Thursday, January 10, 2013

How deadly peanut allergies can be cured... with peanuts: Holding tiny dose under tongue 'can build tolerance'

I have been saying for ages that peanuts are the cure for peanut allergy

A new treatment could help peanut allergy sufferers get over their potentially deadly intolerance to the popular pub snack.

Trials of sublingual immunotherapy treatments, where patients are given doses of allergens in gradually increasing amounts, suggest the technique could one day be used as a cure for the allergy.

However, experts carried out the tests under strict conditions and have warned people not to try a similar experiment themselves.

Around one in a 100 people in the U.S. and UK is allergic to peanuts, and reactions range from mere watery eyes to potentially fatal anaphylactic shock.

For sufferers even eating a tiny amount of peanut can lead to a deadly reaction. Many must carry around special medicines like epinephrine-containing pens for emergency treatment in case they eat contaminated food.

The prevalence of peanut allergy is increasing, however there is as yet no clinical treatment available for sufferers other than strict dietary elimination.

New research published in the the Journal of Allergy and Clinical Immunology this month however shows that giving patients gradually increasing doses of a liquid containing peanut powder could help them to build up a tolerance.

The patients first hold the liquid under the tongue for 2 minutes and then swallow it.

Dr Wesley Burks, a professor at the University of North Carolina School of Medicine, said the results of the research were 'encouraging'.  'The immune response was stronger than we thought it might be, and the side effects of this treatment were relatively small,' he said,  'However, the magnitude of the therapeutic effect was somewhat less than we had anticipated. That's an issue we plan to address in future studies.'

Dr Burks and Dr David Fleischer, of National Jewish Health in Denver, Colorado, recruited 40 peanut allergy sufferers aged between 12 and 37, and randomly gave them either daily peanut sublingual therapy or a placebo.

All were given a baseline oral food challenge of up to 2g of peanut powder to test how much peanut powder they could consume without symptoms.

After 44 weeks, all were given a second oral food challenge.  Those who were able to consume either 5g, or at least 10-fold more peanut powder than their baseline amount, were considered to be responders (i.e., desensitised to peanut).

At 44 weeks, 70 per cent of those who received peanut therapy were responders, compared to 15 per cent of those who were given the placebo.

Among the responders, the median amount of peanut powder they could successfully consume without symptoms increased from 3.5 to 496 milligrams.

After 68 weeks, that amount increased significantly, to 996 milligrams.

Of 10,855 peanut doses given through week 44 of the study, 63.1 per cent were symptom-free. When oral and pharyngeal symptoms were excluded from the analysis, 95.2 per cent of doses were symptom-free.

The study concluded that peanut sublingual therapy safely induced desensitisation in a majority of participants compared to a placebo, and that the longer that treatment continued the more peanut powder they could safely eat.

However, Dr Burks cautions, this is not a treatment that people should try on their own.

For now it's a treatment that should only be given by medical professionals in a carefully monitored clinical trial, he said.


Are our genes to blame? Obesity has 'very strong' genetic component, claim researchers

And I have been saying this for ages too.  And the evidence is not limited to mice

Genes are largely to blame for bulging waistlines, a study has found.  While diet plays a key role in obesity, some people are programmed to get fat easily, research from the US suggests.

Although the work focused on mice, it is believed to be just as relevant to humans.

Lead scientist Dr Brian Parks, from the University of California at Los Angeles (UCLA), said: 'Our research demonstrates that body-fat responses to high-fat, high-sugar diets have a very strong genetic component, and we have identified several genetic factors potentially regulating these responses.

'We found that obesity has similar genetic signatures in mice and humans, indicating the mice are a highly relevant model system to study obesity.

'Overall, our work has broad implications concerning the genetic nature of obesity and weight gain.'

Dramatic increases in obesity over the past few decades have been linked to high-calorie sugar and fat-rich diets as well as sedentary 'couch potato' lifestyles.

But the new research indicates that body-fat responses to food are to a large extent hard-wired in to our DNA.

Over the course of the two-year study, the UCLA team looked at the effect of high-calorie diets on more than 100 strains of laboratory mice.

The scientists located 11 regions of the genetic code associated with obesity and fat gain due to diet. Several of these overlapped with genes identified in human studies.

'We measured the change in fat dynamically at five different points following a high-fat, high-sugar feeding, providing strong evidence for a genetically controlled body-fat set-point,' said Dr Parks.

'Our use of inbred mice strains also enabled detailed analysis of the relationship between obesity traits, gene expression, intestinal flora and diet.'

Dietary responses varied greatly across strains, according to the findings reported in the online edition of the journal Cell Metabolism.

Increases in body fat as a proportion of weight ranged from zero to 600%.

Most mice strains responded during the first four weeks of a high-calorie diet and did not accumulate more fat during the remainder of the study. This suggests they reached a natural upper threshold limit after which continued fat gain was resisted by genetic mechanisms.

'We observed high heritability of about 80% for body-fat percentage across the study timeline,' said co-author Professor Jake Lusis, also from UCLA.

'Changes in body-fat percentage after high-fat, high-sugar feeding were also highly heritable, suggesting that dietary responses are strongly controlled by genetics.'

The findings are consistent with generational patterns of body mass index and obesity seen in humans, said the researchers.

'Our results emphasise the importance of gene-by-environment interactions, with important implications for an understanding of the overall genetic architecture of obesity,' said Prof Lusis said.

'In particular, it will be of interest to examine behavioural and neurological differences among the strains as they relate to obesity traits.'


No comments: