Sex differences in cardiac remodeling post myocardial infarction with acute cigarette smoking

Background

Whether cigarette smoking affects the heart post-myocardial infarction (MI) in a sex-dependent way remains controversial. Using a mouse model, we investigated cardiac remodeling under the influence of acute cigarette smoke (CS) exposure following ischemic injury in both sexes.

Methods

Ten cigarettes were smoked twice daily for 2 weeks followed by MI and then 1 additional week post permanent LAD ligation. Cardiac function, histology, and infarct size were assessed, and inflammatory markers quantified by RT–PCR. Statistical comparisons were performed using an unpaired t test or ANOVA followed by Tukey post hoc test.

Results

We observed that cigarette smoking exacerbated both left and right ventricular remodeling only in males at an early stage of post-MI. Females did not display a significant structural and/or functional alteration within 7 days of cardiac remodeling post-MI upon CS exposure. Worsened right ventricular remodeling in males was independent of pulmonary congestion. CS-exposed males exhibited enhanced increases in left ventricular end systolic and diastolic volumes, as well as reductions in ejection fraction and fractional area changes of left ventricular base. At day 7, infarct size was increased by cigarette smoking in males only, which was accompanied by enhanced collagen deposition in both the infarcted and peri-infarcted areas. Both IL-6 and TNF-α mRNA expression significantly increased in CS-exposed MI male group only at day 7 post-MI suggestive of prolonged inflammation.

Conclusions

These findings indicate that CS exposure worsens the progression of cardiac remodeling post-MI in male sex in a significant manner compared to female sex at least at early stages.

Elaboration of Sterically Stabilized Liposomes for S-Nitrosoglutathione Targeting to Macrophages

S-nitrosoglutathione (GSNO) is a potential therapeutic for infectious disease treatment because of its pivotal role in macrophage-mediated inflammatory responses and host defense in addition to direct antibacterial activities. In this study, sterically stabilized cationic liposomes (SSCL) and sterically stabilized anionic liposomes (SSAL) were developed as nanocarriers for macrophage targeting. Elaborated liposomes were characterized in terms of size, zeta potential, morphology, encapsulation efficiency, in vitro drug release behavior and cytotoxicity. Their versatility in targeting monocytes/macrophages was determined by confocal laser scanning microscopy and transmission electron microscopy. Flow cytometry revealed that cellular uptake of both SSCL and SSAL was governed by several endocytic clathrin- and caveolae-dependent mechanisms. Quantitative assessments of intracellular nitric oxide demonstrated highly efficient uptake of GSNO-loaded SSCL that was twenty-fold higher than that of GSNO-free molecules. GSNO-loaded SSCL displayed strong bacteriostatic effects on Staphylococcus aureus and Pseudomonas aeruginosa, which can be involved in pulmonary infectious diseases. These results reveal the potential of liposomal GSNO as an anti-infective therapeutic due to its macrophage targeting capacity and direct antibacterial effects.

Core–shell alginate@silica microparticles encapsulating probiotics

Lactobacillus rhamnosus GG (LGG) was encapsulated in core–shell alginate–silica microcapsules by coating the electrosprayed ionogel with a silica shell via hydrolysis/condensation of alkoxysilane precursors.

Estrogens control inflammation in experimental colitis

There is now a wealth of experimental evidence indicating that the deficit in endogenous estrogen facilitates the onset of inflammation that can be antagonized by estrogen replacement therapy. This work investigated the role of estrogen in the control of intestinal inflammation in a panel of colitis models, focusing on the morphological changes, the activity of mast cells, the expression of cytokines (IL-1beta, IL-6, and TNF-alpha), fibronectin and reactive oxygen species. Two hundred adult male rats were divided into 4 groups: colitis was induced in Group I and Group II but only the latter was treated with estrogen; Group III received estrogen only, and Group IV saline. Colitis was induced in 4 models using: iodoacetamide; iodoacetamide + enteropathogenic E. coli; 2, 4, 6-Trinitrobenzene sulfonic acid; and dextran sulfate sodium salt. Macroscopic and microscopic evaluations of abdominal structures as well as molecular analysis were made on days 7, 14, 28 and 56. There was a significant improvement in the health condition of the estrogen-treated rats: the inflammation scores were reduced by at least 10-15%, the number of mast cells in the colon decreased by 30%, fibronectin expression was only 50% and reactive oxygen species decreased by 30%. In addition, there was a significant decrease in TNF-alpha, IL-6 and IL-1beta expression by about 25%. In conclusion, there was an improvement in the inflammatory status in all estrogen-treated groups through the duration of the experiment at all-time points. In addition, there was less tissue necrosis as depicted by less fibronectin and a marked antioxidant effect.

