Lymphatic vessels in human adipose tissue.

Despite being considered present in most vascularised tissues, lymphatic vessels have not been properly shown in human adipose tissue (AT). Our goal in this study is to investigate an unanswered question in AT biology, regarding lymphatic network presence in tissue parenchyma. Using human subcutaneous (S-) and visceral (V-) AT samples with whole mount staining for lymphatic specific markers and three-dimensional imaging, we showed lymphatic capillaries and larger lymphatic vessels in the human VAT. Conversely, in the human SAT, microcirculatory lymphatic vascular structures were rarely detected and no initial lymphatics were found.

Microparticles derived from obese adipose tissue elicit a pro-inflammatory phenotype of CD16+, CCR5+ and TLR8+ monocytes.

Macrophage infiltration into adipose tissue (AT) is a hallmark of the chronic inflammatory response in obesity and is supported by an intense monocyte migration towards AT. Although it has been detected an increased proportion of circulating CD16+ monocyte subsets in obese subjects, the mechanisms underlying this effect and the contribution of these cells to the inflamed profile of obese AT are still poorly understood. We investigated whether factors secreted by human obese omental AT could polarize monocytes to CD16+ enriched phenotype, and how these changes could modify their migratory capacity towards adipose tissue itself. We show that explants of human obese omental AT, obtained during bariatric surgery, released higher levels of MIP1-α, TNFα, leptin and also VEGF, together with increasing amounts of microparticles (MP), when compared to explants of lean subcutaneous AT. A higher content of circulating MP derived from preadipocytes and leukocytes was also detected in plasma of obese subjects. Conditioned media or MP released from obese omental AT increased CD16 and CCR5 expression on CD14+CD16- monocytes and augmented their migratory capacity towards the conditioned media from obese omental AT, itself. This effect was inhibited when MIP1-α was neutralized. Additionally, we demonstrate that MP derived from obese omental AT carry and transfer TLR8 to monocytes, thus triggering an increase in CD16 expression in those cells. Our data shows a positive feedback loop between blood monocytes and obese omental AT, which releases chemotactic mediators and TLR8-enriched MP, thus inducing an up-regulation of CD16+ monocytes, favoring leukocyte infiltration in the obese omental AT.

[Analysis of the dumping syndrome on morbid obese patients submitted to Roux en Y gastric bypass]. / Avaliação da síndrome de dumping em pacientes obesos mórbidos submetidos à operação de bypass gástrico com reconstrução em Y de Roux.

OBJECTIVE: The objective of this research was to determine the real prevalence and characteristics of dumping syndrome in a series of cases submitted to laparoscopic Roux-en-Y gastric bypass for morbid obesity. METHODS: We assessed dumping symptoms in 34 patients who had undergone that procedure; they filled a questionnaire, which included the dumping clinical diagnosis score proposed by Sigstad. RESULTS: regarding patients' complaints, dumping prevalence was 44%. This number increased to 76% when applying the Sigstad's score. The most frequent symptoms were 'need for lying down' (88%), fatigue (69%) and sleepiness (69%). Only 28% of the dumpers felt incapable of performing everyday activities. There was no difference in weight loss percentage between dumpers and non-dumpers. CONCLUSION: The Sigstad score is an usefull tool for the diagnostic of dumping, but a critic vision must be adopted when using in patients submitted to the Roux en Y gastric bypass. The dumping syndrome was frequent in this group, although usually under-diagnosed; it neither hampers patients' everyday activities considerably, nor helps in the weight-loosing process.