Muscle Fiber Degeneration Research Articles

Restoring Dystrophin Expression by Skipping Exons 6 and 8 in Neonatal Dystrophic Dogs.

Duchenne muscular dystrophy (DMD) is caused by the mutations in the DMD gene resulting in no dystrophin production. Skipping DMD exons using phosphorodiamidate morpholino oligomers (PMOs) is an emerging treatment strategy that can restore the reading frame of the mutated gene and produce truncated but functional dystrophin protein. To date, four PMOs, including eteplirsen, casimersen, viltolarsen, and golodirsen, have been conditionally approved by the FDA for the treatment of DMD. Since degeneration of muscle fibers and irreversible fibrosis occur from childhood, the earlier treatment is preferred. The canine X-linked muscular dystrophy in Japan (CXMDj), a dog model of DMD, produces no dystrophin and exhibits a severe phenotype similar to human patients from early childhood. As such, CXMDj, which harborsa splice site mutation in intron 6, is a useful model for examining the long-term effects of early PMO treatment. In this chapter, we describe the systemic delivery of a cocktail of four PMOs that can successfully induce multiple exon skipping (exons 6-9) in neonataldystrophic dogs. We also describe the procedures to evaluate the efficacy and toxicity, including clinical grading of dystrophic dogs, ELISA-based quantification of PMOs, histology, RT-PCR, and western blotting.

Establishment of an animal model to study the effects of amputation on the cardiovascular system

Lower limb amputation is a significant change in body structure. Loss of muscle, blood vessels, and blood leads to a redistribution of blood flow and changes in resistance at the end of blood vessels. In view of the significant increase in the prevalence of cardiovascular disease after lower limb amputation, the mechanism of which is still unclear, this study aims to establish an animal research model that can verify and explore the effects of amputation on cardiovascular system, and provide the experimental basis for subsequent animal experiments when exploring the effect of different amputation levels on the cardiovascular system. SPF New Zealand rabbits were divided into normal group ( n = 6) and amputation group ( n = 6). The amputation group was treated with above-knee amputation. The changes of low-density liptein cholesterol (LDL-C) and total cholesterol (TC) in serum of all the rabbits were monitored regularly after the surgery. The arterial pathological examination was conducted after the experimental rabbits were executed. The results showed that compared with the normal group, serum LDL-C content and TC content in the amputation group were significantly increased ( P<0.05); The blood vessels of the amputated rabbits had pathological changes such as degeneration and necrosis of smooth muscle cells in the middle membrane layer and rupture of elastic fibers. At the abdominal aorta and aortic arch, the elastic fiber area expression percentage (EFEP) of the experimental group was significantly lower than that of the normal group. The results suggest that the cardiovascular system of rabbits has the tendency of decreased arterial elasticity and lipid deposition in blood after amputation, indicating that the animal research model on the effect of amputation on the cardiovascular system has been successfully established, and can provide an experimental platform for further study on the mechanism of the effect of amputation on the cardiovascular system.

P.89 Immune-mediated necrotizing myopathy associated with anti-SRP Antibodies: Three cases in Korea

Immune-mediated necrotizing myopathy associated with anti-SRP antibodies (anti-SRP myopathy) is characterized by progressive proximal muscle weakness and markedly elevated creatinine kinase (CK. Here, we report the clinical features of three Korean patient with anti-SRP myopathy. A 63-year-old man presented with progressive proximal muscle weakness and dysphagia. He showed symmetrical proximal weakness. The serum CK was 5,560U/L. The muscle biopsy of the biceps brachii showed mild muscle fiber size variation and a few degenerating muscle fibers. Muscle weakness and dysphagia improved after using steroids and azathioprine, but gradually worsen. At the last follow-up study, serum CK was 1,252 IU/L and the serum anti-SRP antibody was positive. A 46-year-old man was referred to our clinic due to progressive proximal muscle weakness. The serum CK was 6,114 U/L. The muscle biopsy of the vastus lateralis muscle showed marked size variation in muscle fibers and many necrotic fibers. Steroid pulse therapy lowered serum CK level, but muscle weakness did not improve. The serum anti- SRP antibody was positive. After the diagnosis, steroid, methotrexate, and intravenous immunoglobulin were used, but his muscle strength did not improve significantly. 43-year-old woman presented with proximal muscle weakness and elevated serum CK level. The serum CK was greater than 13,000 U/L. Needle EMG showed active generalized myopathy. The muscle biopsy of vastus lateralis muscle revealed a few necrotic fibers without endomysial inflammatory cell infiltration. The serum anti-SRP antibody was positive. After steroid pulse therapy, her muscle weakness did not improve and dysphagia was newly developed. She was currently treated with steroid and azathioprine. Anti-SRP myopathy is one of the most disabling and less responsiveness to treatment and we would like to report cases have rarely been reported in Korea.

