Muscle Weakness | Transforming Growth Factor Beta Signalling in the Development of Muscle Weakness in Pulmonary Arterial Hypertension

Muscle Weakness research study

What is the primary objective of this study?

Pulmonary arterial hypertension (PAH) is a disease that causes raised blood pressure in blood vessels that pick up oxygen from the lungs. It has a life expectancy similar to some cancers. There is treatment available but there is no cure. We now know that PAH is associated with weakness in the muscles in the legs, which contributes to the symptoms patients' experience. Researchers believe that certain proteins found in high levels in the blood of patients with other chronic diseases can affect muscle function and growth. One of these proteins is called growth differentiating factor (GDF) 8, high levels of which are associated with muscle weakness in chronic obstructive pulmonary disease(COPD) and heart failure (HF). Interestingly there are drugs available which block the actions of GDF-8 on muscle cells which has been shown in animals to result in increased muscle size. A related protein called GDF-15 is found in elevated levels in patients PAH, and is linked to prognosis. Our preliminary data suggests that GDF-15 can also directly influence muscle size in a number of situations. We aim to investigate the role of GDF-15 and related molecules in the development of muscle weakness in patients with PAH. We will do this by measuring certain markers of muscle weakness and taking blood and muscle samples in patients and controls. We will then compare the levels of GDF-15 in these tissues in those with and without muscle wasting. We hope this work will lead to a greater understanding of the role of GDF-15 in the development of muscle weakness in patients with PAH. GDF-15 levels may be important in allowing us to define which patients have muscle weakness. In the future we aim to perform a clinical trial of drugs which block the actions of GDF-15.

Who is eligible to participate?

Inclusion Criteria: - Patients with pulmonary arterial hypertension with New York Heart Association stage II - III disease will be eligible for recruitment in the patient portion of the trial. Interested healthy age matched volunteers will also be recruited. Exclusion Criteria: - Patients and volunteers will be excluded if they have significant co-morbidities including other cardiorespiratory disease, metabolic abnormalities including diabetes or thyroid disorders. They will be excluded if they cannot safely exercise and perform a six minute walk test or if they are wheelchair bound.

Which medical condition, disease, disorder, syndrome, illness, or injury is researched?

Muscle Weakness

Pulmonary Arterial Hypertension

Study Interventions

Interventions can include giving participants drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available or noninvasive approaches such as surveys, education, and interviews.

Study Arms

Research studies and clinical trials typically have two or more research arms. An arm is a group of people who receive the same treatment in the study.

PH with wastingThis group of patients with idiopathic pulmonary arterial hypertension exhibit quadriceps wasting

PH no wastingThis groups of patients with idiopathic pulmonary arterial hypertension exhibit no evidence of muscle wasting

ControlsThis group of volunteers does not have pulmonary arterial hypertension and would not be expected to have muscle wasting

Study Status


Start Date: October 2013

Completed Date: August 2016


Type: Observational


Primary Outcome: Plasma growth and differentiation factor 15 levels in participants with and without muscle wasting

Secondary Outcome: Correlation of plasma Growth and differentiation factor 15 levels with muscle strength

Study sponsors, principal investigator, and references

Principal Investigator: Stephen J Wort, MBBS

Lead Sponsor: Imperial College London

Collaborator: Medical Research Council

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