Loss of Myeloid Cell-Specific ß2-Adrenergic Receptor Expression Ameliorates Cardiac Function and Remodeling after Acute Ischemia.

Myeloid cells, including neutrophils, monocytes and macrophages, accumulate quickly after ischemic injury in the heart where they play integral roles in the regulation of inflammation and repair. We previously reported that deletion of ß2-adrenergic receptor (ß2AR) in all cells of hematopoietic origin resulted in generalized disruption of immune cell responsiveness to injury, but with unknown impact on myeloid cells specifically. To investigate this, we crossed floxed ß2AR (F/F) mice with myeloid cell-expressing Cre (LysM-Cre) mice to generate myeloid cell-specific ß2AR knockout mice (LB2) and subjected them to myocardial infarction (MI). Via echocardiography and immunohistochemical analyses, LB2 mice displayed better cardiac function and less fibrotic remodeling after MI than the control lines. Despite similar accumulation of myeloid cell subsets in the heart at 1-day post-MI, LB2 mice displayed reduced numbers of Nu by 4 days post-MI, suggesting LB2 hearts have enhanced capacity for Nu efferocytosis. Indeed, bone marrow-derived macrophage (BMDM)-mediated efferocytosis of Nu was enhanced in LB2-versus F/F-derived cells in vitro. Mechanistically, several pro-efferocytosis-related genes were increased in LB2 myeloid cells, with annexin A1 ( Anxa1 ) in particular elevated in several myeloid cell types following MI. Accordingly, shRNA-mediated knockdown of Anxa1 in LB2 bone marrow prior to transplantation into irradiated LB2 mice reduced Mac-induced Nu efferocytosis in vitro and prevented the ameliorative effects of myeloid cell-specific ß2AR deletion on cardiac function and fibrosis following MI in vivo. Altogether, our data reveal a previously unrecognized role for ß2AR in the regulation of myeloid cell-dependent efferocytosis in the heart following injury.

Long-Term Effects of Very Low Dose Particle Radiation on Gene Expression in the Heart: Degenerative Disease Risks.

Compared to low doses of gamma irradiation (γ-IR), high-charge-and-energy (HZE) particle IR may have different biological response thresholds in cardiac tissue at lower doses, and these effects may be IR type and dose dependent. Three- to four-month-old female CB6F1/Hsd mice were exposed once to one of four different doses of the following types of radiation: γ-IR 137Cs (40-160 cGy, 0.662 MeV), 14Si-IR (4-32 cGy, 260 MeV/n), or 22Ti-IR (3-26 cGy, 1 GeV/n). At 16 months post-exposure, animals were sacrificed and hearts were harvested and archived as part of the NASA Space Radiation Tissue Sharing Forum. These heart tissue samples were used in our study for RNA isolation and microarray hybridization. Functional annotation of twofold up/down differentially expressed genes (DEGs) and bioinformatics analyses revealed the following: (i) there were no clear lower IR thresholds for HZE- or γ-IR; (ii) there were 12 common DEGs across all 3 IR types; (iii) these 12 overlapping genes predicted various degrees of cardiovascular, pulmonary, and metabolic diseases, cancer, and aging; and (iv) these 12 genes revealed an exclusive non-linear DEG pattern in 14Si- and 22Ti-IR-exposed hearts, whereas two-thirds of γ-IR-exposed hearts revealed a linear pattern of DEGs. Thus, our study may provide experimental evidence of excess relative risk (ERR) quantification of low/very low doses of full-body space-type IR-associated degenerative disease development.

Advancement in our understanding of immune response against Encephalitozoon infection.

Microsporidia are a group of obligate, intracellular, spore-forming eukaryotic pathogens, which predominantly infects immunocompromised individuals worldwide. Encephalitozoon spp. is one of the most prevalent microsporidia known to infect humans. Host immune system plays a major role in combating pathogens including Encephalitozoon spp. infecting humans. Both innate and adaptive arms of host immune system work together in combating Encephalitozoon infection. Researchers are conducting studies to elucidate the role of both arms of immune system against Encephalitozoon infection. In addition to cell-mediated adaptive immunity, role of innate immunity is also being highlighted in clearance of Encephalitozoon spp. from host body. Therefore, the current review will give a clear and consolidated update on the role of innate as well as adaptive immunity in protection against Encephalitozoon spp.

