The arthritogenic adjuvant squalene does not accumulate in joints, but gives rise to pathogenic cells in both draining and non-draining lymph nodes

Preclinical toxicology profile of squalene epoxidase inhibitors

Small cell lung cancer (SCLC) is a particularly aggressive subset of lung cancer, and identification of new therapeutic options is of significant interest. We recently reported that SCLC cell lines display a specific vulnerability to inhibition of squalene epoxidase (SQLE), an enzyme in the cholesterol biosynthetic pathway that catalyzes the conversion of squalene to 2,3-oxidosqualene. Since it has been reported that SQLE inhibition can result in dermatitis in dogs, we conducted a series of experiments to determine if SQLE inhibitors would be tolerated at exposures predicted to drive maximal efficacy in SCLC tumors. Detailed profiling of the SQLE inhibitor NB-598 showed that dogs did not tolerate predicted efficacious exposures, with dose-limiting toxicity due to gastrointestinal clinical observations, although skin toxicities were also observed. To extend these studies, two SQLE inhibitors, NB-598 and Cmpd-4″, and their structurally inactive analogs, NB-598.ia and Cmpd-4″.ia, were profiled in monkeys. While both active SQLE inhibitors resulted in dose-limiting gastrointestinal toxicity, the structurally similar inactive analogs did not. Collectively, our data demonstrate that significant toxicities arise at exposures well below the predicted levels needed for anti-tumor activity. The on-target nature of the toxicities identified is likely to limit the potential therapeutic utility of SQLE inhibition for the treatment of SCLC.

The ASIA syndrome: basic concepts

The autoimmune/inflammatory syndrome induced by adjuvants (ASIA), also known as Shoenfeld’s syndrome, encompasses several autoimmune conditions/phenomena that are induced following the exposure to substances with adjuvant activity. The disease spectrum is heterogeneous in respect to clinical presentation as well as severity of the clinical manifestations. Adjuvants are included in vaccination formulations for their immunogenic properties. Despite being generally well tolerated, safe and effective, some genetically predisposed individuals can develop generalized non-specific constitutional symptoms, autoantibody production, new onset, or worsening of disease presentation. In this review, we focus on the current knowledge presented in the literature on ASIA syndrome, increasing physician awareness about the basic concepts of ASIA syndrome and highlight the devastating amount of data accumulated in the last few years concerning the relationship between various adjuvants and autoimmunity.

Squalene is lipotoxic to yeast cells defective in lipid droplet biogenesis

The toxic effect of overloaded lipids on cell physiology and viability was described in various organisms. In this study we focused on the potential lipotoxicity of squalene, a linear triterpene synthesized in eukaryotic cells as an intermediate in sterol biosynthesis. Squalene toxicity was studied in the yeast Saccharomyces cerevisiae, a model unicellular eukaryote established in lipotoxicity studies. Squalene levels in yeast are typically low but its accumulation can be induced under specific conditions, e.g. by inhibition of squalene monooxygenase with the antimycotic terbinafine. At higher levels squalene is stored in lipid droplets. We demonstrated that low doses of terbinafine caused severe impairment of growth and loss of viability of the yeast mutant dga1Δ lro1Δ are1Δ are2Δ unable to form lipid droplets and that these defects were linked to squalene accumulation. The hypersensitivity of the lipid droplet-less mutant to terbinafine was alleviated by decreasing squalene accumulation with low doses of squalene synthase inhibitor zaragozic acid. Our results proved that accumulated squalene is lipotoxic to yeast cells if it cannot be efficiently sequestered in lipid droplets. This supports the hypothesis about the role of squalene in the fungicidal activity of terbinafine. Squalene toxicity may represent also a limiting factor for production of this high-value lipid in yeast.

