Adipose immunohistochemistry for cell size and fibrosis.

<p>Adipose tissue was stained for elastin, as described in Methods. A. Elastin stain, illustrating the outline of the adipocytes, elastin (black stain) and areas of fibrosis (pink). B. Identification of adipocytes using the image analysis software, and the assignment of adipocyte area to the cells. C. Enhancement of image to bring out elastin (green). D. Enhancement of image to bring out collagens (red).</p

Pioglitazone Treatment Reduces Adipose Tissue Inflammation through Reduction of Mast Cell and Macrophage Number and by Improving Vascularity

<div><p>Context and Objective</p><p>Adipose tissue in insulin resistant subjects contains inflammatory cells and extracellular matrix components. This study examined adipose pathology of insulin resistant subjects who were treated with pioglitazone or fish oil.</p><p>Design, Setting and Participants</p><p>Adipose biopsies were examined from nine insulin resistant subjects before/after treatment with pioglitazone 45 mg/day for 12 weeks and also from 19 subjects who were treated with fish oil (1,860 mg EPA, 1,500 mg DHA daily). These studies were performed in a clinical research center setting.</p><p>Results</p><p>Pioglitazone treatment increased the cross-sectional area of adipocytes by 18% (p = 0.01), and also increased capillary density without affecting larger vessels. Pioglitazone treatment decreased total adipose macrophage number by 26%, with a 56% decrease in M1 macrophages and an increase in M2 macrophages. Mast cells were more abundant in obese versus lean subjects, and were decreased from 24 to 13 cells/mm² (p = 0.02) in patients treated with pioglitazone, but not in subjects treated with FO. Although there were no changes in total collagen protein, pioglitazone increased the amount of elastin protein in adipose by 6-fold.</p><p>Conclusion</p><p>The PPARγ agonist pioglitazone increased adipocyte size yet improved other features of adipose, increasing capillary number and reducing mast cells and inflammatory macrophages. The increase in elastin may better permit adipocyte expansion without triggering cell necrosis and an inflammatory reaction.</p></div

Quantitation of images pre and post pioglitazone.

<p>A. Cell size from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102190#pone-0102190-g001" target="_blank">Figure 1B</a> was measured in all adipocytes from a whole slide scan, representing 8000–12000 cells, and the distribution of cell cross-sectional area relative frequency is shown before and after pioglitazone treatment. B. Average adipocytes cross-sectional area. C. Analysis of images illustrated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102190#pone-0102190-g001" target="_blank">Figure 1D</a> for overall collagen. D. Analysis of images illustrated in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0102190#pone-0102190-g001" target="_blank">Figure 1C</a> for elastin. *p<0.05 vs pre-pioglitazone.</p

Baseline characteristics of study subjects.

<p>Baseline characteristics of study subjects.</p

Presentation_1.PDF

<p>Natural killer (NK) lymphocyte-mediated cytotoxicity and cytokine secretion control infections and cancers, but these crucial activities decline with age. NK cell development, homeostasis, and function require IL-15 and its chaperone, IL-15 receptor alpha (IL-15Rα). Macrophages and dendritic cells (DC) are major sources of these proteins. We had previously postulated that additional IL-15 and IL-15Rα is made by skeletal muscle and adipose tissue. These sources may be important in aging, when IL-15-producing immune cells decline. NK cells circulate through adipose tissue, where they may be exposed to local IL-15. The objectives of this work were to determine (1) if human muscle, subcutaneous adipose tissue (SAT), and visceral adipose tissue (VAT) are sources of IL-15 and IL-15 Rα, and (2) whether any of these tissues correlate with NK cell activity in elderly humans. We first investigated IL-15 and IL-15Rα RNA expression in paired muscle and SAT biopsies from healthy human subjects. Both tissues expressed these transcripts, but IL-15Rα RNA levels were higher in SAT than in skeletal muscle. We also investigated tissue obtained from surgeries and found that SAT and VAT expressed equivalent amounts of IL-15 and IL-15Rα RNA, respectively. Furthermore, stromal vascular fraction cells expressed more IL-15 RNA than did adipocytes. To test if these findings related to circulating IL-15 protein and NK cell function, we tested 50 healthy adults aged > 70 years old. Plasma IL-15 levels significantly correlated with abdominal VAT mass in the entire cohort and in non-obese subjects. However, plasma IL-15 levels did not correlate with skeletal muscle cross-sectional area and correlated inversely with muscle strength. Plasma IL-15 did correlate with NK cell cytotoxic granule exocytosis and with CCL4 (MIP-1β) production in response to NKp46-crosslinking. Additionally, NK cell responses to K562 leukemia cells correlated inversely with muscle strength. With aging, immune function declines while infections, cancers, and deaths increase. We propose that VAT-derived IL-15 and IL-15Rα is a compensatory NK cell support mechanism in elderly humans.</p

