| 1. |
- Aare, Sudhakar, et al.
(författare)
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Effects of corticosteroids in the development of limb muscle weakness in a porcine intensive care unit model
- 2013
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Ingår i: Physiological genomics. - : American Physiological Society. - 1531-2267 .- 1094-8341. ; 45:8, s. 312-320
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Tidskriftsartikel (refereegranskat)abstract
- Severe muscle wasting is a debilitating condition in critically ill intensive care unit (ICU) patients, characterized by general muscle weakness and dysfunction, resulting in a prolonged mobilization, delayed weaning from the ventilator, and a decreased quality of life post-ICU. The mechanisms underlying limb muscle weakness in ICU patients are complex and involve the impact of primary disease, but also factors common to critically ill ICU patients such as sepsis, mechanical ventilation (MV), immobilization, and systemic administration of corticosteroids (CS). These factors may have additive negative effects on skeletal muscle structure and function, but their respective role alone remain unknown. The primary aim of this study was to examine how CS administration potentiates ventilator and immobilization-related limb muscle dysfunction at the gene level. Comparing biceps femoris gene expression in pigs exposed to MV and CS for 5 days with only MV pigs for the same duration of time showed a distinct deregulation of 186 genes according to microarray. Surprisingly, the decreased force-generation capacity at the single muscle fiber reported in response to the addition of CS administration in mechanically ventilated and immobilized pigs was not associated with an additional upregulation of proteolytic pathways. On the other hand, an altered expression of genes regulating kinase activity, cell cycle, transcription, channel regulation, oxidative stress response, cytoskeletal, sarcomeric, and heat shock protein, as well as protein synthesis at the translational level, appears to play an additive deleterious role for the limb muscle weakness in immobilized ICU patients.
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| 2. |
- Aare, Sudhakar, et al.
(författare)
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Mechanisms underlying the sparing of masticatory versus limb muscle function in an experimental critical illness model
- 2011
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Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 43:24, s. 1334-1350
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Tidskriftsartikel (refereegranskat)abstract
- Acute quadriplegic myopathy (AQM) is a common debilitating acquired disorder in critically ill intensive care unit (ICU) patients which is characterized by tetraplegia/generalized weakness of limb and trunk muscles. Masticatory muscles, on the other hand, are typically spared or less affected, yet the mechanisms underlying this striking muscle-specific difference remain unknown. This study aims to evaluate physiological parameters and the gene expression profiles of masticatory and limb muscles exposed to factors suggested to trigger AQM, such as mechanical ventilation, immobilization, neuromuscular blocking agents (NMBA), corticosteroids (CS) and sepsis for five days by using a unique porcine model mimicking the ICU conditions. Single muscle fiber cross-sectional area and force-generating capacity, i.e., maximum force normalized to fiber cross-sectional area (specific force), revealed maintained masseter single muscle fiber cross-sectional area and specific-force after five days exposure to all triggering factors. This is in sharp contrast to observations in limb and trunk muscles, showing a dramatic decline in specific force in response to five days exposure to the triggering factors. Significant differences in gene expression were observed between craniofacial and limb muscles, indicating a highly complex and muscle specific response involving transcription and growth factors, heat shock proteins, matrix metalloproteinase inhibitor, oxidative stress responsive elements and sarcomeric proteins underlying the relative sparing of cranial versus spinal nerve innervated muscles during exposure to the ICU intervention.
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| 3. |
- Aare, Sudhakar, et al.
(författare)
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The role of sepsis in the development of limb muscle weakness in a porcine intensive care unit model
- 2012
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Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 44:18, s. 865-877
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Tidskriftsartikel (refereegranskat)abstract
- Severe muscle wasting and loss of muscle function in critically ill mechanically ventilated intensive care unit (ICU) patients have significant negative consequences on their recovery and rehabilitation that persist long after their hospital discharge; moreover the underlying mechanisms are unclear. Mechanical ventilation (MV) and immobilization-induced modifications play an important role in these consequences, including endotoxin induced sepsis. The present study aims to investigate how sepsis aggravates ventilator and immobilization-related limb muscle dysfunction. Hence, biceps femoris muscle gene expression was investigated in pigs exposed to ICU intervention, i.e., immobilization, sedation, and MV, alone or in combination with sepsis for five days. In previous studies, we have shown that ICU intervention alone or in combination with sepsis did not affect muscle fiber size on day 5, but a significant decrease was observed in single fiber maximal force normalized to cross-sectional area (specific force) when sepsis was added to the ICU intervention. According to microarray data, the addition of sepsis to the ICU intervention induced a deregulation of more than 500 genes, such as an increased expression of genes involved in chemokine activity, kinase activity and transcriptional regulation. Genes involved in the regulation of the oxidative stress response, cytoskeletal/sarcomeric and heat shock proteins were on the other hand down-regulated when sepsis was added to the ICU intervention. Thus, sepsis has a significant negative effect on muscle function in critically ill ICU patients and chemokine activity and heat shock protein genes are forwarded to play an instrumental role in this specific muscle wasting condition.