Infections in hemodialysis: a concise review - Part 1: bacteremia and respiratory infections

Hemodialysis (HD) patients are particularly predisposed to infections. It seems that the HD procedure per se as well as disturbances in both innate and adaptive immunity significantly contribute to this susceptibility. Infections are the major cause of morbidity and the second cause of death following cardiovascular events in HD patients. Episodes of bacteremia and pneumonia account for the majority of severe infections in this population. In addition to these bacterial infections another common problem in HD units is the blood transmitted viral infections, particularly infections caused by hepatitis B virus, hepatitis C virus and Human immunodeficiency virus. A number of safety concerns exist for limiting the spread of these viral infections among HD patients and the staff of the unit. The aim of the present review is to present in a concise albeit practical form the difficult aspect of infections in HD. For practical reasons the review is separated in two parts. The present first part covers bacteremia and respiratory infections, while the second part will cover blood transmitted viral infections.

Safety review: squalene and thimerosal in vaccines

Few studies show the reluctance of the people to get vaccinated against A (H1N1) influenza for fear of side effects of squalene (MF59, AS03, AF03) and thimerosal. The aim of this paper is to assess the safety in using these adjuvants and preservative reviewing data of clinical trials relative to which formulation includes these compounds. In the current state of knowledge, these vaccines have proved to be effective even though they more frequently give local adverse events than non-adjuvanted influenza vaccines. Systemic side effects are generally not serious. In the studies, adjuvanted vaccines do not increase neither the risk of Guillain Barre syndrome nor auto-immune diseases. There is no convincing evidence that exposure to thimerosal in vaccines had any deletorious effect on physiological outcome.

Safety of MF59-adjuvanted versus non-adjuvanted influenza vaccines in children and adolescents: an integrated analysis

We reviewed the safety of MF59-adjuvanted versus non-adjuvanted influenza vaccines in children and adolescents (aged 6 months-18 years) in an integrated analysis of all pediatric trials evaluating MF59-containing influenza vaccines completed to date (5 trials). In the MF59-adjuvanted group (n=1181) versus the non-adjuvanted group (n=545) there was no increase in the incidence of unsolicited adverse events and serious adverse events. As expected, solicited local or systemic reactions occurred more frequently in MF59-adjuvanted subjects; however, a majority of reactions were mild and transient. These data support the safety of MF59-adjuvanted influenza vaccines in the pediatric population.

Vaccine Immunopotentiators of the Future

Vaccine adjuvants or immunopotentiators comprise a diverse group of molecules or formulations. Despite a wealth of different candidates, there is a need for better vaccine adjuvants in both veterinary and human medicine. For human vaccines, the immunopotentiator choice has been limited to aluminum salts, until recently. By contrast, a whole range of adjuvants is employed for inactivated veterinary vaccines, due to less stringent safety and regulatory requirements and proven superior vaccine performance. This review highlights recent developments and future trends in immunopotentiators.

Pristane-induced arthritis in the rat

A chronic relapsing arthritis develops after a single subcutaneous injection of small amounts of pristane; the pristane induced arthritis (PIA) model in the rat. PIA is characterized by a sudden onset of disease 2 wk after induction. The main pathological features of PIA include edema accompanied by an acute phase response, infiltration into the joint of mononuclear and polymorphonuclear cells, pannus formation, and erosion of cartilage and bone. PIA is a disease that is largely T-cell dependent that can be adoptively transferred by activated CD4+ T-cells. PIA in rats is followed clinically by macroscopic scoring and is characterized by an early acute phase of severe inflammation after onset that eventually gradually disappears to be followed by less severe relapsing phases of new inflamed joints and increasing cartilage erosion and joint deformity. PIA can be diagnosed by biochemical analyzes in plasma that reflects systemic inflammation (alpha1-acid glycoprotein (AGP) and IL-6) and cartilage erosion (COMP).

Association between occupational exposure to mineral oil and rheumatoid arthritis: results from the Swedish EIRA case-control study

The aim of the present study was to investigate the association between exposure to mineral oil and the risk of developing rheumatoid arthritis (RA), and in addition to perform a separate analysis on the major subphenotypes for the disease; namely, rheumatoid factor (RF)-positive RA, RF-negative RA, anticitrulline-positive RA and anticitrulline-negative RA, respectively. A population-based case–control study of incident cases of RA was performed among the population aged 18–70 years in a defined area of Sweden during May 1996–December 2003. A case was defined as an individual from the study base who for the first time received a diagnosis of RA according to the American College of Rheumatology criteria of 1987. Controls were randomly selected from the study base with consideration taken for age, gender and residential area. Cases (n = 1,419) and controls (n = 1,674) answered an extensive questionnaire regarding lifestyle factors and occupational exposures, including different types of mineral oils. Sera from cases and controls were investigated for RF and anticitrulline antibodies.

