Tackle your Tics, a brief intensive group-based exposure treatment for young people with tics: results of a randomised controlled trial.

Tics can have a serious impact on the quality of life of children and their families. Behavioural therapy is an evidence-based first line treatment for tic disorders. This randomised controlled trial studied the efficacy of a brief, condensed group-based programme for children with tics (Dutch Trial Registry NL8052, 27 September 2019). Tackle your Tics is a four-day group treatment, including exposure and response prevention and supporting components, delivered by therapists and 'experts by experience'. We collected outcome measures at baseline (T1), directly post-treatment (T2), and at three- and 6-months follow-up (T3, T4) including tic severity (primary outcome measure), tic-related impairment, quality of life, tic-related cognitions, emotional/behavioural functioning, family functioning, treatment satisfaction and adherence. Outcomes directly post-treatment improved in both the treatment group (n = 52) and waiting list (n = 54), but showed no statistically significant differences between the conditions (differential change over time T1-T2) on tic severity (Yale Global Tic Severity Scale), quality of life (Gilles de la Tourette Syndrome Quality of Life Scale), tic-related cognitions and family functioning. At longer term (T3), again no between-group difference was found on tic severity, but tic-related impairment, quality of life and emotional/behavioural functioning significantly improved in the treatment group compared to the waiting list. Mean treatment satisfaction scores were favourable for both children and parents. Directly posttreatment, Tackle your Tics showed no superior effect compared to waiting list. However, on longer term this brief four-day group treatment was effective in improving tic-related impairment, quality of life and emotional/behavioural functioning.

Tackle your Tics: pilot findings of a brief, intensive group-based exposure therapy program for children with tic disorders.

Tourette syndrome (TS) and other chronic tic disorders (CTD) are prevalent neurodevelopmental disorders, which can have a huge burden on families and society. Behavioral treatment is a first-line intervention for tic disorders. Despite demonstrated efficacy, tic reduction and utilization rates of behavioral treatment remain relatively low. Patient associations point to an urgent need for easy-to-undergo treatments that focus both on tic reduction and improvement of quality of life. To enhance treatment outcome and overcome treatment barriers, this pilot study's aim was to investigate the feasibility and preliminary results of a brief, intensive group-based treatment. Tackle your Tics is a 4-day intensive and comprehensive group-based program for children and adolescents (9-17 years) with a tic disorder, consisting of exposure and response prevention (ERP) treatment and additional supporting components, such as coping strategies, relaxing activities and parent support. Assessments were performed pre- and post-treatment and at 2 months follow-up, to test outcomes on tic severity and quality of life, and explore premonitory urges, emotional and behavioral functioning and treatment satisfaction (N = 14, of whom 13 completed the treatment). Parents and children rated this treatment positive on a treatment satisfaction questionnaire. On tic severity (Yale Global Tic Severity Scale) and quality of life (Gilles de la Tourette Syndrome Quality of Life Scale for children and adolescents), improvements between pre-treatment and follow-up were found. Intensive ERP in group format is promising as a feasible treatment to improve both tic severity as well as quality of life. Larger controlled trials are needed to establish its effectiveness.

The antifibrotic potential of a sustained release formulation of a PDGFß-receptor targeted rho kinase inhibitor.

Rho kinase activity in hepatic stellate cells (HSCs) is associated with activation, transformation and contraction of these cells, leading to extracellular matrix production and portal hypertension in liver cirrhosis. Inhibition of rho kinase activity can reduce these activities, but may also lead to side effects, for instance systemic hypotension. This can be circumvented by liver-specific delivery of a rho kinase inhibitor to effector cells. Therefore, we targeted the rho kinase inhibitor Y27632 to the key pathogenic cells in liver fibrosis, i.e. myofibroblasts including activated HSCs that highly express the PDGFß-receptor, using the drug carrier pPB-MSA. This carrier consists of mouse serum albumin (MSA) covalently coupled to several PDGFßR-recognizing moieties (pPB). We aimed to create a prolonged release system of such a targeted construct, by encapsulating pPB-MSA-Y27632 in biodegradable polymeric microspheres, thereby reducing short-lasting peak concentrations and the need for frequent administrations. Firstly, we confirmed the vasodilating potency of PDGFß-receptor targeted Y27632 in vitro in a contraction assay using HSCs seeded on a collagen gel. We subsequently demonstrated the in vivo antifibrotic efficacy of pPB-MSA-Y27632-loaded microspheres in the Mdr2-/- mouse model of progressive biliary liver fibrosis. A single subcutaneous microsphere administration followed by organ harvest one week later clearly attenuated liver fibrosis progression and significantly suppressed the expression of fibrosis related genes, such as several collagens, profibrotic cytokines and matrix metalloproteinases. In conclusion, we demonstrate that polymeric microspheres are suitable as drug delivery system for the sustained systemic delivery of targeted protein constructs with antifibrotic potential, such as pPB-MSA-Y27632. This formulation appears suitable for the sustained treatment of liver fibrosis and possibly other chronic diseases.

