Engineering approaches for drug delivery systems production and characterization.

To find and to test the therapeutic effectiveness (and the limited adverse effects) of a new drug is a long and expensive process. It has been estimated a period of ten years and an expense of the order of one billion USD are required. Meanwhile, even if a promising molecule has been identified, there is the need for operative methods for its delivery. The extreme case is given by gene therapy, in which molecules with tremendous in-vitro efficacy cannot be used in practice because of the lack in useful vector systems to deliver them. Most of the recent efforts in pharmaceutical sciences are focused on the development of novel drug delivery systems (DDSs). In this review, the work done recently on the development and testing of novel DDSs, with particular emphasis on the results obtained by European research, is summarized. In the first section of the review the DDSs are analyzed accordingly with their scale-size: starting from nano-scale (liposomes, nanoparticles), up to the micro-scale (microparticles), until the macroscopic world is reached (granules, matrix systems). In the following two sections, non-conventional testing methods (mechanical methods and bio-relevant dissolution methods) are presented; at last, the importance of mathematical modeling to describe drug release and related phenomena is reported.

Hydrogels: experimental characterization and mathematical modelling of their mechanical and diffusive behaviour.

Hydrogels are materials widely used in countless applications, particularly in the biomedical, pharmaceutical, and nutraceutical fields, because of their biocompatibility and their mechanical and transport properties. Several approaches are known to evaluate their properties, but only a few approaches are under development to mathematically describe their behaviour, in terms of how the materials answer to mechanical stimuli and how incorporated active substances are released. In this review, the main properties of hydrogels are summarized and the structure-property relationships are investigated (i.e. how the macromolecular structure influences the properties of macroscopic samples made of hydrogels). A selection criterion is proposed based on the comparison of three characteristic times: relaxation time, diffusion time, and process time. Then, the most common experimental methods to investigate the hydrogel properties are summarized, along with the state-of-the-art of mathematical modelling, with reference to the mechanical and transport properties of hydrogels, with particular attention to the viscoelastic and poroelastic behaviours. Last but not least, some case histories which can be classified as viscoelastic, poroelastic, or poroviscoelastic behaviours are presented.

Modeling the modified drug release from curved shape drug delivery systems - Dome Matrix®.

The controlled drug release from hydrogel-based drug delivery systems is a topic of large interest for research in pharmacology. The mathematical modeling of the behavior of these systems is a tool of emerging relevance, since the simulations can be of use in the design of novel systems, in particular for complex shaped tablets. In this work a model, previously developed, was applied to complex-shaped oral drug delivery systems based on hydrogels (Dome Matrix®). Furthermore, the model was successfully adopted in the description of drug release from partially accessible Dome Matrix® systems (systems with some surfaces coated). In these simulations, the erosion rate was used asa fitting parameter, and its dependence upon the surface area/volume ratio and upon the local fluid dynamics was discussed. The model parameters were determined by comparison with the drug release profile from a cylindrical tablet, then the model was successfully used for the prediction of the drug release from a Dome Matrix® system, for simple module configuration and for module assembled (void and piled) configurations. It was also demonstrated that, given the same initial S/V ratio, the drug release is independent upon the shape of the tablets but it is only influenced by the S/V evolution. The model reveals itself able to describe the observed phenomena, and thus it can be of use for the design of oral drug delivery systems, even if complex shaped.

PoroViscoElastic model to describe hydrogels' behavior.

Hydrogels are three-dimensional, cross-linked hydrophilic polymeric network able of absorb large amount of water. The mechanics of these systems is strictly coupled with the water transport resulting in the peculiar behavior known as poroviscoelasticy. This can be considered as sum of the viscoelastic behavior of the polymeric network and the poroelastic behavior caused by the water movement within the hydrogel. In this work a 3D monophasic model able to depict the poroviscoelastic behavior of these systems, within the field of nonlinear solid mechanics, is developed. The mass and momentum balances equations, supported by constitutive equations from non-equilibrium thermodynamics and by initial and boundary conditions, is implemented through the weak formulation in a commercial FEM-based software. A parametric study is performed in order to assess the relative importance of the model parameters on hydrogels' behavior.

Anti-laminin-1 antibodies in sera and follicular fluid of women with endometriosis undergoing in vitro fertilization.

