Regulation of organ-specific inflammation by CXCR5 during systemic autoimmunity (BA13P.131)

Mice and humans deficient in the Foxp3+ T regulatory cells (Tregs) develop systemic autoimmunity affecting multiple organs and die prematurely. Mice deficient for interleukin (IL)-2 (IL2KO) have reduced Tregs and develop inflammation mainly in liver, colon, pancreas and salivary glands. We found that the CD4+ T-cells in the secondary lymphoid organs IL2KO mice highly express CXCR5, a chemokine receptor and a marker for T-follicular helper (TfH) cells. We hypothesized that CXCR5 expression may regulate inflammation by regulating T-cell recruitment and organ-specific autoantibody production. We found that CXCR5+CD4+ T-cells were highly enriched in these inflamed organs of IL2KO mice. Rendering the IL2KO mice deficient for CXCR5 led to prolonged lifespan compared to CXCR5-sufficient IL2KO mice and protection against inflammation especially in liver and colon and partial protection against inflammation in pancreas and salivary glands. This was accompanied with a reduction of activated B and T cells in the secondary lymphoid organs as well as reduced production of inflammatory cytokines by the T-cells. However, no significant correlation was observed between CXCR5 expression and antibodies to liver and pancreatic auto-antigens. The data suggests that CXCR5 expression regulates organ-specific inflammation during Treg-deficiency -induced systemic autoimmunity, through regulation of T-cell trafficking, with an undetectable contribution to autoantibody production.

The effects of age on associations between markers of HIV progression and markers of metabolic function including albumin, haemoglobin and lipid concentrations

OBJECTIVES

We investigated whether age modified associations between markers of HIV progression, CD4 T lymphocyte count and HIV RNA viral load (VL), and the following markers of metabolic function: albumin, haemoglobin, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC).

METHODS

A retrospective analysis of data from the United Kingdom Collaborative HIV Cohort was carried out. Analyses were limited to antiretroviral-naïve subjects to focus on the impact of HIV disease itself. A total of 16670 subjects were included in the analysis. Multilevel linear regression models assessed associations between CD4 count/VL and each of the outcomes. Statistical tests for interactions assessed whether associations differed among age groups.

RESULTS

After adjustment for gender and ethnicity, there was evidence that lower CD4 count and higher VL were associated with lower TC, LDL-C, haemoglobin and albumin concentrations but higher triglyceride concentrations. Age modified associations between CD4 count and albumin (P < 0.001) and haemoglobin (P = 0.001), but not between CD4 count and HDL-C, LDL-C and TC, or VL and any outcome. Among participants aged < 30, 30-50 and > 50 years, a 50 cells/μL lower CD4 count correlated with a 2.4 [95% confidence interval (CI) 1.7-3.0], 3.6 (95% CI 3.2-4.0) and 5.1 (95% CI 4.0-6.1) g/L lower haemoglobin concentration and a 0.09 (95% CI 0.07-0.11), 0.12 (95% CI 0.11-0.13) and 0.16 (95% CI 0.13-0.19) g/L lower albumin concentration, respectively.

CONCLUSIONS

We present evidence that age modifies associations between CD4 count and plasma albumin and haemoglobin levels. A given reduction in CD4 count was associated with a greater reduction in haemoglobin and albumin concentrations among older people living with HIV. These findings increase our understanding of how the metabolic impact of HIV is influenced by age.

Predictive modeling of insulin release profile from cross-linked chitosan microspheres

Insulin-loaded microspheres composed of chitosan 3% (w/v), and loading 120 IU insulin were produced by emulsion cross-linking method. Cross-linking time was 5 h and glutaraldehyde 3.5% (v/v) was used as cross-linker. Swelling ratio studies were evaluated to predict release of insulin from chitosan microspheres. Bacitracin and sodium taurocholate were incorporated in the formulations as proteolytic enzyme inhibitor and absorption enhancer, respectively. In vitro insulin release studies were performed in phosphate buffer pH 7.4 and also in HCl pH 2 with and without trypsin. Activity of bacitracin was also evaluated. In vitro release showed a controlled profile up to 12 h and the formulation containing 0.15% (w/v) of bacitracin revealed a maximum biological activity of about 49.1 ± 4.1%. Mathematical modeling using Higuchi and Korsmeyer-Peppas suggested a non-Fickian diffusion as the mechanism of insulin release. Insulin-loaded chitosan microspheres for oral delivery showed to be an innovative and reliable delivery system to overcome conventional insulin therapy.