Pharmacokinetics of a sustained release formulation of PDGFß-receptor directed carrier proteins to target the fibrotic liver.

Liver fibrogenesis is associated with excessive production of extracellular matrix by myofibroblasts that often leads to cirrhosis and consequently liver dysfunction and death. Novel protein-based antifibrotic drugs show high specificity and efficacy, but their use in the treatment of fibrosis causes a high burden for patients, since repetitive and long-term parenteral administration is required as most proteins and peptides are rapidly cleared from the circulation. Therefore, we developed biodegradable polymeric microspheres for the sustained release of proteinaceous drugs. We encapsulated the drug carrier pPB-HSA, which specifically binds to the PDGFßR that is highly upregulated on activated myofibroblasts, into microspheres composed of hydrophilic multi-block copolymers composed of poly(l-lactide) and poly ethylene glycol/poly(ϵ-caprolactone), allowing diffusion-controlled release. Firstly, we estimated in mice with acute fibrogenesis induced by a single CCl4 injection the half-life of I125-labeled pPB-HSA at 40 min and confirmed the preferential accumulation in fibrotic tissue. Subsequently, we determined in the Mdr2 −/− mouse model of advanced biliary liver fibrosis how the subcutaneously injected microspheres released pPB-HSA into both plasma and fibrotic liver at 24 h after injection, which was maintained for six days. Although the microspheres still contained protein at day seven, pPB-HSA plasma and liver concentrations were decreased. This reduction was associated with an antibody response against the human albumin-based carrier protein, which was prevented by using a mouse albumin-based equivalent (pPB-MSA). In conclusion, this study shows that our polymeric microspheres are suitable as sustained release formulation for targeted protein constructs such as pPB-HSA. These formulations could be applied for the long-term treatment of chronic diseases such as liver fibrosis.

Polymeric microspheres for the sustained release of a protein-based drug carrier targeting the PDGFß-receptor in the fibrotic kidney.

Injectable sustained release drug delivery systems are an attractive alternative for the intravenous delivery of therapeutic proteins. In particular, for chronic diseases such as fibrosis, this approach could improve therapy by reducing the administration frequency while avoiding large variations in plasma levels. In fibrotic tissues the platelet-derived growth factor receptor beta (PDGFßR) is highly upregulated, which provides a target for site-specific delivery of drugs. Our aim was to develop an injectable sustained release formulation for the subcutaneous delivery of the PDGFßR-targeted drug carrier protein pPB-HSA, which is composed of multiple PDGFßR-recognizing moieties (pPB) attached to human serum albumin (HSA). We used blends of biodegradable multi-block copolymers with different swelling degree to optimize the release rate using the model protein HSA from microspheres produced via a water-in-oil-in-water double emulsion evaporation process. The optimized formulation containing pPB-HSA, showed complete release in vitro within 14days. After subcutaneous administration to mice suffering from renal fibrosis pPB-HSA was released from the microspheres and distributed into plasma for at least 7days after administration. Furthermore, we demonstrated an enhanced accumulation of pPB-HSA in the fibrotic kidney. Altogether, we show that subcutaneously administered polymeric microspheres present a suitable sustained release drug delivery system for the controlled systemic delivery for proteins such as pPB-HSA.

Intravenous administration of recombinant human IL-10 suppresses the development of anti-thy 1-induced glomerulosclerosis in rats.