Among men, exposure to any mineral oil was associated with a 30% increased relative risk of developing RA (relative risk = 1.3, 95% confidence interval = 1.0–1.7). When cases were subdivided into RF-positive RA and RF-negative RA, an increased risk was only observed for RF-positive RA (relative risk = 1.4, 95% confidence interval 1.0–2.0). When RA cases were subdivided according to the presence of anticitrulline antibodies, an increased risk associated with exposure to any mineral oil was observed only for anticitrulline-positive RA (relative risk = 1.6, 95% confidence interval = 1.1–2.2). Analysis of the interaction between oil exposure and the presence of HLA-DR shared epitope genes regarding the incidence of RA indicated that the increased risk associated with exposure to mineral oil was not related to the presence of shared epitope genotypes.

In conclusion, our study shows that exposure to mineral oil is associated with an increased risk to develop RF-positive RA and anticitrulline-positive RA, respectively. The findings are of particular interest since the same mineral oils can induce polyarthritis in rats.

Adjuvant oil induces waves of arthritogenic lymph node cells prior to arthritis onset

A single intradermal injection of the adjuvant-oil squalene induces T cell mediated arthritis in DA rats. The chain of events leading from nonspecific provocation of the immune system to arthritis is largely unknown. Previous studies have demonstrated that lymph node (LN) cells are of pathogenic importance, i.e. cells from LNs draining the injection site can transfer arthritis to naïve DA rats. Recently we have demonstrated cellular uptake of adjuvant oil in draining lymph nodes but also that nondraining LNs become hyperplastic and harbour arthritogenic cells. Here, we aimed to determine from which time-point prior to arthritis onset arthritogenic cells appear in draining inguinal and nondraining axillary/brachial LNs, respectively. We demonstrated that the ability to transfer arthritis was strongly dependent on the time-point after adjuvant-injection with clear-cut differences between draining and nondraining LN cells. Cells harvested at day 5 postinjection (p.i) were not able to transfer arthritis, while at day 8 p.i, a first wave of arthritogenic cells appeared in draining LNs. The ability to transfer arthritis was associated with a pro-inflammatory cytokine profile as indicated by the IL-1beta and IFNgamma expression in cells from draining LNs. Subsequently, at day 11 p.i., just before arthritis onset, arthritogenic cells appeared also in nondraining LNs. These results shed new light on the induction of arthritic diseases, implicating a two step mechanism for the development of pathogenic cells. Firstly, a pro-inflammatory burst in responding lymphoid organs leading to a local pool of arthritogenic cells and, secondly, a transmission of arthritogenecity to other LNs and precipitation of disease in peripheral joints.

Fractionation, structural studies, and immunological characterization of the semi-synthetic Quillaja saponins derivative GPI-0100

Unfractionated GPI-0100 (UFGPI-0100) containing semi-synthetic derivatives of deacylated Quillaja saponins (DS saponins) modified at the glucuronic acid residue was resolved by reverse phase low-pressure liquid chromatography (RP-LPLC) into two fractions, RP18-1 and RP18-2, with different compositions and adjuvanticity. The fraction RP18-1 contained DS saponin adducts of N-dicyclohexylurea, and stimulated Th2 immunity with production of IgG1, while the RP18-2 fraction contained the dodecylamide derivatives of DS saponins and stimulated Th1 immunity with production of IgG2a, IFN-gamma, IL-2, and CTL. The strong immune stimulatory properties of RP18-2, relative to RP18-1, and the formation of RP18-1/RP18-2 mixed micelles may account for the effective stimulation of Th1 immunity by UFGPI-0100. UFGPI-0100 was free of acylated quillaja saponin components, including the more stable QS-7.