Cell and region specificity of Aryl hydrocarbon Receptor (AhR) system in the testis and the epididymis

Aryl hydrocarbon receptor (AhR) plays multiple important functions in adaptive responses. Exposure to AhR ligands may produce an altered metabolic activity controlled by the AhR pathways, and consequently affect drug/toxin responses, hormonal status and cellular homeostasis. This research revealed species-, cell- and region-specific pattern of the AhR system expression in the rat and human testis and epididymis, complementing the existing knowledge, especially within the epididymal segments. The study showed that AhR level in the rat and human epididymis is higher than in the testis. The downregulation of AhR expression after TCDD treatment was revealed in the spermatogenic cells at different stages and the epididymal epithelial cells, but not in the Sertoli and Leydig cells. Hence, this basic research provides information about the AhR function in the testis and epididymis, which may provide an insight into deleterious effects of drugs, hormones and environmental pollutants on male fertility.

In vitro and in vivo evaluation of sandwich-like mesoporous silica nanoflakes as promising anticancer drug delivery system

We present the new promising nanostructure- sandwich-like mesoporous silica nanoflakes synthesized on graphene oxide sheets core. In the first step biocompatibility of the nanoflakes with PEG and without functionalization in human fibroblast, melanoma and breast cancer cells was assessed. In order to define the cellular uptake in vitro and biodistribution in vivo the nanostructures were labelled with fluorescent dye. In the next step, the silica nanostructures were filled by the anticancer drug- methotrexate (MTX) and cytotoxicity of the complex in reference to MTX was evaluated. The WST-1 assay shows mild, but concentration dependent, cytotoxicity of the nanoflakes, most significant for the non-functionalized structures. PEG-modified silica nanoflakes didn't produce a disruption of cell membranes and lactate dehydrogenase (LDH) release. Cell imaging revealed efficient internalization of the silica nanoflakes in cells. Ex vivo organ imaging showed high accumulation of the nanostructures in lungs, bladder and gall bladder, whereas confocal imaging revealed wide nanoflake distribution in all tested tissues, especially at 1h and 4h post intravenous injection. Cytotoxicity of the nanoflake-MTX complex in reference to MTX showed similar cytotoxic potential against cancer cells. These findings may provide useful information for designing drug delivery systems, which may improve anticancer efficacy and decrease side effects.

Study on size effect of the silica nanospheres with solid core and mesoporous shell on cellular uptake

The properties of mesoporous silica nanoparticles including large surface area, large pore volume, easy surface functionalization and control of structure and pore size has made them promising drug carriers. In this study, the effect of different diameters (50 nm, 70 nm, 90 nm, 110 nm and 140 nm) of silica nanospheres with a solid core and mesoporous shell (mSiO2/SiO2) on cellular internalization in mouse fibroblast cells (L929) was evaluated. The physical properties of the nanostructures were characterized with various methods, such as transmission electron microscopy with x-ray dispersion spectroscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy and zeta potential. In order to define the cellular uptake, the nanostructures were labelled with fluorescent dye Alexa647, and imaging and quantitative methods were applied: laser scanning confocal microscopy, flow cytometry and thermogravimetry. Our results indicate that cellular uptake of the studied nanospheres is size-dependent, and nanospheres of 90 nm in diameter showed the most efficient cell internalization. Thus, particle size is an important parameter that determines cellular uptake of nanoparticles and should be considered in designing drug delivery carriers.

