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Histopathological Defects in Intestine in Severe Spinal Muscular Atrophy Mice Are Improved by Systemic Antisense Oligonucleotide Treatment.

Sintusek P, Catapano F, Angkathunkayul N, Marrosu E, Parson SH, Morgan JE, Muntoni F, Zhou H - PLoS ONE (2016)

Bottom Line: We also assessed the therapeutic response of GI histopathology to systemic administration of morpholino antisense oligonucleotide (AON) designed to increase SMN protein expression.Significant anatomical and histopathological abnormalities, with striking reduction of vascular density, overabundance of enteric neurons and increased macrophage infiltration, were detected in the small intestine in SMA mice.We conclude that the observed GI histopathological phenotypes and functional defects observed in these SMA mice are strongly linked to SMN deficiency which can be rescued by systemic administration of AON.

View Article: PubMed Central - PubMed

Affiliation: Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom.

ABSTRACT
Gastrointestinal (GI) defects, including gastroesophageal reflux, constipation and delayed gastric emptying, are common in patients with spinal muscular atrophy (SMA). Similar GI dysmotility has been identified in mouse models with survival of motor neuron (SMN) protein deficiency. We previously described vascular defects in skeletal muscle and spinal cord of SMA mice and we hypothesized that similar defects could be involved in the GI pathology observed in these mice. We therefore investigated the gross anatomical structure, enteric vasculature and neurons in the small intestine in a severe mouse model of SMA. We also assessed the therapeutic response of GI histopathology to systemic administration of morpholino antisense oligonucleotide (AON) designed to increase SMN protein expression. Significant anatomical and histopathological abnormalities, with striking reduction of vascular density, overabundance of enteric neurons and increased macrophage infiltration, were detected in the small intestine in SMA mice. After systemic AON treatment in neonatal mice, all the abnormalities observed were significantly restored to near-normal levels. We conclude that the observed GI histopathological phenotypes and functional defects observed in these SMA mice are strongly linked to SMN deficiency which can be rescued by systemic administration of AON. This study on the histopathological changes in the gastrointestinal system in severe SMA mice provides further indication of the complex role that SMN plays in multiple tissues and suggests that at least in SMA mice restoration of SMN production in peripheral tissues is essential for optimal outcome.

No MeSH data available.


Related in: MedlinePlus

Blood vessel density in duodenum and ileum.(A) Representative image of vWF Immunofluorescence staining in duodenum and ileum of small intestine in control, SMA and PMO25 treated SMA mice. Blood vessels were indicated by vWF (red) staining. DAPI (blue) stains DNA nuclear and was used to outline the intestinal structure. Proportion of vascular density in duodenum (B) and ileum (C). The vascular density was quantified as pixels/unit area using imageJ software. Values in all three groups were then normalized to the mean value in the group of untreated SMA mice. Vascular density was significantly reduced in SMA mice in duodenum (P < 0.001 vs control, P <0.01 vs SMA+PMO25) and ileum (P < 0.05 vs control, P<0.05 vs SMA+PMO25), and was significantly improved after PMO25 treatment. (* P < 0.05, ** P<0.01). Scale bar = 50 μm.
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pone.0155032.g003: Blood vessel density in duodenum and ileum.(A) Representative image of vWF Immunofluorescence staining in duodenum and ileum of small intestine in control, SMA and PMO25 treated SMA mice. Blood vessels were indicated by vWF (red) staining. DAPI (blue) stains DNA nuclear and was used to outline the intestinal structure. Proportion of vascular density in duodenum (B) and ileum (C). The vascular density was quantified as pixels/unit area using imageJ software. Values in all three groups were then normalized to the mean value in the group of untreated SMA mice. Vascular density was significantly reduced in SMA mice in duodenum (P < 0.001 vs control, P <0.01 vs SMA+PMO25) and ileum (P < 0.05 vs control, P<0.05 vs SMA+PMO25), and was significantly improved after PMO25 treatment. (* P < 0.05, ** P<0.01). Scale bar = 50 μm.

Mentions: We and others recently reported decreased vascular density in skeletal muscle and spinal cord in SMA mice [26,27] and in muscle from young SMA patients [27]. To assess the relationship between the involvement of vascular developmental abnormalities in the gut and its relationship to the observed gut phenotype in SMA, we measured the vascular density in the small intestine in SMA mice. Von Willebrand factor (vWF) immunofluorescence staining in duodenum and ileum (Fig 3A) revealed a dramatic decrease in vascular density in SMA mice. There was a significant reduction of blood vessel density in both duodenum (75% reduction) and ileum (65% reduction) in SMA mice compared to littermate controls (Fig 3B and 3C). The decreased vascular density in both duodenum and ileum was significantly improved in SMA mice after systemic PMO25 treatment (P<0.01 and P<0.05 vs SMA in duodenum and ileum, respectively), to near-normal levels (no significance between SMA+PMO25 and control; Fig 3B and 3C).