There is increasing evidence that autoimmune phenomena, including auto-antibody production, may affect fertility in women with endometriosis. The aims of this study are to evaluate anti-laminin-1 antibody (aLN-1) presence in sera and in follicular fluids (FF) of women with endometriosis undergoing IVF and its impact on oocyte maturation and IVF outcome. aLN-1 were measured by a home-made enzyme linked immunosorbent assay in sera and FF obtained from 35 infertile women with endometriosis and in sera from 50 fertile controls and 27 infertile women without endometriosis (IWWE). aLN-1 serum levels were significantly higher in women with endometriosis in comparison with both fertile controls and IWWE (P<0.001 and P<0.05, respectively) and a positive correlation was found between serum- and FF-aLN-1 (r=0.47, P=0.004). According to the cut-off (mean+3 SD of fertile controls), 31% of women with endometriosis were aLN-1 positive. Metaphase II oocyte counts showed inverse correlation with FF-aLN-1 levels (r=-0.549, P=0.0006). Ongoing pregnancy (i.e pregnancy progressing beyond the 12th week of gestation) occurred in 4/11 aLN-1 positive patients and in 7/24 aLN-1 negative with no significant difference (P=0.7). In conclusion, our results highlight that aLN-1 are increased in women with endometriosis and their presence in FF may affect oocyte maturation leading to a reduced fertility. However, aLN-1 seem to have no effect on IVF outcome.

Antibodies to carbonic anhydrase in patients with connective tissue diseases: relationship with lung involvement.

The aim of this study is to evaluate the presence of antibodies to carbonic anhydrase I and/or II (ACAI and ACAII) in patients affected by connective tissue diseases (CTD) and to investigate their association with lung involvement evaluated by High resolution CT scan (HRCT). Ninety-six patients affected by CTD were studied, i.e. 33 rheumatoid arthritis (RA), 8 psoriatic arthritis (PA), 8 ankylosing spondilitis (AS), 23 Systemic Lupus Erythematosus (SLE), 10 Sjogren Syndrome (SS), and 14 Systemic Sclerosis (SSc). ACA were detected by ELISA. The lung involvement was evaluated by means of a previously described HRCT score. According to a receiver operator characteristic curve, patients were divided into those with HRCT score > or = 10 and those with HRCT score < 10, where HRCT score > or = 10 was predictive of interstitial lung disease. ACAI and/or ACAII were detected in 30/96 patients (31.2%) (P < 0.0001 in comparison with controls). In particular, the prevalence of ACAI and/or ACAII was significantly higher in patients with RA (P = 0.002), PA (P < 0.0001), SLE (P = 0.0003) and SSc (P < 0.0001). A positive correlation was found between HRCT scores and CRP or ACAI levels (P = < 0.0001 and P = 0.004, respectively). Thirty-nine of 96 patients (40.6%) showed a HRCT score > or = 10 and both their CRP and ACAI levels were significantly higher when compared with patients showing a HRCT score less than 10 (P < 0.0006 and P = 0.0009, respectively). Moreover, C3 and C4 complement fractions inversely correlated with HRCT scores (P = 0.0004 and P < 0.0001, respectively) and lower values of C3 and C4 complement fractions were found in patients with HRCT score > or = 10 than in those with HRCT score less than 10 (P = 0.014 and P = 0.007, respectively). Due to the lower levels of complement fractions detected in patients with HRCT score > or = 10, a possible immune-complex-mediated pathogenic mechanism of lung involvement could be suggested.

Dilated cardiomyopathy due to thrombotic microangiopathy as the only manifestation of antiphospholipid syndrome: a case report.

Dilated cardiomyopathy due to thrombotic microangiopathy has been rarely reported as a clinical manifestation of antiphospholipid syndrome (APS). We describe the case of a 39-year-old woman affected by systemic lupus erythematosus (SLE) and positive antiphospholipid antibodies (aPL) who presented with orthopnea and peripheral oedema. Diagnosis of dilated cardiomyopathy due to myocardial thrombotic microangiopathy was made and treatment with anticoagulants prevented the worsening of the clinical condition. Interestingly, at variance with other cases, our patient showed no extracardiac signs of APS. The review of the current literature has confirmed that dilated cardiomyopathy due to thrombotic microangiopathy is a rare manifestation of APS.

Anticardiolipin antibody levels in women undergoing first in vitro fertilization/embryo transfer.