Interleukin-6 level and gene polymorphism in spontaneous miscarriage

The aetiology of spontaneous miscarriage, the most common pregnancy complication, remains undefined. One of postulated factors involved in miscarriage pathology is interleukin 6 (IL-6). Therefore, the aim of the study was to evaluate IL-6 and interleukin 6 receptor (IL-6R) gene polymorphisms in patients with spontaneous miscarriage. One hundred fifty-seven patients diagnosed with spontaneous miscarriage and age and gestational time matched controls were included in the case-control study. In all study participants circulating IL-6 levels (chemiluminescent immunoassay) and IL6-174G>C as well as IL6R rs2228145:A>C polymorphisms were evaluated. The distribution of IL6 as well as IL6R alleles and genotypes were similar in the controls and patients with miscarriage. Only a trend of more frequent appearance of -174GC+CC and C allele in the patients with miscarriage was noted. Blood serum concentrations of IL-6 were significantly elevated in patients with miscarriage vs those with physiological pregnancy. Likewise, IL-6 concentrations differ significantly with the types of miscarriage. The highest concentrations of the cytokine was seen in subjects with incomplete miscarriage (4.28 ± 4.88 pg/ml) followed by imminent miscarriage (2.97 ± 2.42 pg/ml), and then missed miscarriage (2.07 ± 1.90 pg/ml), being significantly the lowest in missed miscarriage group. No association between the IL6 genotype and IL-6 serum concentration were noted, both in the miscarriage group and in the control group. The findings of the study support the role of IL-6 in spontaneous miscarriage irrespectively of its type. However, no correlation between circulating IL-6 and IL6 gene polymorphism, as well as IL-6 and IL-6R polymorphisms associations with spontaneous miscarriage were revealed.

TGF-β1 gene polymorphism in renal transplant patients with and without gingival overgrowth

BACKGROUND

The incidence of gingival overgrowth among renal transplant patients treated with cyclosporine A ranges from 13% to 84.6%, and the overgrowth is not only esthetic but also a medical problem. We studied the determination of association between TGF-β1 (TGFB1) gene polymorphism and gingival overgrowth in kidney transplant patients medicated with cyclosporin A.

METHODS

Eighty-four kidney transplant patients with gingival overgrowth and 140 control transplant patients without overgrowth were enrolled into the case control study. TGFB1 polymorphism was determined using the PCR-RFLP assay for +869T > C in codon 10 and +915G > C in codon 25 as well as TaqMan real-time PCR assays for promoter -800G>A and -509C > T SNPs.

RESULTS

In kidney transplant patients suffering from gingival overgrowth, mean score of gingival overgrowth was 1.38 ± 0.60, whereas in control subjects it was 0.0. The patients with gingival overgrowth were characterized by similar distribution of TGFB1 genotypes and allele in comparison to subjects without gingival overgrowth. Among 16 potentially possible haplotypes of TGFB1 gene, only four were observed in the studied sample of kidney transplant patients: G_C_T_G, G_T_C_G, G_C_C_C, and A_C_T_G, with similar frequency in patients with and without gingival overgrowth.

CONCLUSION

No association between the TGFB1 gene polymorphism and gingival overgrowth was revealed in kidney transplant patients administered cyclosporine A.

The effect of 677C>T and 1298A>C MTHFR polymorphisms on sulfasalazine treatment outcome in rheumatoid arthritis

Despite the availability of several new agents for the treatment of rheumatoid arthritis (RA), sulfasalazine remains the mainstay because of both cost and experience with its use. Methylenetetrahydrofolate reductase (MTHFR) is involved in folate metabolism and several polymorphisms have been described in the MTHFR gene. Of these, the 677C>T and 1298A>C polymorphisms have been associated with altered enzyme activity. To examine the association between 677C>T and 1298A>C MTHFR polymorphisms and sulfasalazine efficacy for the treatment of RA, a total of 117 RA patients treated with sulfasalazine (1 g daily; duration of treatment 17 +/- 5 months) were analyzed. The 677C>T and 1298 A>C polymorphisms were detected using a PCR-RFLP method. RA was diagnosed according to the criteria of the American College of Rheumatology (ACR). The remission of RA symptoms was evaluated according to the ACR 20% response criteria. Allele and genotype frequencies were compared by the two-sided Fisher exact test. The frequency of remission was 47.2% and 44.6% in carriers of 677T and 1298C alleles, compared to 40.7% and 42.0% in carriers of 677C and 1298A alleles, respectively. These differences were statistically non-significant. When the multivariate analysis was additionally adjusted for patients' age, gender and RA duration, the association of the MTHFR 677T allele with increased frequency of remission was statistically significant. Although RA remission rate in carriers of the MTHFR 677T and 1298C alleles was more frequently observed, it does not seem that 677C>T and 1298A>C MTHFR polymorphisms have a major influence on treatment outcome in RA patients treated with sulfasalazine.