Thermo-sensitive gels containing lorazepam microspheres for intranasal brain targeting

Thermo-sensitive gels containing lorazepam microspheres were developed and characterized for intranasal brain targeting. Pluronics (PF-127 and PF-68) have been selected since they are thermo-reversible polymers with the property of forming a solution at low temperatures (4-5 °C), and a gel at body temperature (37 °C). This property makes them an interesting material to work with, especially in case of controlled release formulations. The present study focuses on the development of an intranasal formulation for lorazepam, as an alternative route of drug delivery to the brain. Direct transport of drugs to the brain circumventing the brain barrier, following intranasal administration, provides a unique feature and better option to target brain. The presence of mucoadhesive microspheres in the gel vehicle via nasal route can achieve a dual purpose of prolonged drug release and enhanced bioavailability. To optimise the microsphere formulation, Box Behnken design was employed by investigating the effect of three factors, polymer concentration (chitosan), emulsifier concentration (Span 80) and cross-linking agent (glutaraldehyde) on the response variable which is the mean particle size. The concentration of 21% PF-127 and 1% PF-68 were found to be promising gel vehicles. The results showed that the release rate followed a prolonged profile dispersion of the microspheres in the viscous media, in comparison to the microspheres alone. Histopathological studies proved that the optimised formulation does not produce any toxic effect on the microscopic structure of nasal mucosa.

Lymphoid organ cell culture system from Penaeus monodon (Fabricius) as a platform for white spot syndrome virus and shrimp immune-related gene expression

Shrimp cell lines are yet to be reported and this restricts the prospects of investigating the associated viral pathogens, especially white spot syndrome virus (WSSV). In this context, development of primary cell cultures from lymphoid organs was standardized. Poly-l-lysine-coated culture vessels enhanced growth of lymphoid cells, while the application of vertebrate growth factors did not, except insulin-like growth factor-1 (IGF-1). Susceptibility of the lymphoid cells to WSSV was confirmed by immunofluoresence assay using monoclonal antibody against the 28 kDa envelope protein of WSSV. Expression of viral and immune-related genes in WSSV-infected lymphoid cultures could be demonstrated by RT-PCR. This emphasizes the utility of lymphoid primary cell culture as a platform for research in virus-cell interaction, virus morphogenesis, up and downregulation of shrimp immune-related genes, and also for the discovery of novel drugs to combat WSSV in shrimp culture.

Cross-linked chitosan microspheres for oral delivery of insulin: Taguchi design and in vivo testing

Insulin-loaded chitosan microspheres were engineered by emulsion cross-linking method using glutaraldehyde as cross-linker. Taguchi orthogonal method was applied to optimize the production time and reduce the number of experiments required to obtain an optimized formulation. Three variables were evaluated, i.e. chitosan and glutaraldehyde concentrations, and cross-linking time at three levels. The dependent variables were the mean particle size and the encapsulation efficiency. The optimal formulation was obtained with chitosan 3% (w/v), glutaraldehyde 3.5% (v/v), and cross-linking time of 5h, characterized by microspheres with a mean particle size of 29.5 μm, and insulin encapsulation efficiency of 71.6±1.3%. In vivo studies were carried out using male Wistar albino rats, revealing a significant reduction in blood glucose level after administration of the optimized formulation, in comparison to a subcutaneous insulin injection. Chitosan microspheres were superior in terms of sustaining protein release over conventional insulin therapy.

