ABSTRACT
We aimed to clarify the role of matrix metalloproteinases (MMP) as a possible link between neurodegeneration and skin pathology in ALS by determination of gelatinase MMP-2 and MMP-9 in spinal cord and skin of transgenic SOD1((G93A)) mice. To elucidate mechanisms influencing MMPs, markers of oxidative damage (malondialdehyde (MDA), 3-nitrotyrosine (3-NT) and 8-hydroxy-2'-deoxyguanosine (8OH2'dG)) as well as cytokines (tumor necrosis factor alpha (TNF-alpha) and interleukin 1ss (IL-1ss)) were determined. We measured MMP-9, MMP-2, 3-NT, TNF-alpha, and IL-1ss using ELISA, MDA using High Performance Liquid Chromatography (HPLC) and 8OH2'dG using HPLC with electrochemical detection (HPLC-ECD) in SOD1 and WT. MMP-9 was elevated in spinal cord and skin of SOD1 at 90 days (p=0.009, p<0.001) and 120 days (p<0.01, p=0.04). MMP-2 was elevated in the spinal cord at 90 days (p=0.01) and in the skin at 120 days (p=0.039). We observed a correlation of MMP-9 in spinal cord and skin of SOD1 (p=0.04). MDA was elevated in the spinal cord of SOD1 at 90 and 120 days (p=0.00006, p=0.01) and 8OH2'dG at 90 days (p=0.048). IL-1ss was elevated in the spinal cord of SOD1 at 120 days (p=0.02). Our data confirms that gelatinase MMPs are a common factor linking neurodegeneration and skin changes in ALS. It suggests that oxidative stress and microglial-derived cytokines contribute to the elevation of gelatinase MMPs especially in later stages of disease. Our data raises the question whether the skin may function as a biomarker for specific aspects of disease pathology in ALS.
Subject(s)
Amyotrophic Lateral Sclerosis/metabolism , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/metabolism , Skin/metabolism , Spinal Cord/metabolism , Aging/metabolism , Animals , Cytokines/metabolism , Disease Models, Animal , Humans , Interleukin-1beta/metabolism , Mice , Mice, Transgenic , Models, Neurological , Oxidative Stress/physiology , Superoxide Dismutase/genetics , Superoxide Dismutase/metabolism , Superoxide Dismutase-1 , Tumor Necrosis Factor-alpha/metabolismABSTRACT
Amyotrophic lateral sclerosis (ALS) mainly affects the motor neurons but may also include other organs such as the skin. We aimed to determine whether matrix metalloproteinases could provide a link between neuronal degeneration and skin alterations in ALS. We measured CSF, serum and skin tissue MMP-2 and MMP-9 using ELISA and malondialdehyde (MDA), a marker of lipid peroxidation, using High Performance Liquid Chromatography (HPLC) in 54 ALS patients and 36 controls. We found CSF and skin MMP-9 to be elevated in ALS as compared to controls (p<0.001, p=0.03, respectively). We observed CSF MMP-9 to be highest in patients with a rapid progressive course of disease (p=0.008). In contrast, we found no significant differences of CSF, serum or skin concentrations of MMP-2 as compared to controls. CSF MMP-2 concentrations decreased with duration of disease (p=0.04, R=-0.31). MDA was elevated in serum of ALS (p<0.001), though no correlation with MMP-2 or MMP-9 was observed. Our findings indicate a general upregulation of MMP-9 in ALS. MMP-9 seems to play a role in both neurodegeneration and skin changes in ALS and could thus be a common factor linking otherwise distant aspects of disease pathology.
Subject(s)
Amyotrophic Lateral Sclerosis/cerebrospinal fluid , Amyotrophic Lateral Sclerosis/metabolism , Matrix Metalloproteinases/cerebrospinal fluid , Matrix Metalloproteinases/metabolism , Skin/metabolism , Adult , Aged , Aged, 80 and over , Amyotrophic Lateral Sclerosis/blood , Chromatography, High Pressure Liquid , Disease Progression , Enzyme-Linked Immunosorbent Assay , Female , Humans , Male , Malondialdehyde/blood , Malondialdehyde/cerebrospinal fluid , Malondialdehyde/metabolism , Matrix Metalloproteinase 2/blood , Matrix Metalloproteinase 2/cerebrospinal fluid , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/blood , Matrix Metalloproteinase 9/cerebrospinal fluid , Matrix Metalloproteinase 9/metabolism , Matrix Metalloproteinases/blood , Middle Aged , Time FactorsABSTRACT
Magnetic resonance imaging (MRI) has provided important information in characterizing amyotrophic lateral sclerosis (ALS) in humans and in animal models. A frequently used animal model to study mechanisms of pathogenesis and the efficacy of drugs in ALS is a transgenic mouse over-expressing the human mutated G93A-superoxide dismutase 1 (G93A-SOD1). In our study, we applied MRI to find suitable progression markers, which can be used to monitor the development of ALS and to evaluate therapeutic approaches at early stages of the disease. Therefore, we generated parameter maps of the spin-spin relaxation time (T2) and the apparent diffusion coefficient (ADC) starting at day 70 after birth, i.e., before motor scores decline around day 90. Depending on the progression of the disease, G93A-SOD1 mice showed significantly increased values of T2 in the brain stem motor nuclei Nc. V (trigeminal nucleus), VII (facial nucleus), and XII (hypoglossal nucleus), and spinal cord compared to non-transgenic wild-type mice and transgenic mice over-expressing the non-mutated wild-type human SOD1 (tg-SOD1). Similar effects in these motor nuclei were revealed by ADC mapping. Furthermore, in the upper spinal cord, a dorsal-ventral difference with significantly higher T2 values in the ventral part was demonstrated by T2 mapping. While both T2 and ADC might prove useful as progression markers and enable the longitudinal non-invasive evaluation of ALS in G93A-SOD1 mice, the potential is limited by age-dependent effects in case of ADC mapping.