Cardiovascular protection in females linked to estrogen-dependent inhibition of arterial stiffening and macrophage MMP12.

Arterial stiffening is a consequence of aging and a cholesterol-independent risk factor for cardiovascular disease (CVD). Arterial stiffening and CVD show a sex bias, with men more susceptible than premenopausal women. How arterial stiffness and sex interact at a molecular level to confer risk of CVD is not well understood. Here, we used the sexual dimorphism in LDLR-null mice to show that the protective effect of female sex on atherosclerosis is linked to reduced aortic stiffness and reduced expression of matrix metalloproteinase-12 (MMP12) by lesional macrophages. Deletion of MMP12 in LDLR-null mice attenuated the male sex bias for both arterial stiffness and atherosclerosis, and these effects occurred despite high serum cholesterol. Mechanistically, we found that oxidized LDL stimulates secretion of MMP12 in human as well as mouse macrophages. Estrogen antagonizes this effect by downregulating MMP12 expression. Our data support cholesterol-independent causal relationships between estrogen, oxidized LDL-induced secretion of macrophage MMP12, and arterial stiffness that protect against atherosclerosis in females and emphasize that reduced MMP12 functionality can confer atheroprotection to males.

The Role of Leukocytes in Diabetic Cardiomyopathy.

Diabetes is predominant risk factor for cardiovascular diseases such as myocardial infarction and heart failure. Recently, leukocytes, particularly neutrophils, macrophages, and lymphocytes, have become targets of investigation for their potential role in a number of chronic inflammatory diseases such as diabetes and heart failure. While leukocytes contribute significantly to the progression of diabetes and heart failure individually, understanding their participation in the pathogenesis of diabetic heart failure is much less understood. The present review summarizes the role of leukocytes in the complex interplay between diabetes and heart failure, which is critical to the discovery of new targeted therapies for diabetic cardiomyopathy.

Small molecule disruption of G protein ßγ subunit signaling reprograms human macrophage phenotype and prevents autoimmune myocarditis in rats.

The purpose of this study was to determine whether blocking of G protein ßγ (Gßγ) signaling halts heart failure (HF) progression by macrophage phenotype manipulation. Cardiac Gßγ signaling plays a crucial role in HF pathogenesis. Previous data suggested that inhibiting Gßγ signaling reprograms T helper cell 1 (Th1) and Th2 cytokines, suggesting that Gßγ might be a useful drug target for treating HF. We investigated the efficacy of a small molecule Gßγ inhibitor, gallein, in a clinically relevant, experimental autoimmune myocarditis (EAM) model of HF as well as in human macrophage phenotypes in vitro. In the myocardium of HF patients, we observed that G protein coupled receptor kinase (GRK)2 levels were down-regulated compared with healthy controls. In rat EAM, treatment with gallein effectively improved survival and cardiac function, suppressed cardiac remodeling, and further attenuated myocardial protein expression of GRK2 as well as high mobility group box (HMGB)1 and its cascade signaling proteins. Furthermore, gallein effectively inhibited M1 polarization and promoted M2 polarization in vivo in the EAM heart and in vitro in human monocyte-derived macrophages. Taken together, these data suggest that the small molecule Gßγ inhibitor, gallein, could be an important pharmacologic therapy for HF as it can switch the phenotypic reprogramming from M1 to M2 phenotype in a rat model of EAM heart and in human macrophages.

Effects of Non-thermal, Non-cavitational Ultrasound Exposure on Human Diabetic Ulcer Healing and Inflammatory Gene Expression in a Pilot Study.

