Spectroscopic identification of r-process nucleosynthesis in a double neutron-star merger.

The merger of two neutron stars is predicted to give rise to three major detectable phenomena: a short burst of γ-rays, a gravitational-wave signal, and a transient optical-near-infrared source powered by the synthesis of large amounts of very heavy elements via rapid neutron capture (the r-process). Such transients, named 'macronovae' or 'kilonovae', are believed to be centres of production of rare elements such as gold and platinum. The most compelling evidence so far for a kilonova was a very faint near-infrared rebrightening in the afterglow of a short γ-ray burst at redshift z = 0.356, although findings indicating bluer events have been reported. Here we report the spectral identification and describe the physical properties of a bright kilonova associated with the gravitational-wave source GW170817 and γ-ray burst GRB 170817A associated with a galaxy at a distance of 40 megaparsecs from Earth. Using a series of spectra from ground-based observatories covering the wavelength range from the ultraviolet to the near-infrared, we find that the kilonova is characterized by rapidly expanding ejecta with spectral features similar to those predicted by current models. The ejecta is optically thick early on, with a velocity of about 0.2 times light speed, and reaches a radius of about 50 astronomical units in only 1.5 days. As the ejecta expands, broad absorption-like lines appear on the spectral continuum, indicating atomic species produced by nucleosynthesis that occurs in the post-merger fast-moving dynamical ejecta and in two slower (0.05 times light speed) wind regions. Comparison with spectral models suggests that the merger ejected 0.03 to 0.05 solar masses of material, including high-opacity lanthanides.

Synergies of THESEUS with the large facilities of the 2030s and guest observer opportunities.

The proposed THESEUS mission will vastly expand the capabilities to monitor the high-energy sky. It will specifically exploit large samples of gamma-ray bursts to probe the early universe back to the first generation of stars, and to advance multi-messenger astrophysics by detecting and localizing the counterparts of gravitational waves and cosmic neutrino sources. The combination and coordination of these activities with multi-wavelength, multi-messenger facilities expected to be operating in the 2030s will open new avenues of exploration in many areas of astrophysics, cosmology and fundamental physics, thus adding considerable strength to the overall scientific impact of THESEUS and these facilities. We discuss here a number of these powerful synergies and guest observer opportunities.

GRB 090423 at a redshift of z approximately 8.1.

Gamma-ray bursts (GRBs) are produced by rare types of massive stellar explosion. Their rapidly fading afterglows are often bright enough at optical wavelengths that they are detectable at cosmological distances. Hitherto, the highest known redshift for a GRB was z = 6.7 (ref. 1), for GRB 080913, and for a galaxy was z = 6.96 (ref. 2). Here we report observations of GRB 090423 and the near-infrared spectroscopic measurement of its redshift, z = 8.1(-0.3)(+0.1). This burst happened when the Universe was only about 4 per cent of its current age. Its properties are similar to those of GRBs observed at low/intermediate redshifts, suggesting that the mechanisms and progenitors that gave rise to this burst about 600,000,000 years after the Big Bang are not markedly different from those producing GRBs about 10,000,000,000 years later.

Antiproliferative and proapoptotic effects of viable or heat-killed Lactobacillus paracasei IMPC2.1 and Lactobacillus rhamnosus GG in HGC-27 gastric and DLD-1 colon cell lines.

Data from literature suggest the possible use of probiotics as chemopreventive agents against colon cancer, but few investigations are available on their effects on gastric cancer proliferation. In our previous study, a specific Lactobacillus, strain L. paracasei IMPC2.1, was demonstrated to colonize the human gut and positively affect fecal bacteria and biochemical parameters. The aims of the present study were to investigate the effects of L. paracasei IMPC2.1, comparing them with those of Lactobacillus rhamnosus GG (L.GG), either as viable or heat-killed cells, on cell proliferation and apoptosis in a gastric cancer (HGC-27) and a colorectal cancer cell line (DLD-1). Both the gastric and colon cancer cells were sensitive to the growth inhibition and apoptosis induction by both viable or heat-killed cells from L. paracasei IMPC2.1 and L.GG. These findings suggest the possibility for a food supplement, based on dead probiotics, including L. paracasei IMPC2.1 cells, which could represent an effective component of a functional food strategy for cancer growth inhibition, with potential for cancer prevention.

