Reumatismo. 2012; 63(4): 238-45
Grassi W, De Angelis R

Gout is a metabolic disease characterized by hyperuricemia and the deposition of monosodium urate (MSU) crystals in the joints and soft tissues, consisting of a self-limited acute phase characterized by recurrent attacks of synovitis and a chronic phase in which inflammatory and structural changes of the joints and periarticular tissues may lead to persistent symptoms. Acute gout is characterized by a sudden monoarthritis of rapid onset, with intense pain, mostly affecting the big toe (50% of initial attacks), the foot, ankle, midtarsal, knee, wrist, finger, and elbow. Acute flares also occur in periarticular structures, including bursae and tendons. The presence of characteristic MSU crystals in the joint fluid, appearing needle-like and showing strong negative birefringence by polarized microscopy, is pivotal to confirm the diagnosis of gout. The time interval separating the first attack from subsequent episodes of acute synovitis may be widely variable, ranging from a few days to several years. During the period between acute attacks the patient is asymptomatic even if MSU deposition may continue to increase silently. The factors that control the rate, location, and degree of ongoing deposition in gouty patients are not well defined. Chronic gout is the natural evolution of untreated hyperuricemia in patients with gouty attacks followed by pain-free intercritical periods. It is characterized by the deposition of solid MSU crystal aggregates in a variety of tissues including joints, bursae and tendons. Tophi can occur in a variety of locations including the helix of the ear, olecranon bursa, and over the interphalangeal joints. Their development is usually related with both the degree and the duration of hyperuricemia. About 20% of patients with gout have urinary tract stones and can develop an interstitial urate nephropathy. There is a strong association between hyperuricaemia and the metabolic syndrome (the constellation of insulin resistance, hypertension, obesity and dyslipidaemia), and gouty patients often have a medical history of kidney disease, diabetes mellitus and signs of vascular illness such as coronary artery disease, heart failure and stroke, resulting with a poor overall quality of life.

Ann Clin Psychiatry. 2012 Feb; 24(1): 69-81
McIntyre RS, Alsuwaidan M, Goldstein BI, Taylor VH, Schaffer A, Beaulieu S, Kemp DE

One goal of the Canadian Network for Mood and Anxiety Treatments (CANMAT) is to develop evidence-based and best practice educational programs and recommendations. Our group conducted a comprehensive literature review to provide evidence-based recommendations for treating metabolic comorbidity in individuals with major depressive disorder (MDD) and bipolar disorder (BD).We searched PubMed for all English-language articles published January 1966 to November 2010 using BD and MDD cross-referenced with metabolic syndrome, obesity, diabetes mellitus, hypertension, and dyslipidemia. That search was augmented by a review of articles reporting outcomes of an intervention targeting components of metabolic syndrome in individuals with MDD or BD.Consensus exists for the recommendation that individuals with MDD and BD should be routinely screened for risk factors that increase risk for metabolic syndrome. For excess weight, the best-studied pharmacologic approaches are metformin and topiramate, with emerging evidence for liraglutide and modafinil. For binge eating disorder, the best evidence in mood disorders was for cognitive-behavioral therapy as well as topiramate, zonisamide, and in select cases selective serotonin reuptake inhibitors. For dysglycemia, dyslipidemia, and hypertension, evidence supports cognitive-behavioral interventions and anti-diabetic, antilipidemic, and antihypertensive treatments.Comprehensive care of individuals with mood disorders should include routine evaluation of the risk and presence of metabolic syndrome and its components. Systematic evaluation of preventative and targeted treatments of metabolic syndrome in mood disorder populations is insufficient.

