A mechanistic study on reduced toxicity of irontecan by coadministered thalidomide, a tumor necrosis factor-a inhibitor

Dose-limiting diarrhea and myelosuppression compromise the success of irinotecan (7-ethyl-10-[4-[1-piperidino]-1-piperidino] carbonyloxycamptothecin) (CPT-11)-based chemotherapy. A recent pilot study indicates that thalidomide attenuates the toxicity of CPT-11 in cancer patients. This study aimed to investigate whether coadministered thalidomide modulated the toxicities of CPT-11 and the underlying mechanisms using several in vivo and in vitro models. Diarrhea, intestinal lesions, cytokine expression, and intestinal epithelial apoptosis were
monitored. Coadministered thalidomide (100 mg/kg i.p. for 8 days) significantly attenuated body weight loss, myelosuppression, diarrhea, and intestinal histological lesions caused by CPT-11 (60 mg/kg i.v. for 4 days). This was accompanied by inhibition of tumor necrosis factor-, interleukins 1 and 6 and interferon-, and intestinal epithelial apoptosis. Coadministered
thalidomide also significantly increased the systemic exposure of CPT-11 but decreased that of SN-38 (7-ethyl-10-hydroxycampothecin). It significantly reduced the biliary excretion and cecal exposure of CPT-11, SN-38, and SN-38 glucuronide. Thalidomide hydrolytic products inhibited hydrolysis of CPT-11 in rat liver microsomes but not in primary rat hepatocytes. In addition, thalidomide and its major hydrolytic products, such as phthaloyl glutamic acid (PGA), increased the intracellular accumulation of CPT-11 and SN-38 in primary rat hepatocytes. They also significantly decreased the transport of CPT-11 and SN-38 in Caco-2 and parental MDCKII cells. Thalidomide and PGA also significantly inhibited P-glycoprotein (PgP/MDR1), multidrug resistance-associated protein (MRP1)- and MRP2-mediated CPT-11 and SN-38 transport in MDCKII cells. These results provide insights into the pharmacodynamic and  pharmacokinetic mechanisms for the protective effects of thalidomide against CPT-11-induced intestinal toxicity.

Modulation of tumor necrosis factor receptors 1 and 2 in chronic hepatitis B and C: The differences and implications in pathogenesis

Tumor necrosis factor (TNF) plays a role in the pathogenesis of chronic hepatitis B (CHB) and chronic hepatitis C (CHC). The difference in the cytokine responses between hepatitis B virus (HBV) and hepatitis C virus (HCV) infections may have implications in the pathogenesis of these diseases. We performed a comparative study to examine the possible differences in the TNF-TNF receptor (TNFR) response between CHB and CHC. We studied the cytokine levels of 38 patients with CHB, 40 patients with CHC and 9 patients with dual hepatitis B and C, and compared them with the baseline levels of 12 healthy controls. The plasma levels of TNF-, interferon-, interleukin (IL)-2, IL-4, IL-10 and soluble TNFR-1 and 2 (sTNFR-1 and 2) were quantified by enzyme-linked immunosorbent assays. The expression of TNFR-1 and 2 in liver tissues was examined in 30 cases of CHB and 15 cases of CHC by semiquantitative reverse transcription polymerase chain reaction. The results showed that sTNFR-1 levels correlated with liver inflammation in all patients, whereas this correlation was not found with sTNFR-2 or other cytokines. Liver inflammation indicators were higher in HCV RNA+ than in HCV RNA– CHC. Most significantly, sTNFR-1 levels correlated with liver inflammation in CHB, but not in CHC. However, the expression of TNFR-1 and 2 in liver was similar between CHB and CHC. These findings suggest that the TNFR signal transduction pathway is modulated differently in HBV and HCV infection.

Differential tumor necrosis factor receptor 2-mediated editing of virus-specific CD8+ effector T cells

