[Show abstract][Hide abstract] ABSTRACT: The presence of non-progressive cognitive impairment is recognized as a common feature in a substantial proportion of patients with Duchenne muscular dystrophy (DMD). Concurrently, the amyloid beta peptide (Aβ42) protein has been associated with changes in memory and cognitive functions. Also, it has been shown that different subtypes of neural stem/progenitor cells (CD 34, CD 45, nestin) are involved in the innate repair of plasticity mechanisms by the injured brain, in which Nerve Growth Factor (NGF) acts as chemotactic agents to recruit such cells. Accordingly, the present study investigated levels of CD 34, CD 45, nestin and NGF in an attempt to investigate makers of neural regeneration in DMD. Neural damage was assayed in terms of Aβ42. Results showed that Aβ42 (21.9 ± 6.7 vs. 12.13 ± 4.5) was significantly increased among DMD patients compared to controls. NGF (165.8 ± 72 vs. 89.8 ± 35.9) and mononuclear cells expressing nestin (18.9 ± 6 vs. 9 ± 4), CD 45 (64 ± 5.4 vs. 53.3 ± 5.2) and CD34 (75 ± 6.2 vs. 60 ± 4.8) were significantly increased among DMD patients compared to controls. In conclusion cognitive function decline in DMD patients is associated with increased levels of Aβ42, which is suggested to be the cause of brain damage in such patients. The significant increase plasma NFG and in the number of mononuclear cells bearing CD34, CD45 and nestin indicates that regeneration is an ongoing process in these patients. However, this regeneration cannot counterbalance the damage induced by dystrophine mutation and increased Aβ42.
[Show abstract][Hide abstract] ABSTRACT: It is hypothesized that Down syndrome (DS) patients are associated with abnormalities of the immune system. Accordingly, this study was conducted to measure replicative aging and apoptosis in lymphocytes, which play an important role in the immune system, before and after being biostimulated with He:Ne laser. Replicative aging was measured in terms of telomerase activity, and ETS-2 gene relative expression. Apoptosis was measured in terms of DNA fragmentation and apoptosis genes (Fas, FasL and Bax) and antiapoptotic Bcl-2 protein. Results showed that Telomerase activity, ETS-2 mRNA expression, plasma DNA fragmentation, Fas and FasL were significantly higher among DS patients compared to controls: Telomerase activity (1.5 ± 0.5 vs. 0.9 ± 0.4, p < 0.001); ETS2 mRNA expression (0.6 ± 0.1 vs. 0.43 ± 0.04, p < 0.0001); plasma DNA fragmentation (0.45% ± 0.12 vs. 0.2% ± 0.1, p < 0.0001); Fas protein (5.3 ± 1.2 vs. 2.3 ± 0.2, p < 0.0001); FasL mRNA relative expression (0.37 ± 0.05 vs. 0.24 ± 0.01, p < 0.001); Bax mRNA relative expression (0.9 ± 0.1 vs. 0.5 ± 0.1, p < 0.00001). Bcl-2 protein was significantly low in DS patients compared to controls (8.6 ± 1.3 vs. 10 ± 2.1, p < 0.01). He:Ne laser biostimulation applied to evaluate lymphocytes’ response significantly increased the former parameters in DS patients compared to their level before irradiation, except for Bcl-2, which was significantly decreased. In conclusion: increased telomerase activity associated with increased activity and overexpression of ETS-2 on chromosome 21 in DS patients may contribute to the increased rate of early senescence in circulating lymphocytes, which consequently contributes to the abnormalities of the immune system observed in DS. Increased apoptosis is due to increased oxidative stress, which induces an increase in the apoptotic genes Bax, Fas and FasL accompanied by a decrease in the antiapoptotic gene Bcl-2.
Egyptian Journal of Medical Human Genetics 01/2013; 14(2):171–176.
[Show abstract][Hide abstract] ABSTRACT: In Down syndrome (DS), trisomy 21 leads to overexpression of gene coding for specific enzymes. This overexpression translates directly into biochemical aberrations that affect multiple interacting metabolic pathways which culminates in cellular dysfunction and contributes to the unique pathogenesis of DS. The aim of this study is to evaluate parameters of immune response in terms of cytokines [tumor necrosis factor-α (TNF-α) and interlukin-2 (IL-2)] together with the quantitative expression of cystathionine beta synthase (CBS), whose transsulfuration pathway generates cysteine and hydrogen sulfide (H2S). H2S is known to boost host defense at physiological concentrations and to display cytotoxic activity at higher concentrations. Calcineurin activity (CAN) was also measured as its dysregulation has been shown to cause immune suppression. Subjects were 60 DS patients vs. 30 age and socioeconomic matching healthy controls. In their blood, the cytokines: TNF-α and IL-2, together with CBS and its by product H2S as well as CAN activity, were measured. Results showed that CBSmRNA relative expression (0.56 ± .06 vs. 0.32 ± .02), plasma H2S (72 ± 8.5 vs. 50.8 ± 4.1) and TNF-α (8.11 ± .01 vs. 3.6 ± 0.9) were significantly higher among DS patients compared to controls, while CAN (0.27 ± 0.1 vs. 0.45 ± 0.2 units), was significantly decreased in blood of DS patients compared to controls. IL-2 (36.4 ± 2.6 vs. 37.4 ± 0.9) showed no significant difference between DS patients and controls. Accordingly it can be concluded that excessive synthesis of multiple gene products derived from overexpression of the genes present on chromosome 21 may be the cause for decreased immunity in DS patients compared to controls.