Colon specific chitosan microspheres for chronotherapy of chronic stable angina

In the present work, chitosan microspheres with a mean diameter between 6.32 μm and 9.44 μm, were produced by emulsion cross-linking of chitosan, and tested for chronotherapy of chronic stable angina. Aiming at developing a suitable colon specific strategy, diltiazem hydrochloride (DTZ) was encapsulated in the microspheres, following Eudragit S-100 coating by solvent evaporation technique, exploiting the advantages of microbiological properties of chitosan and pH dependent solubility of Eudragit S-100. Different microsphere formulations were prepared varying the ratio DTZ:chitosan (1:2 to 1:10), stirring speed (1000-2000 rpm), and the concentration of emulsifier Span 80 (0.5-1.5% (w/v)). The effect of these variables on the particle size and encapsulation parameters (production yield (PY), loading capacity (LC), encapsulation efficiency (EE)) was evaluated to develop an optimized formulation. In vitro release study of non-coated chitosan microspheres in simulated gastrointestinal (GI) fluid exhibited a burst release pattern in the first hour, whereas Eudragit S-100 coating allowed producing systems of controlled release diffusion fitting to the Higuchi model, and thus suitable for colon-specific drug delivery. DSC analysis indicated that DTZ was dispersed within the microspheres matrix. Scanning electron microscopy revealed that the microspheres were spherical and had a smooth surface. Chitosan biodegradability was proven by the enhanced release rate of DTZ in presence of rat caecal contents.

Disseminated Rhodococcus equi infection in dromedary camels (Camelus dromedarius)

Rhodococcus (R). equi, a recognized pathogen in horses, is emerging as a human opportunistic pathogen, especially in immunocompromized people. It affects also New World camelids, but there are no reports of R. equi infection in Old World camelids yet. Four cases of disseminated R. equi infection in adult breeding dromedaries occurred at one camel farm near Dubai within 16 months of each other. At necropsy the lungs were diffusely consolidated with large caseous areas. Histology revealed severe suppurative to necrotising pneumonia with multiple encapsulated abscesses. Immunohistochemistry enabled the detection of 15- to 17-kDa antigens (VapA) of R. equi in the lung sections. High numbers of R. equi were isolated from the lung lesions as well as from liver, spleen and mediastinal lymph nodes, indicative of septicaemia. The isolated strains were PCR-positive for the specific virulence plasmid (VapA-Gen) of R. equi, indicating virulent strains and containing an 85-kb type I plasmid. This is the first report of disseminated R. equi infection in Old World camelids. Since adult camels in general do not suffer from bacterial caused pneumonia (except tuberculosis), this is a new emerging disease for camels.

Multiparticulate system for colon targeted delivery of ondansetron

Targeted delivery of drugs to colon has the potential for local treatment of a variety of colonic diseases. The main objective of the study was to develop a multiparticulate system containing chitosan microspheres for the colon targeted delivery of ondansetron for the treatment of irritable bowel syndrome. This work combines pH-dependent solubility of eudragit S-100 polymers and microbial degradability of chitosan polymers. Chitosan microspheres containing ondansetron were prepared by emulsion cross linking method. The effect of process variables like chitosan concentration, drug-polymer ratio, emulsifier concentration and stirring speed were studied on particle size and entrapment efficiency of chitosan microspheres. In vitro drug release studies in simulated gastro intestinal fluids showed a burst drug release pattern in the initial hour necessitating microencapsulation around the chitosan microspheres. The optimized formulation was then subjected to microencapsulation with eudragit S-100 by solvent evaporation technique. The effect of different coat/core ratio on particle size, drug entrapment efficiency and in vitro drug release were studied. Formulation which contain 1:10 core/coat ratio released lesser amount of drug in the upper gastro intestinal conditions and so selected as best formulation and then subjected to in vitro drug release studies in presence of rat ceacal contents to assess biodegradability of chitosan microspheres in colon. In order to study the drug release mechanism in vitro drug release data was fitted into various kinetic models. Analysis of regression values suggested that the possible drug release mechanism was Peppas model.

In vitro susceptibility of viridans streptococci to leaf extracts of Mangifera Indica

The susceptibility of Viridans streptococci to leaf extracts of Mangifera indica was studied on 53 clinical isolates from 39 patients. All the isolates were found to be susceptible to both water and methanol extract of M. indica leaves. Minimum inhibitory concentration (MIC) of methanol extract for all isolates were <50 mg/mL and MIC of water extract for all isolates were <200 mg/mL. Methanol extract was found to have better action against Viridans streptococci than water extract.