Modulation of Beta2 and Beta3 integrins in experimental colitis induced by iodoacetamide and enteropathogenic E. coli

Integrins can modulate the infiltration of inflammatory cells and the secretion of various inflammatory mediators, essential players in the pathogenesis of colitis. This study explores the role of beta2 and beta3 integrin signaling and their possible role in experimental colitis. A total of 160 adult male Sprague-Dawly rats were divided into 4 equal groups: methylcellulose, bacteria, iodoacetamide and iodoacetamide plus bacteria. Clinical symptoms and signs of colitis were checked daily and colonic tissues were biopsied on days 3, 14, 28, and 56 post induction. Histological studies along with histochemical analysis and polymerase chain reaction of beta2, beta3 and alphavbeta3 were performed according to standard procedures. The symptoms and signs were consistent with previously reported data on active colitis. The highest expression of beta3 integrin was in the combined treatment mostly on platelets, endothelial and inflammatory cells. In the same group, the expression of alphavbeta3 integrin complex reached the highest score after 56 days in all colonic layers. Beta2 integrin expression showed a 3-4-fold increase in the combined treatment group at all time points and kept increasing till day 56. It was mostly expressed in the mucosa and submucosa. In addition, the expression of both αvβ3 and αiiβ3 integrins was also elevated 2- to 10-fold, respectively, in the same colitis groups throughout the duration of the experiment. In conclusion, the combined treatment of IA and Enteropathogenic E. coli led to a significant upregulation of all the tested integrins throughout the experimental duration. Such upregulation of integrins could have contributed to the increase and chronicity of inflammation.

Effect of triple costimulation blockade on islet allograft survival in sensitized mice

BACKGROUND

Islet allograft rejection in sensitized recipients is difficult to control by costimulation blockade using anti-CD154 and cytotoxic T-lymphocyte antigen-4 immunoglobulin (CTLA4Ig). Because leukocyte function antigen (LFA) 1 is highly expressed on memory T cells, adding an LFA-1 blockade may inhibit memory T-cell activities. We examined the effects on islet allograft survival of triple costimulation blockade in presensitized recipient mice.

METHODS

C57BL/6 mice were sensitized by transplantation under the kidney capsule or intraperitoneal injection of Balb/c islets. Four weeks after transplantation, sensitization was confirmed by flow-cytometric detection of alloreactive antibodies. Diabetes was induced by a single intravenous injection of streptozotocin. Recipients were transplanted with 200 Balb/c islets under the right kidney capsule. Graft function was assessed by daily blood glucose and body weight records. Transplanted animals were divided into 3 treatment groups: group 1, control antibody; group 2, anti-CD154 and CTLA-4 Ig double therapy; group 3, anti-CD154, CTLA4Ig, and anti-LFA-1 triple therapy. Injections were administered every second day from day -2 to day 8.

RESULTS

Naïve mice rejected islet allografts between days 7 and 29 (mean 16 +/- 6 d; n = 5), sensitized mice in group 1 between days 0 and 14 (mean 7 +/- 5 d; n = 8), in group 2 between days 4 and 16 (mean 8 +/- 4 d; n = 7), and in group 3 between days 4 and 26 (mean 11 +/- 7 d; n = 10).

CONCLUSION

Triple costimulation blockade with anti-CD154, CTLA4Ig, and anti-LFA-1 was not sufficient to improve islet allograft survival in sensitized recipients.

Crohn's disease in the elderly

We compared eleven patients in whom symptoms of Crohn's disease appeared at age greater than or equal to 65 with a younger group in whom symptoms had appeared earlier. Only 64% of the older patients were initially recognized as having Crohn's disease, as compared with 96% of the younger patients even though clinical characteristics and initial response to medical treatment were similar in both groups. A higher rate of complications occurred in the older group and follow-up data showed that they had higher mortality and a greater need for continuous treatment. We suggest that awareness of Crohn's disease in the elderly is less than in the young; the diagnosis is more often missed despite the similarity of the clinical features to those of younger patients.