A study is investigating whether certain substances present in the blood could help provide a better understanding of how patients progress during rehabilitation after a stroke. The research, led by the Vall d’Hebron Research Institute (VHIR), found associations between three potential blood biomarkers and aspects of functional recovery, such as walking, regaining muscle strength or carrying out daily activities. The findings open a pathway for studying whether, in the future, a blood test could complement standard clinical assessments, although they do not yet allow prediction of individual recovery.

The study, published in Scientific Reports, is part of the SMARRTS study, led by the VHIR Neurovascular Diseases Research Group and the Physical Medicine and Rehabilitation Research Group, together with the Neurorehabilitation and Brain Injury Unit of Vall d’Hebron University Hospital, in collaboration with other Spanish centres. This line of research was recently presented at the National Congress of the Spanish Society of Rehabilitation and Physical Medicine (SERMEF), held in Barcelona.

Dr Anna Rosell, senior researcher and head of the Neurovascular Diseases Group at VHIR, and Dr Susana Rodríguez González, member of Vall d'Hebron’s Neurorehabilitation and Brain Injury Unit and SERMEF, and principal investigator of the VHIR Physical Medicine and Rehabilitation Group, explain that the objective “is to investigate whether certain blood molecules reflect processes of brain repair and neuroplasticity, as well as their relationship with patients’ progress during rehabilitation”.

“Currently, rehabilitation physicians assess recovery using clinical scales and functional tests that measure mobility, strength, gait and independence”, explain the researchers, who stress that “the long-term goal is to explore whether a simple blood sample could provide information that complements conventional clinical assessment”.

Three potential biomarkers associated with recovery

The study is prospective (follow-up over time), observational (without intervention in treatments) and multicentre (conducted at several centres). Researchers analysed 62 patients who had experienced a first stroke and 43 control participants. Patients were assessed before starting rehabilitation and again after one month, three months and six months, combining blood samples with functional testing.

The researchers studied four molecules linked to brain repair and neuroplasticity, that is, the nervous system’s ability to reorganise its connections: endostatin, GDF-10, uPA and uPAR. The results particularly highlight three of them (endostatin, GDF-10 and uPAR) as potential biomarkers for studying recovery.

According to Rosell and Rodríguez González, “patients with higher levels of GDF-10 and uPAR before starting rehabilitation subsequently showed poorer outcomes in certain parameters, such as gait speed, muscle strength and arm motor function”.

They also explain that “a greater decrease in endostatin during the first month was associated with greater subsequent improvement in certain motor and strength capacities. Conversely, an increase in GDF-10 was associated with better recovery of arm function, daily independence and walking ability”. The researchers caution that “the observed associations do not demonstrate that these biomarkers cause a particular recovery trajectory, nor do they yet allow their use for predicting an individual patient’s recovery”.

Towards more personalised rehabilitation

Rosell and Rodríguez González explain that “if these findings are validated, biomarkers could help us understand different recovery patterns and investigate which patients might benefit from specific rehabilitation intensities or strategies. They could also help explore differences in response to therapies”. This line of research also builds on previous studies of angiogenin, another blood molecule whose changes were associated with functional outcomes and showed differences according to treatment intensity.

Nevertheless, the specialists point out that “the sample size is relatively small and the observational design does not allow definitive distinction between changes associated with the natural recovery process after stroke and those specifically related to rehabilitation”. For this reason, they consider it “necessary to expand the sample size, validate the findings in independent groups and incorporate additional clinical and biological factors”. They also stress “the need for funding to develop larger multicentre studies”.

“The ultimate goal,” as the researchers emphasise, “is not to replace the clinical assessment of patients, but to add a potential biological dimension to the evaluation of recovery in the future”. “To achieve this, it will be necessary to demonstrate that the information provided by these biomarkers genuinely improves clinical decision-making before considering their incorporation into rehabilitation programmes”, they conclude.