Subcutaneous adipose tissue accumulation protects systemic glucose tolerance and muscle metabolism.

The protective effects of lower body subcutaneous adiposity are linked to the depot functioning as a "metabolic sink" receiving and sequestering excess lipid. This postulate, however, is based on indirect evidence. Mechanisms that mediate this protection are unknown. Here we directly examined this with progressive subcutaneous adipose tissue removal. Ad libitum chow fed mice underwent sham surgery, unilateral or bilateral removal of inguinal adipose tissue or bilateral removal of both inguinal and dorsal adipose tissue. Subsequently mice were separated into 5 week chow or 5 or 13 week HFD groups (N = 10 per group). Primary outcome measures included adipocyte distribution, muscle and liver triglycerides, glucose tolerance, circulating adipocytokines and muscle insulin sensitivity. Subcutaneous adipose tissue removal caused lipid accumulation in femoral muscle proximal to excision, however, lipid accumulation was not proportionally inverse to adipose tissue quantity excised. Accumulative adipose removal was associated with an incremental reduction in systemic glucose tolerance in 13 week HFD mice. Although insulin-stimulated pAkt/Akt did not progressively decrease among surgery groups following 13 weeks of HFD, there was a suppressed pAkt/Akt response in the non-insulin stimulated (saline-injected) 13 week HFD mice. Hence, increases in lower body subcutaneous adipose removal resulted in incremental decreases in the effectiveness of basal insulin sensitivity of femoral muscle. The current data supports that the subcutaneous depot protects systemic glucose homeostasis while also protecting proximal muscle from metabolic dysregulation and lipid accumulation. Removal of the "metabolic sink" likely leads to glucose intolerance because of decreased storage space for glucose and/or lipids.

Diet-induced obesity causes visceral, but not subcutaneous, lymph node hyperplasia via increases in specific immune cell populations.

OBJECTIVES: The spatial proximity of adipose depots to secondary lymph nodes allows a unique relation between the two systems. Obesity, predominately visceral adiposity, links to numerous diseases; hence, we postulate that secondary lymphatics within this region contributes to disease risk. MATERIAL AND METHODS: Male C57BL/6 mice were fed standard CHOW (18% kcal fat) or Western diet (45% kcal fat) for 7 weeks. Visceral and subcutaneous lymph nodes and associated adipose depots they occupy were excised. Lymph node morphology and resident immune cell populations were characterized via histopathology, immunofluorescence and flow cytometry. Adipose tissue immune cell populations were also characterized. RESULTS: Obesity caused lymph node expansion, increased viable cell number and deviations in immune cell populations. These alterations were exclusive to visceral lymph nodes. Notably, pro-inflammatory antigen presenting cells and regulatory T cells increased in number in the visceral lymph node. Obesity, however, reduced T regulatory cells in visceral lymph nodes. The visceral adipose depot also had greater reactivity towards HFD than subcutaneous, with a greater percent of macrophages, dendritic and CD8+ T cells. Immune cell number, in both the visceral and subcutaneous, however decreased as adipose depots enlarged. CONCLUSION: Overall, HFD has a greater influence on visceral cavity than the subcutaneous. In the visceral lymph node, but not subcutaneous, HFD-induced obesity decreased cell populations that suppressed immune function while increasing those that regulate/activate immune response.

Inhibition of adipose tissue PPARγ prevents increased adipocyte expansion after lipectomy and exacerbates a glucose-intolerant phenotype.

OBJECTIVES: Adipose tissue plays a fundamental role in glucose homeostasis. For example, fat removal (lipectomy, LipX) in lean mice, resulting in a compensatory 50% increase in total fat mass, is associated with significant improvement in glucose tolerance. This study was designed to further examine the link between fat removal, adipose tissue compensation and glucose homeostasis using a peroxisome proliferator-activated receptor γ (PPAR γ; activator of adipogenesis) knockout mouse. MATERIAL AND METHODS: The study involved PPARγ knockout (FKOγ) or control mice (CON), subdivided into groups that received LipX or Sham surgery. We reasoned that as the ability of adipose tissue to expand in response to LipX would be compromised in FKOγ mice, so would improvements in glucose homeostasis. RESULTS: In CON mice, LipX increased total adipose depot mass (~60%), adipocyte number (~45%) and changed adipocyte distribution to smaller cells. Glucose tolerance was improved (~30%) in LipX CON mice compared to Shams. In FKOγ mice, LipX did not result in any significant changes in adipose depot mass, adipocyte number or distribution. LipX FKOγ mice were also characterized by reduction of glucose tolerance (~30%) compared to shams. CONCLUSIONS: Inhibition of adipose tissue PPARγ prevented LipX-induced increases in adipocyte expansion and produced a glucose-intolerant phenotype. These data support the notion that adipose tissue expansion is critical to maintain and/or improvement in glucose homeostasis.

Increased matrix metalloproteinase 2 activity in the human internal mammary artery is associated with ageing, hypertension, diabetes and kidney dysfunction.