Front Genet. 2011; 2: 71
Leamy LJ, Gordon RR, Pomp D

The genetic basis of quantitative traits such as body weight and obesity is complex, with several hundred quantitative trait loci (QTLs) known to affect these and related traits in humans and mice. It also has become increasingly evident that the single-locus effects of these QTLs vary considerably depending on factors such as the sex of the individuals and their dietary environment, and we were interested to know whether this context-dependency also applies to two-locus epistatic effects of QTLs as well. We therefore conducted a genome scan to search for epistatic effects on 13 different weight and adiposity traits in an F(2) population of mice (created from an original intercross of the FVB strain with M16i, a polygenic obesity model) that were fed either a control or a high-fat diet and half of which harbored a transgene (PyMT) that caused the development of metastatic mammary cancer. We used a conventional interval mapping approach with SNPs to scan all 19 autosomes, and found extensive epistasis affecting all of these traits. More importantly, we also discovered that the majority of these epistatic effects exhibited significant interactions with sex, diet, and/or presence of PyMT. Analysis of these interactions showed that many of them appeared to involve QTLs previously identified as affecting these traits, but whose single-locus effects were variously modified by two-locus epistatic effects of other QTLs depending on the sex, diet, or PyMT environment. It was concluded that this context-dependency of epistatic effects is an important component of the genetic architecture of complex traits such as those contributing to weight and obesity.

Front Genet. 2011; 2: 27
Alfaradhi MZ, Ozanne SE

Metabolic disorders have seen an increased prevalence in recent years in developed as well as developing countries. While it is clear lifestyle choices and habits have contributed to this epidemic, mounting evidence suggests the nutritional milieu during critical stages of development in early life can "program" individuals to develop the metabolic syndrome later in life. Extensive epidemiological data presents an association between maternal obesity and nutrition during pregnancy and offspring obesity, and a number of animal models have been established in order to uncover the underlying mechanisms contributing to the programming of physiological systems. It is hard to distinguish the causal factors due to the complex nature of the maternal-fetal relationship; however, in order to develop adequate prevention strategies it is vital to identify which maternal factor(s) - be it the diet, diet-induced obesity or weight gain - and at which time during early development instigate the programmed phenotype. Curtailing the onset of obesity at this early stage in life presents a promising avenue through which to stem the growing epidemic of obesity.

Front Genet. 2011; 2: 24
Symonds ME, Sebert S, Budge H

The prevalence of obesity continues to increase particularly in developed countries. To establish the primary mechanisms involved, relevant animal models which track the developmental pathway to obesity are required. This need is emphasized by the substantial rise in the number of overweight and obese children, of which a majority will remain obese through adulthood. The past half century has been accompanied with unprecedented transitions in our lifestyle. Each of these changes substantially contributes to enhancing our capacity to store energy into adipose tissues. The complex etiology of adiposity is critical as a majority of models investigating obesity utilize a simplistic high-fat/low-carbohydrate diet, fed over a short time period to comparatively young inbred animals maintained in fixed environment. The natural history of obesity is much more complex involving many other mechanisms and this type of challenge may not be the optimal experimental intervention. Such processes include changes in adipose tissue composition with time and the transition from brown to white adipose tissue. Brown adipose tissue, due its unique ability to rapidly produce large amounts of heat could have a pivotal role in energy balance and is under epigenetic regulation mediated by the histone H3k9-specific demethylase Jhdma2a. Furthermore, day length has a potential role in determining endocrine and metabolic responses in brown fat. The potential to utilize novel models and interventions across a range of animal species in adipose tissue development may finally start to yield sustainable strategies by which excess fat mass can, at last, be avoided in humans.

Front Genet. 2011; 2: 16
Zielke LG, Bortfeldt RH, Tetens J, Brockmann GA

The gene encoding the brain-derived neurotrophic factor (BDNF) has been repeatedly associated with human obesity. As such, it could also contribute to the regulation of energy partitioning and the amount of secreted milk fat during lactation, which plays an important role in milk production in dairy cattle. Therefore, we performed an association study using estimated breeding values (EBVs) of bulls and yield deviations of German Holstein dairy cattle to test the effect of BDNF on milk fat yield (FY). A highly significant effect (corrected p-value = 3.362 × 10(-4)) was identified for an SNP 168 kb up-stream of the BDNF transcription start. The association tests provided evidence for an additive allele effect of 5.13 kg of fat per lactation on the EBV for milk FY in bulls and 6.80 kg of fat of the own production performance in cows explaining 1.72 and 0.60% of the phenotypic variance in the analyzed populations, respectively. The analyses of bulls and cows consistently showed three haplotype groups that differed significantly from each other, suggesting at least two different mutations in the BDNF region affecting the milk FY. The FY increasing alleles also had low but significant positive effects on protein and total milk yield which suggests a general role of the BDNF region in energy partitioning, rather than a specific regulation of fat synthesis. The results obtained in dairy cattle suggest similar effects of BDNF on milk composition in other species, including man.