AIM: Interleukin-10 (IL-10) is a cytokine with potent antifibrotic and anti-inflammatory properties. However, IL-10 has a very short plasma half-life in vivo. This prompted the question whether a short intravenous treatment might have prolonged effects on more chronic processes like sclerosis. METHODS: Glomerulosclerosis was induced by anti-Thymocyte 1 (Anti-Thy 1) antibody. Four days after induction, an intravenous injection of recombinant human IL-10 (rhIL-10) was given for 3 consecutive days. Untreated rats received vehicle only (phosphate-buffered saline). Parameters of inflammation and fibrosis were assessed at protein and mRNA levels. Untreated rats showed renal histopathological changes as compared to normal rats. RESULTS: Glomerular matrix expansion and inflammatory cell influx was observed and an increase in glomerular-inducible nitric oxide synthetase and α-smooth muscle actin (α-SMA) were found on the protein level, factors that were clearly attenuated by IL-10 treatment. In particular, the decrease of matrix metalloproteinase-13 levels between days 4 and 7 was completely prevented by IL-10. In contrast, IL-10 did not significantly reduce mRNA levels for procollagen α1(1), α-SMA, and transforming growth factor 1. CONCLUSION: A short-term treatment with rhIL-10 after induction of Anti-Thy 1 antibody nephritic rats attenuated intraglomerular inflammation, and at the protein level also influenced the parameters reflecting matrix deposition and degradation. Despite in fact that IL-10 was shown to be effective in the inhibition of matrix deposition, it had no beneficial effect on proteinuria. LAY ABSTRACT: Interleukin-10 is a cytokine with potent antifibrotic and anti-inflammatory properties. Its short plasma half-life raises the question whether a short intravenous treatment might have prolonged effects on chronic disease like sclerosis. To confirm this, recombinant human interleukin-10 was used to treat glomerulosclerosis in rats. The disease was induced by Anti-Thy 1 antibody. Four days after induction, an intravenous injection of IL-10 was given for 3 consecutive days. Untreated rats received vehicle only (phosphate-buffered saline). Parameters of inflammation and fibrosis were assessed at protein and mRNA levels. In this study, untreated rats showed renal histopathological changes as compared to normal rats. Glomerular matrix expansion and inflammatory cell influx was observed, and increases in glomerular nitric oxide synthetase and α-smooth muscle actin α-SMA were found on the protein level. In contrast, treated rats clearly showed reduction of all these parameters. In particular, the decrease of anti-matrix metalloproteinase-13 (MMP-13) levels between days 4 and 7 was completely prevented by IL-10. However, IL-10 did not significantly reduce mRNA levels for procollagen α1(1), α-SMA, and TGFß-1. Based on these results, it can be concluded that a short-term treatment with rhIL-10 after induction of Anti-Thy 1 antibody in nephritic rats attenuated intraglomerular inflammation, and at the protein level also influenced the parameters reflecting matrix deposition and degradation. Despite in fact that IL-10 was shown to be effective in the inhibition of matrix deposition, it had no beneficial effect on proteinuria.

Reduction of fibrogenesis by selective delivery of a Rho kinase inhibitor to hepatic stellate cells in mice.

One of the pathways activated during liver fibrosis is the Rho kinase pathway, which regulates activation, migration, and contraction of hepatic stellate cells (HSC). Inhibition of this kinase by the Rho kinase inhibitor Y27632 [(+)-(R)-trans- 4-(1-aminoethyl)-N-(4-pyridyl)cyclohexanecarboxamide dihydrochloride] has been shown to reduce fibrosis in animal models. However, kinase expression is ubiquitous, so any inhibitor may affect many cell types. We hypothesize that cell-specific delivery of a kinase inhibitor will be beneficial. Therefore, we conjugated Y27632 to the carrier mannose-6-phosphate (M6P) human serum albumin (HSA), which is taken up specifically in activated HSC through the M6P/insulin-like growth factor II receptor. This conjugate decreased protein expression of phosphorylated myosin light chain 2 (pMLC2) and vinculin, downstream of Rho kinase, in activated primary HSC and decreased the migration and contraction of HSC. In an ex vivo model, free Y27632 decreased contractility of rat aortas, whereas the Y27-conjugate did not, showing that the Y27-conjugate does not affect nontarget tissue. In chronic CCl(4)-induced liver fibrosis, both free drug and conjugate reduced HSC activation; however, only the Y27-conjugate significantly reduced collagen deposition. Treatment with the Y27-conjugate, but not with free drug, reduced pMLC2 expression in livers 24 h after injection, demonstrating prolonged inhibition of the Rho kinase pathway. The Rho kinase inhibitor Y27632 can be specifically targeted to HSC using M6PHSA, decreasing its effects in nontarget tissues. The targeted drug effectively reduced fibrotic parameters in vivo via the inhibition of the Rho kinase pathway.

