Damage to the peripheral nervous system, referred to as polyneuropathy, is a common complication of diabetes which is often diagnosed at a late point only. In the journal “Diabetes/Metabolism Research and Reviews,” researchers from the DZD report on the identification of biomarkers that can be measured in the blood and are associated with distal sensorimotor polyneuropathy. 

Distal sensorimotor polyneuropathy (DSPN) is the most common polyneuropathy in people with type 2 diabetes. However, it can also develop in people without manifest diabetes. Older age, obesity, prediabetes and dyslipidemia have emerged as risk factors. Characteristic symptoms are pain, paresthesia (burning, tingling), but also numbness, unsteady gait or muscle weakness.  

Analysis of more than 1,000 blood samples
Researchers from the German Diabetes Center (DDZ) in Düsseldorf, in collaboration with researchers from the German Center for Diabetes Research (DZD) at Helmholtz Zentrum München and with partners from other institutions, have now been able to show that specific biomarkers can be detected in higher concentrations in the blood of DSPN patients than in people without DSPN. They analyzed blood samples from 1,032 participants in the KORA study. KORA examines the state of health of the population in Augsburg and the surrounding area. 177 study participants already had DSPN at the start of the study.  

Of 88 biomarkers examined, 2 were associated with DSPN: the proteins CTSC and PDGFRα. People with high CTSC and PDGFRα levels were particularly likely to have DSPN. This applied to study participants with and without type 2 diabetes.

Association only with pre-existing polyneuropathy
In addition, 5 other biomarkers (CDH3, JAM-B, LAYN, RGMA and SCARA5) were positively associated with DSPN in people with diabetes, who made up one-fifth of the study cohort. The biomarker GCP5 was associated with DSPN in people without diabetes only.  

Some of the participants in the KORA study did not develop DSPN until several years into the study. However, the researchers were unable to observe an association between the biomarkers examined and the recurrence of the disease. 

Often, DSPN is recognized only at a very late point. If they confirm their significance in further studies, the biomarkers identified could be used for screening, for example – to detect the disease earlier and monitor its progression. It is possible that CTSC and PDGFRα are also involved in the development of DSPN. They would then be potential working points for the development of new drugs. 

Original publication:
Christian Herder, Barbara Thorand, Alexander Strom, Wolfgang Rathmann, Margit Heier, Wolfgang Koenig, Helen Morrison, Dan Ziegler, Michael Roden, Annette Peters, Gidon J. Bönhof und Haifa Maalmi. Associations between multiple neurological biomarkers and distal sensorimotor polyneuropathy: KORA F4/FF4 study. Diabetes/Metabolism Research and Reviews 2024