Janina Rafałowska

Autophagic Degeneration of Motor Neurons in a Model of Slow Glutamate Excitotoxicity in Vitro

There is increasing evidence that so-called “autophagic cell death” participates in cell degeneration in certain pathological conditions. Autophagy might be involved in some neurodegenerative processes, including lateral amyotrophic sclerosis (SLA). The exact mechanism leading to progressive motor neuron (MN) loss remains unclear, but glutamate-mediated mechanism is thought to be responsible. Previous ultrastructural studies by the authors performed on a model of SLA in vitro, based on chronic glutamate excitotoxicity, revealed a subset of morphological features characteristic to different modes of neuronal death, including autophagic degeneration. The contribution of this pathway of MNs death is evaluated in organotypic cultures of rat lumbar spinal cord chronically exposed to specific glutamate uptake blockers: DL-threo-β-hydroxyaspartate (THA) and L-transpyrrolidine-2,4-dicarboxylate (PDC). The study documents the various steps of authophagy in slowly evolving process of MN neurodegeneration. The cells undergoing autophagy usually exhibited sequestration of some parts of cytoplasm with normal and/or degenerated organelles, whereas other parts of cytoplasm as well as neuronal nucleus remained unchanged. The advanced autophagic changes were often associated with other modes of MN death, especially with apoptosis. Numerous MNs revealed apoptotic nuclear features with typical peripheral margination of nuclear chromatin, accompanied by severe autophagic or autophagic-necrotic degeneration of the cytoplasm. These results support the opinion of unclear distinction between different modes of cell death and indicate the involvement of autophagey in MNs neurodegeneration in vitro.

CADASIL or CADVaSIL

In the present study, morphological examination of patients from two unrelated Polish families with CADASIL was performed. Using light microscopy, there were evident changes characteristic to the disease. On electron microscopy, deposits of granular osmiophillic material (GOM) were found not only in cerebral arteries and veins but also in cerebral capillaries and vessels of the internal organs. These findings indicate that pathological process in CADASIL is generalized and involves also small vessels devoid of smooth muscle cells. Therefore, we propose to consider a replacement for the name CADASIL that better reflects the morphological picture of the disease like, for example, cerebral autosomal dominant vasculopathy with subcortical infarcts and leukoencephalopathy (CADVaSIL) or, to preserve the commonly known acronym, cerebral autosomal dominant angiopathy with subcortical infarcts and leukoencephalopathy.

CADASIL: what component of the vessel wall is really a target for Notch 3 gene mutations?

Abstract Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) is a hereditary cerebrovascular disease leading to cognitive decline, dementia and recurrent strokes. The underlying angiopathy of the small vessels is characterized by basophilic degeneration of the media, Notch 3 protein accumulation in vessel wall and a unique type of ultrastructural deposits located nearby the basal lamina. In some cases of CADASIL, morphological changes similar to those observed in panarteritis nodosa (PAN) were found. PAN-like changes manifested as fibrinoid necrosis of the tunica media and perivascular inflammatory infiltrates were found in arteries not only in the central nervous system but also in internal organs. Presence of PAN-like changes indicates that some autoimmunological mechanisms can participate in the CADASIL process. Although vascular smooth muscle cells seem to be a primary target of the pathogenic process triggered by mutations in Notch 3 gene they are probably not the only target. This article gives a brief overview on the morphologic spectrum of the vascular pathological changes in CADASIL and discusses some of the relevant mechanisms that lead from Notch 3 mutations to ischemic infarcts.

CADASIL: new cases and new questions

We described the first two unrelated Polish families with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). In the morphological examination with light microscopy, two kinds of changes were observed: (1) panarteritis nodosa-like changes with eosinophilic fibrinoid necrosis of the vessel wall and perivascular inflammatory infiltrates and (2) basophilic granular material in the tunica media characteristic of CADASIL. At electron microscopy, we found deposits of granular osmophilic material (GOM) within the wall of arteries, veins and capillary vessels. Our findings imply two questions requiring further investigation: Why in the genetically determined vascular disorder are the features of systemic inflammatory vascular disease present? Why in capillary walls deprived of smooth muscle cells are deposits of GOM present?

Role of endoglin and transforming growth factor-beta in progressive white matter damage after an ischemic stroke.