Association of allograft inflammatory factor-1 gene polymorphism with rheumatoid arthritis

Human allograft inflammatory factor-1 (AIF-1) is a cytoplasmic protein primarily identified in human and rat allografts, and data from several studies suggest an important role for AIF-1 in inflammatory processes. The aim of this study was to examine the association between AIF1 rs2269475:C>T polymorphism and rheumatoid arthritis (RA). AIF1 genotype was determined by means of the polymerase chain reaction-restriction fragment length polymorphism method in 276 White patients with RA and 236 healthy subjects. The frequency of the AIF1 rs2269475 TT genotype was significantly higher in the patients with RA than in the controls (OR=5.59, 95% CI: 1.22-25.55). The frequency of T allele carriers in the patient group with RA was 31.9% vs 19.1% among controls (P=0.0003). Moreover, the frequency of individuals positive for anti-cyclic citrullinated peptide (anti-CCP) antibodies was significantly elevated in the T allele carriers (OR=8.82, 95% CI: 2.06-37.7). It is noteworthy that no significant linkage disequilibria between the AIF1 C/T and DRB1 alleles associated with RA development and anti-CCP antibody production [including the most frequent, i.e. *04 (32.7%) and *01 (23.5%)] (P>0.1) were found. Our results show that the AIF1 rs2269475 T allele is associated with increased risk of RA development. Moreover, the frequency of individuals positive for anti-CCP antibodies is significantly increased among T allele carriers.

Reduced folate carrier-1 80G>A polymorphism affects methotrexate treatment outcome in rheumatoid arthritis

The folate antagonist methotrexate (MTX) is a drug currently used in the treatment of rheumatoid arthritis (RA). MTX enters the cells through the reduced folate carrier (RFC-1) and is activated to polyglutamates. Previous studies have shown that RFC-1 expression may influence the efficacy of therapy with MTX. The studies suggest that G80A polymorphism in RFC-1 is associated with altered folate/antifolate levels and the subjects carrying homozygous mutant 80AA genotype tend to have higher plasma folate and MTX concentrations and higher erythrocyte polyglutamate levels compared with those with the wild type or heterozygous genotype. It is possible that this polymorphism might influence MTX treatment outcome in patients with RA. In the present study, we examined the association between RFC-1 G80A polymorphism and treatment outcome in patients with RA administered MTX. The study was carried out on 174 patients diagnosed with RA treated with MTX (7.5-15.0 mg weekly) plus low doses of methylprednisone. The RFC-1 80G>A polymorphism (resulting in a histidine-to-arginine substitution at codon 27 of RFC-1) was detected using a polymerase chain reaction-restriction fragment length polymorphism method. The probability of remission of RA symptoms was 3.32-fold higher in carriers of 80AA genotype as compared with patients with 80GG genotype (P=0.021, OR=3.32, 95% CI: 1.26-8.79). The frequency of A allele among MTX responders was 62.1, compared to 47.8% in a group of poor MTX responders (P=0.013, OR=1.78, 95% CI: 1.13-2.81). Moreover, the increase of aminotransferase activity was noted more frequently in carriers of 80AA genotype. The present data suggest that evaluation of RFC-1 gene 80G>A polymorphism may be a useful tool to optimize MTX therapy in patients with RA.

Interleukin-18 promoter polymorphism in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease in which interleukin (IL)-18 plays an important role. However, there are controversial reports on IL-18 promoter polymorphism as an independent marker of RA susceptibility. The aim of present study was to examine the IL-18 promoter polymorphism in patients with RA, and its association with disease susceptibility, activity and severity. We examined 309 patients with RA from a Polish population diagnosed according to the criteria of American College of Rheumatology. An allele-specific polymerase chain reaction was used for analysis of the polymorphisms in positions - 137 and - 607 in promoter region of IL-18 gene. A significantly decreased number of subjects with AC/AC and AG/AG diplotypes was observed among RA patients as compared with healthy controls (OR - 0.51, 95%CI 0.28-0.95, P = 0.045) and (OR - 0.12, 95% CI 0.02-0.97, P = 0.042), respectively. Nevertheless, there was no significant association with disease activity, joint erosions, extra-articular manifestations, rheumatoid factor. Above results suggest that IL-18-137 and - 607 promoter polymorphisms are not the significant factors influencing RA course and severity in a Polish population.

