Hyaluronic acid is increased in the skin and urine in patients with amyotrophic lateral sclerosis

Potential skin involvement in ALS: revisiting Charcot's observation - a review of skin abnormalities in ALS

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease affecting motor neurons of the brain and spinal cord, leading to progressive paralysis and death. Interestingly, many skin changes have been reported in ALS patients, but never as yet fully explained. These observations could be due to the common embryonic origin of the skin and neural tissue known as the ectodermal germ layer. Following the first observation in ALS patients' skin by Dr Charcot in the 19th century, in the absence of bedsores unlike other bedridden patients, other morphological and molecular changes have been observed. Thus, the skin could be of interest in the study of ALS and other neurodegenerative diseases. This review summarizes skin changes reported in the literature over the years and discusses about a novel in vitro ALS tissue-engineered skin model, derived from patients, for the study of ALS.

Morphological abnormalities in mitochondria of the skin of patients with sporadic amyotrophic lateral sclerosis

OBJECTIVES

Mitochondrial dysfunction has been reported in the central nervous system, hepatocytes and peripheral blood lymphocytes from patients with sporadic amyotrophic lateral sclerosis (SALS). However, the status of skin mitochondria has not been reported, in spite of the fact that SALS patients present skin abnormalities. The objective of the present study was to compare mitochondrial ultrastructural parameters in keratinocytes from patients with SALS and healthy controls.

METHODS

Our study was based on the analysis of 112 skin mitochondria from 5 SALS patients and 99 organelles from 4 control subjects by electron microscopy.

RESULTS

Computerized image analysis showed that mitochondrial major axis length, area and perimeter of the organelle were significantly smaller in SALS respect of healthy control subjects. Morphologically, SALS mitochondria presented cristolysis and breakage of the outer membrane.

CONCLUSIONS

Mitochondrial dysfunction in the skin may possibly reflect changes occurring in mitochondria of the central nervous system. The analysis of mitochondrial morphology in this tissue may be of value to follow disease progression and, eventually, the effectiveness of current therapies for SALS.

Critical parameters for the analysis of anionic oligosaccharides by desorption electrospray ionization mass spectrometry

Sulfated oligosaccharides derived from glycosaminoglycans (GAGs) are fragile compounds, highly polar and anionic. We report here on the rare but successful application of desorption electrospray ionization (DESI) - LTQ-Orbitrap mass spectrometry (MS) to the high-resolution analysis of anionic and sulfated oligosaccharides derived from the GAGs hyaluronic acid and heparin. For that purpose, key parameters affecting DESI performance, comprising the geometric parameters of the DESI source, the probed surface and the spraying conditions, applied spray voltage, flow rates and solvent composition were investigated. Under suitable conditions, the DESI technique allows the preservation of the structural integrity of such fragile compounds. DESI enabled the sensitive detection of anionic hyaluronic acid and heparin oligosaccharides with a limit of detection (LOD) down to 5 fmol (≈10 pg) for the hyaluronic acid decasaccharide. Detection of hyaluronic acid oligosaccharides in urine sample was also successfully achieved with LOD values inferior to the ng range. Multistage tandem mass spectrometry (MS(n) ) through the combination of the DESI source with a hybrid linear ion trap-orbitrap mass spectrometer allowed the discrimination of isomeric sulfated oligosaccharides and the sequence determination of a hyaluronic acid decasaccharide. These results open promising ways in glycomic and glycobiology fields where structure-activity relationships of bioactive carbohydrates are currently questioned.

Increased progranulin in the skin of amyotrophic lateral sclerosis: an immunohistochemical study

It has been demonstrated that progranulin (PGRN) is a neurotrophic factor that enhances neuronal survival and axonal growth. Several lines of evidence have indicated that PGRN plays a role in the pathomechanism of amyotrophic lateral sclerosis (ALS). However, there has no study of PGRN in ALS skin. We made a quantitative immunohistochemical study of the expression of PGRN in the skin from 18 patients with sporadic ALS and 13 control subjects. Immunohistochemistry for PGRN demonstrated cytoplasmic activity in the epidermis and in some blood vessels and glands. Numerous PGRN-positive (PGRN+) cells were observed in the epidermis in ALS patients, which became more marked as ALS progressed. PGRN immunoreactivity of PGRN+cells was markedly positive in the epidermis in ALS patients. The proportion of PGRN+cells in the epidermis in ALS patients was significantly higher (p<0.001) than in controls. There was a significant positive relationship (r = 0.83, p<0.001) between the proportion and duration of illness in ALS patients. These data suggest that changes of PGRN in ALS skin are related to the disease process and that metabolic alteration of PGRN may take place in the skin of patients with ALS.