Pregabalin synchronizes the regeneration of nerve and muscle fibers optimizing the gait recovery of MDX dystrophic mice.

Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder induced by mutations in the dystrophin gene, leading to a degeneration of muscle fibers, triggering retrograde immunomodulatory, and degenerative events in the central nervous system. Thus, neuroprotective drugs such as pregabalin (PGB) can improve motor function by modulating plasticity, together with anti-inflammatory effects. The present work aimed to study the effects of PGB on axonal regeneration after axotomy in dystrophic and non-dystrophic mice. For that, MDX and C57BL/10 mouse strains were subjected to peripheral nerve damage and were treated with PGB (30 mg/kg/day, i.p.) for 28 consecutive days. The treatment was carried out in mice as soon as they completed 5 weeks of life, 1 week before the lesion, corresponding to the peak period of muscle degeneration in the MDX strain. Six-week-old mice were submitted to unilateral sciatic nerve crush and were sacrificed in the 9th week of age. The ipsi and contralateral sciatic nerves were processed for immunohistochemistry and qRT-PCR, evaluating the expression of proteins and gene transcripts related to neuronal and Schwann cell activity. Cranial tibial muscles were dissected for evaluation of neuromuscular junctions using α-bungarotoxin, and the myelinated axons of the sciatic nerve were analyzed by morphometry. The recovery of motor function was monitored throughout the treatment through tests of forced locomotion (rotarod) and spontaneous walking track test (Catwalk system). The results show that treatment with PGB reduced the retrograde cyclic effects of muscle degeneration/regeneration on the nervous system. This fact was confirmed after peripheral nerve injury, showing better adaptation and response of neurons and glia for rapid axonal regeneration, with efficient muscle targeting and regain of function. No side effects of PGB treatment were observed, and the expression of pro-regenerative proteins in neurons and Schwann cells was upregulated. Morphometry of the axons was in line with the preservation of motor endplates, resulting in enhanced performance of dystrophic animals. Overall, the present data indicate that pregabalin is protective and enhances regeneration of the SNP during the development of DMD, improving motor function, which can, in turn, be translated to the clinic.

Impact of Radiation-induced Trismus on Patients’ Life Quality

Head and neck cancers (HNC) account for 10–15% of all cancers globally. Curative radiation therapy (RT) and concurrent chemoradiotherapy (CCRT) with or without surgery are widely accepted standard treatment modalities for these patients. Radiation-induced fibrosis is one of the side effects of these treatments, and it causes degeneration, inflammation, pain, and atrophy of the masticatory muscle fibers and the temporomandibular joint, resulting in trismus. Trismus, also known as hypomobility of the mouth, is defined as a restricted opening of the mouth. Radiation-induced trismus (RIT) can occur within the first three months of treatment or up to 12–48 months later during the follow-up period. It has a significant negative influence on daily activities and vital oral functions, including speech problems, difficulty eating or drinking, psychological problems, malnutrition, dehydration, and difficulty with oral hygiene, reducing the quality of life (QoL). Given the underappreciated nature of trismus and its negative consequences in HNC patients receiving RT or C-CRT, the purpose of this review was to provide a concise review of the physical, social, and emotional implications of RIT and their impact on QoL measures, as well as the available evaluation methods for physicians in the related medical fields.