Interleukin-6 gene polymorphism in renal transplant patients with and without gingival overgrowth

OBJECTIVE

To determine whether there is an association between genotypes of interleukin-6 (IL-6) and gingival overgrowth in kidney transplant patients.

METHODS

Sixty-three unrelated kidney transplant patients suffering from gingival overgrowth as well 125 control transplant patients without overgrowth were enrolled into the study. Gingival overgrowth was assessed by two independent periodontal specialists at 6 months after transplantation. During the post-transplant period, all patients were given medication, which included cyclosporin A, diltiazem or verapamil, prednisone, and azathioprine. IL-6 polymorphism was determined using the polymerase chain reaction-restriction fragment length polymorphism assay.

RESULTS

In kidney transplant patients suffering from gingival overgrowth mean score of gingival overgrowth was 1.41+/-0.64, whereas in control subjects it was 0.0. Patients with gingival overgrowth induced by immunosuppressive medication were characterized by genotypes similar to the controls distribution of IL-6. There were no significant differences of analyzed genotypes' distribution, i.e. -174G/G, -174G/C and -174C/C between patients with gingival overgrowth 33.3%, 39.7%, 27.0% and without gingival overgrowth 30.4%, 49.6% and 20.0%, respectively. The risk of gingival overgrowth was the highest among patients carrying -174C/C genotype (OR 1.48), but did not differ markedly from the other genotypes, i.e. -174G/G (OR 1.15) and -74G/C (OR 0.67). Similar to genotypes, the distribution of alleles was similar in patients with gingival overgrowth and healthy gingiva. The -174G allele was found in 53.2% and 46.8% of subjects whereas -174C allele was revealed in 46.8% and 44.8% of patients with and without gingival overgrowth, respectively. The evaluated risk of gingival overgrowth in patients with -174G allele was 1.09 versus those with healthy gingiva. The medication regimen administered in both groups of the study was comparable.

CONCLUSION

No association between the IL-6 gene polymorphism and gingival overgrowth was revealed in kidney transplant patients administered cyclosporin A as a principal immunosuppressive agent.

P-glycoprotein drug transporter MDR1 gene polymorphism in renal transplant patients with and without gingival overgrowth

OBJECTIVE

To determine whether there is association between genotypes of drug transporter multidrug resistant (MDR)1 gene coding drug transporter P-glycoprotein and gingival overgrowth in kidney transplant patients.

METHODS

Fifty-four unrelated kidney transplant patients suffering from gingival overgrowth as well 120 control transplant patients without overgrowth were enrolled into the study. Gingival overgrowth was assessed by two independent periodontal specialists at 6 months after transplantation. During the post-transplant period all patients were given medication, which included cyclosporine A, diltiazem or verapamil, prednisone, azathioprine. MDR1 C3435T polymorphism was determined using the polymerase chain reaction-restriction fragment length polymorphism assay.

RESULTS

In kidney transplant patients suffering from gingival overgrowth mean score of gingival overgrowth was 1.43 +/- 0.63, whereas in control subjects was 0.0. Patients with gingival overgrowth induced by immunosuppressive medication were characterized by similar distribution of MDR1 genotypes. There were no significant differences of 3435CC, 20.4% and 22.5%, 3435CT, 61.1% and 54.2% and 3435TT, 18.5% and 23.3% genotypes (frequencies) between patients with and without gingival overgrowth. The risk of gingival overgrowth was the highest among patients carrying 3435CT genotype (OD 1.33), but did not differ markedly from the other genotypes, i.e. 3435CC (OD 0.88) and 3435TT (OD 0.75). Likewise to genotypes, distribution of alleles was similar in patients with gingival overgrowth and healthy gingiva. The wild-type allele 3435C was found in 50.9% and 49.6% of subjects whereas the mutated allele 3435T was revealed in 49.1% and 50.4% of patients with and without gingival overgrowth, respectively. The evaluated risk of gingival overgrowth in patients with 3435C allele was 1.06 versus 0.95 in those with healthy gingiva. The medication regimen administered in both groups of the study was comparable. Immunohistochemical studies revealed expression of P-glycoprotein in ducts of the salivary gland.

