Hepatotoxicity of intravenous cyclosporin A in patients with acute ulcerative colitis on total parenteral nutrition

Cyclosporine A-loaded colon-targeted oral nanomicelles self-assembly by galactosylated carboxymethyl chitosan for efficient ulcerative colitis therapy

An oral galactosylated carboxymethyl chitosan polymeric nanomicelles (Gal-N-CMCS NPs) embedded in chitosan-alginate hydrogel (CA-Gel) was developed to load cyclosporine A (CyA) as therapeutic agents against ulcerative colitis (UC). Galactose modified CMCS with macrophage targeting characteristic and CyA via a simple ultrasonication method to form Gal-N-CMCS/CyA NPs, and mixed CA-Gel to acquire the final formulation (Gal-N-CMCS/CyA Gel). The generated Gal-N-CMCS/CyA NPs displayed a desirable particle size (206.8 nm), negative surface charge (-19.5 mV), and high encapsulating efficiency (89.6%). The morphology and release profiles were also charactered by transmission electron microscope [1] and dialysis method, respectively. Strikingly, the mucus penetration of Gal-N-CMCS/CyA NPs exceeded 90% within 90 min. The Gal-N-CMCS NPs internalized by macrophages were 3.3-fold higher than CMCS-N NPs, thereby, enhancing the anti-inflammatory activities of NPs. Meanwhile, these NPs exhibited excellent biocompatibility, reduced the toxic effect of CyA, and targeting ability on inflammatory macrophages both in vitro and in vivo. Most importantly, in vivo studies revealed that CyA NPs could efficiently target the inflamed colon, remarkably alleviate inflammation, repair mucosal and reconstructed colonic epithelial barriers in UC mice induced by dextran sulfate sodium (DSS) via Toll-like receptor 4 -Nuclear factor kappa-B (TLR4-NF-κB) pathway. Our findings suggest that these high-performance and facilely fabricated Gal-N-CMCS/CyA NPs could be developed as a promising drug carrier for oral UC treatment.

Olfactory ensheathing cells improve the survival of porcine neural xenografts in a Parkinsonian rat model

BACKGROUND

Parkinson's disease (PD) features the motor control deficits resulting from irreversible, progressive degeneration of dopaminergic (DA) neurons of the nigrostriatal pathway. Although intracerebral transplantation of human fetal ventral mesencephalon (hfVM) has been proven effective at reviving DA function in the PD patients, this treatment is clinically limited by availability of hfVM and the related ethical issues. Homologous tissues to hfVM, such as porcine fetal ventral mesencephalon (pfVM) thus present a strong clinical potential if immune response following xenotransplantation could be tamed. Olfactory ensheathing cells (OECs) are glial cells showing immunomodulatory properties. It is unclear but intriuging whether these properties can be applied to reducing immune response following neural xenotransplantation of PD.

METHODS

To determine whether OECs may benefit neural xenografts for PD, different compositions of grafting cells were transplanted into striatum of the PD model rats. We used apomorphine-induced rotational behavior to evaluate effectiveness of the neural grafts on reviving DA function. Immunohistochemistry was applied to investigate the effect of OECs on the survival of neuroxenografts and underlying mechanisms of this effect.

RESULTS

Four weeks following the xenotransplantation, we found that the PD rats receiving pfVM + OECs co-graft exhibited a better improvement in apomorphine-induced rotational behavior compared with those receiving only pfVM cells. This result can be explained by higher survival of DA neurons (tyrosine hydroxylase immunoreactivity) in grafted striatum of pfVM + OECs group. Furthermore, pfVM + OECs group has less immune response (CD3⁺ T cells and OX-6⁺ microglia) around the grafted area compared with pfVM only group. These results suggest that OECs may enhance the survival of the striatal xenografts via dampening the immune response at the grafted sites.