Genes Dev. 2012 Feb 1; 26(3): 259-70
Krishnan J, Danzer C, Simka T, Ukropec J, Walter KM, Kumpf S, Mirtschink P, Ukropcova B, Gasperikova D, Pedrazzini T, Krek W

Dietary obesity is a major factor in the development of type 2 diabetes and is associated with intra-adipose tissue hypoxia and activation of hypoxia-inducible factor 1α (HIF1α). Here we report that, in mice, Hif1α activation in visceral white adipocytes is critical to maintain dietary obesity and associated pathologies, including glucose intolerance, insulin resistance, and cardiomyopathy. This function of Hif1α is linked to its capacity to suppress β-oxidation, in part, through transcriptional repression of sirtuin 2 (Sirt2) NAD(+)-dependent deacetylase. Reduced Sirt2 function directly translates into diminished deacetylation of PPARγ coactivator 1α (Pgc1α) and expression of β-oxidation and mitochondrial genes. Importantly, visceral adipose tissue from human obese subjects is characterized by high levels of HIF1α and low levels of SIRT2. Thus, by negatively regulating the Sirt2-Pgc1α regulatory axis, Hif1α negates adipocyte-intrinsic pathways of fatty acid catabolism, thereby creating a metabolic state supporting the development of obesity.

Circulation. 2012 Feb 1;
Kim JK

Insulin resistance is a major characteristic of type 2 diabetes and develops in multiple organs including skeletal muscle, liver, adipose tissue, and heart(1). Insulin resistance is caused by obesity and therefore establishes an important causal relationship between obesity and type 2 diabetes(2). Insulin resistance also develops in aging, but this process is less well understood. Obesity is a complex physiological state with alterations in lipid metabolism, dysregulated production of hormones, ectopic accumulation of fat, mitochondrial dysfunction, and chronic low-grade inflammation(3,4). All of these abnormalities may independently cause insulin resistance and affect glucose homeostasis, which make insulin resistance as equally complex as obesity itself. (SELECT FULL TEXT TO CONTINUE).

Circulation. 2012 Feb 1;
Hasegawa Y, Saito T, Ogihara T, Ishigaki Y, Yamada T, Imai J, Uno K, Gao J, Kaneko K, Shimosawa T, Asano T, Fujita T, Oka Y, Katagiri H

BACKGROUND: Nuclear factor-kappa B (NF-κB) signaling plays critical roles in physiological and pathological processes, such as responses to inflammation and oxidative stress. METHODS AND RESULTS: To examine the role of endothelial NF-κB signaling in vivo, we generated transgenic mice expressing dominant-negative IκB under the Tie2 promoter/enhancer (E-DNIκB mice). These mice exhibited functional inhibition of NF-κB signaling specifically in endothelial cells. Although E-DNIκB mice displayed no overt phenotypic changes when young and lean, they were protected from the development of insulin resistance associated with obesity, whether diet- or genetically-induced. Obesity-induced macrophage infiltration into adipose tissue and plasma oxidative stress markers were decreased, while blood flow and mitochondrial contents in muscle and active-phase locomotor activity were increased in E-DNIκB mice. In addition to inhibition of obesity-related metabolic deteriorations, blockade of endothelial NF-κB signaling prevented age-related insulin resistance and vascular senescence and, notably, prolonged lifespan. These anti-aging phenotypes were also associated with decreased oxidative stress markers, increased muscle blood flow, enhanced active-phase locomotor activity and aortic up-regulations of mitochondrial sirtuin-related proteins. CONCLUSIONS: The endothelium plays important roles in obesity- and age-related disorders through intracellular NF-κB signaling, thereby, ultimately, impacting lifespan. Endothelial NF-κB signaling is a potential target for treating the metabolic syndrome as well as for anti-aging strategies.