Cellular targeting of the apoptosis-inducing compound gliotoxin to fibrotic rat livers.

Liver fibrosis is associated with proliferation of hepatic stellate cells (HSCs) and their transformation into myofibroblastic cells that synthesize scar tissue. Several studies indicate that induction of apoptosis in myofibroblastic cells may prevent fibrogenesis. Gliotoxin (GTX) was found to induce apoptosis of hepatic cells and caused regression of liver fibrosis. However, the use of apoptosis-inducing drugs may be limited due to lack of cell specificity, with a risk of severe adverse effects. In previous studies, we found that mannose-6-phosphate-modified human serum albumin (M6P-HSA) selectively accumulated in liver fibrogenic cells. The aim of this study therefore was to couple GTX to M6P-HSA and test its pharmacological effects in vitro and in rats with liver fibrosis. The conjugate GTX-M6P-HSA bound specifically to HSCs and reduced their viability. Apoptosis was induced in cultures of human hepatic myofibroblasts (hMFs) and in liver slices obtained from rats with liver fibrosis. In vivo treatment with GTX or GTX-M6P-HSA in bile duct ligated rats revealed a significant decrease in alpha-smooth muscle actin mRNA levels and a reduced staining for this HSC marker in fibrotic livers. In addition, although GTX also affected hepatocytes, GTX-M6P-HSA did not significantly affect other liver cells. In conclusion, we developed an HSC-specific compound that induced apoptosis in human hMFs, rat HSCs, and in fibrotic liver slices. In vivo, both GTX and GTX-M6P-HSA attenuated the number of activated HSCs, but GTX also affected hepatocytes. This study shows that cell-selective delivery of the apoptosis-inducing agent GTX is feasible in fibrotic livers.

Dissemination of rat cytomegalovirus through infected granulocytes and monocytes in vitro and in vivo.

The role of leukocytes in the in vivo dissemination of cytomegalovirus was studied in this experiment. Rat cytomegalovirus (RCMV) could be transferred to rat granulocytes and monocytes by cocultivation with RCMV-infected fibroblasts in vitro. Intravenous injection of purified infected granulocytes or monocytes resulted in a systemic infection in rats, indicating that our model is a powerful tool to gain further insight into CMV dissemination and the development of new antivirals.

Conditions influencing the in vitro antifungal activity of lactoferrin combined with antimycotics against clinical isolates of Candida. Impact on the development of buccal preparations of lactoferrin.

Lactoferrin, an iron-binding glycoprotein, is a potential agent for the treatment of oropharyngeal Candidiasis. The aim of the present study was to test the capability of lactoferrin, combined or not combined with conventional antifungal agents, to inhibit the growth of different Candida species under various experimental conditions to be of guidance in the development of a suitable pharmaceutical formulation containing lactoferrin. The anti-Candida activities of lactoferrin were considerably higher using RPMI instead of SLM as assay medium. They were moreover increased by raising the medium pH from 5.6 to 7.5. With the 'standard' antifungal agent fluconazole similar results were found as for lactoferrin, but the medium type and pH did not affect MIC values of amphotericin B. The addition of saliva to medium did not reduce the antifungal activities of the individual compounds. Synergistic inhibitory effects on Candida growth were found for combinations of lactoferrin and fluconazole or amphotericin B, irrespective of the medium type and pH, or the addition of saliva. This indicates that for treatment of oral Candidiasis a formulation containing lactoferrin seems appropriate; results may be optimized if the formulation is provided with buffer capacity to attain pH 7.5 in the mucosal fluid. The synergistic effects between lactoferrin and 'standard' antifungals indicate that combinations should be considered in such a formulation.

The metabolic fate of the Anti-HIV active drug carrier succinylated human serum albumin after intravenous administration in rats.