CONCLUSIONS

Using allogeneic OECs as a co-graft material for xenogeneic neural grafts could be a feasible therapeutic strategy to enhance results and applicability of the cell replacement therapy for PD.

In Vitro Analysis of CsA-Induced Hepatotoxicity in HepG2 Cell Line: Oxidative Stress and α2 and β1 Integrin Subunits Expression

BACKGROUND

Cyclosporine A (CsA)-induced hepatotoxicity could be due to a reduction in α2β1 integrin expression that may either be from the direct effect of CsA itself or from reactive oxygen species (ROS) overproduction.

OBJECTIVES

In this study we aimed to identify the cellular mechanisms underlying CsA-induced hepatic injury by investigating the activation patterns of the antioxidant enzymes, using HepG2 as an in vitro model.

MATERIALS AND METHODS

HepG2 cells were cultured with different concentrations of CsA (0, 0.1, 1, 10 μg/ml) for 72 h. Effect of CsA on, 1) cellular integrity, 2) glutathione reductase (GR) and glutathione peroxidase (GPx) activity, 3) cellular levels of glutathione (GSH), 4) intracellular ROS, 5) ALT and AST activities, 6) urea production and 7) α2β1 integrin expression were assayed.

RESULTS

CsA treatment demonstrated a dose dependent increase in intracellular levels of ROS, GPx activity and decrease in GSH levels (P<0.05). GR activity was mildly attenuated in 1 and 10 µg/ml concentrations of CsA. Alanine aminotranferase (ALT) and aspartate aminotransferase (AST) levels increased in CsA treated cells, while urea synthesis was significantly decreased following treatment with higher concentrations of CsA (P<0.05). Significant down-regulation of β1integrin expression was observed in 1 and 10 µg/ml CsA treated cells while α2 integrin mRNA was significantly down-regulated in all CsA treated cells.

CONCLUSIONS

The observed reduction of α2β1 integrin expression following CsA treatment could be proposed as a possible pathway of CsA-induced hepatotoxicity. Further studies are required to elucidate whether this attenuated expression is due to the direct effect of CsA or caused by overproduction of ROS.

Effects of erdosteine on cyclosporin-A-induced nephrotoxicity

AIM

In cyclosporin-A (CsA)-induced toxicity, oxidative stress has been implicated as a potential responsible mechanism. Therefore, we aimed to investigate the protective role of erdosteine against CsA-induced nephrotoxicity in terms of tissue oxidant/antioxidant parameters and light microscopy in rats.

MATERIALS AND METHODS

Wistar albino rats were randomly separated into four groups. Group 1 rats treated with sodium chloride served as the control, group 2 rats were treated with CsA, group 3 with CsA plus erdosteine, and group 4 with erdosteine alone. Animals were killed and blood samples were analyzed for blood urea nitrogen (BUN), serum creatinine (Cr), uric acid (UA), total protein (TP), and albumin (ALB) levels. Kidney sections were analyzed for malondialdehyde (MDA) and nitric oxide (NO) levels and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities, as well as for histopathological changes.

RESULTS

In the CsA group, MDA, GSH-Px, BUN, and Cr levels were increased. The TP and ALB levels were decreased. These changes had been improved by erdosteine administration. Other biochemical parameters did not show any significant change.

CONCLUSION

These results indicate that erdosteine produces a protective mechanism against CsA-induced nephrotoxicity and suggest a role of oxidative stress in pathogenesis.