Comparison of microanatomy of ascending aorta and pulmonary trunk with age: A cross-sectional study

Cardiovascular disease (CVD) accounts for the leading cause of mortality worldwide and it has a strong association with age. Aging brings about structural and functional changes in vessels, culminating in CVD. This study aims at determining and comparing the structural age changes in the two great vessels of heart, ascending aorta (AA) and pulmonary trunk (PT).Human ascending aorta and pulmonary trunk samples were obtained during autopsy from 55 individuals of different age group. After processing, they were stained with eosin haematoxylin and special stains to identify connective tissue fibres and smooth muscle cells. Thickness of each tunic of the vessel wall, full wall thickness, quantity of smooth muscle cells and severity of fragmentation of elastic fibres were detected.In all age groups, PT was thinner than AA. Average full wall thickness of AA was greatest in the sixth decade of life while that of PT in the fourth decade. Elastic fibres were long, straight and arranged in a lamellar pattern in tunica media of both the vessels in fetal life. They underwent fragmentation from first decade of life in PT and from third decade in AA. Grade5 fragmentation was noticed only in PT. Degeneration of smooth muscle cells occurred in both the vessels with age, but was very little in PT.Both the great vessels showed degenerative changes with advancing age, but after the first decade of life, the changes were very less in PT when compared to AA.

Sphingosine Phosphate Lyase Is Upregulated in Duchenne Muscular Dystrophy, and Its Inhibition Early in Life Attenuates Inflammation and Dystrophy in Mdx Mice.

Duchenne muscular dystrophy (DMD) is a congenital myopathy caused by mutations in the dystrophin gene. DMD pathology is marked by myositis, muscle fiber degeneration, and eventual muscle replacement by fibrosis and adipose tissue. Satellite cells (SC) are muscle stem cells critical for muscle regeneration. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid that promotes SC proliferation, regulates lymphocyte trafficking, and is irreversibly degraded by sphingosine phosphate lyase (SPL). Here, we show that SPL is virtually absent in normal human and murine skeletal muscle but highly expressed in inflammatory infiltrates and degenerating fibers of dystrophic DMD muscle. In mdx mice that model DMD, high SPL expression is correlated with dysregulated S1P metabolism. Perinatal delivery of the SPL inhibitor LX2931 to mdx mice augmented muscle S1P and SC numbers, reduced leukocytes in peripheral blood and skeletal muscle, and attenuated muscle inflammation and degeneration. The effect on SC was also observed in SCID/mdx mice that lack mature T and B lymphocytes. Transcriptional profiling in the skeletal muscles of LX2931-treated vs. control mdx mice demonstrated changes in innate and adaptive immune functions, plasma membrane interactions with the extracellular matrix (ECM), and axon guidance, a known function of SC. Our cumulative findings suggest that by raising muscle S1P and simultaneously disrupting the chemotactic gradient required for lymphocyte egress, SPL inhibition exerts a combination of muscle-intrinsic and systemic effects that are beneficial in the context of muscular dystrophy.

Oculopharyngeal muscular dystrophy coexisting with myasthenia gravis.

Oculopharyngeal muscular dystrophy (OPMD) and myasthenia gravis are both rare conditions of different pathophysiological nature, so a fortuitous association is unlikely. However, antiacetylcholine receptor antibodies may be found in other genetic myopathies and this is probably not coincidental. Muscle fibre degeneration can induce innate immune responses that may break immune tolerance and allow the generation of autoantibodies to muscle proteins. We report a patient with atypical OPMD who also had acetylcholine receptor antibody-mediated myasthenia gravis. This report raises awareness of the diagnostic and treatment implications of the association of myasthenia gravis with genetic myopathies.

Microenergy acoustic pulse therapy restores function and structure of pelvic floor muscles after simulated birth injury.

