Human umbilical cord
mesenchymal stem cells as treatment of adjuvant
rheumatoid arthritis in a rat model.
Source
Sahar Greish, Noha Abogresha, Department of Physiology, Faculty of Medicine,
Suez Canal University, 4111 Ismailia, Egypt.
Abstract
AIM:
To investigate the effect of human umbilicalcord
stem cells, both mesenchymal and hematopoietic
(CD34+), in the treatment of arthritis.
METHODS:
Mesenchymal stem cells (MSCs) and hematopoietic
(CD34+) stem cells (HSC) were isolated from human umbilical cord blood obtained from the umbilical cord of healthy
pregnant donors undergoing full-term normal vaginal delivery. MSC, HSC, methotrexate
(MTX) and sterile saline were injected intra-articularly into the rat hindpaw
with complete freunds adjuvant (CFA) induced arthritis after the onset of
disease (day 34), when arthritis had become well established (arthritis score ≥
2). Arthritic indices were evaluated and the levels of interleukin (IL)-1,
tumor necrosis factor (TNF)-α and interferon (IFN)-γ and anti-inflammatory
cytokine IL-10 in serum were determined using enzyme-linked immunosorbent
assay. Animals of all groups were sacrificed 34 d after beginning treatment,
except positive control (PC) which was sacrificed at 10, 21 and 34 d for
microscopic observation of disease progression. We used hematoxylin, eosin and
Masson's trichrome stains for histopathological examination of cartilage and
synovium.
RESULTS:
The mean arthritis scores were similar in all groups at 12 and 34 d post
immunization, with no statistical significant difference. Upon the injection of
stem cells (hematopoietic and mesenchymal), the
overall arthritis signs were significantly improved around 21 d after receiving
the injection and totally disappeared at day 34 post treatment in MSC group.
Mean hindpaw diameter (mm) in the MSC rats was about half that of the PC and
MTX groups (P = 0.007 and P = 0.021, respectively) and 0.6 mm less than the HSC
group (P = 0.047), as indicated by paw swelling. Associated with these
findings, serum levels of TNF-α, IFN-γ and IL-1 decreased significantly in HSC
and MSC groups compared to PC and MTX groups (P < 0.05), while the expression
of IL-10 was increased. Histopathological examination with H and E stain
revealed that the MTX treated group showed significant reduction of leucocytic
infiltrate and hypertrophy of the synovial tissue with moderate obliteration of
the joint cavity. Stem cells treated groups (both
hematopoietic CD34+ and mesenchymal), showed significant reduction in
leucocytic infiltrate and hypertrophy of the synovial tissue with mild
obliteration of the joint cavity. With Masson's trichrome, stain sections from
the PC group showed evidence of vascular edema of almost all vessels within the
synovium in nearly all arthritic rats. Vacuoles were also visible in the outer
vessel wall. The vessel became hemorrhagic and finally necrotic. In addition,
there was extensive fibrosis completely obliterating the joint cavity. The mean
color area percentage of collagen in this group was 0.324 ± 0.096, which was
significantly increased when compared to the negative control group. The mean
color area percentage of collagen in hematopoietic CD34+ and mesenchymal groups
was 0.176 ± 0.0137 and 0.174 ± 0.0197 respectively, which showed a marked
decrement compared to the PC group, denoting a mild increase in synovial tissue
collagen fibers.