Increased expression of TDP-43 in the skin of amyotrophic lateral sclerosis

OBJECTIVES

Transactivation-responsive DNA-binding protein-43 (TDP-43) was identified as a major component of the ubiquitin-positive inclusions in sporadic amyotrophic lateral sclerosis (ALS). However, there has been no study of TDP-43 in ALS skin. The present study investigates TDP-43 in ALS skin.

MATERIALS AND METHODS

We made a quantitative immunohistochemical study of the expression of TDP-43 in the skin from 15 patients with ALS and 15 control subjects.

RESULTS

The proportion of TDP-43-positive (TDP-43+) cells in the epidermis in ALS patients was significantly higher (P < 0.001) than in controls. There was a significant positive relationship (r = 0.62, P < 0.02) between the proportion and duration of illness in ALS patients. The optical density of TDP-43+ cells in the epidermis in ALS patients is markedly stronger (P < 0.001) than in controls. There was a significant positive relation (r = 0.72, P < 0.01) between the immunoreactivity and duration of illness in ALS patients.

CONCLUSIONS

These data suggest that changes of TDP-43 in ALS skin are likely to be related to the disease process and that metabolic alterations of TDP-43 may take place in the skin of patients with ALS.

An immunohistochemical study of ubiquitin in the skin of sporadic amyotrophic lateral sclerosis

Ubiquitin (UB)-immunoreactive filamentous inclusions, absent in normal cases and in any other disorder, have been found in patients with amyotrophic lateral sclerosis (ALS) and it has been suggested that they may be characteristic of this disorder. However, there has been no study of UB in ALS skin. We made a quantitative immunohistochemical study of the expression of UB in the skin from 19 patients with sporadic ALS and 19 control subjects. The proportion of UB-positive (UB+) cells in the epidermis in ALS patients was significantly higher (p<0.001) than in controls. There was a significant positive relationship (r=0.92, p<0.001) between the proportion and duration of illness in ALS patients. The optical density of UB+ cells in the epidermis in ALS patients is markedly stronger (p<0.001) than in controls. There was a significant positive relation (r=0.58, p<0.01) between the immunoreactivity and duration of illness in ALS patients. These data suggest that changes of UB in ALS skin are related to the disease process and that metabolic alterations of UB may take place in the skin of patients with ALS.

Pep-1 as a novel probe for the in situ detection of hyaluronan

Hyaluronan (HA) is expressed by most tissues, including skin. Localization of HA in the skin is assessed by histology with HA-binding protein (HABP) serving as the probe. Reports have suggested that HA expression in skin is altered in a number of diseases. However, interlaboratory variations in HABP staining profiles, even in normal skin, suggest a need to standardize methods and/or identify new probes. We report the staining patterns of a HA-binding peptide (termed "Pep-1") in human and mouse skin. After acetone fixation, Pep-1 stained HA in the intercellular spaces of the epidermis, whereas staining in the dermis was weak and diffuse in both human and mouse skin. HABP staining of the epidermis and dermis were comparable in human skin but failed to stain the vital epidermis of mouse skin. In human skin, Pep-1 stained the basal, spinous, and granular layers, whereas HABP failed to stain the basal layer. Precipitation of HA in situ resulted in dermal staining but weak staining in the epidermis for HABP and Pep-1. Our results may suggest that Pep-1 is sensitive to HA conformation. Furthermore, Pep-1 may represent a new probe to study HA expression in the skin.

The metabolic hypothesis in amyotrophic lateral sclerosis: insights from mutant Cu/Zn-superoxide dismutase mice

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by selective loss of motor neurons and progressive muscle atrophy. A subset of patients harbors point mutations in the gene encoding Cu/Zn-superoxide dismutase (SOD1), which allowed the generation of transgenic mice that express different SOD1 mutations and develop an ALS-like pathology. Recently, we reported in these mice the occurrence of a characteristic defect in energy homeostasis and the beneficial effect on the course of the disease of a high-energy fat-enriched diet. In this review, we discuss the implication of these findings in the light of classical clinical observations concerning metabolic alterations in human ALS.