The pharmacokinetics and metabolic fate of the intrinsically active (anti-HIV) drug carrier succinylated human serum albumin (Suc-HSA) was studied in rats. Suc-HSA was prepared by derivatizing HSA with 1,4-[14C]-succinic anhydride, a modification by which all available epsilon NH2-groups in HSA were converted into carboxylic groups. After i.v. injections of 0.3, 1.0, 3.0 and 10.0 mg/kg in freely moving rats, Suc-HSA showed a dose dependent elimination pattern, indicating a saturable elimination pathway. The Michaelis-Menten parameters Vmax and Km were 98.7 micrograms.min-1.kg-1 and 8.5 micrograms.ml-1 respectively. The kinetics of Suc-HSA was influenced by anaesthesia. In anaesthetised animals, Vmax and Km were found to be 26.9 micrograms.min-1.kg-1 and 0.26 microgram.ml-1, respectively. This implies an intrinsic clearance of 100 ml.min-1.kg-1, which is about 10-fold higher as compared to 12 ml.min-1.kg-1 in freely moving animals. Intravenous administration of a sub-saturable dose of 3.0 mg.kg-1 1,4-[14C]-Suc-HSA to freely moving rats resulted in a biphasic elimination with an initial t 1/2 of 20 min and a terminal t 1/2 of 40 hrs. Excretion of metabolites in urine and faeces lasted for at least 48 hours. About 70% of the radioactive dose was excreted in urine, whereas maximally 2% was detected in faeces. Suc-HSA was degraded to its individual amino acids including succinylated lysine (the only radioactive product formed). Succinylated lysine was not further metabolised and mainly excreted via the urine. Immunohistochemical staining showed that even after 48 hrs Suc-HSA could be detected in livers. Together with the urinary excretion patterns, this points to a gradual degradation of Suc-HSA.

Characteristics of the hepatic stellate cell-selective carrier mannose 6-phosphate modified albumin (M6P(28)-HSA).

BACKGROUND/AIMS: Drug targeting to hepatic stellate cells (HSC) may improve the pharmacological effects of antifibrotic drugs. Recently, albumin substituted with 28 mannose 6-phosphate moieties (M6P(28)-HSA) was found to distribute selectively to HSC in fibrotic rat livers. To assess whether this albumin can be used as a carrier for intracellular drug delivery, we explored the cellular handling of M6P(28)-HSA in HSC. METHODS/RESULTS: Application of competitive substrates for the M6P/IGFII receptor or other receptors showed that the binding of M6P-HSA to the M6P/IGFII receptor is specific. Binding was strong to activated HSC, but not to quiescent HSC. Furthermore, M6P(28)-HSA was extensively internalized by these cells. Using monensin, a specific inhibitor of the lysosomal pathway, proof was obtained that M6P-HSA is endocytosed via this route. The experiments performed with tissue slices, prepared from rat and human livers, revealed a specific binding and uptake of M6P(28)-HSA in both normal and cirrhotic livers. In livers from cirrhotic patients, HSC contributed predominantly to the uptake of this neoglycoprotein. CONCLUSIONS: Based on our in vivo data demonstrating the HSC-selectivity and on our in vitro data demonstrating binding and rapid internalization in activated HSC, we conclude that M6P(28)-HSA is applicable as a stellate cell-selective carrier for antifibrotic drugs that act intracellularly. This may have implications for the design of new strategies for the treatment of liver fibrosis.

Antiviral activities of lactoferrin.

Lactoferrin (LF) is an iron binding glycoprotein that is present in several mucosal secretions. Many biological functions have been ascribed to LF. One of the functions of LF is the transport of metals, but LF is also an important component of the non-specific immune system, since LF has antimicrobial properties against bacteria, fungi and several viruses. This review gives an overview of the present knowledge about the antiviral activities and, when possible, the antiviral modes of action of this protein. Lactoferrin displays antiviral activity against both DNA- and RNA-viruses, including rotavirus, respiratory syncytial virus, herpes viruses and HIV. The antiviral effect of LF lies in the early phase of infection. Lactoferrin prevents entry of virus in the host cell, either by blocking cellular receptors, or by direct binding to the virus particles.

Disease-induced drug targeting using novel peptide-ligand albumins.