Eur J Nutr. 2012 Feb 3;
Silva DA, Petroski EL, Peres MA

PURPOSE: This study proposes to examine the accuracy of four anthropometric indexes of obesity to identify the presence of hypertension and assess differences in the estimation and strength of effect measures of the association between each anthropometric measure and hypertension in Brazilian adults. METHODS: A population-based cross-sectional study was carried out with a sample of 1,720 adults from Florianópolis, Brazil. Receiver operating characteristic (ROC) curves were performed to identify the sensitivity and specificity of the best cutoff values for anthropometric indexes (body mass index-BMI, waist circumference-WC, waist-to height ratio-WHtR and conicity index-C-index) for prediction of hypertension. The associations between anthropometric indexes and hypertension were analyzed by Poisson regression expressed as Prevalence Ratios (95% CI) adjusted for socio-demographic variables, health behavior, height, and anthropometric indexes. RESULTS: Of the four anthropometric indexes studied, BMI, WC, and WHtR were found to have the largest areas under the ROC curve relative to hypertension in both sexes. The cutoff values in women and men associated with presence of hypertension were BMI of 24.9 and 24.6 kg/m², WC of 86.2 and 89.5 cm, WHtR of 0.49 and 0.50, and C-index of 1.15 and 1.18, respectively. WC and BMI had greater magnitude of association with presence of hypertension, adjusting for socio-demographic variables, health behavior, height, and anthropometric indexes in women and men, respectively. CONCLUSIONS: Anthropometric indexes provide an effective, simple, inexpensive, and non-invasive means for a first-level screening for hypertension.

Surg Endosc. 2012 Feb 1;
Romero F, Nicolau J, Flores L, Casamitjana R, Ibarzabal A, Lacy A, Vidal J

BACKGROUND: Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGBP) are associated with similar type 2 diabetes mellitus (T2DM) resolution rates for morbidly obese subjects. However, the mechanisms underlying the resolution of T2DM after SG have not been clarified to date. This study aimed to compare the early changes in gastrointestinal hormones involved in insulin and glucagon secretion in morbidly obese T2DM subjects undergoing SG or RYGBP. METHODS: This prospective study investigated 12 subjects with T2DM who had undergone SG (n = 6) or RYGBP (n = 6). Five body mass index (BMI)-matched obese non-diabetic subjects and five BMI-matched obese diabetic subjects served as control subjects. Glucose, insulin, glucagon, glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and GLP-2 were determined after a standardized mixed liquid meal before surgery and 6 weeks afterward. RESULTS: After 6 weeks, five of the six subjects in each surgical group presented with T2DM remission, although the area under the curve (AUC)(0-120) of glucose was greater than that of the non-diabetic control subjects (P < 0.01). Postsurgically, the indices of insulin and glucagon secretion were comparable between the two surgical groups. The AUC(0-120) of GLP-1 (P < 0.05) and GLP-2 (P < 0.05) was significantly and comparably enlarged after SG and RYGB. The postsurgical GIP response was significantly associated with the glucagon response throughout the meal test (ρ = 0.747; P < 0.01). CONCLUSIONS: The data show that in a cohort of morbidly obese T2DM subjects, SG and RYGBP are associated with an early improvement in glucose tolerance, similar changes in insulin and glucagon secretion, and a similar GLP-1, GIP, and GLP-2 response to a standardized mixed liquid meal.

Curr Hypertens Rep. 2012 Feb 2;
Thethi T, Kamiyama M, Kobori H

Obesity is a risk factor for type 2 diabetes mellitus (DM) and is associated with chronic kidney disease. Activation of the renin-angiotensin-aldosterone system (RAAS) is common in obesity. The RAAS is an important mediator of hypertension. Mechanisms involved in activation of the RAAS in obesity include sympathetic stimulation, synthesis of adipokines in the RAAS by visceral fat, and hemodynamic alterations. The RAAS is known for its role in regulating blood pressure and fluid and electrolyte homeostasis. The role of local/tissue RAAS in specific tissues has been a focus of research. Urinary angiotensinogen (UAGT) provides a specific index of the intrarenal RAAS. Investigators have demonstrated that sex steroids can modulate the expression and activity of the different components of the intrarenal RAAS and other tissues. Our data suggest that obese women without DM and hypertension have significantly higher levels of UAGT than their male counterparts. These differences existed without any background difference in the ratio of microalbumin to creatinine in the urine or the estimated glomerular filtration rate, raising a question about the importance of baseline gender differences in the endogenous RAAS in the clinical spectrum of cardiovascular diseases and the potential utility of UAGT as a marker of the intrarenal RAAS. Animal studies have demonstrated that modifying the amount of angiotensin, the biologically active component of the RAAS, directly influences body weight and adiposity. This article reviews the role of the RAAS in renal injury seen in obesity and the metabolic syndrome.