BACKGROUND: The clinical relevance of antiphospholipid antibodies (aPL) in women undergoing in vitro fertilization/embryo transfer (IVF/ET) and the role of IVF treatment in affecting antiphospholipid levels are controversial. The aim of this study was to evaluate anticardiolipin antibody (aCL) levels and the effect of IVF treatment on aCL in women undergoing their first IVF/ET cycle. METHODS: Immunoglobulin G (IgG)- and IgM-aCL were determined by enzyme-linked immunosorbent assay in 50 women undergoing IVF/ET, 18 due to endometriosis, 16 to tubal factor (TF) and 16 to male factor, before starting treatment (T0), on the day of oocyte retrieval (T1) and 14 days after ET (T2). A group of 31 age-matched fertile women served as controls. RESULTS: aCL levels detected at T0 in patients were not significantly different compared with the control group. IgG- but not IgM-aCL significantly increased at T2 in comparison with T0 (P < 0.001) and T1 (P < 0.05). The difference between T2 and T0 reached statistical significance in patients with endometriosis (P = 0.003) or TF (P = 0.018). No relationship was found between aCL and pregnancy. CONCLUSIONS: Our results indicate that IVF treatment increases IgG-aCL levels in patients with endometriosis and TF, but their presence seems to have no clinical relevance.

Antiprothrombin antibodies: a comparative analysis of homemade and commercial methods. A collaborative study by the Forum Interdisciplinare per la Ricerca nelle Malattie Autoimmuni (FIRMA).

OBJECTIVE: Prothrombin (PT) is a target for antibodies with lupus anticoagulant (LA) activity, suggesting the possible application of anti-prothrombin antibody (aPT) assays in patients with antiphospholipid syndrome (APS). Different methods - both homemade and commercial - for the detection of aPT are available, but they seem to produce conflicting results. The purpose of this study was to compare the performance of different assays on a set of well-characterized serum samples. PATIENTS AND METHODS: Sera were gathered from 4 FIRMA institutions, and distributed to 15 participating centres. Forty-five samples were from patients positive for LA and/or anticardiolipin antibodies (aCL) with or without APS, and 15 were from rheumatoid arthritis (RA) patients negative for antiphospholipid antibodies. The samples were evaluated for IgG and IgM antibodies using a homemade direct aPT assay (method 1), a homemade phosphatidylserine-dependent aPT assay (aPS/PT, method 2), and two different commercial kits (methods 3 and 4). In addition, a commercial kit for the detection of IgG-A-M aPT (method 5) was used. RESULTS: Inter-laboratory results for the 5 methods were not always comparable when different methods were used. Good inter-assay concordance was found for IgG antibodies evaluated using methods 1, 3, and 4 (Cohen k > 0.4), while the IgM results were discordant between assays. In patients with thrombosis and pregnancy losses, method 5 performed better than the others. CONCLUSION: While aPT and aPS/PT assays could be of interest from a clinical perspective, their routine performance cannot yet be recommended because of problems connected with the reproducibility and interpretation of the results.

The immune responsiveness in hepatitis C virus infected patients: effects of interferon-alfa/ribavirin combined treatment on the lymphocyte response with special reference to B cells.

Previous data demonstrated that an elevated percentage of hepatitis C virus (HCV) infected patients are endotoxemic. Endotoxemic patients are poor responders to the interferon (IFN)- alpha/ribavirin (RIB) treatment and exhibit lower serum levels of IFN-gamma and interleukin (IL)-10 than the responder counterpart. Here we provide evidence that in endotoxemic HCV+ patients absolute numbers of CD19(+) cells (B cells) are higher than those observed in the non-endotoxemic counterpart at the end of the combined treatment. Moreover, anti lactoferrin (LF) antibodies are more elevated in non-responder HCV+ patients than in the responders. In turn, these autoantibodies may affect the antiviral activity of LF, on the one hand, and, on the other hand abrogate the LF binding to lipopolysaccharides (LPS). Such an interaction hampers the binding of LPS to LPS binding protein, thus inhibiting LPS fixation to CD14(+) cells and, ultimately, leading to a decreased release of proinflammatory cytokines.

Raynaud's phenomenon and antiphospholipid antibodies in systemic lupus erythematosus: is there an association?