BackgroundThe mechanisms of the microenergy acoustic pulse (MAP) therapy on restoring structure and function of pelvic floor muscles (PFM) after simulated birth injury are not well understood.MethodsA total 24 female Sprague-Dawley rats were randomly grouped into sham control (sham), vaginal balloon dilation and ovariectomy (VBDO), VBDO + β-aminopropionitrile (BAPN, an irreversible LOX inhibitor), and VBDO + BAPN and treated with MAP (n=6 in each group). The MAP therapy was administered 2 times per week for 4 weeks with 1-week washout, the functional and histological studies were conducted in all 24 rats. The viscoelastic behavior of the PFM, including iliococcygeus (IC) and pubococcygeus (PC), was examined with a biomechanical assay. The structure of the PFM was assessed by immunofluorescence and Masson’s trichrome staining.ResultsThe leak point pressure (LPP) assay demonstrated that the MAP therapy group had higher LPPs compared to that of VBDO and BAPN groups. In the sham group, the muscular stiffness (K) of IC muscle was significantly higher than that of PC muscle while the pelvic floor muscle rebound activity (MRA) of PC muscle was stronger than that of IC muscle (291.26±45.33 and 241.18±14.23 N/cm2, respectively). Both VBDO and BAPN decreased the MRA and increased the K in both IC and PC. Histologic examination revealed increased fibrous tissue (collagen) and degeneration of muscle fibers in both VBDO and BAPN groups. MAP therapy significantly reduced the collagen content and improved the architecture of muscle fibers.ConclusionsMAP appears to restore the structure and function of PFM by regenerating muscular fibers and improving biomechanical properties in an animal model of simulated birth injury.

Genetics and muscle pathology in the diagnosis of muscular dystrophies: An update.

Muscular dystrophies are a clinically and genetically heterogeneous group of disorders involving the skeletal muscles. They have a progressive clinical course and are characterized by muscle fiber degeneration. Congenital muscular dystrophies (CMD) include dystroglycanopathies, merosin-deficient CMD, collagen VI-deficient CMD, SELENON-related rigid spine muscular dystrophy, and LMNA-related CMD. Childhood and adult-onset muscular dystrophies include dystrophinopathies, limb-girdle muscular dystrophies, Emery-Dreifuss muscular dystrophy, facioscapulohumeral muscular dystrophy, and myotonic dystrophy. Traditionally, muscle biopsy and histopathology along with special pathology techniques such as immunohistochemistry or immunoblotting were used for the diagnosis of muscular dystrophies. However, recent advances in molecular genetic testing, especially the next-generation sequencing technology, have revolutionized the diagnosis of muscular dystrophies. Identification of the underlying genetic basis helps in appropriate management and prognostication of the affected individual and genetic counseling of the family. In addition, identification of the exact disease-causing mutations is necessary for accurate prenatal genetic testing and carrier testing, to prevent recurrence in the family. Mutation identification is also essential for initiating mutation-specific therapies (which have been developed recently, especially for Duchenne muscular dystrophy) and for enrolment of patients into ongoing therapeutic clinical trials. The 'genetic testing first' approach has now become the norm in most centers. Nonetheless, muscle biopsy-based testing still has an important role to play, especially for cases where genetic testing is negative or inconclusive for the etiology.

Does oral ciprofloxacin affect the structure of thoracic aorta in adult and senile male albino rats? A clue to fluoroquinolones-induced risk of aortic dissection.