CONCLUSION

No association between the MDR1 gene polymorphism and gingival overgrowth was revealed in kidney transplant patients administered cyclosporine A as a principal immunosuppressive agent. Further studies are needed to elucidate the role of P-glycoprotein in drug transport in salivary glands.

Comparison of MEGX (monoethylglycinexylidide) and antipyrine tests in patients with liver cirrhosis

The aim of the study was to compare the feasibility of the MEGX (monoethylglycinexylidide) and antipyrine tests in reference to standard biochemical parameters used for liver assessment in cirrhotic patients. The study was carried out in 44 subjects: 14 healthy controls and 30 cirrhotic patients classified according to the Child-Pugh's score to subgroups A (n=11), B (n=12) and C (n=7). All subjects underwent two dynamic liver tests, i.e. MEGX (monoethylglycinexylidide) and antipyrine test in a crossover schedule with at least 5-day interval. For the MEGX, lidocaine was administrated intravenously, at a dose of 1 mg/kg, and blood samples for MEGX assay were collected after 15 minutes. MEGX concentrations were measured by fluorescence polarization immunoassay. The antipyrine concentrations were evaluated following a single oral administration of 1000 mg antipyrine. The blood was sampled for 24 hours after the drug administration, and antipyrine concentrations were measured spectrophotometrically. Standard biochemical parameters used for liver assessment were measured by means of routine laboratory methods. It was concluded that in patients liver with cirrhosis, liver dynamic tests were better predictors of hepatic function. The MEGX test was more feasible in clinical setting, but it was noted that antipyrine test was more sensitive in staging liver cirrhosis.

Effect of unilateral nephrectomy on the pharmacokinetics of amikacin in humans

As unilateral nephrectomy is not a rare surgical procedure, it gives rise to the question whether drugs predominantly eliminated through the urinary tract can be handled effectively by the remaining kidney. Amikacin is predominantly excreted via glomerular filtration with only a small fraction undergoing tubular reabsorption, and can be used as a model drug of glomerular elimination. The study was carried out in 28 subjects, 10 one month and 10 one year after unilateral nephrectomy, as well as in 8 healthy subjects. The pharmacokinetics of amikacin was investigated after a 1-h infusion of 5 mg kg(-1) amikacin. Blood samples were collected for 24 h after the end of infusion. Pharmacokinetic parameters of amikacin were calculated using a one-compartment open model for intravenous administration. Amikacin concentrations were significantly elevated in nephrectomized patients as compared with control subjects, both 1 month and 1 year after the surgery, and were similar at these two time-points following unilateral nephrectomy. Pharmacokinetic parameters of amikacin in patients subjected to unilateral nephrectomy were significantly different from those observed in the control subjects. As compared with the controls, an increase in AUC (area under the serum concentration-time curve) by 81% (P < 0.001) and 63% (P < 0.01) 1 month and 1 year after nephrectomy was observed, respectively. The lambda(z) (elimination rate constant) was reduced by 39% (P < 0.001) after 1 month and by 38% (P < 0.001) 1 year after the operation and t 1/2 was prolonged by 70% (P < 0.001) and by 43% (P < 0.01) at the respective time-points following unilateral nephrectomy. CLT (total body clearance of the drug from plasma) and CL(BW) (clearance per kg body weight) were both significantly decreased in unilaterally nephrectomized subjects in comparison with the controls. CLT and CL(BW) were reduced by 53% (P < 0.001) and 42% (P < 0.01) 1 month after nephrectomy, and by 45% (P<0.001) and 42% (P<0.01) 1 year after the surgery, respectively. No significant differences among studied groups were found in C0 (initial serum drug concentration) and Vd (apparent volume of distribution). The results suggest that unilateral nephrectomy impairs elimination of amikacin, and possibly other drugs predominantly eliminated via glomerular filtration.