UNLABELLED: Small therapeutic oligopeptides (two to 12 amino acids), designed for interaction with cytokine and growth factor receptors, unfortunately, are rapidly removed from the body. Efficient glomerular filtration and carrier-mediated membrane transport processes are involved in their clearance. By coupling of such peptides to macromolecules, elimination via these pathways is prevented and exposure to the particular receptors can be largely improved. Some of these constructs undergo receptor-mediated endocytoses and can be used as carriers to deliver associated drugs to various cell types in the body. It has been shown that, in the case of neo-glycoprotein carriers, down-regulation of the receptors aimed at can occur in the diseased state. We therefore designed a new type of polypeptide carrier, homing on receptors that are known to be highly upregulated in the pathological target tissue. For this purpose we designed ligand peptides (minimized proteins) representing the receptor-recognizing domains of PDGF and collagen type VI, aimed at receptors that are highly expressed, particularly on activated hepatic stellate cells (HSC). This myofibroblast-type of cell largely contributes to connective tissue expansion during liver fibrosis. Drug carriers for the stellate cell have not been reported before. METHODS: Cyclic octapeptide moieties (n10--12) with affinity for the two receptors were coupled to HSA (pPB-HSA and pCVI-HSA, respectively). Receptor binding experiments confirmed binding of these ligand peptides to their receptors in vitro. IN VITRO STUDIES: rat HSC were isolated and purified according to standard techniques. The cells were cultured for 2 days (quiescent phenotype) or for 10 days (activated phenotype). Cell cultures were incubated with the carriers and the binding (at 4 degrees C), uptake (at 37 degrees C), and degradation were determined with radioactive and immunohistochemical methods. The results were compared with data obtained with unmodified HSA. IN VIVO STUDIES: the organ distribution of pCVI-HSA and pPB-HSA was determined 10 min after i.v. injection of tracer doses in normal and fibrotic rats, 3 weeks after bile duct ligation. Hepatocellular distribution was scored after double-immunostaining of the liver sections with an antibody against the designated hepatic cell type in combination with anti-HSA IgG. IN VITRO STUDIES: All three carriers preferentially bound to the activated rather than to quiescent HSC. Binding to cells was inhibitable by an excess of unlabelled pCVI-HSA, endocytosis was inhibitable by 2 mM monensin suggestive of lysosomal routing of the proteins, whereas pPB-HSA, at least partly, remained at the cell surface. Degradation products of the carriers were detected extracellularly after incubation with fibrotic rat liver slices during 2-h experiments. IN VIVO STUDIES: 62+/-6% of the dose of pCVI-HSA accumulated in fibrotic livers at 10 min after injection, of which the major part was taken up in HSC. 48+/-9% of pPB-HSA accumulated in fibrotic rat livers and this carrier was also mainly taken up by HSC (5). Similar amounts of both constructs were taken up in normal rat livers, but predominantly in other cell types. The preferential homing to the stellate cells, only in the fibrotic liver is explained by the marked proliferation of this cell type as well as overexpression of the targeted receptors on these cells in the diseased state. CONCLUSIONS: The in vivo results support the in vitro studies showing accumulation of these modified albumins in HSC in fibrotic rat livers and, in particular, in the stellate cells. The results demonstrate the specificity of the stellate cell targeting and imply applicability of pCVI-HSA as carriers for drugs that act intracellularly. In addition, pPB-HSA may be used to deliver drugs that act extracellularly, such as receptor antagonists. This concept may create new opportunities for delivery of conventional drugs that are not effective enough in vivo and/or display serious extrahepatic side-effects. Minimized proteins attached to soluble or particle type of macromolecules represent a novel carrier modality of which selective body distribution is induced by the disease process to be targeted. They can be utilized as receptor antagonists and at the same time can deliver therapeutic agents to the desired site of action (dual targeting).

Successful targeting to rat hepatic stellate cells using albumin modified with cyclic peptides that recognize the collagen type VI receptor.

The key pathogenic event in liver fibrosis is the activation of hepatic stellate cells (HSC). Consequently, new antifibrotic therapies are directed toward an inhibition of HSC activities. The aim of the present study was to develop a drug carrier to HSC, which would allow cell-specific delivery of antifibrotic drugs thus enhancing their effectiveness in vivo. We modified human serum albumin (HSA) with 10 cyclic peptide moieties recognizing collagen type VI receptors (C*GRGDSPC*, in which C* denotes the cyclizing cysteine residues) yielding pCVI-HSA. In vivo experiments showed preferential distribution of pCVI-HSA to both fibrotic and normal rat livers (respectively, 62 +/- 6 and 75 +/- 16% of the dose at 10 min after intravenous injection). Immunohistochemical analysis demonstrated that pCVI-HSA predominantly bound to HSC in fibrotic livers (73 +/- 14%). In contrast, endothelial cells contributed mostly to the total liver accumulation in normal rats. In vitro studies showed that pCVI-HSA specifically bound to rat HSC, in particular to the activated cells, and showed internalization of pCVI-HSA by these cells. In conclusion, pCVI-HSA may be applied as a carrier to deliver antifibrotic agents to HSC, which may strongly enhance the effectiveness and tissue selectivity of these drugs. This approach has the additional benefit that such carriers may block receptors that play a putative role in the pathogenesis of liver fibrosis.