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| 4. |
- Akerblad, P, et al.
(författare)
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Gene expression analysis suggests that EBF-1 and PPAR gamma 2 induce adipogenesis of NIH-3T3 cells with similar efficiency and kinetics
- 2005
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Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 23:2, s. 206-216
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Tidskriftsartikel (refereegranskat)abstract
- Differentiation of multipotent mesenchymal stem cells into lipid-accumulating adipocytes is a physiological process induced by transcription factors in combination with hormonal stimulation. We have used Affymetrix microarrays to compare the adipogenic differentiation pathways of NIH-3T3 fibroblasts induced to undergo in vitro differentiation by ectopic expression of early B cell factor (EBF)-1 or peroxisome proliferator-activated receptor (PPAR)gamma 2. These experiments revealed that commitment to the adipogenic pathway in the NIH-3T3 cells was not reflected in gene expression until 4 days after induction of differentiation. Furthermore, gene expression patterns at the earlier time points after stimulation indicated that EBF-1 and PPAR gamma 2 induced different sets of genes, while the similarities increased upon differentiation, and that several genes linked to adipocyte differentiation were also transiently induced in the vector-transduced cells. These data suggest that the initial activation of genes associated with adipocyte development is independent of commitment to the adipogenic pathway and that EBF-1 and PPAR gamma 2 induce adipocyte differentiation with comparable kinetics and efficiency.
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| 5. |
- Albinsson, Sebastian, et al.
(författare)
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Can microRNAs control vascular smooth muscle phenotypic modulation and the response to injury?
- 2010
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Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; okt
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Tidskriftsartikel (refereegranskat)abstract
- Vascular smooth muscle cell (VSMC) migration and proliferation are critical events in vascular proliferative diseases. Recent studies have established micro-RNAs (miRNAs) as important mediators for the modulation of VSMC phenotype by targeting transcription factors and the cytoskeleton, which act as molecular switches for VSMC differentiation. The importance of miRNAs for VSMC development, differentiation and function is evident by the fact that loss of the miRNA processing enzyme Dicer in VSMCs results in embryonic lethality due to severe vascular abnormalities. In addition, a role of specific miRNAs for neointimal hyperplasia following vascular injury has been reported which provides interesting possibilities for future therapeutical targets against vascular disease. Herein, we summarize recent advances regarding the role of miRNAs in VSMC phenotype modulation and response to injury.
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| 6. |
- Asp, Julia, 1973, et al.
(författare)
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Comparison of human cardiac gene expression profiles in paired samples of right atrium and left ventricle collected in vivo
- 2012
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Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 44:1, s. 89-98
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Tidskriftsartikel (refereegranskat)abstract
- Studies of expressed genes in human heart provide insight into both physiological and pathophysiological mechanisms. This is of importance for extended understanding of cardiac function as well as development of new therapeutic drugs. Heart tissue for gene expression studies is generally hard to obtain, particularly from the ventricles. Since different parts of the heart have different functions, expression profiles should likely differ between these parts. The aim of the study was therefore to compare the global gene expression in cardiac tissue from the more accessible auricula of the right atrium to expression in tissue from the left ventricle. Tissue samples were collected from five men undergoing aortic valve replacement or coronary artery bypass grafting. Global gene expression analysis identified 542 genes as differentially expressed between the samples extracted from these two locations, corresponding to similar to 2% of the genes covered by the microarray; 416 genes were identified as abundantly expressed in right atrium, and 126 genes were abundantly expressed in left ventricle. Further analysis of the differentially expressed genes according to available annotations, information from curated pathways and known protein interactions, showed that genes with higher expression in the ventricle were mainly associated with contractile work of the heart. Transcription in biopsies from the auricula of the right atrium on the other hand indicated a wider area of functions, including immunity and defense. In conclusion, our results suggest that biopsies from the auricula of the right atrium may be suitable for various genetic studies, but not studies directly related to muscle work.
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| 7. |
- Banduseela, Varuna C., et al.