An <em>ACACB</em> Variant Implicated in Diabetic Nephropathy Associates with Body Mass Index and Gene Expression in Obese Subjects

<div><p>Acetyl coenzyme A carboxylase B gene (<i>ACACB</i>) single nucleotide polymorphism (SNP) rs2268388 is reproducibly associated with type 2 diabetes (T2DM)-associated nephropathy (DN). <i>ACACB</i> knock-out mice are also protected from obesity. This study assessed relationships between rs2268388, body mass index (BMI) and gene expression in multiple populations, with and without T2DM. Among subjects without T2DM, rs2268388 DN risk allele (T) associated with higher BMI in Pima Indian children (n = 2021; p-additive = 0.029) and African Americans (AAs) (n = 177; p-additive = 0.05), with a trend in European Americans (EAs) (n = 512; p-additive = 0.09), but not Germans (n = 858; p-additive = 0.765). Association with BMI was seen in a meta-analysis including all non-T2DM subjects (n = 3568; p-additive = 0.02). Among subjects with T2DM, rs2268388 was not associated with BMI in Japanese (n = 2912) or EAs (n = 1149); however, the T allele associated with higher BMI in the subset with BMI≥30 kg/m² (n = 568 EAs; p-additive = 0.049, n = 196 Japanese; p-additive = 0.049). Association with BMI was strengthened in a T2DM meta-analysis that included an additional 756 AAs (p-additive = 0.080) and 48 Hong Kong Chinese (p-additive = 0.81) with BMI≥30 kg/m² (n = 1575; p-additive = 0.0033). The effect of rs2268388 on gene expression revealed that the T risk allele associated with higher <i>ACACB</i> messenger levels in adipose tissue (41 EAs and 20 AAs with BMI>30 kg/m²; p-additive = 0.018) and ACACB protein levels in the liver tissue (mixed model p-additive = 0.03, in 25 EA bariatric surgery patients with BMI>30 kg/m² for 75 exams). The T allele also associated with higher hepatic triglyceride levels. These data support a role for <i>ACACB</i> in obesity and potential roles for altered lipid metabolism in susceptibility to DN.</p> </div

Association of rs2268388 with BMI in non-diabetic subjects.

<p>Association of rs2268388 with BMI in non-diabetic subjects.</p

Liver ACACB expression by rs2268388.

<p>Liver ACACB expression by rs2268388.</p

Association of rs2268388(C/T) with BMI in full-heritage Pima Indian longitudinal cohort.

<p>model 1: > = 1 nondiabetic exam age <18 and subsequently developed DM; total n = 642; total exam N = 5321;</p><p>P values were adjusted for age, gender, sibship, and repeated exams (matrix: autoregressive; additive genetic model).</p><p>model 2: All individuals- all examinations; total n = 3197; total exam N = 19385;</p><p>P values were adjusted for age, gender, sibship, diabetic status, duration of diabetes, and repeated exams (matrix: autoregressive; additive genetic model).</p><p>T allele is defined as risk allele for higher BMI z-score.</p><p>n_CC, n_CT, n_TT: number of individuals in each genotypic group. N_exams: number of exams.</p

Demographic data of the study cohorts.

<p>EA: European American; AA: African American.</p>*<p>The analysis used age & sex standardized z scores (mean: 0.288±1.04). Mean shown is mean of max z-scores converted to BMI units using mean & SD of 12 year-old females.</p>**<p>Age shown is age at max BMI z-score; not necessarily same as age at max BMI.</p>***<p>max BMI from age >15 yrs. N = 637 since 5 kids had no exams after age 15.</p