Much of the CD8+ T cell response in H2b mice with influenza pneumonia is directed at the nucleoprotein366-374 (NP366) and acid polymerase224-233 (PA224) peptides presented by the H2Db MHC class I glycoprotein. These DbNP366- and DbPA224-specific T cell populations are readily analyzed by staining with tetrameric complexes of MHC+ peptide (tetramers) or by cytokine production subsequent to in vitro stimulation with the cognate peptides. The DbPA224-specific CD8+ effector T cells make more tumor necrosis factor (TNF) α than the comparable CD8+DbNP366+ set, a difference reflected in the greater sensitivity of the CD8+DbPA224+ population to TNF receptor (TNFR) 2-mediated apoptosis under conditions of in vitro culture. Freshly isolated CD8+DbNP366+ and CD8+DbPA224+ T cells from influenza-infected TNFR2-/- mice produce higher levels of IFN-γ and TNF-α after in vitro stimulation with peptide, although the avidity of the T cell receptor-epitope interaction does not change. Increased numbers of both CD8+DbPA224+ and CD8+DbNP366+ T cells were recovered from the lungs (but not the spleens) of secondarily challenged TNFR2-/- mice, a pattern that correlates with the profiles of TNFR expression in the TNFR2+/+ controls. Thus, it seems that TNFR2-mediated editing of influenza-specific CD8+ T cells functions to limit the numbers of effectors that have localized to the site of pathology in the lung but does not modify the size of the less activated responder T cell populations in the spleen. Therefore, the massive difference in magnitude for the secondary, although not the primary, response to these DbNP366 and DbPA224 epitopes cannot be considered to reflect differential TNFR2-mediated T cell editing.

Cytokine regulation of skeletal muscle fatty acid metabolism: effect of interleukin-6 and tumor necrosis factor-α

IL-6 and TNF-α have been associated with insulin resistance and type 2 diabetes. Furthermore, abnormalities in muscle fatty acid (FA) metabolism are strongly associated with the development of insulin resistance. However, few studies have directly examined the effects of either IL-6 or TNF-α on skeletal muscle FA metabolism. Here, we used a pulse-chase technique to determine the effect of IL-6 (50-5,000 pg/ml) and TNF-α (50-5,000 pg/ml) on FA metabolism in isolated rat soleus muscle. IL-6 (5,000 pg/ml) increased exogenous and endogenous FA oxidation by ≃50% (P < 0.05) but had no effect on FA uptake or incorporation of FA into endogenous lipid pools. In contrast, TNF-α had no effect on FA oxidation but increased FA incorporation into diacylglycerol (DAG) by 45% (P < 0.05). When both IL-6 (5,000 pg/ml) and insulin (10 mU/ml) were present, IL-6 attenuated insulin's suppressive effect on FA oxidation, increasing exogenous FA oxidation (+37%, P < 0.05). Furthermore, in the presence of insulin, IL-6 reduced the esterification of FA to triacylglycerol by 22% (P < 0.05). When added in combination with IL-6 or leptin (10 μg/ml), the TNF-α-induced increase in DAG synthesis was inhibited. In conclusion, the results demonstrate that IL-6 plays an important role in regulating fat metabolism in muscle, increasing rates of FA oxidation, and attenuating insulin's lipogenic effects. In contrast, TNF-α had no effect on FA oxidation but increased FA incorporation into DAG, which may be involved in the development of TNF-α-induced insulin resistance in skeletal muscle.

Interleukin-6 and tumor necrosis factor-α are not increased in patients with type 2 diabetes: Evidence that plasma interleukin-6 is related to fat mass and not insulin responsiveness

Aims/hypothesis. Our aim was to examine the possible direct relationship of interleukin-6 and TNFα with insulin sensitivity in humans. Methods. We carried out two series of euglycaemic-hyperinsulinaemic clamp experiments. In the first (CLAMP1), skeletal muscle mRNA expression and plasma concentrations of IL-6 and TNFα were examined in patients with Type 2 diabetes (n=6), subjects matched for age (n=6), and young healthy (n=11) control subjects during a 120-min supra-physiological hyperinsulinaemic (40 mU·m -2·min-1) euglycaemic clamp. In the second series of experiments (CLAMP2), patients with Type 2 diabetes (n=6) and subjects matched for age (n=7) were studied during a 240-min high-physiological hyperinsulinaemic (7 mU·m-2·min-1) euglycaemic clamp, during which arterial and venous (femoral and subclavian) blood samples were measured for IL-6 and TNFα flux. Results. In both experiments the glucose infusion rate in the patients was markedly lower than that in the other groups. In CLAMP1, basal skeletal muscle IL-6 and TNFα mRNA were the same in all groups. They were not affected by insulin and they were not related to the glucose infusion rate. In CLAMP2, neither cytokine was released from the arm or leg during insulin stimulation in either group. In both experiments plasma concentrations of these cytokines were similar in the patients and in the control subjects, although in CLAMP1 the young healthy control group had lower (p<0.05) plasma IL-6 concentrations. Using data from all subjects, a strong positive correlation (r=0.85; p<0.00001) was observed between basal plasma IL-6 and BMI. Conversely, a negative relationship (r=-0.345; p<0.05) was found between basal plasma TNFα and BMI, although this was not significant when corrected for BMI. When corrected for BMI, no relationship was observed between either basal plasma IL-6 or TNFα and GIR. Conclusions/interpretation. These data show that the increased circulating IL-6 concentrations seen in patients with Type 2 diabetes are strongly related to fat mass and not insulin responsiveness, and suggest that neither IL-6 nor TNFα are indicative of insulin resistance.