The purpose of this clinical study was to assess, in a limited patient population, the potential for a novel advanced wound care treatment based on low-frequency (20 kHz) low-intensity (spatial peak temporal peak intensity <100 mW/cm2; i.e., pressure amplitude of 55 kPa) ultrasound (LFLI-US), to affect wound closure rate in human diabetic foot ulcers (DFUs) and to effect changes in the relative expression of pro-inflammatory and anti-inflammatory genes. The ratio of expression of these genes, termed the M1/M2 score because it was inspired by the transition of macrophages from pro-inflammatory (M1) to anti-inflammatory (M2) phenotypes as wound healing progresses, was previously presented as a potential healing indicator for DFUs treated with the standard of care. We previously found that non-cavitational, non-thermal LFLI-US delivered with a pulse repetition frequency of 25 Hz was effective at improving wound healing in a pilot study of 20 patients with chronic venous ulcers. In this study, we assessed the potential for weekly LFLI-US exposures to affect wound healing in patients with diabetic ulcers, and we analyzed temporal changes in the M1/M2 score in debrided diabetic wound tissue. Although this was a limited patient population of only 8 patients, wounds treated with LFLI-US exhibited a significantly faster reduction in wound size compared with sham-treated patients (p < 0.001). In addition, the value of the M1/M2 score decreased for all healing diabetic ulcers and increased for all non-healing diabetic ulcers, suggesting that the M1/M2 score could be useful as an indicator of treatment efficacy for advanced DFU treatments. Such an indicator would facilitate clinical decision making, ensuring optimal wound management and thus contributing to reduction of health care expenses. Moreover, the results presented may contribute to an understanding of the mechanisms underlying ultrasonically assisted chronic wound healing. Knowledge of these mechanisms could lead to personalized or patient-tailored treatment.

Drug delivery strategies to control macrophages for tissue repair and regeneration.

Tissue repair and regeneration is a complex process. Our bodies have an excellent capacity to regenerate damaged tissues in many situations. However, tissue healing is impaired in injuries that exceed a critical size or are exacerbated by chronic inflammatory diseases like diabetes. In these instances, biomaterials and drug delivery strategies are often required to facilitate tissue regeneration by providing physical and biochemical cues. Inflammation is the body's response to injury. It is critical for wound healing and biomaterial integration and vascularization, as long as the timing is well controlled. For example, chronic inflammation is well known to impair healing in chronic wounds. In this review, we highlight the importance of a well-controlled inflammatory response, primarily mediated by macrophages in tissue repair and regeneration and discuss various strategies designed to promote regeneration by controlling macrophage behavior. These strategies include temporally controlled delivery of anti-inflammatory drugs, delivery of macrophages as cellular therapy, controlled release of cytokines that modulate macrophage phenotype, and the design of nanoparticles that exploit the inherent phagocytic behavior of macrophages. A clear outcome of this review is that a deeper understanding of the role and timing of complex macrophage phenotypes or activation states is required to fully harness their abilities with drug delivery strategies.

Tumor necrosis factor-α and interleukin-1ß gene polymorphisms and risk of brain abscess in North Indian population.

OBJECTIVE: Brain abscess develops in response to a parenchymal infection with pyogenic bacteria. Tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) are the most crucial pro-inflammatory cytokines with both beneficial and destructive properties for the central nervous system. The present study evaluated the association of specific alleles/genotypes of TNF-α and IL-1ß with brain abscess. MATERIAL AND METHODS: A total of 90 brain abscess patients and 100 healthy controls were included in the study. Predisposing factors were identified in 56 (62.2%) patients with brain abscess. TNF-α (-308 G>A) and IL-1ß (-511 CA) and C allele in IL-1ß (-511 CA) and IL-1ß (-511 C

Distinct cytokine pattern in response to different bacterial pathogens in human brain abscess.

Brain abscess is a focal suppurative process. Host inflammatory response in Gram type and specific bacteria has not been studied in brain abscess. A total of 57 brain abscess patients with monomicrobial infections were studied for Th1 (TNF-α, IFN-γ, IL1-ß), Th2 (IL-4, IL-10) and Th17 (IL-17, IL-23) cytokine response by reverse-transcriptase PCR and ELISA. Th1 and Th17 cytokines were significantly elevated in Gram positive (Staphylococcus aureus and Streptococcus intermedius) and Th2 cytokine (IL-10) in Gram negative (Bacteroides fragilis and Escherichia coli) infections (p<0.05). Cytokine levels were significantly higher in abscess than blood (p<0.001). Elevated levels of several inflammatory cytokines (TNF-α, IFN-γ, IL1-ß, IL-17 and IL-23) were associated with the duration of symptoms; predisposing factors also influenced the levels of several cytokines. The expression of inflammatory cytokines in abscess was influenced by the bacterial pathogen, duration of symptoms and predisposing factors. Local milieu of brain plays significant role in secretion of various cytokines.