Lack of effect of physical exercise on pharmacokinetics of acetaminophen tablets in healthy subjects

The study was designed to evaluate the effect of physical exercise on the pharmacokinetics of acetaminophen. Ten healthy volunteers were drawn to the investigation. Each person was subjected to the pharmacokinetic study twice, i.e. at rest and on an exercise day. On the exercise day the subjects were performing 3 hours long physical exercise which consisted of a walk on a treadmill at 3 mph for 20 minutes of each half an hour. Acetaminophen was given orally at a single dose of 1.0 g prior to the exercise. Blood for pharmacokinetic assay was sampled within 24 hours following the drug administration. Acetaminophen concentrations were determined by the FPIA method. The total concentrations versus time curve were described by the one-compartment open model for extravascular administration. It was revealed, that the standard submaximal physical exercise does not affect the pharmacokinetics of acetaminophen statistically significantly.

A blood-tumor barrier limits gene transfer to experimental liver cancer: the effect of vasoactive compounds

We have evaluated gene transfer efficiency to tumor nodules in diethylnitrosoamine (DENA)-induced hepatocellular carcinoma (HCC) in rats using adenoviral vectors administered by three different routes: intraportal, intra-arterial and intratumoral injection. Our results showed that intraportal infusion could not transduce tumor nodules greater than 1 mm in diameter while the intra-arterial route allowed transduction of nodules up to 2-5 mm in diameter. Tumors greater than this size were resistant to transduction by intravascular route, but could be transduced by direct intratumoral injection, indicating that the obstacle preventing gene transfer to tumor cells was mainly at the level of tumor vasculature and not at the level of neoplastic cells. We have studied the extracellular matrix in tumoral lesions to assess whether nodules with different size and histological pattern have different profiles in relation to transduction efficacy. Immunohistochemical detection showed a high expression of fibronectin (FN), laminin (LN) and alpha-smooth muscle actin (alpha-SMA) in those large HCC, which were resistant to adenoviral infection. Intra-arterial infusion of vasoactive compounds (histamine, angiotensin II or nitric oxide donor nitroglycerin) before vector administration enhanced gene transfer to tumor nodules that were poorly transduced without pre-treatment. Nitroglycerin was active to enhance transduction of large tumors with trabecular or pseudoglandular histological pattern, which were impermeable to adenoviral vectors even after histamine or angiotensin treatments. Our data indicate the presence of a physical barrier between blood and neoplastic cells, which prevents transduction of the tumor by vectors given by the intravascular route. The thickness and impermeability of the barrier increases as the tumor nodule grows. Vasoactive compounds may be of value in gene therapy of liver cancer by increasing transduction efficiency by intravascularly administered vectors.

Pharmacokinetics of intravenously administered digoxin and histopathological picture in rabbits with experimental bile duct obstruction

This study aimed to examine the effect of obstructive cholestasis on the pharmacokinetics of digoxin. Eighteen male rabbits were randomly ascribed to the two study groups: the sham-operated control group and the examined group - with common and cystic bile duct ligations. Digoxin was administered intravenously as a single dose of 0.02 mg/kg, and blood samples were withdrawn for up to 24 h. Digoxin concentrations were determined by the FPIA method. The pharmacokinetic parameters were calculated using a noncompartmental analysis. During the whole observation period the blood serum concentrations of digoxin were statistically higher in animals with obstructive cholestasis versus the controls. A significant increase in the area under the plasma concentration-time curve, decrease in the total body clearance and in the volume of distribution on the 6th day after the bile ducts ligation as compared to the sham-operated controls, were observed. The obtained results suggest an impaired elimination of digoxin in obstructive cholestasis in rabbits.

Pharmacokinetics of propranolol and atenolol in patients after partial gastric resection: a comparative study

OBJECTIVE

Partial gastric resection alters the anatomy and secretory activity of the gastrointestinal tract. It might be expected that the consequences of such changes should affect the pharmacokinetics, especially concerning the absorption of orally administered drugs. Propranolol and atenolol, as representatives of lipophilic and hydrophilic beta-adrenoreceptor antagonists, have been studied in order to define their pharmacokinetic characteristics in patients after partial gastrectomy.