Effects of erdosteine on cyclosporine-A-induced hepatotoxicity in rats

Cyclosporine A (CsA) is a potent immunosuppressive agent used for organ transplantations and various autoimmune disorders. However, hepatotoxicity due to CsA remains one of the major side effects. The use of antioxidants reduces the adverse effects of CsA. The aim of this study was to determine the protective effects of erdosteine on CsA-induced liver injury through tissue oxidant/antioxidant parameters and to evaluate light microscopic alterations in rat-liver tissues. Rats were randomly divided into four experimental groups: The control group received sunflower oil (2 mL/kg/day, per orally; p.o.), while the other groups were treated with CsA (25 mg/kg/day, p.o.) or erdosteine (10 mg/kg/day, p.o.) or CsA+erdosteine, respectively. Serum aspartate aminotransferase and alanine aminotransferase levels, tissue malondialdehyde and nitric oxide levels, and superoxide dismutase, glutathione peroxidase and catalase enzyme activities were measured. Histological examination was performed. CsA caused a significant deterioration in the hepatic function tests, morphology, and gave rise to severe oxidative stress in the liver. Erdostein significantly improved the functional and histological parameters and attenuated the oxidative stresss induced by CsA. Erdostein protects liver tissue against oxygen free radicals and prevents hepatic dysfunction and morphological abnormalities associated with chronic CsA administration.

The elderly as a sensitive population in environmental exposures: making the case

The US population is aging. CDC has estimated that 20% of all Americans will be 65 or older by the year 2030. As a part of the aging process, the body gradually deteriorates and physiologic and metabolic limitations arise. Changes that occur in organ anatomy and function present challenges for dealing with environmental stressors of all kinds, ranging from temperature regulation to drug metabolism and excretion. The elderly are not just older adults, but rather are individuals with unique challenges and different medical needs than younger adults. The ability of the body to respond to physiological challenge presented by environmental chemicals is dependent upon the health of the organ systems that eliminate those substances from the body. Any compromise in the function of those organ systems may result in a decrease in the body's ability to protect itself from the adverse effects of xenobiotics. To investigate this issue, we performed an organ system-by-organ system review of the effects of human aging and the implications for such aging on susceptibility to drugs and xenobiotics. Birnbaum (1991) reported almost 20 years ago that it was clear that the pharmacokinetic behavior of environmental chemicals is, in many cases, altered during aging. Yet, to date, there is a paucity of data regarding recorded effects of environmental chemicals on elderly individuals. As a result, we have to rely on what is known about the effects of aging and the existing data regarding the metabolism, excretion, and adverse effects of prescription medications in that population to determine whether the elderly might be at greater risk when exposed to environmental substances. With increasing life expectancy, more and more people will confront the problems associated with advancing years. Moreover, although proper diet and exercise may lessen the immediate severity of some aspects of aging, the process will continue to gradually degrade the ability to cope with a variety of injuries and diseases. Thus, the adverse effects of long-term, low-level exposure to environmental substances will have a longer time to be manifested in a physiologically weakened elderly population. When such exposures are coupled with concurrent exposure to prescription medications, the effects could be devastating. Public health officials must be knowledgeable about the sensitivity of the growing elderly population, and ensure that the use of health guidance values (HGVs) for environmental contaminants and other substances give consideration to this physiologically compromised segment of the population.

[Hepatotoxicity induced by new immunosuppressants]

Immunosuppressants are among the pharmacological agents with the greatest potential to cause adverse reactions, although induction of hepatotoxicity is paradoxical from the pathogenic point of view, since the response of the innate and acquired immune system is a key element in the chain of events leading to chemical liver damage. Hepatotoxicity induced by immunosuppressants is difficult to evaluate since these drugs are sometimes used to treat liver diseases, or in combination with other drugs that can also cause hepatotoxicity, or in the context of liver transplantation, in which rejection or biliary complications can act as confounding factors. In addition, immunosuppressant therapy can favor the development of infections, which by themselves can cause liver damage, or reactivate latent chronic viral hepatitis. Corticosteroids and calcineurin inhibitors only exceptionally cause hepatotoxicity. Methotrexate at high doses and in patients with risk factors can induce advanced fibrosis and cirrhosis. Thiopurine agents can cause a spectrum of hepatic lesions, including hepatocellular of cholestatic lesions, and hepatic vascular alterations. Leflunomide has high hepatotoxic potential, especially when combined with methotrexate. Anti-tumor necrosis factor-alpha agents have rarely been associated with hepatotoxicity, often with detectable autoantibodies, and most of the reactions - some severe - have been linked to infliximab, especially when used in patients with rheumatological diseases.

