Environmental Chemicals That Accumulate in Fat

Summary

A crucial factor in evaluating the risk of dioxins, and related endocrine disruptor compounds (dioxins for short) in the human population is the accumulation of these chemicals in the human body. Human data on tissue background levels is extremely limited, and there are no studies in UK populations, although there are several European studies looking at blood levels of dioxins. Adipose tissue concentrations were 139 ng of TEQ (total dioxin-like compounds) per kg lipid weight (5.4 ± 4.6 ng of TCDD per kg lipid weight). However, given the different dietary habits of Japanese populations, compared to European populations, these estimates may differ considerably from UK values. Thus determining human tissue concentrations of dioxins is an important issue for assessing the risk to public health from these compounds, and this information is currently lacking for European populations. This information will also guide and inform the necessity fro continued measures to reduce the environmental dioxin levels in the UK.

Aims

Primary outcomes:

1. Investigation of the toxicodynamics of/dioxin distribution in adipose of a morbidly obese and comparative control population
2. Characterisation of the burden of dioxins in liver and adipose tissue, and the relationship with blood levels of dioxins, in a UK population

Secondary outcome:

Determining whether bariatric surgery-induced weight loss causes an increase in tissue concentration of dioxin-like compounds

The primary aims of this study will yield useful information to refine the risk assessment process for the obese population.

Experimental Methodology This proposal seeks to examine thirty non-obese patients taking liver (500mg) and adipose tissue (visceral and subcutaneous: 40g each) samples at the time of gastric/abdominal surgery; and thirty obese patients, taking liver (500mg) and adipose tissue (visceral and subcutaneous: 40g each) samples at the time of undertaking Roux -en-y bariatric surgery. Weight and bioimpedance and a food diary will be performed prior to surgery.

A further body weight and bioimpedance will be undertaken at 3, 6, 9 and 12 months from the obese population. A subcutaneous adipose biopsy will be taken under local anaesthetic from these individuals at after bariatric surgery (minimum of 10% body weight loss). A record of weight loss since bariatric surgery will documented with the change in body composition. The statistical power for seeing an effect of gastroplasty, assuming a coefficient of variation of TEQ measurements of 75% and an increase in TEQ of two-fold, is 90% at P\<0.05 for a population of thirty individuals.

Should subjects need additional surgery (eg. cholecystectomy, diagnostic laproscopy) either as a consequence of bariatric surgery or for any other reasons during the 24 month following initial operation, a liver biopsy and visceral fat biopsy will be taken during the future surgery. If subjects undergo abdominal wall surgeries (eg. Apronectomy, ventral hernia repair) in the 24 months following initial bariatric surgery, an subcutaneous fat biopsy will be taken during the future surgery.

Conditions

• Obesity

Interventions

PROCEDURE

Bariatric surgery

Roux-en-Y surgery

Sponsors & Collaborators

• University of Hull

  collaborator OTHER

• Hull University Teaching Hospitals NHS Trust

  lead OTHER_GOV

Principal Investigators

• Thozhukat Sathyapalan · Hull University Teaching Hospitals NHS Trust

Study Design

Allocation

NON_RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2012-10-12

Primary Completion

2015-12-30

Completion

2016-01-30

Countries

• United Kingdom

Study Locations