Human adipose-derived mesenchymal stem cell-conditioned medium ameliorates polyneuropathy and foot ulceration in diabetic BKS db/db mice

Abstract
Background
Diabetic polyneuropathy (DPN) is the most common and early developing complication of diabetes mellitus, and the key contributor for foot ulcers development, with no specific therapies available.
Different studies have shown that mesenchymal stem cell (MSC) administration is able to ameliorate DPN; however, limited cell survival and safety reasons hinder its transfer from bench to bedside. MSCs secrete a broad range of antioxidant, neuroprotective, angiogenic, and immunomodulatory factors (known as conditioned medium), which are all decreased in the peripheral nerves of diabetic patients. Furthermore, the abundance of these factors can be boosted in vitro by incubating MSCs with a preconditioning stimulus, enhancing their therapeutic efficacy. We hypothesize that systemic administration of conditioned medium derived from preconditioned MSCs could reverse DPN and prevent foot ulcer formation in a mouse model of type II diabetes mellitus.

Methods
Diabetic BKS db/db mice were treated with systemic administration of conditioned medium derived from preconditioned human MSCs; conditioned medium derived from non-preconditioned MSCs or vehicle after behavioral signs of DPN was already present. Conditioned medium or vehicle administration was repeated every 2 weeks for a total of four administrations, and several functional and structural parameters characteristic of DPN were evaluated. Finally, a wound was made in the dorsal surface of both feet, and the kinetics of wound closure, re-epithelialization, angiogenesis, and cell proliferation were evaluated.

Results
Our molecular, electrophysiological, and histological analysis demonstrated that the administration of conditioned medium derived from non-preconditioned MSCs or from preconditioned MSCs to diabetic BKS db/db mice strongly reverts the established DPN, improving thermal and mechanical sensitivity, restoring intraepidermal nerve fiber density, reducing neuron and Schwann cell apoptosis, improving angiogenesis, and reducing chronic inflammation of peripheral nerves. Furthermore, DPN reversion induced by conditioned medium administration enhances the wound healing process by accelerating wound closure, improving the re-epithelialization of the injured skin and increasing blood vessels in the wound bed in a skin injury model that mimics a foot ulcer.

Conclusions
Studies conducted indicate that MSC-conditioned medium administration could be a novel cell-free therapeutic approach to reverse the initial stages of DPN, avoiding the risk of lower limb amputation triggered by foot ulcer formation and accelerating the wound healing process in case it occurs.

Cite this document

De Gregorio, C., Contador, D., Díaz, D., Cárcamo, C., Santapau, D., Lobos-Gonzalez, L., Acosta, C., Campero, M., Carpio, D., Gabriele, C., Gaspari, M., Aliaga-Tobar, V., Maracaja-Coutinho, V., Ezquer, M., & Ezquer, F. (2020). Human adipose-derived mesenchymal stem cell-conditioned medium ameliorates polyneuropathy and foot ulceration in diabetic BKS db/db mice. Stem Cell Research & Therapy, 11(1), 168. https://doi.org/10.1186/s13287-020-01680-0

Subjects

conditioned medium

;

deferoxamine

;

diabetic foot ulcer

;

diabetic polyneuropathy

;

mesenchymal stem cells

;

culture media, conditioned

;

diabetes mellitus, type 2

;

diabetic foot

;

humans

;

mesenchymal stem cell transplantation

;

mesenchymal stem cells

;

mice

;

polyneuropathies

;

adipose derived stem cell

;

angiogenesis

;

animal cell

;

animal experiment

;

animal model

;

animal tissue

;

article

;

behavior disorder

;

cell proliferation

;

chronic inflammation

;

controlled study

;

db/db mouse

;

diabetic neuropathy

;

electrophysiology parameters

;

epithelization

;

female

;

foot ulcer

;

functional assessment

;

histopathology

;

human

;

human cell

;

human tissue

;

mesenchymal stem cell transplantation

;

molecular biology

;

mouse

;

nerve fiber

;

nervous system function

;

nervous system parameters

;

neuroapoptosis

;

non insulin dependent diabetes mellitus

;

nonhuman

;

priority journal

;

retreatment

;

schwann cell

;

skin blood vessel

;

skin injury

;

temperature sensitivity

;

wound closure

;

wound healing

;

conditioned medium

;

diabetic foot

;

mesenchymal stem cell

;

non insulin dependent diabetes mellitus

;

pharmacology

;

polyneuropathy