Targeting of superoxide dismutase to the liver results in anti-inflammatory effects in rats with fibrotic livers.

BACKGROUND/AIMS: The rapid clearance from plasma and the limited uptake of superoxide dismutase (SOD) in the liver hampers the effectiveness of this enzyme in liver diseases. We therefore compared the pharmacokinetics and in vivo efficacy of SOD with two modified forms of this protein: SOD coupled to the copolymer DIVEMA and mannosylated-SOD. METHODS: Reactive oxygen scavenging activity of SOD conjugates was tested in livers of bile duct ligated rats. Intrahepatic production of reactive oxygen species (ROS) and neutrophil infiltration were studied immunohistochemically and related to the organ and cellular distribution of radiolabeled SOD conjugates. RESULTS: Native SOD was rapidly cleared from the circulation and accumulated in renal tubuli. The enzyme had no effect on the intrahepatic ROS production. Covalent attachment of SOD to DIVEMA yielded a polyanionic conjugate with a prolonged elimination half-life compared to native SOD. In contrast to native SOD, DIVEMA-SOD was taken up by the liver via scavenger receptors. Mannosylation of SOD (Man-SOD) resulted in a conjugate that was rapidly cleared from the blood. This Man-SOD was taken up by non-parenchymal liver cells. The pharmacokinetics of SOD and its derivatives were similar in normal and bile duct ligated rats. Efficacy studies with Man-SOD revealed only a slight decrease in intrahepatic ROS production. However, DIVEMA-SOD exhibited a potent inhibitory effect on ROS production in the liver. Nearly complete ROS-scavenging activity was observed in the portal areas. CONCLUSIONS: Considering the prolonged half-life, the increased delivery of SOD to the target cells, and the concomitant increased effectiveness, application of DIVEMA-SOD seems a promising new approach to attenuate intrahepatic inflammatory processes.

Homing of negatively charged albumins to the lymphatic system: general implications for drug targeting to peripheral tissues and viral reservoirs.

The present study shows the lymphatic distribution of the negatively charged anti-HIV-1 agents succinylated or aconytilated human serum albumins (HSAs) in rats. Quantitation of blood and lymphatic concentrations of these proteins was performed through fluorescence detection of the fluorescein isothiocyanate (FITC)-labeled proteins. At several time points after i.v. injection, samples were taken from the cannulated thoracic duct and the carotid artery. Distribution of the negatively charged albumins (NCAs) to lymph was much more rapid than that of albumin itself and was dependent on the total net negative charge added to the protein: the half-life times of lymphatic equilibration were 15, 30, and 120 min for FITC-labeled aconytilated HSA, FITC-labeled succinylated HSA, and FITC-labeled HSA, respectively. Lymph to blood concentration ratios of the studied compounds obtained at steady state approached unity. In addition, the fluorescence in both body fluids was shown to represent unchanged labeled proteins. It was therefore inferred that the NCAs efficiently passed the endothelial barrier from blood to the interstitial compartment. Subsequently, we studied whether a specialized process was involved in the endothelial passage of the NCAs to the lymph. The following observations supported such a mechanism: a) preinjection of the scavenger receptor blockers polyinosinic- and formaldehyde-treated HSA reduced the transport from blood to the lymphatic compartment of FITC-labeled aconytilated HSA by more than 90%; b) the rate of lymphatic distribution was largely reduced when the body temperature of the rat was lowered to 28 degrees; and c) pre-administration of chloroquine resulted in a significant reduction in the lymphatic distribution of the NCAs. These data collectively indicate that a scavenger receptor-mediated process is involved in the transendothelial transport of NCAs. In situ localization in lymph nodes of the rat showed that FITC-labeled aconytilated and succinylated HSA are mainly present in the germinal center and parafollicular zones. The efficient distribution of these anionized proteins to the lymphatic system is of particular interest for HIV therapy, taking into account that replication of HIV mainly takes place in the lymphoid system. The observation that macromolecules, through charge modification, can extravasate through a receptor-mediated transcytotic process is potentially of major importance for the delivery of drugs with macromolecular carriers to cells not directly in contact with the blood.

