The Clinical And Histopathological Features Of Facioscapulohumeral Muscular Dystrophy (FSHD) And The Study Of Vascular Factors In The Pathogenesis Of FSHD

Objective:By analyzing the clinical data and histopathological features of 26 cases with facioscapulohumeral muscular dystrophy(FSHD), we summerized the characters of inflammatory infiltration and vascular inflammation, observed the number of new-born vessels, analysed the expression of related genes quantitatively via real-time fluorescent quantitative PCR(RT-PCR) and explored the role of vascular factor in the pathogenesis of FSHD.Methods:26 FSHD patients who performed muscle biopsy in the Peripheral nerve and muscular disease institute of Shandong Qilu hospital from 2007 to 2009 were selected as subjects, all of whom fitted the clinical diagnosing criteria. According to the HE staining,26 cases with FSHD were divided into non-inflammatory group and inflammatory group. According to the sites of inflammatory infiltration, inflammatory group were further divided into three subgroups:endomysial inflammation, perivasculitis and transmural vasculitis. We compared clinical features of two groups, including sexuality, family history, age of onset, course, leision, symmetrical or not, CK level and EMG.20 cases with infalmmatory myopathy (10 with polymyositis(PM) and 10 with dermatomyositis(DM)) were selected as inflammtory controls. Another 10 cases without neuromuscular diseases were selected as normal controls. Immunohistochemical staining was performed in muscle specimens of FSHD cohort and inflammatory controls with anti-CD4, anti-CD8, anti-CD20 and anti-CD68 antibody. In muscle specimens with perivasculitis, Anti-CD3, anti-SMA body were tested and dual-immunofluorescence was performed to verify further that vasculitis occurred in some of FSHD cases. Anti-CD34 immunohistochemical staining was performed in FSHD and normal controls to observe changes in the number of vessels. In FSHD cohort and normal controls, the expressions of VEGF A,VEGF C,FRG1,VE-cadherin and DUX4 mRNA were analyzed quantitatively via RT-PCR.Results:1. The age of onset was 25.23±12.57 years old and the mean course was 7.81±7.31years. The ratio of male to female was 1.6:1. Five of them had family history. The main clinical features were progressive weakness and atrophy of facial, shoulder girdles and proximal upper limbs muscles. The lower distal limbs and pelvic girdle muscles were involved in 18 cases.24 cases were involved asymmetrically.2. The main pathological features were shown as follows.20 cases showed pathological changes of myodystrophy, including necrotic fibers with phagocytosis, regenerative fibers, hypertrophic and splitting fibers, increased fibers with centrally placed nuclei and significant proliferation of connective tissues;6 cases showed mild myogenic changes, including mild or moderate variation in fibers' size and scattered small angular fibers. Untypical ragged red fibers could be seen in 2 cases, and rimmed vaculoes in 1 cases. Intermyofibrillar networks were disorganized and there were lobulated fibers in 5 cases, moth-eaten fibers in 4 cases, whirled fibers in 4cases, target or core fibers in 2 cases.17 of them had focal inflammatory cell infiltration, including endomysial inflammation (4/17), perivasculitis (7/17), and transmural vasculitis (6/17). Immunohistochemical stainning confirmed inflammatory cells were mainly CD4+ T lymphocytes and CD20+ B lymphocytes.3. The type of inflammatory cells in DM was similar to FSHD, while in PM, CD8+ T lymphocytes were dominant.4. Immunohistochemical staining confirmed that new-born vessles proliferated significantly in inflammatory group of FSHD when compared to non-inflammatory group of FSHD and controls.5. The expressions of VEGF-A,VEGF-C,FRG1,VE-cadherin,DUX4 mRNA in muscle tissues of FSHD were as follows:①FRG1:the difference of expression of FRG1 mRNA in FSHD cohort (1.39±0.12) and controls (1.47±0.07) had no statistical significance. But the expression of FRG1 mRNA in flammatory group of FSHD(1.84±0.41) increased obviously than non-inlammatory group of FSHD(0.97±0.21)(P<0.05). Expression of it in transmural vasculitis subgroup(2.14±0.17) was higher than endomysial inflammation subgroup (1.42±0.14) (P<0.05), but had no statistical significance compared to perivasculitis subgroup.②DUX4:the difference of expression of DUX4 mRNA in FSHD cohort (1.39±0.12) and controls (0.27±0.09)had no statistical significance (P>0.05).The difference of expression in subgroups of FSHD had no statistical significance neither.③VEGF-C: the expression of VEGF-C mRNA in FSHD cohort (1.58±0.26) was higher than controls(0.76±0.15) (P<0.01).The expression of VEGF-C mRNA in flammatory group of FSHD (2.26±0.71) was higher than non-inlammatory group of FSHD(0.43±0.03) (P<0.01).Expression of it in transmural vasculitis subgroup(2.82±0.15)and perivasculitis subgroup (2.37±0.53) was higher than endomysial inflammation subgroup(0.82±0.21) (P <0.01). But there was no statistical significance in difference between transmural vasculitis subgroup and perivasculitis subgroup.④VEGF-A: the expression of VEGF-A mRNA in FSHD cohort (2.29±0.36) was higher than controls(0.89±0.16) (P<0.01).The expression of VEGF-A mRNA in flammatory group of FSHD (3.09±0.33)was higher than non-inlammatory group of FSHD(0.68±0.19) (P<0.05).Expression of it in transmural vasculitis subgroup(3.84±0.33)was higher than endomysial inflammation subgroup (1.53±0.49) (P<0.05) and perivasculitis subgroup (2.91±0.27) (P<0.05).⑤VE-cadherin:the expression of VE-cadherin mRNA in FSHD cohort (0.87±0.11) was higher than controls(0.28±0.05) (P<0.05).⑥The expression of VE-cadherin mRNA in flammatory group of FSHD(1.28±0.17)was higher than non-inlammatory group of FSHD(0.25±0.01) (P <0.05). Expression of it in transmural vasculitis subgroup(1.52±0.25) was higher than endomysial inflammation subgroup(0.45±0.13) (P<0.05), but had no statistical significance compared to perivasculitis subgroup (1.36±0.12).Perivasculitis subgroup was higher than endomysial inflammation subgroup (P<0.05). The expression of VEGF-A,VEGF-C,FRG1, VE-cadherin in in flammatory group of FSHD was higher significantly than non-inlammatory group of FSHD, especially in transmural vasculitis. And the difference of expression parelled with expression of FRG1. (VEGF-A rs=0.447, P<0.02; VEGF-C rs=0.382, P<0.05; VE-cadherinrs=0.459, P<0.02)Conclusion:1.Typical transmural vasculitis can be seen in FSHD with inflammatory infiltration, besides endomysial inflammation and perivasculitis.2. New-born vessels proliferate significantly in muscle tissues of FSHD with inflammatory infiltration.3. The expressions of VEGF-A,VEGF-C and VE-cadherin up-regulate significantly in muscle tissues of FSHD with inflammatory infiltration, especially in vasculitis, which parallel with the expression of FRG1.4. Vascular pathological factor may have something to do with pathogenesis of FSHD.