Graphene quantum dots induce apoptosis, autophagy, and inflammatory response via p38 mitogen-activated protein kinase and nuclear factor-κB mediated signaling pathways in activated THP-1 macrophages.

The biomedical application of graphene quantum dots (GQDs) is a new emerging area. However, their safety data are still in scarcity to date. Particularly, the effect of GQDs on the immune system remains unknown. This study aimed to elucidate the interaction of GQDs with macrophages and the underlying mechanisms. Our results showed that GQDs slightly affected the cell viability and membrane integrity of macrophages, whereas GQDs significantly increased reactive oxygen species (ROS) generation and apoptotic and autophagic cell death with an increase in the expression level of Bax, Bad, caspase 3, caspase 9, beclin 1, and LC3-I/II and a decrease in that of Bcl-2. Furthermore, low concentrations of GQDs significantly increased the expression of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-8, whereas high concentrations of GQDs elicited opposite effects on the cytokines production. SB202190, a selective inhibitor of p38 mitogen-activated protein kinase (MAPK), abolished the cytokine-inducing effect of GQDs in macrophages. Moreover, GQDs significantly increased the phosphorylation of p38 MAPK and p65, and promoted the nuclear translocation of nuclear factor-κB (NF-κB). Taken together, these results show that GQDs induce ROS generation, apoptosis, autophagy, and inflammatory response via p38MAPK and NF-κB mediated signaling pathways in THP-1 activated macrophages.

Pharmacokinetic mechanisms for reduced toxicity of irinotecan by coadministered Thalidomide

The clinical use of irinotecan (CPT-11) is hindered by dose-limiting diarrhea and myelosuppression. Recent clinical studies indicate that thalidomide, a known tumor necrosis factor-alpha inhibitor, ameliorated the toxicities induced by CPT-11. However, the mechanisms for this are unknown. This study aimed to investigate whether combination of thalidomide modulated the toxicities of CPT-11 using a rat model and the possible role of the altered pharmacokinetic component in the toxicity modulation using in vitro models. The toxicity model was constructed by treatment of healthy rats with CPT-11 at 60 mg/kg per day by intravenous (i.v.) injection. Body weight, acute and delayed-onset diarrhea, blood cell counts, and macroscopic and microscopic intestinal damages were monitored in rats treated with CPT-11 alone or combined therapy with thalidomide at 100 mg/kg administered by intraperitoneal (i.p.) injection. Single dose and 5-day multiple-dose studies were conducted in rats to examine the effects of concomitant thalidomide on the plasma pharmacokinetics of CPT-11 and its major metabolites SN-38 and SN-38 glucuronide (SN-38G). The effect of CPT-11 on thalidomide's pharmacokinetics was also checked. Rat liver microsomes and a rat hepatoma cell line, H4-II-E cells, were used to study the in vitro metabolic interactions between these two drugs. H4-II-E cells were also used to investigate the effect of thalidomide and its hydrolytic products on the transport of CPT-11 and SN-38. In addition, the effect of thalidomide and its hydrolytic products on rat plasma protein binding of CPT-11 and SN-38 was examined. Administration of CPT-11 by i.v. for 4 consecutive days to rats induced significant body weight loss, decrease in neutrophil and lymphocyte counts, severe acute- and delayed-onset diarrhea, and intestinal damages. These toxicities were alleviated when CPT-11 was combined with thalidomide. In both single-dose and 5-day multiple-dose pharmacokinetic study, coadministered thalidomide significantly increased the area under the plasma concentration-time curve (AUC) of CPT-11, but the AUC and elimination half-life (t(1/2)) of SN-38 were significantly decreased. However, CPT-11 did not significantly alter the pharmacokinetics of thalidomide. Thalidomide at 25 and 250 microM and its hydrolytic products at a total concentration of 10 microM had no significant effect on the plasma protein binding of CPT-11 and SN-38, except for that thalidomide at 250 microM caused a significant increase in the unbound fraction (f(u)) of CPT-11 by 6.7% (P < 0.05). The hydrolytic products of thalidomide (total concentration of 10 microM), but not thalidomide, significantly decreased CPT-11 hydrolysis by 16% in rat liver microsomes (P < 0.01). The formation of both SN-38 and SN-38G from CPT-11, SN-38 glucuronidation, or intracellular accumulation of both CPT-11 and SN-38 in H4-II-E cells followed Michaelis-Menten kinetics with the one-binding site model being the best fit for the kinetic data. Coincubation or 2-hr preincubation of thalidomide at 25 microM and 250 microM and its hydrolytic products at 10 microM did not show any significant effects on CPT-11 hydrolysis and SN-38 glucuronidation. However, preincubation of H4-II-E cells with thalidomide (250 microM), its hydrolytic products (total concentration of 10 microM), or phthaloyl glutamic acid (one major thalidomide hydrolytic product, 10 microM) significantly increased the intracellular accumulation of SN-38, but not CPT-11 (P < 0.01). The dose-limiting toxicities of CPT-11 were alleviated by combination with thalidomide in rats and the pharmacokinetic modulation by thalidomide may partially explain its antagonizing effects on the toxicities of CPT-11. The hydrolytic products of thalidomide, instead of the parental drug, modulated the hepatic hydrolysis of CPT-11 and intracellular accumulation of SN-38, probably contributing to the altered plasma pharmacokinetics of CPT-11 and SN-38. Further studies are needed to explore the role of both pharmacokinetics and pharmacodynamic components in the protective effect of thalidomide against the toxicities of CPT-11.