OBJECTIVE: To evaluate the association of IgG and IgM antibodies directed against different negatively charged phospholipids (that is, anticardiolipin (aCL), antiphosphatidylinositol, antiphosphatidylserine, and antiphosphatidic acid) and anti-beta(2)-glycoprotein I (abeta(2)GPI), with Raynaud's phenomenon in patients with systemic lupus erythematosus (SLE). METHODS: Ninety three patients with SLE (81 female), 40 with and 53 without Raynaud's phenomenon, were included in the study. IgG and IgM antiphospholipid antibodies and abeta(2)GPI were determined by enzyme linked immunosorbent assay (ELISA). RESULTS: Fifty patients (54%) were positive for IgG and/or IgM antibodies to one or more phospholipid antigens or to beta(2)GPI. The prevalence of all autoantibodies evaluated, either IgG or IgM, was higher in patients without than in those with Raynaud's phenomenon. A negative association was found between IgG aCL and Raynaud's phenomenon (p=0.038), whereas autoantibodies other than aCL were not significantly associated with Raynaud's phenomenon. CONCLUSION: Our results demonstrate no positive association between antiphospholipid antibodies and Raynaud's phenomenon in SLE and indicate that measurement of anti-negatively charged phospholipid antibodies other than aCL is not useful as a serological marker predictive for Raynaud's phenomenon.

Immune abnormalities and endotoxemia in patients with ulcerative colitis and in their first degree relatives: attempts at neutralizing endotoxin-mediated effects.

Proinflammatory cytokines released from monocytes/macrophages, in particular tumor necrosis factor (TNF)-alpha, interleukin (IL)-1, IL-6, and IL-8 seem to play an important role in Inflammatory Bowel Disease (ulcerative colitis and Crohn's disease). Endotoxins or lipopolysaccharides, derived from the outer membrane of Gram-negative bacteria interact with CD14 on surface membrane of macrophages, thus triggering a signal cascade, which leads to the production and release of proinflammatory cytokines, particularly TNF-alpha. Therefore, in IBD, lipopolysaccharides could play a pathogenic role. In this respect, plasma endotoxins have been demonstrated in a not negligible percentage of patients with ulcerative colitis and in their unaffected relatives. The presence of circulating endotoxins could be due, at least in part, to the impaired natural immunity in either patients with ulcerative colitis or in their first degree unaffected relatives. Lactoferrin is an iron-binding glycoprotein, which binds to the lipid A region of lipopolysaccharide with a high affinity and this interaction prevents the binding of lipopolysaccharide to CD14, thus inhibiting the release of proinflammatory cytokines. Therefore, based on the possible pathogenic role exerted by endotoxins in ulcerative colitis, lactoferrin may deserve attention as a possible therapeutical agent in experimental models of Inflammatory Bowel Disease.

Safety of conventional drugs and biologic agents for Rheumatoid Arthritis.

While initial researches documented that Rheumatoid Arthritis (RA) patients who took biologic agents had decreased symptoms with those receiving traditional treatment, safety of the drugs remains a concern. The authors in this paper review the safety of the RA new therapeutic approach utilizing biological agents and compare it with the safety of conventional disease-modifying anti-rheumatic drugs (DMARDs).

Modifications of the immune responsiveness in patients with hepatitis C virus infection following treatment with IFN-alpha/ribavirin.

The balance between T helper (h)1 and Th2 responsiveness seems to represent a key event in the evolution of hepatitis C virus (HCV) infection. In particular, Th1 cytokines [interleukin (IL-2) and interferon (IFN-gamma)] have been demonstrated to mediate the antiviral immune response. Serum levels of Th1 cytokines (IL-2 and IFN-gamma) as well as of Th2 products (IL-4 and IL-10) were determined in a group of HCV-positive patients before and after treatment with IFN-alpha and Ribavirin (RIB). Results indicate that responder patients exhibited increased levels of IFN-gamma and IL-10, while this enhancement was not observed in non-responder patients. In this respect, the major effect exerted by the combined therapy with IFN-alpha/RIB could be represented by the attainment of a re-equilibrium between inflammatory (Th1) and antiinflammatory (Th2) mechanisms. In this framework, according to current literature, novel therapeutical approaches to treat HCV infection are represented by administration of recombinant IL-2 and IL-10.

Biological and clinical significance of endotoxemia in the course of hepatitis C virus infection.