Egyptian Journal of Medical Human Genetics 01/2013; 14(3):307–310.
[Show abstract][Hide abstract] ABSTRACT: Dystrophin deficiency associated with Duchenne muscular dystrophy (DMD) results in chronic inflammation and severe skeletal muscle degeneration, where the extent of muscle fibrosis contributes to disease severity. The microenvironment of dystrophic muscles is associated with variation in levels of markers of degeneration and regeneration. Since in dystrophic muscle apoptosis precedes necrosis, markers of apoptosis can be used as indicators of degeneration, while regeneration can be measured in terms of cytokines and growth factor expression"; and then throughout the text use "markers of apoptosis/degeneration. The present study is an attempt to evaluate the extent of degeneration and regeneration in DMD patient blood. Subjects were 24 boys with DMD diagnosed at the molecular level versus 20 age and socioeconomic matching healthy boys. In their blood, levels of Fas and FasL and Bax/Bcl-2 and plasma DNA fragmentation were measured as markers of apoptosis. The cytokine tumor necrosis factor alfa (TNF-alpha), and the growth factors: basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) were measured as markers of regeneration. Plasma DNA fragmentation (0.38% +/- 0.12 vs. 0.2% +/- 0.15) and Fas (9.9 +/- 2.8 vs. 2 +/- 0.1, p < 0.001) together with FasL mRNA expression in circulating lymphocytes (0.47 +/- .09 vs. 0.24 +/- .04, p < 0.001) were significantly increased in DMD patients compared to controls. There was a significant increase in Bax (0.19 +/- 0.7 vs. 0.05 +/- 0.1, p < 0.00001) expression and a significant decrease in Bcl-2 protein (6.4 +/- 1.6 vs 10 +/- 2.8, p < 0.00001) as compared to controls. Among markers of regeneration, TNF- alpha (30.2 +/- 9.5 vs. 3.6 +/- 0.9) and bFGF (21.7 +/- 10.3 vs. 4.75 +/- 2.2) were significant increased while VEGF was significantly decreased (190 +/- 115 vs. 210 +/- 142.) in blood of DMD patients compared to controls. Our results indicate that Fas/FasL and Bax/Bcl-2 are involved in muscle atrophy and degeneration in DMD patients, while regeneration process does not cope with the degeneration.
Acta myologica: myopathies and cardiomyopathies: official journal of the Mediterranean Society of Myology / edited by the Gaetano Conte Academy for the study of striated muscle diseases 12/2009; 28(3):94-100.
[Show abstract][Hide abstract] ABSTRACT: Replicative aging and oxidative stress are two plausible theories explaining the etiology of muscular dystrophy. The first theory indicates that replicative aging of myogenic cells (satellite cells), owing to enhanced myofiber turnover, is a plausible explanation of the progression of Duchenne muscular dystrophy (DMD). The oxidative stress theory indicates that failure of muscle regeneration to keep up with the ongoing apoptosis and necrosis following oxidative stress, that normally associates muscular exercise, leads to muscle atrophy in DMD. To test for these two theories, markers of replicative aging and oxidative stress were assessed in the blood of 30 DMD patients vs. 20 normal healthy age matching controls. Markers of replicative aging showed significantly lower telomerase activity, significantly increased expression of receptors for advanced glycation end products (RAGEs) mRNA and Bax mRNA (an apoptotic gene) in DMD compared to controls. There was a significant increase in markers of oxidative stress among DMD patients compared to controls, measured in terms of increased apoptotic percentage in circulating mononuclear cells, increased lipid peroxidation measured in terms of plasma malondialdehyde (MDA) and increased protein carbonyls. Levels of plasma nitric oxide (NO), which neutralizes oxygen radicals, and expression of inducible nitric oxide synthase (iNOS) mRNA in neutrophils was significantly lower among DMD compared to controls. Biostimulation of WBC by helium neon (He:Ne) laser irradiation induced a significant increase in the expression of iNOS mRNA and plasma NO levels, but still at a lower level compared to controls. He:Ne laser irradiation induced a marked decrease in markers of oxidative stress among DMD patients compared to their level before irradiation, measured in terms of decreased plasma protein carbonyls, decreased plasma MDA, and decreased apoptosis percentage. CONCLUSION: This study points to that oxidative stress is the prime cause for muscle degeneration in DMD and points out to the possible ameliorative effect of He:Ne laser on this
Acta myologica: myopathies and cardiomyopathies: official journal of the Mediterranean Society of Myology / edited by the Gaetano Conte Academy for the study of striated muscle diseases 08/2007; 26(1):14-21.