An optical supernova associated with the X-ray flash XRF 060218.

Long-duration gamma-ray bursts (GRBs) are associated with type Ic supernovae that are more luminous than average and that eject material at very high velocities. Less-luminous supernovae were not hitherto known to be associated with GRBs, and therefore GRB-supernovae were thought to be rare events. Whether X-ray flashes--analogues of GRBs, but with lower luminosities and fewer gamma-rays--can also be associated with supernovae, and whether they are intrinsically 'weak' events or typical GRBs viewed off the axis of the burst, is unclear. Here we report the optical discovery and follow-up observations of the type Ic supernova SN 2006aj associated with X-ray flash XRF 060218. Supernova 2006aj is intrinsically less luminous than the GRB-supernovae, but more luminous than many supernovae not accompanied by a GRB. The ejecta velocities derived from our spectra are intermediate between these two groups, which is consistent with the weakness of both the GRB output and the supernova radio flux. Our data, combined with radio and X-ray observations, suggest that XRF 060218 is an intrinsically weak and soft event, rather than a classical GRB observed off-axis. This extends the GRB-supernova connection to X-ray flashes and fainter supernovae, implying a common origin. Events such as XRF 060218 are probably more numerous than GRB-supernovae.

Discovery of a transient absorption edge in the X-ray spectrum of GRB 990705.

We report the discovery of a transient equivalent hydrogen column density with an absorption edge at approximately 3.8 kiloelectron volts in the spectrum of the prompt x-ray emission of gamma-ray burst (GRB) 990705. This feature can be satisfactorily modeled with a photoelectric absorption by a medium located at a redshift of approximately 0.86 and with an iron abundance of approximately 75 times the solar one. The transient behavior is attributed to the strong ionization produced in the circumburst medium by the GRB photons. The high iron abundance points to the existence of a burst environment enriched by a supernova along the line of sight. The supernova explosion is estimated to have occurred about 10 years before the burst. Our results agree with models in which GRBs originate from the collapse of very massive stars and are preceded by a supernova event.

Taking advantage of viral immune evasion: virus-derived proteins represent novel biopharmaceuticals.

In healthy individuals, natural and adaptive immune responses are able to control virus entry into the host. In particular, CD8(+)-mediated cytotoxicity, sustained by the intervention of CD4+ cells, represents the major key event leading to virus eradication. On the other hand, viruses are able to evade from host immune response via several mechanisms, and special emphasis will be placed on hepatitis C virus and chronic Epstein-Barr infections also in view of personal data. Virokines, viroreceptors, and serpins greatly contribute to viral immune escape, and, among virokines, interleukin (IL)-10 has been object of intensive studies. Finally, all these products have been used as biopharmaceuticals, and, for instance, viral IL-10, chemokine-binding proteins, and serpins exhibit in animal models immunosuppressive, anti-inflammatory, and antiatherogenic activities. As far as their use in human trials is concernded, many cautions are required in order to avoid deleterious side effects and, in particular, the purity of the product, its route and frequency of administration, as well as the immune status of the patient should be taken into serious account.

Ablation of T-helper 1 cell derived cytokines and of monocyte-derived tumor necrosis factor-alpha in hereditary hemorrhagic telangiectasia: immunological consequences and clinical considerations.

Experimental evidences on the adaptive immune response in patients with hereditary hemorragic telagiectasia (HHT) are lacking. Here, we report in 9 patients with HHT a multiple deficit involving the intracellular expression of T helper (h)1-derived cytokines [Interferon (IFN)-gamma, Interleukin (IL)-2 and Tumor Necrosis Factor (TNF)-alpha] and of monocyte-derived TNF-alpha. On the other hand, percentages of Th2-derived cytokines (IL-4, IL-5 and IL-10) were normal or, in some cases, above normality. Quite interestingly, monocyte-derived IL-10 was detectable in 5 out of 9 patients in a percentage of cells comparable to controls or exceeding normal levels. Taken together, these data point out, in HHT, an ablation of Th1-responses, while Th2-type cytokines are preserved, thus exerting either a suppressive effect on Th1-cells (via IL-4 and IL-10) or an antiinflammatory response on monocyte-derived TNF-alpha (via IL-10). Furthermore, monocyte-derived IL-10 may also contribute to the antiinflammatory activity seen in HHT. According to current literature even if patients with HHT do not exhibit certain diseases, such as autoimmune diseases, cancer and abnormal responses to pathogens, the observed immune deficits need to be diagnosed and therapeutically corrected.