The protective effect of N-acetylcysteine against cyclosporine A-induced hepatotoxicity in rats

The immunosuppressive agent cyclosporine A (CsA) has been reported to exert measurable hepatotoxic effects. One of the causes leading to hepatotoxicity is thought to be reactive oxygen radical formation. The aim of this study was to investigate the effects of N-acetylcysteine (NAC) treatment on CsA-induced hepatic damage by both analysing superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), aspartate aminotransferase (AST) and alanine transaminase (ALT) activities with malondialdehyde (MDA) and nitric oxide (NO) levels, and using an histological approach. CsA administration produced a decrease in hepatic SOD activity, and co-administration of NAC with CsA resulted in an increase in SOD activity. MDA and NO levels increased in the CsA group and NAC treatment prevented those increases. A significant elevation in serum AST and ALT activities was observed in the CsA group, and when NAC and CsA were co-administered, the activities of AST and ALT were close to the control levels. CsA treatment caused evident morphological alterations. Control rats showed no abnormality in the cytoarchitecture of the hepatic parenchyma. The co-administration of NAC with CsA showed no signs of alteration and the morphological pattern was almost similar to the control group. In conclusion, CsA induced liver injury and NAC treatment prevented the toxic side effects induced by CsA administration through the antioxidant and radical scavenging effects of NAC.

Hepatotoxic effect of cyclosporin A in the mitochondrial respiratory chain

Cyclosporin A (CyA), a potent immunosuppressant, was used to determine the hepatotoxic effect in long-term treatments. Male Wistar rats were used in these experiments. They were given CyA chronically at doses used in patients for 120 days, and at doses of 5, 10, 15 and 20 mg kg(-1) day(-1). These doses amount to CyA values in blood of 200 +/- 24, 314 +/- 40, 445 +/- 33 and 598 +/- 53 ng ml(-1), respectively. A significant increase in glutamate dehydrogenase (GLDH) was found in the groups treated with 15 and 20 mg kg(-1) day(-1), which would point to mitochondria as the potential target of the toxic action of CyA. The mitochondrial respiratory chain of rat livers was studied in enzyme complexes I and II. Enzyme complex I was determined by spectrophotometry at 340 nm using NADH oxidase with the respirable substrate 10 mm NADH; enzyme complex II was determined by monitoring succinate dehydrogenase by oxymetry using the respirable substrate 10 mm succinate. The results show the inhibition of NADH oxidase in the groups treated with 10, 15 and 20 mg kg(-1) day(-1), an effect dependent both on time and on CyA concentration. Enzyme complex II showed a decrease in oxygen consumption. These findings were confirmed by histological studies (hematoxylin-eosin technique).

CONCLUSIONS

Long-term treatment with CyA at doses of 15 and 20 mg kg(-1) day(-1), amounting to concentrations in blood of 445 +/- 33 and 598 +/- 53 ng ml(-1), causes alterations in the mitochondria, revealed by the increase in serum GLDH and by the functional alteration of enzyme complexes I and II of the mitochondrial respiratory chain.

Medical therapy for refractory pediatric Crohn's disease

Crohn's disease is a common indication for referral to pediatric gastroenterology. While most patients with Crohn's disease respond to standard induction therapy, steroid-refractory or steroid-dependent disease is a frequently encountered problem. This review discusses the data existing in both the adult and pediatric literature for medical therapy of refractory pediatric Crohn's disease.