We morphologically examined human brains several years after a territorial ischemic stroke to assess the development of progressing white matter damage and its pathomechanisms. Our investigations focused on the role of TGF‐β, one of the factors whose expression increases after tissue damage, and its receptor endoglin in the propagation of postischemic injury. Examination of the white matter adjacent to the postapoplectic cavity revealed structural changes in the capillary vessels, disturbed microcirculation, and deep endothelial cell damage with DNA fragmentation in the TUNEL reaction. Many oligodendrocytes also revealed DNA damage and an increased expression of caspase‐3. In the rarefied white matter, the microvessel immune reaction to TGF‐β was diminished while the expression of endoglin was heterogeneous: absent in some capillaries but increased in others in comparison to the vessels located more peripherally from the cavity and in the control material. We conclude that endoglin and TGF‐β can be involved in the development of the microangiopathy responsible for the propagation of postischemic white matter injury in humans. We suggest that disturbances in endoglin expression can influence TGF‐β signaling and, consequently, vessel structure and function. Pronounced endoglin expression can lead to decreased vessel wall integrity while a lack of the constitutively expressed protein is probably a mirror of deep vessel damage.

Effects of liposomes with polyisoprenoids, potential drug carriers, on the cardiovascular and excretory system in rats

BACKGROUND The unpredictable side effects of a majority currently used drugs are the substantial issue, in which patients and physicians are forced to deal with. Augmenting the therapeutic efficacy of drugs may prove more fruitful than searching for the new ones. Since recent studies show that new cationic derivatives of polyisoprenoid alcohols (APrens) might exhibit augmenting properties, we intend to use them as a component of liposomal drug carriers. In this study we investigate if these compounds do not per se cause untoward effects on the living organism. METHODS Male Sprague-Dawley rats received for four weeks daily injections (0.5 ml sc) of liposomes built of dioleoyl phosphatidylethanolamine (DOPE), liposomes built of DOPE and APren-7 (ratio 10:1) or water solvent. Weekly, rats were observed in metabolic cages (24h); blood and urine were sampled for analysis; body weight (BW) and systolic blood pressure (SBP) were determined. After chronic experiment, kidneys and heart were harvested for histological and morphometric analysis. RESULTS The 4-week BW increments were in the range of 97 ± 4 to 102 ± 4%, intergroup differences were not significant. Microalbuminuria was the lowest in the group receiving liposomes with APren-7 (0.22 ± 0.03 mg/day). Water and food intake, plasma and urine parameters were similar in all groups. CONCLUSIONS Newly designed liposomes containing APren-7 did not affect functions of the excretory and cardiovascular systems, and renal morphology; therefore we find them suitable as a component of liposomal drug carriers.

Diverse Expression of Selected SMN Complex Proteins in Humans with Sporadic Amyotrophic Lateral Sclerosis and in a Transgenic Rat Model of Familial Form of the Disease

Background and Objective There is circumstantial evidence linking sporadic amyotrophic lateral sclerosis (ALS) cases to a malfunction or deficit of a multimeric SMN complex that scrutinizes cellular RNAs; the core of this complex is survival motor neuron (SMN, or gemin 1) protein. We intended to verify this hypothesis by comparing the expression of both SMN and several other functionally associated gemins in the anterior horn motoneurons of patients who died of sporadic ALS (sALS), of transgenic rats with overexpression of the mutated human superoxide dismutase 1 gene (SOD1G93A) that represent a model of familial ALS (fALS), and of the respective controls. Methods Using archival material of paraffin blocks with samples of human and rat spinal cords, immunohistochemical reactions with antibodies against SMN and gemins 2, 3, and 4 were performed and assessed by light microscopy. Results The expression of SMN and all other studied gemins was observed in motoneurons of sALS patients, fALS rats, and in all controls, although the intensity varied. The immunolabeling was most intense in sALS patients with relatively fast disease course, and decreased with increasing disease duration in both the human sALS and rat fALS material. Irrespective of the disease stage, sALS material showed no or very low gemin 2 immunoreactivity, while clear gemin 2 immnoreactivity was observed in all fALS rats and control material. Conclusion The deficient expression of gemin 2 in spinal cord motoneurons in human sALS may lead to a dysfunction and loss of neuroprotective action of the SMN complex.

Phenomenon of Schwann cell apoptosis in a case of congenital hypomyelinating neuropathy with basal lamina onion bulb formation

We analyzed a sural nerve biopsy of a child with congenital hypomyelinating neuropathy. A lack of normally myelinated fibres, abnormal architecture of premyelin fibres and basal lamina onion bulbs were identified. The most prominent pathological finding was the appearance of significant death of Schwann cells with apoptotic morphology. This new finding may suggest that abnormal premyelin fibres are susceptible to death and that their disappearance is responsible for empty basal lamina onion bulb formation.