METHODS

The study was carried out in 29 patients after gastric resection with Billroth I (B1) anastomosis and in 18 healthy volunteers as controls. Pharmacokinetics of propranolol and atenolol was investigated after a single oral dose of 80 mg and 100 mg, respectively, following a cross-over schedule. Blood samples were collected ten times during the 24 h after the drug administration. Pharmacokinetic parameters of propranolol and atenolol were calculated using a one-compartment open model with first-order absorption.

RESULTS

The average blood plasma concentrations of propranolol in gastrectomised patients were lower than those in controls, reaching significance between 1.5 h and 6.0 h of the observation period. Pharmacokinetic parameters of propranolol were different in subjects submitted to surgery compared with healthy persons. We observed a significant decrease in the area under the concentration-time curve (32%) and the peak plasma concentration (20%), and an increase in half-life (25%). Mean plasma concentrations and pharmacokinetic parameters of atenolol in patients following partial gastric resection were not significantly different from those in the controls. No relationship between time interval following partial gastrectomy and pharmacokinetic parameters of the investigated drugs was noted.

CONCLUSION

Partial gastrectomy with B1 anastomosis affects the pharmacokinetics of propranolol (lipophilic drug) but not atenolol (hydrophilic drug).

Combined gene therapy with suicide gene and interleukin-12 is more efficient than therapy with one gene alone in a murine model of hepatocellular carcinoma

BACKGROUND/AIMS

Gene therapy has emerged as a new form of treatment for unresectable hepatocellular carcinoma (HCC). We evaluate here the effect of IL-12 and the suicide gene thymidine kinase as single agents and in combination to treat experimental liver cancer.

METHODS

Recombinant adenoviruses expressing mouse interleukin-12 (AdCMVIL-12) or thymidine kinase of herpes simplex virus (AdCMVtk) or lacZ reporter gene (AdCMVlacZ) were constructed. The efficacy of the treatment was evaluated in a murine HCC model based on subcutaneous implantation of liver tumor cells (BNL).

RESULTS

Transduction of BNL cells after in vitro infection with AdCMVlacZ was very low at multiplicity of infection (moi) of 100, whereas 10-15% of cells were transduced when using moi 1,000. Similarly, production of IL-12 was detectable only in BNL cells infected with AdCMVIL-12 at moi 1,000. In vitro infection of BNL cells with AdCMVIL-12 at moi 100 did not abrogate tumorigenicity, whereas moi 1,000 resulted in inhibition of tumor growth in all mice as well as in abrogation of tumor formation in 3 out of 8 animals. In vivo studies showed that intratumor injection of AdCMVIL-12 induced a dose-dependent effect on tumor regression. However, none of the animals exhibited complete tumor elimination with this treatment. We observed that suppression of tumor growth was more intense in animals treated with the combination of AdCMVIL-12 plus AdCMVtk than in animals which received AdCMVtk or AdCMVIL-12 alone. The combined treatment resulted in a significant increase in animal survival, and 25% of treated animals were free of tumor for over 100 days without recurrence of the disease.

CONCLUSIONS

Combination of AdCMVIL-12 and AdCMVtk is more efficient than either of the two vectors alone for the treatment of the murine model of HCC used in this study.

Regression of colon cancer and induction of antitumor immunity by intratumoral injection of adenovirus expressing interleukin-12