In this study, the effect of oral ciprofloxacin on the structure of the thoracic aorta in rats was investigated. Twenty four male albino rats were divided into 4 groups (6 rats/group): group I (adult control), group II (adult rats treated with ciprofloxacin), group III (senile control), and group IV (senile rats treated with ciprofloxacin). Rats in groups II and IV received ciprofloxacin via oral gavage in a daily dose of 3.5 mg/kg/d for 14 days, while control rats received equivalent amount of distilled water used to dissolve the drug. After 2 weeks, all rats were sacrificed, thoracic aortae were dissected, and half of the specimens were processed for paraffin sections and examined by light microscopy. The other half of the specimens were prepared for scanning electron microscopy. Sections from rats treated with ciprofloxacin showed evident damaging effect on aortic wall particularly in (group IV). Aortic intima showed, focal desquamation of the lining epithelium. Tunica media exhibited loss of the normal concentric arrangement and degeneration of the smooth muscle cells. Immune staining for alpha smooth muscle actin showed muscle damage. Interestingly, some sections in (group IV) showed out-pouch (aneurysm like) of the aortic wall. There was dense collagen fibers deposition. Scanning electron microscopic observations of (group IV) revealed uneven intima, adherent blood cells and fibrin filaments to damaged intima, and out-pouch formation. It was concluded that oral ciprofloxacin caused deleterious structural changes in the thoracic aortic wall of rats explaining clinical observations of fluoroquinolones induced risk of aortic dissection and aneurysm.

1,2-Dehydropyrrolizidine Alkaloids: Their Potential as a Dietary Cause of Sporadic Motor Neuron Diseases.

Sporadic motor neuron diseases (MNDs), such as amyotrophic lateral sclerosis (ALS), can be caused by spontaneous genetic mutations. However, many sporadic cases of ALS and other debilitating neurodegenerative diseases (NDDs) are believed to be caused by environmental factors, subject to considerable debate and requiring intensive research. A common pathology associated with MND development involves progressive mitochondrial dysfunction and oxidative stress in motor neurons and glial cells of the central nervous system (CNS), leading to apoptosis. Consequent degeneration of skeletal and respiratory muscle cells can lead to death from respiratory failure. A significant number of MND cases present with cancers and liver and lung pathology. This Perspective explores the possibility that MNDs could be caused by intermittent, low-level dietary exposure to 1,2-dehydropyrrolizidine alkaloids (1,2-dehydroPAs) that are increasingly recognized as contaminants of many foods consumed throughout the world. Nontoxic, per se, 1,2-dehydroPAs are metabolized, by particular cytochrome P450 (CYP450) isoforms, to 6,7-dihydropyrrolizines that react with nucleophilic groups (-NH, -SH, -OH) on DNA, proteins, and other vital biochemicals, such as glutathione. Many factors, including aging, gender, smoking, and alcohol consumption, influence CYP450 isoform activity in a range of tissues, including glial cells and neurons of the CNS. Activation of 1,2-dehydroPAs in CNS cells can be expected to cause gene mutations and oxidative stress, potentially leading to the development of MNDs and other NDDs. While relatively high dietary exposure to 1,2-dehydroPAs causes hepatic sinusoidal obstruction syndrome, pulmonary venoocclusive disease, neurotoxicity, and diverse cancers, this Perspective suggests that, at current intermittent, low levels of dietary exposure, neurotoxicity could become the primary pathology that develops over time in susceptible individuals, along with a tendency for some of them to also display liver and lung pathology and diverse cancers co-occurring with some MND/NDD cases. Targeted research is recommended to investigate this proposal.

Comprehensive transcriptomic analysis shows disturbed calcium homeostasis and deregulation of T lymphocyte apoptosis in inclusion body myositis

ObjectiveInclusion body myositis (IBM) has an unclear molecular etiology exhibiting both characteristic inflammatory T-cell activity and rimmed-vacuolar degeneration of muscle fibers. Using in-depth gene expression and splicing studies, we aimed at understanding the different components of the molecular pathomechanisms in IBM.MethodsWe performed RNA-seq on RNA extracted from skeletal muscle biopsies of clinically and histopathologically defined IBM (n = 24), tibial muscular dystrophy (n = 6), and histopathologically normal group (n = 9). In a comprehensive transcriptomics analysis, we analyzed the differential gene expression, differential splicing and exon usage, downstream pathway analysis, and the interplay between coding and non-coding RNAs (micro RNAs and long non-coding RNAs).ResultsWe observe dysregulation of genes involved in calcium homeostasis, particularly affecting the T-cell activity and regulation, causing disturbed Ca2+-induced apoptotic pathways of T cells in IBM muscles. Additionally, LCK/p56, which is an essential gene in regulating the fate of T-cell apoptosis, shows increased expression and altered splicing usage in IBM muscles.InterpretationOur analysis provides a novel understanding of the molecular mechanisms in IBM by showing a detailed dysregulation of genes involved in calcium homeostasis and its effect on T-cell functioning in IBM muscles. Loss of T-cell regulation is hypothesized to be involved in the consistent observation of no response to immune therapies in IBM patients. Our results show that loss of apoptotic control of cytotoxic T cells could indeed be one component of their abnormal cytolytic activity in IBM muscles.

