissue. This observation agrees with the efficiency of EGFP gene delivery resulting in 1-200 EGFP gene copies per endogenous haploid genome. However, the transcription efficiency of the exogenous EGFP gene was at a ratio of 0.2-10 copies with respect to the endogenous GAPDH gene, suggesting that optimized gene constructs for expression in cardiac tissue could increase the final efficacy of gene transfer.

CONCLUSIONS

We conclude that the retrovenous injection of naked DNA in the coronary sinus employing the catheterization technique is an easy and probably safe method for whole cardiac gene transfer.

Entrainment to Light of Circadian Activity Rhythms in Tench (Tinca tinca)

The present article analyzes locomotor activity rhythms in Tinca tinca. To that end, three different experiments were conducted on 24 animals (20 g body weight) kept in pairs in 60-liter aquaria fitted with infrared sensors connected to a computer to continuously record fish movements. The first experiment was designed to study the endogenous circadian clock under free-running conditions [ultradian 40:40 min LD pulses and constant dark (DD)] and after shifting the LD cycle. Our results demonstrate that tench has a strictly nocturnal activity pattern, an endogenous rhythm being evident in 45.8% of the fish analyzed. The second experiment was conducted to test the influence of different photoperiods (LD 6:18, 12:12, 18:6, and 22:2) on locomotor activity, the results showing that even under an extremely long photoperiod, tench activity is restricted to dark hours. The third experiment examined the effect of light intensity on locomotor activity rhythms. When fish were exposed to decreasing light intensities (from 300:0 lux to 30:0, 3:0, and 0.3:0 lux) while maintaining a constant photoperiod (LD 12:12), the highest percentage of locomotor activity was in all cases associated with the hours of complete darkness (0 lux). In short, our results clearly show that (a) tench is a species with a strictly nocturnal behavior, and (b) daily activity rhythms gradually entrain after shifting the LD cycle and persist under free-running conditions, pointing to their circadian nature. However, light strongly influences activity rhythms, since (c) the length of the active phase is directly controlled by the photophase, and (d) strictly nocturnal behavior persists even under very dim light conditions (0.3 lux). The above findings deepen our knowledge of tench behavior, which may help to optimize the aquacultural management of this species, for example, by adjusting feeding strategies to their nocturnal behavior.

Antigens and Cytokine Genes in Antitumor Vaccines

Studies against cancer, including clinical trials, have shown that a correct activation of the immune system can lead to tumor rejection whereas incorrect signaling results in no positive effects or even anergy. We have worked assuming that two signals, GM-CSF (granulocyte and macrophage colony-stimulating factor) and tumor antigens are necessary to mediate an antitumor effective response. To study which is the ideal temporal sequence for their administration, we have used a murine model of antimelanoma vaccine employing whole B16 tumor cells or their membrane protein antigens (TMPs) in combination with gm-csf transfer before or after the antigen delivery. Our results show that: (i) When gm-csf tisular transfection is performed before TMP delivery, a tumor growth inhibition is observed, but with a limit effect when administering high antigen doses; in contrast, when signals are inverted, the limited effect is lost and greater antitumor efficacy is obtained. (ii) A similar behavior, but with stronger positive results, is observed employing gm-csf transfection and whole tumor cells as antigens. While negative results are obtained with gm-csf before cells, the best results (total survival of treated mice) are obtained when GM-CSF is administered in transfected cells. We conclude that optimal antitumoral response can be obtained when the antigen signal is given before (or simultaneous with) GM-CSF production, while the inversion of the signals could result in the undesired inhibition or anergy of the immune response.

Response of plasma and gastrointestinal melatonin, plasma cortisol and activity rhythms of European sea bass (Dicentrarchus labrax) to dietary supplementation with tryptophan and melatonin

Melatonin is an effective antioxidant, immunostimulant, gonadal maturating regulator and antistress indoleamine that may be potentially useful for fish farmers. We have explored two possible ways of increasing plasma melatonin levels through the diet: direct melatonin supplementation (ME diet) and supplementation with the melatonin precursor tryptophan (TRP diet). To this end, a group of sea bass was fed a commercial diet (STD diet) at a regular time for 16 days, after which plasma, intestine, and bile samples were taken at four different time points: 120 min before, and 15, 180 and 480 min after feeding. Locomotor activity, intestinal and biliary melatonin, and plasma melatonin, serotonin and cortisol levels were measured. This same sampling process and analyses were also carried out after feeding sea bass TRP diet or ME diet for 1 week. Our results show that melatonin, but not tryptophan supplementation of the diet increases plasma, intestine and bile levels of melatonin. Plasma serotonin levels, on the other hand, were increased by dietary tryptophan, but not by melatonin, confirming the availability of supplemented tryptophan for serotonin synthesis. Both treatments were equally effective in reducing the high cortisol levels observed with the STD diet.

Pig liver gene therapy by noninvasive interventionist catheterism

The efficacy of noninvasive interventionist catheterism in large animals as an alternative to the hydrodynamic procedure, described for small animals, is evaluated. Basically, gene transfer is performed by implantation and fixation of a balloon catheter within the suprahepatic vein of anesthetized pigs, through the femoral vein. The catheter tip is identified by fluoroscopy, injecting a contrast solution that marks large or small hepatic territories. Animals were injected with a 100 ml pTG7101 plasmid solution (40 microg/ml), which contains the human alpha-1 antitrypsin gene, perfused at a rate of 7.5 ml/s and efficacy and toxicity of the procedure were evaluated. The results show: (i) the highest efficacy in protein production is reached when perfusion is limited to small areas of the liver; (ii) no relevant hepatic toxicity was observed; (iii) gene transfer is mainly located in the areas around the central vein, as seen in the immunohistochemical studies; (iv) the electron microscopy studies indicate that the areas with good transfection efficacy show the presence of abundant endocytic vesicles that may even fuse among themselves. These data suggest that retrovenous injection by noninvasive interventionist catheterism could become an efficient procedure for hepatic gene transfer with potential clinical applications.