Interleukin-12 (IL-12) has been shown to possess potent immunoregulatory and antitumoral effects. We have evaluated the anti-oncogenic potential and the mechanisms of the antitumoral effect of in vivo adenovirus-mediated transfer of IL-12 gene in a murine model of colon cancer. AdCMVIL-12 was constructed to permit coordinated production of p40 and p35 subunits of IL-12 gene to obtain the maximum IL-12 bioactivity. Infection of murine colon cancer CT-26 cells in vitro with AdCMVIL-12 resulted in the production of high levels of IL-12. In vivo gene therapy of colon cancer nodules by intratumoral injection of AdCMVIL-12 induced a local increase in IL-12 and interferon-gamma levels and a complete regression of the tumor in 26 of 34 (76%) mice. Tumor disappeared between days 7 and 10 after vector administration. The antitumoral effect was mediated by CD8+ T cells and was associated with the generation of cytotoxic T lymphocytes against colon cancer cells. Animals that eliminated the tumor were protected against a second administration of neoplastic cells. Treatment with AdCMVIL-12 of one tumor nodule also caused regression of established tumors at distant sites. These data demonstrate that AdCMVIL-12 is a useful therapeutic tool for established colon cancer in mice and should be considered for application in humans.

Gene therapy of viral hepatitis and hepatocellular carcinoma

Gene therapy represents an attractive approach to treat a great variety of diseases, both inherited and acquired, and it is moving slowly from a proof-of-principle phase to a wide application in most medical fields. Liver cancer and viral hepatitis are natural targets for this new therapeutic alternative due to the lack of success of conventional antitumoral and antiviral treatments and the ominous prognosis related with liver tumours. Gene therapy for viral hepatitis is aimed to boost the patient immune response against viral antigens or to make cells resistant to infection by blocking the viral life cycle. Gene transfer techniques applied to the treatment of hepatocellular carcinoma include drug sensitization by suicide genes, genetic immunotherapy, normal tissue protection by transfer of the multidrug resistance gene, replacement of tumour suppressor genes, inhibition of oncogenes and modifications of the biology of the tumour (antiangiogenesis). However, major advances in our understanding of the regulation of gene expression, design of the expression cassettes and development of more efficient gene transfer vectors are mandatory before gene therapy can become a widely used therapeutic modality.

Antitumor effect of allogenic fibroblasts engineered to express Fas ligand (FasL)

Fas ligand is a type II transmembrane protein which can induce apoptosis in Fas-expressing cells. Recent reports indicate that expression of FasL in transplanted cells may cause graft rejection and, on the other hand, tumor cells may lose their tumorigenicity when they are engineered to express FasL. These effects could be related to recruitment of neutrophils by FasL with activation of their cytotoxic machinery. In this study we investigated the antitumor effect of allogenic fibroblasts engineered to express FasL. Fibroblasts engineered to express FasL (PA317/FasL) did not exert toxic effects on transformed liver cell line (BNL) or colon cancer cell line (CT26) in vitro, but they could abrogate their tumorigenicity in vivo. Histological examination of the site of implantation of BNL cells mixed with PA317/FasL revealed massive infiltration of polymorphonuclear neutrophils and mononuclear cells. A specific immune protective effect was observed in animals primed with a mixture of BNL or CT26 and PA317/FasL cells. Rechallenge with tumor cells 14 or 100 days after priming resulted in protection of 100 or 50% of animals, respectively. This protective effect was due to CD8+ cells since depletion of CD8+ led to tumor formation. In addition, treatment of pre-established BNL tumors with a subcutaneous injection of BNL and PA317/FasL cell mixture at a distant site caused significant inhibition of tumor growth. These data demonstrate that allogenic cells engineered with FasL are able to abolish tumor growth and induce specific protective immunity when they are mixed with neoplastic cells.

Pharmacokinetics of intragastrically administered digoxin in rabbits with experimental bile duct obstruction

A change in the functioning of the liver as a result of experimental cholestasis could result in a change in the biotransformation of drugs. The aim of this study was to evaluate the effect of extrahepatic cholestasis on the pharmacokinetics of digoxin. The investigation was performed on male rabbits randomly divided into two groups: sham-operated and animals with bile-duct ligation. Digoxin (0.02 mg kg-1) was administered intragastrically as a single dose. Biomedical and anatomo-pathological tests and pharmacokinetic assays were performed before the operation and on the 6th day after surgery. A significant increase in area under the serum concentration-time curve and in mean residence time, a decrease in total body clearance, a reduction in the volume of distribution and increases in maximum concentration and the time to reach maximum concentration were observed in animals with the bile-duct ligation. These results suggest reduced elimination of digoxin in animals with obstructive cholestasis.