Anti-heparan sulfate antibodies in neurological disease

Antibodies to heparan sulfate (HS) have previously been found in association with peripheral neuropathy. We tested sera from patients with neuropathies and with other neurological diseases for antibodies to HS using an avidin-biotin enzyme-linked immunosorbent assay (ELISA) system. Increased titers of anti-HS antibodies were found in 3.4% of patients with neuropathy, and in 3% of patients with other neurological diseases. In all cases, however, an inflammatory disease was present, including chronic inflammatory neuropathy, cerebral vasculitis, or multiple sclerosis. Antibodies to HS appear not to be specific for neuropathy, as they occur in several inflammatory diseases. They might contribute to the associated breakdown of the blood-brain or blood-nerve barrier.

Leukemia inhibitory factor induces epidermal hyperplasia in patients with amyotrophic lateral sclerosis

We investigated the biochemical and morphologic alteration in skin of amyotrophic lateral sclerosis patients. We found an obvious high expression of leukemia inhibitory factor and distinct epidermal hyperplasia in the skin of amyotrophic lateral sclerosis patients compared with disease controls. The thickness and cell density, as well as the leukemia inhibitory factor immunostain density, of the epidermis in amyotrophic lateral sclerosis patients correlated positively with duration of illness. The striking fact was the significant epidermal hyperplasia correlating with leukemia inhibitory factor expression in amyotrophic lateral sclerosis patients (r = 0.94, p < 0.001). In vitro experiments revealed that leukemia inhibitory factor stimulated keratinocyte proliferation in primary keratinocyte culture and induced epidermal hyperplasia in skin organ culture. These findings lead to the hypothesis that a high expression of leukemia inhibitory factor is closely associated with epidermal hyperplasia in amyotrophic lateral sclerosis patients.

Antibodies to chondroitin sulfates A, B, and C: clinico-pathological correlates in neurological diseases

Anti-chondroitin sulfates (ChSs) antibodies have been reported in neuropathy and neurodegenerative diseases. Differences in specificities may account for their association with different diseases. Sera from 303 neurological patients were tested for antibodies to ChSs A, B, C. Titers >/=51,200 were found in 16 patients (eight peripheral neuropathy, three motor neuron disease, four multiple sclerosis, one myelitis). Three patients also had anti-sulfatides antibodies, which in two cases cross-reacted with ChSs. By indirect immunofluorescence, positive sera stained nuclei on normal human peripheral nerve sections. These findings indicate that human anti-ChSs antibodies are broadly reactive and not specific to any neurological disease.

Amyotrophic lateral sclerosis: increased hyaluronic acid in the media of the basilar artery

Hyaluronic acid in the basilar artery of 10 patients with sporadic amyotrophic lateral sclerosis (ALS) and 7 age-matched control subjects was examined histochemically and densitometrically. The intensity of staining with alcian blue was significantly increased (P=0.0007) in the media in ALS patients compared with that in control subjects. The staining was virtually eliminated by Streptomyces hyaluronidase. These results clearly indicate an increase of hyaluronic acid in the media of the basilar artery in ALS patients.

Antibodies to chondroitin sulfate C: a new detection assay and correlations with neurological diseases

Antibodies to chondroitin sulfate C (ChS C) have been previously associated with sensory axonal neuropathy. Investigation of these antibodies has, however, been limited by the lack of a sensitive and reliable test for their detection. We developed a new enzyme-linked immunoassorbent assay (ELISA), where biotinylated ChS C was made to adhere to avidin-coated microwells. The new ELISA showed a much greater sensitivity than other currently available ELISAs for detection of anti-ChS C antibodies. A total of 480 sera (466 patients and 14 normal volunteers) were tested at increasing dilutions for anti-ChS C antibody activity. Normal subjects had IgM anti-ChS C antibody titers of up to 3,200 and mildly elevated titers of 6,400 were seen in a variety of diseases. Eleven patients had titers of 12,800 or higher. These included seven patients with sensory axonal neuropathy, three with amyotrophic lateral sclerosis and one with corticobasal ganglionic degeneration. These studies indicate that anti-ChS antibodies do occur in patients with axonal sensory neuropathy, but are not limited to that disease.