Dysregulation of matrix metalloproteinase (MMP)-2 in the vasculature has been suggested to be associated with increased prevalence of cardiovascular disease and renal injury. In this descriptive study, we hypothesized that arterial MMP-2 activity is elevated in the presence of cardiovascular risk factors such as diabetes, hypertension, smoking and ageing, and that it correlates with the degree of kidney function. MMP-2 activity in internal mammary arteries (n = 37) was measured using gelatinolytic zymography, and cutoffs were determined using sample-derived medians. Patient demographics and clinical data were analyzed, and the estimated glomerular filtration rate (eGFR) was calculated. High MMP-2 activity (>60,000 units) was associated with age, hypertension and diabetes (p = 0.0034, 0.06 and 0.0034, respectively). Multivariate analysis showed that age and diabetes were independent predictors of high MMP-2 activity. There is a trend towards increased MMP-2 activity and reduced eGFR (p = 0.010). The current exploratory work describes that the activity of MMP-2 in the internal mammary artery is correlated with age, hypertension, diabetes and eGFR. It is the first report suggesting that MMP-2 in the arterial vasculature could be the possible mediator crucial in linking the progression of kidney function to cardiovascular disease.

Infliximab improves endothelial dysfunction in systemic vasculitis: a model of vascular inflammation.

BACKGROUND: Endothelial vasomotor dysfunction and markers of systemic inflammation are independent determinants of cardiovascular risk. However, the link between clinical inflammation and endothelial dysfunction is unclear. The aim of this study was to use anti-neutrophil cytoplasmic antibody-associated systemic vasculitis (AASV) as a model of systemic inflammation in which to test the hypothesis that inflammation is associated with endothelial dysfunction and can be reversed with anti-tumor necrosis factor-alpha (TNF-alpha) therapy. METHODS AND RESULTS: Fourteen patients with active AASV and 21 age-matched control subjects were studied. Endothelial function was assessed through the use of forearm plethysmography and related to clinical disease activity: Birmingham Vasculitis Activity Score (BVAS) and serum levels of C-reactive protein (CRP), interleukin-6 (IL-6), and TNF-alpha. The effects of anti-TNF-alpha therapy (infliximab), either alone (n=6) or in combination with standard treatment (n=4), on endothelial function were subsequently determined. Patients had a mean BVAS of 11+/-1, and CRP and IL-6 were higher in the AASV group than in control subjects (34.8+/-10.5 versus 1.6+/-0.2 pg/mL, P<0.001; 9.0+/-0.7 versus 6.7+/-0.6 pg/mL, P=0.02). Forearm blood flow response to acetylcholine (ACh) was reduced in the patients compared with control subjects (P=0.002), but sodium nitroprusside (SNP) responses were not (P=0.3). The response to ACh improved with infliximab treatment (P=0.004) in particular, with infliximab alone (P=0.03). CONCLUSIONS: AASV is associated with endothelial dysfunction. Anti-TNF-alpha therapy, alone or in combination with standard treatment, results in clinical remission, reduced inflammation, and improved endothelium-dependent vasomotor responses.

Inflammation and arterial stiffness in systemic vasculitis: a model of vascular inflammation.

OBJECTIVE: Arterial stiffness, an independent determinant of cardiovascular risk, is regulated by both structural and functional factors, including endothelium-derived nitric oxide. Endothelial dysfunction is associated with acute and chronic systemic inflammation. However, the role of systemic inflammation in arterial stiffening has not been determined. The aim of this study was to investigate the relationship between inflammation and arterial stiffness in patients with antineutrophil cytoplasmic antibody-associated systemic vasculitis (AASV) as a model of systemic inflammation. METHODS: Thirty-one patients with AASV (15 with active disease) and 32 age-matched controls were studied. Pulse wave velocity (PWV) and the augmentation index (AIx) were assessed noninvasively and related to serum levels of C-reactive protein (CRP), interleukin-6, and tumor necrosis factor alpha. RESULTS: In subjects with active disease, the AIx, PWV, and level of CRP were elevated compared with that in controls (mean +/- SEM 31 +/- 3% versus 22 +/- 2% [P = 0.003], 9.2 +/- 0.7 versus 7.5 +/- 0.3 meters/second [P = 0.03], and 16.0 +/- 4.0 versus 1.1 +/- 0.1 mg/liter [P < 0.001], respectively). However, PWV and the AIx were not significantly different between patients with disease in remission and controls (8.0 +/- 0.5 versus 7.5 +/- 0.3 meters/second and 19 +/- 3% versus 22 +/- 2%, respectively). The CRP level was positively correlated with both PWV and the AIx. Multiple regression analysis indicated that age, mean arterial pressure (MAP), and CRP were independently related to PWV, and that age, MAP, CRP, sex, and heart rate were associated with the AIx. CONCLUSION: These data indicate that AASV is associated with increased arterial stiffness, and that stiffness correlates with the degree of active inflammation.

A study of the cumulus-corona cell complex in in-vitro fertilization and embryo transfer; a prognostic indicator of the failure of implantation.