Histopathological Defects in Intestine in Severe Spinal Muscular Atrophy Mice Are Improved by Systemic Antisense Oligonucleotide Treatment.

Sintusek P, Catapano F, Angkathunkayul N, Marrosu E, Parson SH, Morgan JE, Muntoni F, Zhou H - PLoS ONE (2016)

Blood vessel density in duodenum and ileum.(A) Representative image of vWF Immunofluorescence staining in duodenum and ileum of small intestine in control, SMA and PMO25 treated SMA mice. Blood vessels were indicated by vWF (red) staining. DAPI (blue) stains DNA nuclear and was used to outline the intestinal structure. Proportion of vascular density in duodenum (B) and ileum (C). The vascular density was quantified as pixels/unit area using imageJ software. Values in all three groups were then normalized to the mean value in the group of untreated SMA mice. Vascular density was significantly reduced in SMA mice in duodenum (P < 0.001 vs control, P <0.01 vs SMA+PMO25) and ileum (P < 0.05 vs control, P<0.05 vs SMA+PMO25), and was significantly improved after PMO25 treatment. (* P < 0.05, ** P<0.01). Scale bar = 50 μm.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4862622&req=5

pone.0155032.g003: Blood vessel density in duodenum and ileum.(A) Representative image of vWF Immunofluorescence staining in duodenum and ileum of small intestine in control, SMA and PMO25 treated SMA mice. Blood vessels were indicated by vWF (red) staining. DAPI (blue) stains DNA nuclear and was used to outline the intestinal structure. Proportion of vascular density in duodenum (B) and ileum (C). The vascular density was quantified as pixels/unit area using imageJ software. Values in all three groups were then normalized to the mean value in the group of untreated SMA mice. Vascular density was significantly reduced in SMA mice in duodenum (P < 0.001 vs control, P <0.01 vs SMA+PMO25) and ileum (P < 0.05 vs control, P<0.05 vs SMA+PMO25), and was significantly improved after PMO25 treatment. (* P < 0.05, ** P<0.01). Scale bar = 50 μm.
Mentions: We and others recently reported decreased vascular density in skeletal muscle and spinal cord in SMA mice [26,27] and in muscle from young SMA patients [27]. To assess the relationship between the involvement of vascular developmental abnormalities in the gut and its relationship to the observed gut phenotype in SMA, we measured the vascular density in the small intestine in SMA mice. Von Willebrand factor (vWF) immunofluorescence staining in duodenum and ileum (Fig 3A) revealed a dramatic decrease in vascular density in SMA mice. There was a significant reduction of blood vessel density in both duodenum (75% reduction) and ileum (65% reduction) in SMA mice compared to littermate controls (Fig 3B and 3C). The decreased vascular density in both duodenum and ileum was significantly improved in SMA mice after systemic PMO25 treatment (P<0.01 and P<0.05 vs SMA in duodenum and ileum, respectively), to near-normal levels (no significance between SMA+PMO25 and control; Fig 3B and 3C).

Bottom Line: We also assessed the therapeutic response of GI histopathology to systemic administration of morpholino antisense oligonucleotide (AON) designed to increase SMN protein expression.Significant anatomical and histopathological abnormalities, with striking reduction of vascular density, overabundance of enteric neurons and increased macrophage infiltration, were detected in the small intestine in SMA mice.We conclude that the observed GI histopathological phenotypes and functional defects observed in these SMA mice are strongly linked to SMN deficiency which can be rescued by systemic administration of AON.

View Article: PubMed Central - PubMed

Affiliation: Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, London, United Kingdom.

ABSTRACT
Gastrointestinal (GI) defects, including gastroesophageal reflux, constipation and delayed gastric emptying, are common in patients with spinal muscular atrophy (SMA). Similar GI dysmotility has been identified in mouse models with survival of motor neuron (SMN) protein deficiency. We previously described vascular defects in skeletal muscle and spinal cord of SMA mice and we hypothesized that similar defects could be involved in the GI pathology observed in these mice. We therefore investigated the gross anatomical structure, enteric vasculature and neurons in the small intestine in a severe mouse model of SMA. We also assessed the therapeutic response of GI histopathology to systemic administration of morpholino antisense oligonucleotide (AON) designed to increase SMN protein expression. Significant anatomical and histopathological abnormalities, with striking reduction of vascular density, overabundance of enteric neurons and increased macrophage infiltration, were detected in the small intestine in SMA mice. After systemic AON treatment in neonatal mice, all the abnormalities observed were significantly restored to near-normal levels. We conclude that the observed GI histopathological phenotypes and functional defects observed in these SMA mice are strongly linked to SMN deficiency which can be rescued by systemic administration of AON. This study on the histopathological changes in the gastrointestinal system in severe SMA mice provides further indication of the complex role that SMN plays in multiple tissues and suggests that at least in SMA mice restoration of SMN production in peripheral tissues is essential for optimal outcome.

No MeSH data available.


Related in: MedlinePlus