Anti-tumour necrosis factor-α therapy for severe enteropathy in patients with common variable immunodeficiency (CVID)

We present three common variable immunodeficiency (CVID) patients with
severe inflammatory bowel disease of unknown aetiology, resistant to steroid
treatment, treated with infliximab.After exclusion of any infection, infliximab
was given at a dose of 5 mg/kg every 4 weeks for a 3 month induction followed
by every 4–8 weeks depending on clinical response. Two of these patients had
predominantly small bowel disease; they both showed clinical response to
infliximab with weight gain and improvement of quality of life scores. The
third patient had large bowel involvement with profuse watery diarrhea; this
patient improved dramatically within 48 hours of having infliximab
treatment. All three patients have been maintained on infliximab treatment
for between 5 and 53 months (mean 37 months) with no evidence of increased
susceptibility to infections in the patients with small bowel disease, although
the third patient developed two urinary tract infections and a herpes zoster
infection following therapy. This is the first small case series to show that
infliximab is a useful addition to current therapy in this rare group of patients
with potentially life threatening enteritis.

Hydrogen sulfide attenuates carbon tetrachloride-induced hepatotoxicity, liver cirrhosis and portal hypertension in rats

BACKGROUND : Hydrogen sulfide (H(2)S) displays vasodilative, anti-oxidative, anti-inflammatory and cytoprotective activities. Impaired production of H(2)S contributes to the increased intrahepatic resistance in cirrhotic livers. The study aimed to investigate the roles of H(2)S in carbon tetrachloride (CCl(4))-induced hepatotoxicity, cirrhosis and portal hypertension.

METHODS AND FINDINGS : Sodium hydrosulfide (NaHS), a donor of H(2)S, and DL-propargylglycine (PAG), an irreversible inhibitor of cystathionine γ-lyase (CSE), were applied to the rats to investigate the effects of H(2)S on CCl(4)-induced acute hepatotoxicity, cirrhosis and portal hypertension by measuring serum levels of H(2)S, hepatic H(2)S producing activity and CSE expression, liver function, activity of cytochrome P450 (CYP) 2E1, oxidative and inflammatory parameters, liver fibrosis and portal pressure. CCl(4) significantly reduced serum levels of H(2)S, hepatic H(2)S production and CSE expression. NaHS attenuated CCl(4)-induced acute hepatotoxicity by supplementing exogenous H(2)S, which displayed anti-oxidative activities and inhibited the CYP2E1 activity. NaHS protected liver function, attenuated liver fibrosis, inhibited inflammation, and reduced the portal pressure, evidenced by the alterations of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), albumin, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and soluble intercellular adhesion molecule (ICAM)-1, liver histology, hepatic hydroxyproline content and α-smooth muscle actin (SMA) expression. PAG showed opposing effects to NaHS on most of the above parameters.

CONCLUSIONS :  Exogenous H2S attenuates CCl4-induced hepatotoxicity, liver cirrhosis and portal hypertension by its multiple functions including anti-oxidation, anti-inflammation, cytoprotection and anti-fibrosis, indicating that targeting H2S may present a promising approach, particularly for its prophylactic effects, against liver cirrhosis and portal hypertension.