In-vitro morphological changes and proliferation of cells of the cumulus oophorus, in particular cells of the corona radiata, were seen to differ between individuals and between oocytes of the same cohort in an unselected series of 159 IVF cycles. Cell proliferation did not relate to indications for treatment, type and length of ovarian stimulation, age of patient, ovarian response and quality of oocyte, fertilization rate or embryo morphology. A direct relationship, however, was demonstrated between the proliferative capacity of these cells and the incidence of clinical pregnancy. No pregnancies resulted when there was an absence of morphological change or proliferation of these cells. In cycles where the proliferative capacity of these cells varied between oocytes of a single cohort the pregnancy rate was 40% per cycle, and in cycles where cells associated with all oocytes underwent extensive proliferation the pregnancy rate was 49% (P < 0.001). Thus, regardless of the apparent quality of gametes or embryo, no pregnancies arose if the cumulus-corona complex was incapable of replication. We have, therefore, identified two populations of oocytes based on the proliferative capacity of cumulus-corona cells in vitro, one being associated with a failure of implantation.

Dysmyelination in NCTR-Balb/C mouse mutant with a lysosomal storage disorder. Morphological survey.

A morphological survey of the central nervous system of a NCTR-Balb/C mouse afflicted by neurovisceral storage disease was performed. It has been demonstrated that this mutant is characterized by primary dysmyelination, which is evident as early as 12 days of age. The failure of myelin formation in the CNS was shown by histochemical and ultrastructural methods. Inasmuch as neither lipid-containing macrophages nor infiltrating mononuclear cells were apparent, secondary demyelination could be excluded. The multiform ultrastructural appearance of the storage material in the various CNS cell types suggested heterogeneity of the accumulated substances. The storage materials which reacted positively with periodate-Schiff reagent, but not with other histochemical stains, are most likely the accumulated gangliosides and neutral glycosphingolipids identified previously in this mutant's brain. Considering the probable role of cholesterol ester in the early phases of myelinogenesis, in conjunction with the fact that the NCTR-Balb/C mouse carries a defect in the esterification of exogenously derived cholesterol, it is possible that the later metabolite is relevant to the impaired myelin formation.

A lysosomal storage disorder in mice characterized by a dual deficiency of sphingomyelinase and glucocerebrosidase.

Lipid and lysosomal enzyme levels in the tissues of a strain of mice afflicted with an autosomal rescessive neuroviscereal storage disorder were examined. Sphingomyelinase and glucocerebrosidase activities were consistently diminished in a wide variety of tissues obtained from the affected mice. The activities of these enzymes were clearly attenuated in new-born mice, which at this age, were otherwise indistinguishable from littermates and age-matched controls. The deficiency of sphingomyelinase was more pronounced than glucocerebrosidase. There was progressive accumulation of sphingomyelin, glucocerebroside, lactosylceramide and unesterified cholesterol in the tissues of these mice in the postnatal period. Gangliosides GM2 and GM3 accumulated in the brain of the animals, and GM3 and asialo-GM2 were stored in the liver. Furthermore, there was a large increase in the quantity of hepatic bis(monoacylglycero)phosphate. The accumulation of lipids was parallelled by a progressive elevation in the activity of several lysosomal hydrolases in various tissues. Heterozygous mice were biochemically indistinguishable from normal controls. The phenotypic manifestations in these metabolically mutated animals are compared with those in Niemann-Pick disease and Gaucher's disease in humans.

Penetration of gown material by organisms from the surgical team.

The routes by which viable organisms shed by the surgical team reach the wound are not yet fully understood. Bacteriologic studies show that shedding is greater in surgeons than their assistants or scrub nurses, and is increased by activity and temperature, but is primarily related to the individual's shedding characteristics. Comparison of the ability of 3 types of cotton gowns to contain the surgical team's bacterial effluent shows that the body exhaust system gowns developed by Charnley are superior to more conventional gowns. It is clear that viable organisms can penetrate very closely woven Ventile (pore size 10 microns) as well as balloon cloth (pore size 50 microns). Ventile used without a body exhaust system does not appear to increase gown efficiency. Penetration of gown material by organisms from the surgical team is responsible for 20% of wound contamination. The gown glove cuff junction is an important leakage point for organisms shed by the surgical team. A newly designed "mitt" cuff more effectively seals this area than the conventional stockinette cuff.

Microwave absorption by normal and tumor cells.

Energy levels exist in mammalian cells which result in the absorption of microwaves between 66 and 76 gigahertz. Many of these energy levels occur when water molecules associate with the various chemical groups of macromolecules. The absorption spectra of cells between 66 and 76 gigahertz, therefore, is determined by the structure of in vivo water lattices, and these seem to reflect indirectly the structural makeup of macromolecules or macromolecular complexes. Tumor cells absorb 66-, 68-, and 70-gigahertz microwaves less strongly and 69-, 72-, and 75-gigahertz microwaves more strongly than normal cells. These differences in the strength of attenuation at each frequency suggest that either the ratio of RNA to DNA or the relative number of certain types of chemical groups in tumor cells is different from that in normal cells.