Demand-feeding rhythms and feeding-entrainment of locomotor activity rhythms in tench (Tinca tinca)

Tench (Tinca tinca) has been described as a strictly nocturnal species whose locomotor activity rhythms, albeit strongly synchronised by light, have an endogenous nature. Aside from light, a number of other environmental factors, such as mealtime, can act as circadian system synchronisers in fish; however, there is a scarcity of information on tench feeding rhythms. This study describes daily self-feeding rhythms in tench, and analyses the role of feeding time on synchronisation of locomotor activity rhythms. Tench were able to operate string sensor-activated self-feeders, and they displayed a strictly nocturnal behavior, both under indoor and outdoor conditions. Locomotor activity remained strictly nocturnal irrespective of whether tench were fed only during the scotophase (D-feeding) or the photophase (L-feeding). However, no statistically significant differences were detected between both groups in terms of food intake or growth performance. Furthermore, unlike L-feeding, D-feeding elicited a clear anticipatory activity (FAA). When tench were given the possibility of feeding at both times of the day, they showed a clear preference for D-feeding. Finally, in fish exposed to constant darkness (DD), feeding time acted as a true zeitgeber and FAA was observed. When animals were fasted under DD conditions, locomotor activity free-run and 6 out of 12 individuals yielded significant results in the periodogram analysis. Under DD, fish resynchronised when regular food was resumed, with some tench displaying FAA. The obtained results indicated the existence of a feeding-entrainable oscillator (FEO) in tench.

Dual positivity for cytoplasmic and perinuclear anti-neutrophil antibodies in a patient with Henoch-Schönlein purpura

We herein describe the case of a 60-year-old man who presented clinical and histopathological evidence of Henoch-Schönlein purpura. Antineutrophil antibodies (ANCA) showed positive results on an enzyme-linked immunosorbent assay and immunofluorescence for anti-myeloperoxidase and anti-proteinase 3 antibodies. Dual positivity for both cytoplasmatic (C-ANCA) and perinuclear (P-ANCA) antineutrophil antibodies has been found previously in a small number of reports, but to our knowledge this is the first time the simultaneous presence of C-ANCA and P-ANCA has been observed in Henoch-Schönlein purpura.

A validation study of the hospital anxiety and depression scale (HADS) in a Spanish population

The present study aims to validate the Spanish version of the Hospital Anxiety and Depression Scale (HADS) and to determine the use of this tool for screening mood and anxiety disorders. Psychometric properties of the HADS were assessed in different groups of general medical outpatients attending the Hospital Clínic in Barcelona (N=385), and psychiatric diagnoses were made using DSM-IV criteria. A two-factor solution corresponding to the original two subscales of the HADS was found. The Spanish version of the HADS had good internal consistency and external validity, with favorable sensitivity and specificity in identifying cases of psychiatric disorder as defined by the Structured Clinical Interview for DSM-IV (SCID-I). The psychometric properties of the HADS and its brevity make it useful for screening for psychiatric disorders in the medically ill.

On the nature of "HLA-B42" alloantibodies. Specific reagents for HLA-Cw*17?

An almost complete and bidirectional association exists between HLA-Cw*17 and the HLA-B antigens B41 and B42. Serological and molecular analysis of an individual in which HLA-B*4101 was identified in the absence of Cw*17 provides experimental evidence to prove a previously proposed hypothesis predicting that alloantisera classified as "B41+B42" are instead specific reagents for HLA-Cw*17.

Diversity of HLA-B61 alleles and haplotypes in East Asians and Spanish Gypsies

The distribution of HLA-B61 alleles and their association with HLA-C and DRB1 alleles were investigated in six East Asian populations (South Korean, Chinese Korean, Man (Manchu), Northern Han, Mongolian and Buryat) and Spanish Gypsies and compared to our previous report on the Japanese population. The alleles were identified using a group-specific polymerase chain reaction (PCR) and genomic DNA followed by hybridization with sequence-specific oligonucleotide probes (SSOP). Both HLA-B*4002 and B*4006 were commonly detected in the South Korean, Chinese Korean, Man, Northern Han and Japanese populations, while HLA-B*4002 was predominant in the Mongolian and Buryat populations. Strong associations of B*4002 with Cw*0304 and of B*4006 with Cw*0801 were commonly observed in these East Asian populations. In contrast, in Spanish Gypsies, only HLA-B*4006 was found and the allele exhibited a strong association with Cw*1502. HLA-B*4003 was also identified in the South Korean, Chinese Korean, Northern Han, Mongolian and Japanese populations at relatively low frequencies, and exhibited an association with Cw*0304. Moreover, the association of these B61 alleles with the DRB1 alleles revealed considerable diversity among the different populations. HLA-B*4004 and B*4009 were not observed in these populations. Consequently, the frequencies of the B61 alleles varied among the different East Asian populations, but the individual B61 alleles were carried by specific haplotypes often regardless of the ethnic differences.