KIF1A-related autosomal dominant spastic paraplegias (SPG30) in Russian families.

BACKGROUND: Spastic paraplegia type 30 (SPG30) caused by KIF1A mutations was first reported in 2011 and was initially considered a very rare autosomal recessive (AR) form. In the last years, thanks to the development of massive parallel sequencing, SPG30 proved to be a rather common autosomal dominant (AD) form of familial or sporadic spastic paraplegia (SPG),, with a wide range of phenotypes: pure and complicated. The aim of our study is to detect AD SPG30 cases and to examine their molecular and clinical characteristics for the first time in the Russian population. METHODS: Clinical, genealogical and molecular methods were used. Molecular methods included massive parallel sequencing (MPS) of custom panel 'spastic paraplegias' with 62 target genes complemented by familial Sanger sequencing. One case was detected by the whole -exome sequencing. RESULTS: AD SPG30 was detected in 10 unrelated families, making it the 3rd (8.4%) most common SPG form in the cohort of 118 families. No AR SPG30 cases were detected. In total, 9 heterozygous KIF1A mutations were detected, with 4 novel and 5 known mutations. All the mutations were located within KIF1A motor domain. Six cases had pure phenotypes, of which 5 were familial, where 2 familial cases demonstrated incomplete penetrance, early onset and slow relatively benign SPG course. All 4 complicated cases were caused by novel mutations without familial history. The phenotypes varied from severe in two patients (e.g. lack of walking, pronounced mental retardation) to relatively mild non-disabling symptoms in two others. CONCLUSION: AD SPG30 is one of the most common forms of SPG in Russia, the disorder has pronounced clinical variability while pure familial cases represent a significant part.

[Dimephosphon restores functions of the injured spinal cord].

In clinical practice, dimephosphon is used as a vasoactive agent in cases of traumatic brain injury. We have studied the influence of dimephosphon on the functional recovery of dog spinal cord after lesion. The spinal cord trauma was modeled using the methods described by Allen. In a period of time from the 1st to 10th day after injury, experimental group of animals was treated intravenously with 2.5% dimephosphon solution (18.75 mg/kg).The recovery of conduction in descending spinal nerves was studied using the transcranial magnetic stimulation technique on the Neurotest complex comprising a transcranial magnetic stimulator and a computer analyzer. The state of sacrolumbar motoneurons was determined by the method of stimulation electromyography that allows both H-reflex and M-wave responses to be recorded. The status of experimental animals, their locomotor activity and pain sensation were evaluated using standard clinical assessment. Morphological analysis performed with paraffin sections (hematoxylin-eosin staining) demonstrated that dimephosphon decreased the initiation of apoptosis and necrosis and supported the recovery of injured parts of spinal cord. Thus, the results revealed a beneficial effect of dimephosphon administration on the functional recovery of injured spinal cord.

Survival and phenotypic characteristics of axotomized neurons in spinal ganglia.

Trauma to the peripheral processes of sensory neurons of different subpopulations was followed by indirect immunohistochemical analysis of the expression of Bcl-X(L) and Bax, which are, respectively, antiapoptotic and proapoptotic proteins of the Bcl-2 family, and also of the cytokine interleukin-1beta, with the aim of identifying the roles of these substances in controlling apoptosis. The survival abilities of these neurons after central and peripheral axotomy were compared by studying the expression of the high molecular weight component of the neurofilament triplet NF200 and isolectin B4 (IB4). By day 30 after central axotomy, there were no changes in the total numbers of neurons in ganglia L(IV)-L(V) in rats, though there were significant reductions in the numbers of NF200+ neurons. In spinal ganglion L(V) of mice, the proapoptotic protein was detected in the nuclei of 46% of small neurons, which account for 20% of all neurons in the ganglion. By day 30 after nerve compression, Bax was expressed in the nuclei of 30% of neurons and the cytoplasm of 20% of neurons. In intact animals, the antiapoptotic protein Bcl-X(L) was seen in the cytoplasm of 30% of small neurons, as well as in satellite cells surrounding large and intermediate neurons. By day 30 after nerve trauma, Bcl-X(L) was not expressed in spinal ganglion L(V). Interleukin-1beta was present in the cytoplasm of 17% of neurons belonging to the subpopulations of large and intermediate neurons. By day 30 after nerve compression, interleukin-1 beta+ neurons were not identified.

[Survival and phenotypic characterisctic of axotomized dorsal root ganglion neurons]. / Vyzhivanie i fenotipicheskaia kharakteristika aksotomirovannykh neironov spinal'nykh gangliev.

Using indirect inmunohistochemical method, the expression of Bcl-XL and Bax, anti- and proapoptotic proteins of Bcl-2 family, as well as of cytokine IL-1beta were studied to demonstrate the role of these substances in apoptosis regulation of sensory neurons of different subpopulations after the severance of their peripheral processes. For comparison of the capacity of these neurons to survive after central and peripheral axotomy, the expression of high-molecular component of neurofilament triplet NF200 and isolectin B4 (IB4) binding were studied. At day 30 after central axotomy, the total number of neurons in LIV-LV ganglia of rat was not changed, but the number of NF200+ neurons was decreased. In mouse Lv dorsal root, proapoptotic BaX protein was demonstrated in the nuclei of 46% of small neurons that accounts for 20% of the total neuronal number in this ganglion. By day 30 after the nerve crush separate Bax expression was found in the nuclei of 30% and in the cytoplasm of 20% of neurons. In intact animals, dorsal root ganglion antiapoptotic Bcl-XL protein was expressed in the cytoplasm of 30% of small neurons, as well as in satellite cells surrounding large and intermediate neurons. At day 30 after the nerve crush Bcl-XL expression in LV ganglion was not detected. IL-1beta was present in the cytoplasm of 17% of neurons belonging predominantly to the subpopulations of large and intermediate neurons. By day 30 after the nerve crush IL-1(+-neurons were not found.

Effect of dipeptide N-acetylaspartylglutamate on denervation-induced changes in the volume of rat skeletal muscle fibers.

N-acetylaspartylglutamate prevents the denervation-induced increase in the volume of muscle fibers in rat diaphragm, the phenomenon being more pronounced for the hydrolysable isomer. The effect of dipeptide manifested against the background of blockade of metabotropic glutamate receptors. It was hypothesized that N-acetylaspartylglutamate is involved in the regulation of the volume of skeletal muscle fibers via activation of ionotropic receptors by both dipeptide and glutamate molecules.

Immunohistochemical study of rat soleus muscle in various modes of denervation.

Immunohistochemical study with monoclonal antibodies against fast myosin heavy chains showed that excision of a fragment of sciatic nerve does not change, while compression of the nerve decreased the relative content of fast muscle fibers in rat soleus muscle. The content of fast fibers in the muscles of contralateral limbs decreased in both models of denervation. Hence, contralateral limbs cannot be used as the control in experiments with disturbed neurotrophic function. Possible mechanisms underlying changes in the immunohistochemical profiles of experimental and contralateral limbs are discussed.