Endotoxins or lipopolysaccharides (LPS), major components of the cell wall of Gram-negative bacteria, once released from the bacterial outer membrane bind to specific receptors and, in particular, to a membrane-bound receptor, the CD14 (mCD14) and the toll-like receptor 4 present on monocytes/ macrophages. In turn, LPS-activated monocytes/ macrophages release in the host tissue an array of so-called proinflammatory cytokines and, among them, Tumor Necrosis Factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-8 and IL-12 are the major mediators. Before therapy (To) and at the end of 6-month interferon (IFN)-alpha/Ribavirin (RIB) treatment (T6), circulating endotoxin levels were measured in responder and non responder HCV+ patients. At T0, 57% of the non responders were endotoxin-positive and had, on average, 54 pg/ml of plasma LPS while in 50% of the responder patients endotoxin were found with an average of 29 pg/ml. At T6, in responders LPS were no longer detectable, while in 42% of the non responders LPS were found (average levels 45 pg/ml). In terms of serum cytokine concentration, at T6 IFN-gamma levels when compared to those detected at T0 were increased in both endotoxin-positive and endotoxin-negative patients. However, at T6 IL-10 concentration was significantly increased only in the group of endotoxin-negative subjects (responder patients), in comparison to T0 values. The origin of endotoxemia in HCV+ patients seems to be multifactorial, likely depending on impaired phagocytic functions and reduced T-cell mediated antibacterial activity. In these patients, however, one cannot exclude the passage of LPS from the gut flora to the blood stream, owing a condition of altered intestinal permeability. At the same time, a less efficient detoxification of enteric bacterial antigens at the hepatic level should be taken into consideration. Finally, novel therapeutic attempts aimed to neutralize LPS in the host are discussed.

The role of the liver in the response to LPS: experimental and clinical findings.

The liver plays an important physiological role in lipopolysaccharide (LPS) detoxification and, in particular, hepatocytes are involved in the clearance of endotoxin of intestinal derivation. In experimental shock models, tumor necrosis factor (TNF)-alpha induces hepatocyte apoptosis and lethal effects are due to secreted TNF-alpha and not to cell-associated TNF-alpha. An exaggerated production of TNF-alpha has been reported in murine viral infections, in which mice become sensitized to low amounts of LPS and both interferon (IFN)-gamma and IFN-alpha/beta are involved in the macrophage-induced release of TNF-alpha. The prominent role of LPS and TNF-alpha in liver injury is also supported by studies of ethanol-induced hepatic damage. In humans, evidence of LPS-induced hepatic injury has been reported in cirrhosis, autoimmune hepatitis, and primary biliary cirrhosis and a decreased phagocytic activity of the reticulo-endothelial system has been found in these diseases. The origin of endotoxemia in hepatitis C virus (HCV) infected patients seems to be multifactorial and LPS may be of exogenous or endogenous derivation. In endotoxemic HCV-positive patients responsive to a combined treatment with IFN-alpha/ribavirin (RIB), endotoxemia was no longer detected at the end of the therapeutic regimen. By contrast, 48% of the non-responders to this treatment were still endotoxemic and their monocytes displayed higher intracellular TNF-alpha and interleukin (IL)-1beta levels than responders. Moreover, in responders, an equilibrium between IFN-gamma and IL-10 serum levels was attained. In the non-responders, serum levels of IL-10 did not increase following treatment. This may imply that an imbalance between T helper (Th)1 and Th2 derived cytokines could be envisaged in the non-responders.

Anti-neutrophil cytoplasmic antibodies in echinococcus granulosus hydatid disease.

The authors studied the presence of ANCA, evaluated by indirect immunofluorescence (IIF) and ELISA for anti-lactoferrin (LF), and anti-myeloperoxidase antibodies (anti-MPO), in sera of 69 patients with cystic echinococcosis (CE). According to Caremani's classification, 27 patients were considered to have active cysts and 42 patients were considered to have inactive cysts. ANCA were detected in 9 out of 27 patients (33.3%) with active cysts and in 3 out of 42 patients (7.1%) with inactive cysts. Differences between the two groups were statistically significant (P < 0.05). Anti-LF antibodies were found in seven patients (10.14%) and anti-MPO antibodies in ten patients (14.5%).

In vitro effects of naloxone on T-lymphocyte-dependent antibacterial activity in hepatitis C virus (HCV) infected patients and in inflammatory bowel disease (IBD) patients.