Aspirin : a review of its neurobiological properties and therapeutic potential for mental illness

There is compelling evidence to support an aetiological role for inflammation, oxidative and nitrosative stress (O&NS), and mitochondrial dysfunction in the pathophysiology of major neuropsychiatric disorders, including depression, schizophrenia, bipolar disorder, and Alzheimer's disease (AD). These may represent new pathways for therapy. Aspirin is a non-steroidal anti-inflammatory drug that is an irreversible inhibitor of both cyclooxygenase (COX)-1 and COX-2, It stimulates endogenous production of anti-inflammatory regulatory 'braking signals', including lipoxins, which dampen the inflammatory response and reduce levels of inflammatory biomarkers, including C-reactive protein, tumor necrosis factor- and interleukin (IL)--6 , but not negative immunoregulatory cytokines, such as IL-4 and IL-10. Aspirin can reduce oxidative stress and protect against oxidative damage. Early evidence suggests there are beneficial effects of aspirin in preclinical and clinical studies in mood disorders and schizophrenia, and epidemiological data suggests that high-dose aspirin is associated with a reduced risk of AD. Aspirin, one of the oldest agents in medicine, is a potential new therapy for a range of neuropsychiatric disorders, and may provide proof-of-principle support for the role of inflammation and O&NS in the pathophysiology of this diverse group of disorders.

Regulation of granulocyte colony-stimulating factor and its receptor in skeletal muscle is dependent upon the type of inflammatory stimulus

The cytokine granulocyte colony-stimulating factor (G-CSF) binds to its receptor (G-CSFR) to stimulate hematopoietic stem cell mobilization, myelopoiesis, and the production and activation of neutrophils. In response to exercise-induced muscle damage, G-CSF is increased in circulation and G-CSFR has recently been identified in skeletal muscle cells. While G-CSF/G-CSFR activation mediates pro- and anti-inflammatory responses, our understanding of the role and regulation in the muscle is limited. The aim of this study was to investigate, in vitro and in vivo, the role and regulation of G-CSF and G-CSFR in skeletal muscle under conditions of muscle inflammation and damage. First, C2C12 myotubes were treated with lipopolysaccharide (LPS) with and without G-CSF to determine if G-CSF modulates the inflammatory response. Second, the regulation of G-CSF and its receptor was measured following eccentric exercise-induced muscle damage and the expression levels we investigated for redox sensitivity by administering the antioxidant N-acetylcysteine (NAC). LPS stimulation of C2C12 myotubes resulted in increases in G-CSF, interleukin (IL)-6, monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-α (TNFα) messenger RNA (mRNA) and an increase in G-CSF, IL-6, and MCP-1 release from C2C12 myotubes. The addition of G-CSF following LPS stimulation of C2C12 myotubes increased IL-6 mRNA and cytokine release into the media, however it did not affect MCP-1 or TNFα. Following eccentric exercise-induced muscle damage in humans, G-CSF levels were either marginally increased in circulation or remain unaltered in skeletal muscle. Similarly, G-CSFR levels remained unchanged in response to damaging exercise and G-CSF/G-CSFR did not change in response to NAC. Collectively, these findings suggest that G-CSF may cooperate with IL-6 and potentially promote muscle regeneration in vitro, whereas in vivo aseptic inflammation induced by exercise did not change G-CSF and G-CSFR responses. These observations suggest that different models of inflammation produce a different G-CSF response.

Molecular targets in arthritis and recent trends in nanotherapy

Due to its severity and increasing epidemiology, arthritis needs no description. There are various forms of arthritis most of which are disabling, very painful, and common. In spite of breakthroughs in the field of drug discovery, there is no cure for arthritis that can eliminate the disease permanently and ease the pain. The present review focuses on some of the most successful drugs in arthritis therapy and their side effects. Potential new targets in arthritis therapy such as interleukin-1β, interleukin-17A, tumor necrosis factor alpha, osteopontin, and several others have been discussed here, which can lead to refinement of current therapeutic modalities. Mechanisms for different forms of arthritis have been discussed along with the molecules that act as potential biomarkers for arthritis. Due to the difficulty in monitoring the disease progression to detect the advanced manifestations of the diseases, drug-induced cytotoxicity, and problems with drug delivery; nanoparticle therapy has gained the attention of the researchers. The unique properties of nanoparticles make them highly attractive for the design of novel therapeutics or diagnostic agents for arthritis. The review also focuses on the recent trends in nanoformulation development used for arthritis therapy. This review is, therefore, important because it describes the relevance and need for more arthritis research, it brings forth a critical discussion of successful drugs in arthritis and analyses the key molecular targets. The review also identifies several knowledge gaps in the published research so far along with the proposal of new ideas and future directions in arthritis therapy.