Involvement of the transforming growth factor beta in the pathogenesis of hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is characterized by vessel alterations such as dilatation of postcapillary venules and arterio-venous communications, which account for the major clinical manifestations of the disease. Two types of HHT have been characterized HHT-1 and HHT-2, respectively, depending the former on endoglin mutations and the latter on activin receptor-like kinase 1 (ALK-1) mutations. Both endoglin and ALK-1 bind to the transforming growth factor (TGF) superfamily which, physiologically, regulates the activities of endothelial cells and also those related to the extracellular matrix. In this review, the salient features of TGF-beta will be outlined with special reference to its activity on the immune system and on tumorigenesis. Furthermore, the involvement of TGF-beta in the pathogenesis of some gastrointestinal diseases will be discussed and, in particular, in the course of liver disease, Helicobacter pylori infection and inflammatory bowel disease. In the light of these data and of animal model of HHT, the potential risk of developing other diseases in HHT patients will be discussed.

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.

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.

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.

The immunocompromised host: immune alterations in splenectomized patients and clinical implications.

The spleen plays a paramount role in the host protection against invading microorganisms. In support of the above concept, in splenectomized patients there is increasing evidence of overwhelming postsplenectomy infections (OPSI). OPSI are caused by Streptococcus pneumoniae in about 80% of cases, but also Gram-negative bacteria are implicated in a certain number of cases. Therapeutically, penicillin and pneumococcal vaccines represent valid therapeutic approaches in Gram-positive OPSI. However, the effectiveness of polyvalent polysaccharide pneumococcal vaccines is still debated and, thus, other therapeutic strategies should be validated for combating OPSI. According to our personal data, a deficit of phagocytic activities and of T helper (h)-1 cells is very frequent in splenectomized patients. In sera, we found reduced levels of both Interferon-gamma and Interleukin (IL)-4. These data are in accordance with the recent observation on the protective role of T cells against S. pneumoniae. In fact, patients deficient in IL-12 develop severe pneumococcal infections and undergo apoptosis of Th(1) cells.

Nutrition and immunity: laboratory and clinical aspects.

It is well known that inappropriate nutrient intake accounts for the maintenance of the immunological equilibrium, in humans and animals. Vitamins, elements, lipids, proteins and nucleic acids play an important role in the regulation of cellular and humoral immune responses since single or multiple deficits of these food components have been shown to cause immune abnormalities. For instance, in the course of protein-calorie malnutrition bacterial and/or viral infections represent the major cause of death. Ageing is characterized by a decline of many immune functions, and this process is called immunosenescence. Here, we report novel findings on the inability of superantigens to activate old CD8+, natural killer and B cells, as an expression of cell amnesia. In the elderly, this lack of activation could lead to lethal effects in the case of severe staphylococcal infections. Quite interestingly, recent findings outlined some similarities between human immune deficiency virus (HIV)-1 infection and ageing in terms of immune changes. The model of HIV-infection may be useful for the interpretation of ageing mechanisms and possible therapeutical interventions. Finally, the role of nutrition in different pathological conditions and the use of medical foods for correcting of immune deficits will be described.

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.

Modifications of the immune responsiveness in patients with autoimmune thyroiditis: evidence for a systemic immune alteration.

Hashimoto's thyroiditis, the most common form of autoimmune thyroid disease, is characterised by lymphocytic infiltration of the thyroid gland, gradual destruction of the organ and production of thyroid specific auto antibodies (antithyroid peroxidase and antithyroglobulin antibodies). There are evidences that cast doubt on the pathogenetic role of these antibodies in thyroid autoimmunity. It is very likely that cellular destruction is mediated by other cellular mechanisms, such as auto reactive T-lymphocytes, natural killer and cytokines. However, other studies performed in animal models have led to the conclusion that organ specific autoimmune thyroiditis should be regarded as a polygenic disease with a penetrance that is strongly influenced by environmental factors. According to our recent results, patients affected by autoimmune thyroiditis exhibited a decreased percentage of NK and CD25 + bearing cells significantly in comparison to normal controls. Altogether these data indicated that in the patients with autoimmune thyroid disease a certain degree of peripheral immune deficiency was present.