Protective Effect of Rutin Trihydrate Against Dose-Dependent, Cisplatin-Induced Cardiac Toxicity in Isolated Perfused Rat's Heart.

BackgroundCisplatin is a common anticancer drug with potential cardiac and renal toxicities. Rutin, a natural compound present in various medicinal plants, has been shown to protect against chemotherapy-induced toxicities. In this study, we explored the protective effect of rutin against the dose-dependent cardiotoxic effects of cisplatin such as perfusion pressure, histopathologic effect on the myocardium, and oxidative stress in isolated perfused rat hearts.MethodologyThe cardiotoxic effects of cisplatin were studied at three dosages (1, 7, and 14 mg/L) in isolated perfused rat hearts. The dose-dependent, cisplatin-induced toxic effects on left ventricular pressure (LVP), heart rate (HR), dp/dt (maximum), dp/dt (minimum), perfusion pressure, pressure-time index, contractility index, and duration of diastole were assessed. The effects of cisplatin were measured one minute before perfusion of cisplatin and 60 minutes after perfusion of the isolated rat hearts.ResultsCisplatin (1-14 mg/L) caused a significant (p < 0.05) dose-dependent reduction in LVP. The percentage LVP values reduced from 94 ± 9 (control untreated hearts) to 70 ± 6, 69 ± 5, and 65 ± 4 in hearts treated with 1, 7, and 14 mg/L of cisplatin, respectively. Similarly, cisplatin at similar doses caused a marked reduction in the values of dp/dt (maximum), dp/dt (minimum), and pressure-time index in isolated rat hearts. The respective percentage values of these parameters compared to those of untreated hearts were significantly reduced from 101 ± 7 to 72 ± 5, 92 ± 8 to 69 ± 4, and 92 ± 12 to 57 ± 7 in hearts treated with 14 mg/L of cisplatin. Perfusion of hearts with rutin trihydrate (1 µM/L) 10 minutes before administration of cisplatin and throughout the experiment attenuated the detrimental effects of cisplatin on cardiac functions in isolated rat hearts (p < 0.05). In addition, cisplatin-induced degeneration and necrosis of cardiac muscle cells reduced with the concurrent administration of rutin and restored normal heart histology. Moreover, cisplatin-induced reduction in glutathione and increased level of malondialdehyde in the myocardium was reversed by concurrent administration of rutin in isolated rat hearts.ConclusionsCisplatin produced a dose-dependent impairment of several parameters of cardiac function such as LVP, contractility index, and pressure-time index. It caused histopathological alterations in isolated rat hearts. These harmful effects of cisplatin were suppressed by rutin trihydrate, suggesting the potential protective effects of rutin against cisplatin-induced cardiotoxicity. Rutin trihydrate also improved the reduced glutathione contents and suppressed the malondialdehyde contents in the cardiac tissue of isolated rat hearts, suggesting that the observed beneficial effects of rutin trihydrate in this study could be related to its antioxidant properties.