Multimodal approach for diagnosis of bacterial etiology in brain abscess.

BACKGROUND AND PURPOSE: Proton magnetic resonance spectroscopy (PMRS) has high sensitivity and specificity for the detection of pyogenic brain abscess and the categorization of bacteria. But the metabolite patterns failed to evaluate the etiology of disease when the culture results are sterile. The aim of the present study is to compare the multimodality techniques viz., conventional culture, MR spectroscopy and 16S rRNA PCR and sequencing for rapid diagnosis of etiology in brain abscess and evaluate the PMRS in culture sterile samples and also demonstrate the sensitivity and specificity of these techniques. METHODS: Thirty five patients underwent MRI on a 3T MRI and in-vivo PMRS for the diagnosis and evaluation of various resonances of metabolites such as lipid (LIP), lactate (LAC), acetate (AC), amino acid (AC), succinate (SUC). Pus was collected for identification of etiologic agents by culture and molecular method. RESULTS: In 35 samples, metabolite patterns were as follows: LIP/LAC/AA, n=17, LIP/LAC/AA/SUC with or without AC, n=17 and LIP/LAC/AA/AC, n=1. Culture showed bacterial growth in 22 samples (18 aerobic/facultative anaerobic, 9 anaerobic) whereas molecular method was detected 26 aerobic/facultative anaerobic, 13 anaerobic, 4 microaerophilic bacteria. Among the 13 sterile samples, molecular method detected 16 microorganisms along with 3 mixed infections and PMRS recognized metabolite patterns as LIP/LAC/AA, n= 5 and LIP/LAC/AA/SUC with or without AC, n=8. The sensitivity of in-vivo PMRS in sterile samples was 100% and 75%, and specificity was 75% and 100% for aerobic and anaerobic organisms respectively. CONCLUSION: Based on metabolite resonances, PMRS can detect slow growing and fastidious organisms and classify them into aerobic and anaerobic bacteria which are difficult to culture by conventional method. It can categorize microorganisms even in culture sterile samples with rational sensitivity and specificity which may allow early choice of targeted therapy.

Evaluation of ELISA, neck muscle, tongue and eyelid examinations for the diagnosis of swine cysticercosis in a highly endemic area of north India.

Swine cysticercosis is very common in the developing countries where pigs are raised. Undercooked measly pork consumption leads to taeniasis; Taenia carriers act as source of human and swine cysticercosis and neurocysticercosis. Diagnosis of swine cysticercosis is important to break the cycle of disease transmission. The present study compared the neck muscle, tongue and eye examinations, and serum ELISA with different preparations (crude lysate, cyst fluid, scolex and cyst wall antigens) of Taenia solium cyst for the diagnosis of swine cysticercosis. Total of 24 pigs initially identified by neck muscle, tongue and eyelid examinations were purchased from local slaughter house and subjected to MRI for confirmation of cysticercosis. Sera from 20 MRI confirmed infected pigs and 50 disease free controls were subjected to ELISA with T. solium cyst antigens. Neck muscle examination was 100% sensitive and 75% specific for the diagnosis of swine cysticercosis, whereas tongue and eye examinations were 70% and 25% sensitive, respectively. ELISA with crude lysate had 85% sensitivity and 98% specificity. ELISA with cyst fluid, scolex and cyst wall antigens showed 70%, 65%, and 45% sensitivity, respectively. The present study showed that neck muscle examination was highly sensitive but less specific, while ELISA with crude antigens had reasonable sensitivity and high specificity for diagnosis of swine cysticercosis. ELISA with crude lysate can be used as a screening tool for swine infection.