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.

Combination therapy with ribavirin and alpha interferon for the treatment of chronic hepatitis C refractory to interferon.

BACKGROUND: Up to 80% of hepatitis C patients are refractory to treatment with interferon-alpha. These patients are not likely to benefit from higher dosages or longer duration of interferon alone. The addition of ribavirin has been shown to improve the response rate in patients resistant to a previous course of interferon-alpha alone. AIM: To evaluate whether a sustained hepatitis C virus (HCV) RNA response could be obtained with combination therapy of interferon-alpha and ribavirin in patients who did not respond to or relapsed after a standard interferon-alpha treatment. METHODS: A total of 73 patients, 59 non-responders and 14 relapsers after interferon-alpha alone, were treated with a combination of ribavirin (1000-1200 mg/day) and interferon-alpha (3 MU three times a week) for 24 weeks. Alanine aminotransferase levels and HCV RNA were checked for 24 weeks after completion of therapy. RESULTS: At the end of the combination therapy, 36 patients (49%) showed alanine aminotransferase normalization and in 20 patients (27%), HCV RNA was undetectable in serum. At the end of the 24 weeks follow-up period, only 12 patients (16%) had a sustained response with serum negativity of HCV RNA. This response was significantly higher in relapsers than in non-responders: five (36%) vs. seven (12%) patients (P=0.03), respectively. Adverse effects were restricted to flu-like symptoms and moderate haemolytic anaemia. CONCLUSIONS: Combination of interferon-alpha and ribavirin is quite limited, both in scope and efficacy, in HCV patients who had a non-response to monotherapy with interferon. Better results may be expected in relapsers, but larger studies are necessary.

Embryonal cardiotoxicity of the Helicobacter pylori lipopolysaccharide.

Helicobacter (H.) pylori is the causative agent of the peptic ulcer disease and a co-factor in the development of gastric malignancies. Recently, it has been maintained that chronic H. pylori infections in adults are linked to a higher risk of coronary heart diseases. In this respect, the acute toxic effects of the H. pylori lipopolysaccharide (LPS) on embryonal cardiomyocytes at different developmental stages was evaluated. White Leghorn chick embryos and smooth (S)--form NCTC 11637 strain H. pylori organisms were used. Both whole heath-killed H. pylori suspensions (3.10(6) bacteria/egg) and isolated S-LPS (500 ng/egg) or S-Lipid A (500 ng/egg) were non-lethal to 4-day embryos, becoming moderately lethal (5% to 30%) to 6- and 8-day embryos and highly lethal (> 90%) to 10- to 17-day embryos. The contractile activity of isolated atrial fragments from 10-day embryos was completely inhibited, within 5 min, following treatments with heath-killed H. pylori (3 x 10(6)/ml), or S-LPS (500 ng/ml), or S-Lipid A (500 ng/ml); the block determined by S-LPS and S-Lipid A was irreversible, while the block by bacterial suspensions was completely reversible upon withdrawal. Following a 24-hour treatment with S-LPS or S-Lipid A of single-cell cultures of cardiomyocytes (isolated from 10-day embryos) a dose-dependent cell loss was observed, as assessed by total protein dosage and direct counting of adherent cells. Propidium Iodide/Annexin V FACS-analysis confirmed the occurrence of cellular necrosis, but did not show any evidence of apoptotic processes. The release of superoxide anion radicals by cultured cardiomyocytes was as follows: S-Lipid A (25 micrograms/ml) > S-LPS (25 micrograms/ml) > heath killed H. pylori suspensions (3 x 10(6)/ml); control cultures did not release detectable amounts of superoxide anion radicals. Furthermore, cultured cardiomyocytes produced increased amounts of NO (N-monomethylarginine-inhibitable) following stimulation with S-LPS (25 micrograms/ml) or S-Lipid A (25 micrograms/ml) (but not heath killed H. pylori 3 x 10(6)/ml suspensions). Under all the above experimental conditions S-polysaccharide proved to be non-toxic. Concluding, H. pylori LPS is relatively non-toxic to the less differentiated cardiomyocytes; cardiomyocytes which are more advanced in their biochemical differentiation become highly sensitive to LPS and produce ROS and NO. ROS are probably responsible for the early toxic actions, while both ROS and NO are likely to be involved in the later degenerative/necrotic effects.