Mechanisms regulating cerebral hypoperfusion in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

Cerebral small vessel disease (CSVD) is a leading cause of stroke and dementia. As the most common type of inherited CSVD, cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is characterized by the NOTCH3 gene mutation which leads to Notch3 ectodomain deposition and extracellular matrix aggregation around the small vessels. It further causes smooth muscle cell degeneration and small vessel arteriopathy in the central nervous system. Compromised cerebral blood flow occurs in the early stage of CADASIL and is associated with white matter hyperintensity, the typical neuroimaging pathology of CADASIL. This suggests that cerebral hypoperfusion may play an important role in the pathogenesis of CADASIL. However, the mechanistic linkage between NOTCH3 mutation and cerebral hypoperfusion remains unknown. Therefore, in this mini-review, it examines the cellular and molecular mechanisms contributing to cerebral hypoperfusion in CADASIL.

Trichinosis in the Rostov oblast

In the Russian Federation, cases of infection with trichinosis in a population of people or animals are annually recorded. Trichinosis is intestinal and tissue helminthiasis of humans and a number of mammals, caused all over the world by nematodes. A person becomes infected with the parasite by eating meat containing live encapsulated Trichinella larvae. Mating takes place in the gastrointestinal tract, fertilized females are introduced into the intestinal mucosa with their anterior thinned ends. The clinical picture of trichinosis is accompanied by the development of myositis, degeneration of muscle fibers, and multiple edema. Deaths are not uncommon due to necrotic ulcerative lesions of the intestine and internal bleeding.

Candesartan prevents arteriopathy progression in cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy model.

Cerebral small vessel disease (CSVD) causes dementia and gait disturbance due to arteriopathy. Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is a hereditary form of CSVD caused by loss of high-temperature requirement A1 (HTRA1) serine protease activity. In CARASIL, arteriopathy causes intimal thickening, smooth muscle cell (SMC) degeneration, elastic lamina splitting, and vasodilation. The molecular mechanisms were proposed to involve the accumulation of matrisome proteins as substrates or abnormalities in transforming growth factor β (TGF-β) signaling. Here, we show that HTRA1-/- mice exhibited features of CARASIL-associated arteriopathy: intimal thickening, abnormal elastic lamina, and vasodilation. In addition, the mice exhibited reduced distensibility of the cerebral arteries and blood flow in the cerebral cortex. In the thickened intima, matrisome proteins, including the hub protein fibronectin (FN) and latent TGF-β binding protein 4 (LTBP-4), which are substrates of HTRA1, accumulated. Candesartan treatment alleviated matrisome protein accumulation and normalized the vascular distensibility and cerebral blood flow. Furthermore, candesartan reduced the mRNA expression of Fn1, Ltbp-4, and Adamtsl2, which are involved in forming the extracellular matrix network. Our results indicate that these accumulated matrisome proteins may be potential therapeutic targets for arteriopathy in CARASIL.

The effect of leg ischemia/reperfusion injury on the liver in an experimental breast cancer model

Background/Aim: Ischemia/reperfusion (I/R) injury occurs during breast cancer surgery, especially those involving a modified radical mastectomy, lumpectomy, and axillary lymph node dissection. Tissue damage and stress due to I/R alter immune system functions, especially those of the myeloid cells. The immunologic impact of this I/R injury on myeloid-derived cancerous cells remains unknown. We sought to investigate the effect of I/R injury in the extremity close the breast tumor location on myeloid cell population in the liver and liver metastasis. Methods: 4T1 breast tumors were created in the left inguinal breast region of the experimental animals. When the tumor reached 0.5 cm in diameter, ischemia was produced on the left down-extremity for 90 min and reperfusion was induced for short (3 days), middle (7 days), and long terms (14 days). At the end of the reperfusion period, proximal limbs and livers were harvested. The limb and liver samples were histopathologically examined with H&E staining. Immune cell percentages were determined in the liver by flow cytometry. Results: There was an increase in muscle fiber degeneration and disorganization in the I/R induced proximal legs on days 3 and 7 of I/R in both tumor free and tumor bearing animals with a further impact in tumor bearing mice. Even though I/R injury did not affect tumor metastasis to the liver, it had an impact on liver myeloid cell percentages in both tumor free and tumor bearing animals. Additionally, tumor bearing mice demonstrated higher myeloid cell percentages in both the pre-I/R and post-I/R experimental groups. There was a remarkable change in the levels of granulocytic, and monocytic myeloid cells and macrophages due to the I/R injury. Conclusion: With the formation of short-term I/R injury in a distant site, tumor development and/or seeding to metastasis sites after surgery could be prevented. This study contributes to the understanding of the inflammatory process after I/R injury occurring during interventions.