Naloxone acts as an opioid antagonist, displacing opioid drugs from cellular receptors. Among opioid substances, beta-endorphins are able to bind to several cell receptors, even including those expressed by immune cells. In this respect, evidence has been provided that in the course of viral infections, as well as in patients with ulcerative colitis high levels of beta-endorphins are detectable. Here, peripheral blood lymphocytes (PBL) from 21 HCV infected patients and 14 patients with IBD, respectively, were incubated with Naloxone and Naloxone + Ca2+ in order to evaluate a putative modulation of PBL-mediated antibacterial activity. In fact, previous studies have demonstrated a reduction of this T-cell activity in HCV and IBD patients. In general terms, the above treatment led to a recovery of the depressed antibacterial activity. In some cases, increase in T lymphocyte function was obtained with Naloxone alone, while in other cases the combination Naloxone + Ca2+ gave rise to a restorative effect. Of note, in some instances, lymphocytes were unresponsive to pharmacological modulation. The overall results suggest that beta-endorphins may down modulate T-cell antibacterial response in HCV and in IBD patients by saturating peripheral receptors on immune cells. Therefore, it is likely that Naloxone and/or Naloxone + Ca2+ may displace opioid drugs, thus antagonizing their effects.

Helicobacter pylori infection, immune response and vaccination.

It is well known that abnormal immune responses may play a pathogenic role in the H. pylori-related gastropathy. Indeed, as far as humoral immune response is concerned, it is still debated whether specific anti-H. pylori antibodies have a protective or noxious effect in infected hosts. Besides proinflammatory cytokines released from macrophages, such as tumor-necrosis factor-a and interleukin-1beta, and IFN-gamma derived from T-helper 1 lymphocytes, also interleukin-10, a product of T-helper 2 lymphocytes with antiinflammatory properties, seems to be surprisingly involved in the pathogenesis of H. pylori-induced gastritis. In addition, lipopolysaccharide derived from the outher membrane of H. pylori acts as a chemoattractant for monocytes and induces release of free radicals, interleukin-1beta, interleukin-6, interleukin-8 and tumor necrosis factor-alpha. On the other hand, H. pylori lipopolysaccharide could be responsible for the increased polyamine concentrations in the gastric mucosa and polyamines, such as putrescine, spermidine and spermine, could be involved in the increased cell proliferation and consequent possible neoplastic transformation of the gastric mucosa. Incubation of peripheral blood mononuclear cells with H. pylori increases significantly the surface expression of CD95 receptor (Fas), thus suggesting that these bacteria are able to induce apoptosis. In animal models, different types of vaccination have been investigated, including stimulation of nasal and rectal lymphoid tissue, as well as adoptive transfer of T cell from donors immunized with H. pylori. However, results obtained are frequently disappointing. In humans, urease of H. pylori was safely used as oral vaccine in the absence or presence of adjuvants with encouraging results. Finally, DNA vaccines could offer in the future advantages for prophylactic H. pylori eradication, especially where population is infected by this microorganism since childhood.

Enteric bacteria, lipopolysaccharides and related cytokines in inflammatory bowel disease: biological and clinical significance.

Ulcerative colitis (UC) and Crohn's disease (CD) [inflammatory bowel disease (IBD)] are both characterized by an exaggerated immune response at the gut associated lymphoreticular tissue level. Such an abnormal and dysregulated immune response may be directed against luminal and/or enteric bacterial antigens, as also supported by murine models of inflammatory bowel disease (IBD) caused by organisms such as Citrobacter rodentium and Helicobacter hepaticus. Bacterial endotoxins or lipopolysaccharides (LPS) have been detected in the plasma of IBD patients and an abnormal microflora and/or an increased permeability of the intestinal mucosa have been invoked as cofactors responsible for endotoxemia. At the same time, the evidence that phagocytosis and killing exerted by polymorphonuclear cells and monocytes and the T-cell dependent antibacterial activity are decreased in IBD patients may also explain the origin of LPS in these diseases. In IBD, pro-inflammatory cytokines and chemokines have been detected in elevated amounts in mucosal tissue and/or in peripheral blood, thus suggesting a monocyte/macrophage stimulation by enteric bacteria and/or their constituents (e.g. LPS). On these grounds, in experimental models and in human IBD, anti-cytokine monoclonal antibodies and interleukin receptor antagonists are under investigation for their capacity to neutralize the noxious effects of immune mediators. Finally, the administration of lactobacilli is beneficial in human IBD and, in murine colitis, this treatment leads to a normalization of intestinal flora, reducing the number of colonic mucosal adherent and translocated bacteria.