Galactosyl derivative ofNω-nitro-L-arginine: Study of antiproliferative activity on human thyroid follicular carcinoma cells

Galactosylated Pro-Drug of Ursodeoxycholic Acid: Design, Synthesis, Characterization, and Pharmacological Effects in a Rat Model of Estrogen-Induced Cholestasis

Ursodeoxycholic acid (UDCA) is considered the first-choice therapy for cholestatic disorders. To enhance solubility and exploit specific transporters in liver, we synthesized a new galactosyl pro-drug of UDCA (UDCAgal). Ethinylestradiol (EE)-induced cholestasis was used to study and compare the effects of UDCAgal with UDCA on bile flow, hepatic canalicular efflux transporter expression, and inflammation. UDCAgal resulted quite stable both at pH 7.4 and 1.2 and regenerated the parent drug after incubation in human plasma. Its solubility, higher than UDCA, was pH- and temperature-independent. UDCAgal displayed a higher cell permeation compared to UDCA in liver HepG2 cells. Moreover, in cholestatic rats, UDCAgal showed a higher potency compared to UDCA in reducing serum biomarkers (AST, ALT, and ALP) and cytokines (TNF-α and IL-1β). The higher effect of UDCAgal on the increase in bile salt export pump and multidrug resistance-associated protein 2 transcription indicated an improved spillover of bile acids from the liver. UDCAgal showed a reduction in CCL2, as well as TNF-α, IL-1β, and cyclooxygeanse-2 mRNAs, indicating a reduction in hepatic neutrophil accumulation and inflammation. Moreover, UDCAgal, similarly to UDCA, heightens bile flow and modulates biliary acids secretion. These results indicate that UDCAgal has a potential in the treatment of cholestatic disease.

NITRIC OXIDE SYNTHASE ACTIVITY AND ITS CONCENTRATION IN THE TISSUES OF HUMAN THYROID CARCINOMAS

The study of the activity of the constitutive form of nitric oxide synthase (cNOS) revealed that in the papillary thyroid carcinomas it corresponded to that detected in unchanged extratumoral tissue, while the enzyme activity in follicular carcinoma was half lesser. At the same time, the activity of inducible nitric oxide synthase (іNOS) was higher in the papillary and follicular carcinomas. Such changes in the enzyme activity were associated with an increase in its level in papillary carcinomas, and with minor changes in follicular carcinomas. In medullary carcinomas the parameters under study corresponded to those in unchanged tissue, and in the papillary carcinoma metastases without changes in enzyme activity of nitric oxide formation, the level of the latter was much higher. Elevated levels of nitric oxide and іNOS activity in papillary thyroid carcinomas did not depend significantly on the aggression characteristics of the latter, being however absent in tumors of T4 category on a background of reduced cNOS activity and less expressed in tumors surrounded by the tissue in the presence of a chronic thyroiditis. Furthermore, in the papillary carcinomas of papillary or follicular structure nitric oxide level did not differ from the normal range, being slightly higher in tumors of solid or heterogeneous structure with presence of solid areas, whereas in carcinomas of papillary-follicular structure it was twice, and in tissue of solidinsular structure three times higher. іNOS hyperactivity was observed in the carcinomas of different structure, except for tumors of solid structure, in the tumor of which enzyme activity was within the normal range, and in tumor of solid-insular structure where it was significantly higher (as well as cNOS activity) compared with tumors of other structure. Nitric oxide generating system is involved in the transformation of thyroid cells and progression of tumor growth, including through apoptosis regulation, as shown by the results of an analysis of data obtained both in the present study and previously. The nature of such involvement in papillary thyroid carcinomas with different histological structure is different. Key words: nitric oxide; constitutive and inducible nitric oxide synthase; thyroid carcinoma; apoptosis.

Galactosyl prodrug of palmitoylethanolamide: synthesis, stability, cell permeation and cytoprotective activity

N-Palmitoylethanolamide (PEA) is emerging as a novel therapeutic agent in the treatment of neuropathic pain and neurodegenerative diseases. Unfortunately, PEA poorly reaches the central nervous system (CNS), after peripheral administration, since it is inactivated through intracellular hydrolysis by lipid amidases. Since prodrug approach is one of the most popular methods used to increase cell permeability, the aim of this paper consists in the synthesis of a new galactosyl prodrug of PEA, the palmitoylethanolamide-succinamyl-D-galactos-6'-yl ester (PEAGAL). Biological experiments both in neuroblastoma and in C6 glioma cells, together with quantitative analyses performed through a LC-MS-MS technique, demonstrate the better efficacy of PEAGAL compared to PEA and its higher cell permeation. Our results encourage further experiments in animal models of neuropathic pain and of neurological disorders and/or neurodegenerative diseases, in order to promote a more effective peripherally administrated derivative of PEA.

The galactosylation of N(ω)-nitro-L-arginine enhances its anti-nocifensive or anti-allodynic effects by targeting glia in healthy and neuropathic mice

This study has investigated whether the galactosyl ester prodrug of N(ω)-nitro-L-arginine (NAGAL), shows enhanced analgesic efficacy in healthy mice and in models of visceral and neuropathic pain: the writhing test and the spared nerve injury (SNI), respectively. NAGAL was compared to methyl ester pro-drug of N(ω)-nitro-l-arginine (L-NAME), a widely exploited non-specific nitric oxide synthase (NOS) inhibitor, for analgesic potential. The writhing test revealed that the ED(50) value, along with the 95% confidence limit (CL) was 3.82 (1.77-6.04) mg/kg for NAGAL and, 36.75 (20.07-68.37) mg/kg for L-NAME. Notably, NAGAL elicited a greater anti-allodynic effect than L-NAME did in neuropathic mice. Biomolecular and morphological studies revealed that spared nerve injury increased the expressions of pro-inflammatory enzymes (caspase-1) and two glial cell biomarkers: integrin alpha M (ITGAM) and glial fibrillary acidic protein (GFAP) in the spinal cord. Finally, GLUT-3, an isoform of the hexose transporters capable to bind NAGAL and inducible NOS (iNOS), were found to be over-expressed in the activated astrocytes of the spinal cord of neuropathic mice. NAGAL administration normalized expression levels of these biomarkers. NAGAL showed a greater efficacy in inhibiting visceral pain and allodynia than L-NAME possibly by a greater cell permeation through the hexose transporter which is highly over-expressed by activated glia.