Cyclosporine, tacrolimus, and mycophenolate mofetil in the treatment of inflammatory bowel disease

In the past decade, immunosuppressive drugs have come to play an integral role in the treatment of patients with inflammatory bowel disease. Cyclosporine, microemulsion cyclosporine, tacrolimus, and mycophenolate mofetil can be considered for the treatment of patients with refractory inflammatory Crohn's disease, fistulizing Crohn's disease, and severe ulcerative colitis. This article reviews the use of cyclosporine, tacrolimus, and mycophenolate mofetil in patients with inflammatory bowel disease, with emphasis on pharmacology, results in controlled clinical trials, and safety, and issues related to dosing and toxicity monitoring.

Novel mechanism of Vitamin E protection against cyclosporine A cytotoxicity in cultured rat hepatocytes

Cyclosporine A (CsA) is the immunosuppressor most frequently used in transplant surgery and in the treatment of autoimmune diseases. It has been shown that CsA is able to generate reactive oxygen species and lipid peroxidation which are directly involved in the CsA hepatotoxicity. As antioxidant, Vitamin E (VitE) has been used to diminish the toxicity of CsA in vitro. Besides its direct action as the classical antioxidant implicated in preventing lipid peroxidation, we decided to investigate the effect of VitE on the endogenous antioxidant defense system, such as Mn and CuZn superoxide dismutase (MnSOD, CuZnSOD) catalase and glutathione peroxidase (GPx) on CsA cytotoxicity in primary cultures of rat hepatocytes. In cells incubated in the presence of CsA, there was an increase in the expression and activity of MnSOD and CuZnSOD but not in that of catalase and GPx. However, when hepatocytes were coincubated with CsA and VitE, an increase in the expression and activity in all antioxidant enzymes (MnSOD, CuZnSOD, catalase and GPx) was observed. In conclusion, we suggest (a) that the imbalance between SOD and catalase/GPx by the effect of CsA is the main mechanism responsible for peroxide accumulation and cell death in hepatocytes, and (b) that the presence of VitE in culture media reduces the oxidative stress through the inhibition of lipid peroxidation, but also through the increase of the expression and activity of catalase and GPx which allows the restoration of SOD and catalase/GPx coordination, indispensable for the correct cell defense against ROS.

Review article: monitoring for drug side-effects in inflammatory bowel disease

The side-effects suitable for monitoring in patients with inflammatory bowel disease being treated with the four main groups of drugs (5-aminosalicylic acid preparations, azathioprine and 6-mercaptopurine, methotrexate, and corticosteroids) are reviewed. On the basis of the reported frequency, severity and timing of side-effects, a practical scheme of monitoring is recommended. This includes a baseline measurement of full blood count, creatinine and liver function tests in all patients. In the absence of worrying symptoms, we recommend the following: (i) no monitoring for sulfasalazine; (ii) for other 5-aminosalicylic acid preparations, the measurement of creatinine at 6 and 12 months and then annually; (iii) for azathioprine/6-mercaptopurine, thiopurine methyltransferase genotype/phenotype determination has no role in treatment monitoring, but a full blood count at 2 weeks, 1 month, 3 months and then every 3 months should be performed; (iv) for methotrexate, a full blood count and liver function tests should be performed every 3 months; (v) for steroids, dual energy X-ray absorptiometry bone scanning should be performed at the start of therapy, every year in which steroids are used if the T score is < 0, and every 3-5 years if the T score is > 0.

Safety of corticosteroids and immunosuppressive agents in ulcerative colitis

For many years, corticosteroids have been the mainstay for treating acute ulcerative colitis. In patients with refractory disease, immunosuppressive therapy may be indicated, including azathioprine or its metabolite 6-mercaptopurine, cyclosporin and possibly methotrexate. Their benefits in ulcerative colitis must be weighed up against their possible adverse effects, the availability of surgical cure for this condition, and the long-term risk of carcinoma complicating colitis that applies in patients with chronic extensive disease. Information about the safety of corticosteroids and immunosuppressive agents has accumulated as a result of their extensive use in inflammatory bowel disease, organ transplantation and various other disorders.