Albumin modified with mannose 6-phosphate: A potential carrier for selective delivery of antifibrotic drugs to rat and human hepatic stellate cells.

The hallmark of liver fibrosis is an increased extracellular matrix deposition, caused by an activation of hepatic stellate cells (HSC). Therefore, this cell type is an important target for pharmacotherapeutic intervention. Antifibrotic drugs are not efficiently taken up by HSC or may produce unwanted side-effects outside the liver. Cell-specific delivery can provide a solution to these problems, but a specific drug carrier for HSC has not been described until now. The mannose 6-phosphate/insulin-like growth factor II (M6P/IGF-II) receptor, which is expressed in particular upon HSC during fibrosis, may serve as a target-receptor for a potential carrier. The aim of the present study was to examine if human serum albumin (HSA) modified with mannose 6-phosphate (M6P) is taken up by HSC in fibrotic livers. A series of M6Px-modified albumins were synthetized: x = 2, 4, 10, and 28. Organ distribution studies were performed to determine total liver uptake. The hepatic uptake of M6Px-HSA increased with increasing M6P density. M6Px-HSA with a low degree of sugar loading (x = 2-10) remained in the plasma and accumulated for 9% +/- 0.5% or less in fibrotic rat livers. An increase in the molar ratio of M6P:HSA to 28:1 caused an increased liver accumulation to 59% +/- 9% of the administered dose. Furthermore, we determined quantitatively the in vivo intrahepatic distribution of M6Px-HSA using double-immunostaining techniques. An increased substitution of M6P was associated with an increased accumulation in HSC; 70% +/- 11% of the intrahepatic staining for M6P28-HSA was found in HSC. We also demonstrate that M6P-modified bovine serum albumin (BSA) accumulates in slices of normal and cirrhotic human livers. After incubation of this neoglycoprotein with human tissue, the protein is found in nonparenchymal liver cells. Because M6P-modified albumins are taken up by HSC in fibrotic livers, this neoglycoprotein can be applied as a selective drug carrier for HSC. This technology may create new opportunities for the pharmacological intervention of liver fibrosis.

Targeting of sugar- and charge-modified albumins to fibrotic rat livers: the accessibility of hepatic cells after chronic bile duct ligation.

BACKGROUND/AIMS: In normal rat livers, cell-selective delivery of drugs to hepatocytes, endothelial cells and Kupffer cells can be achieved by coupling drugs to lactosaminated human serum albumin (lacHSA), succinylated HSA (sucHSA) and mannosylated HSA (manHSA), respectively. Since fibrosis is associated with increased matrix deposition and sinusoidal capillarization, and since these modified albumins may serve as carriers for anti-fibrotic drugs, we determined the hepatic disposition of these albumins in rats with liver fibrosis. METHODS: At different time points after bile duct ligation, a bolus dose of either lacHSA, sucHSA or manHSA (fluorescein labelled) was intravenously injected and pharmacokinetic parameters were determined. Organ distributions of the 125I-labelled carriers were assessed in normal and fibrotic rats. In addition, their intrahepatic distributions were determined by immunohistochemical inspection. RESULTS: In rats with liver fibrosis, the plasma disappearance rate of the three proteins was significantly altered as compared to control rats. A moderately decreased clearance for lacHSA, an increased plasma clearance for manHSA and sucHSA, and an increased volume of distribution for all three proteins was found. Despite these pharmacokinetic alterations, tissue distribution studies still showed selective accumulation of the three modified proteins in livers of diseased animals. Moreover, the intrahepatic distribution of these drug-carriers during fibrosis was similar to distribution in normal livers. CONCLUSIONS: This study demonstrates that cell-specific delivery of sugar- and charge-modified albumins in fibrotic livers is possible. Despite the increased matrix deposition during fibrosis, the accessibility of the different liver cell types for the carriers was not significantly altered as compared to normal livers. The availability of a complete set of carriers for the different liver cell types provides opportunities for the development of effective therapeutic strategies based on drug targeting.