Degeneration and Regeneration of Smooth Muscle Cells in Two Different Abdominal Aortic Aneurysm Models in Rabbits

We aimed to investigate the formation and self-healing process of rabbit abdominal aortic aneurysm (AAA) by focus on the degeneration and regeneration of smooth muscle cells (SMCs) in elastase-induced AAA model and enlarging AAA model in rabbits. Sixty rabbits were equally divided into 2 aneurysm groups (Group A and Group B). Rabbits received a 10-min incubation of elastase in Group A (10 units/µL) and Group B (1 unit/µL). Rabbits underwent aortic stenosis above the incubated segment in Group B. Aortic diameter was measured and rabbits were sacrificed for histopathological and immunohistochemical studies. The incubated aorta dilated immediately and ran up to maxima by day 21 in Group A. All aneurysms formed by day 21 and enlarged progressively in Group B. SMCs content, elastin content and intima-media thickness decreased significantly by day 0 in Group A. SMCs and elastic fibers were destroyed gradually in Group B, however, SMCs content was significantly lower than Group A by day 70. Intimal thickness increased significantly by day 70 in the Aneurysm groups. MMP2 maintained moderate expression in Group A, which decreased significantly by day 3 in Group B. MMP9 and RAM11 expressions were higher by day 1, but decreased significantly by day 3 in Group B. Irreversible degeneration of SMCs is critical to a rapid formation of elastase-induced rabbit AAA model, and SMCs excessive regeneration accounts for the selfhealing process. SMCs degradation and regeneration remain relatively stable in an enlarging AAA model. SMCs should be the key target for studying the mechanism of AAA and intervention therapy.

The effect of mesenchymal stem cells lyophilisate on femoral artery of rat anastomosis: A histopathological and histomorphometric study

Background and objectiveMesenchymal Stem Cells (MSCs) are well known for their tissue regeneration enhancing effect and their contribution to immune regulation. However, their contribution to the healing process of femoral artery anastomosis, especially to endothelialization, has not been studied sufficiently in the clinic. This study was carried out to evaluate the effects of MSC-lyophilisate from the human umbilical cord on anastomosis experimental study in rats histopathologically. MethodAfter intraperitoneal anesthesia was applied to the rats, the femoral artery was exposed with a 2 cm incision in the right femoral region. After the artery was cut in the experiment and sham groups, femoral artery end-to-end anastomosis was performed using the primary suture technique. MSC-lyophilisate was poured in powder form onto the anastomosed outer surface of the vessel in the treatment group and saline solution was poured to the sham group. No intervention was made to the control group. The data analysis was performed with IBM SPSS Statistics 25. ResultsIn the experiment group, flattening of the inner elastic lamina, morphological changes and vacuolization in the muscle fibers, inflammation in the adventitia and significant vascular wall thickening were observed in the femoral arteries of the rats after the intervention. According to the histopathological scoring results, tissue samples belonging to sham and experimental groups showed marked pathological findings such as endothelial damage, flattened areas where the folded structure in the inner elastic lamina disappeared, muscle fiber degeneration and inflammation in the adventitia. ConclusionHuman umbilical cord-origin MSC-lyophilisate application holds an important place in femoral artery surgery. We evaluate that it will be meaningful to determine the MSC-lyophilisate dose for hemostasis without creating thrombus after anastomosis. MSC-lyophilisate will be used to provide hemostasis in areas with local bleeding in the future. In addition, it is recommended to make plans for an in-depth examination of possible problems and cases in future studies.