(författare)
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Gene expression and muscle fiber function in a porcine ICU model
- 2009
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Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 39:3, s. 141-159
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Tidskriftsartikel (refereegranskat)abstract
- Skeletal muscle wasting and impaired muscle function in response to mechanical ventilation and immobilization in intensive care unit (ICU) patients are clinically challenging partly due to 1) the poorly understood intricate cellular and molecular networks and 2) the unavailability of an animal model mimicking this condition. By employing a unique porcine model mimicking the conditions in the ICU with long-term mechanical ventilation and immobilization, we have analyzed the expression profile of skeletal muscle biopsies taken at three time points during a 5-day period. Among the differentially regulated transcripts, extracellular matrix, energy metabolism, sarcomeric and LIM protein mRNA levels were downregulated, while ubiquitin proteasome system, cathepsins, oxidative stress responsive genes and heat shock proteins (HSP) mRNAs were upregulated. Despite 5 days of immobilization and mechanical ventilation single muscle fiber cross-sectional areas as well as the maximum force generating capacity at the single muscle fiber level were preserved. It is proposed that HSP induction in skeletal muscle is an inherent, primary, but temporary protective mechanism against protein degradation. To our knowledge, this is the first study that isolates the effect of immobilization and mechanical ventilation in an ICU condition from various other cofactors.
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| 8. |
- Banduseela, Varuna, et al.
(författare)
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Impaired autophagy, chaperone expression, and protein synthesis in response to critical illness interventions in porcine skeletal muscle
- 2013
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Ingår i: Physiological Genomics. - : American Physiological Society. - 1094-8341 .- 1531-2267. ; 45:12, s. 477-486
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Tidskriftsartikel (refereegranskat)abstract
- Critical illness myopathy (CIM) is characterized by a preferential loss of the motor protein myosin, muscle wasting, and impaired muscle function in critically ill intensive care unit (ICU) patients. CIM is associated with severe morbidity and mortality and has a significant negative socioeconomic effect. Neuromuscular blocking agents, corticosteroids, sepsis, mechanical ventilation, and immobilization have been implicated as important risk factors, but the causal relationship between CIM and the risk factors has not been established. A porcine ICU model has been used to determine the immediate molecular and cellular cascades that may contribute to the pathogenesis prior to myosin loss and extensive muscle wasting. Expression profiles have been compared between pigs exposed to the ICU interventions, i.e., mechanically ventilated, sedated, and immobilized for 5 days, with pigs exposed to critical illness interventions, i.e., neuromuscular blocking agents, corticosteroids, and induced sepsis in addition to the ICU interventions for 5 days. Impaired autophagy as well as impaired chaperone expression and protein synthesis were observed in the skeletal muscle in response to critical illness interventions. A novel finding in this study is impaired core autophagy machinery in response to critical illness interventions, which when in concert with downregulated chaperone expression and protein synthesis may collectively affect the proteostasis in skeletal muscle and may exacerbate the disease progression in CIM.
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| 9. |
- Becirovic Agic, Mediha, et al.
(författare)
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Quantitative trait loci associated with angiotensin II and high-salt diet induced acute decompensated heart failure in Balb/CJ mice
- 2019
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Ingår i: Physiological Genomics. - : AMER PHYSIOLOGICAL SOC. - 1094-8341 .- 1531-2267. ; 51:7, s. 279-289
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Tidskriftsartikel (refereegranskat)abstract
- Genetic background of different mouse strains determines their susceptibility to disease. We have previously shown that Balb/CJ and C57BL/6J mice develop cardiac hypertrophy to the same degree when treated with a combination of angiotensin II and high-salt diet (ANG II+ Salt). but only Balb/CJ show impaired cardiac function associated with edema development and substantial mortality. We hypothesized that the different response to ANG II +Salt is due to the different genetic backgrounds of Balb/CJ and C57BL/6J. To address this we performed quantitative trait locus (QTL) mapping of second filial generation (F2) of mice derived from a backcross between Balb/CJ and first filial generation (Fl) of mice. Cardiac function was measured with echocardiography, glomerular filtration rate using FITC-inulin clearance, fluid and electrolyte balance in metabolic cages, and blood pressure with tail-cuff at baseline and on the fourth day of treatment with ANG II+Salt. A total of nine QTLs were found to be linked to different phenotypes in ANG II + Salt-treated F2 mice. A QTL on chromosome 3 was linked to cardiac output. and a QTL on chromosome 12 was linked to isovolumic relaxation time. QTLs on chromosome 2 and 3 were linked to urine excretion and sodium excretion. Eight genes located at the different QTLs contained coding nonsynonymous SNPs published in the mouse genome database that differ between Balb/CJ and C57BL/6J. In conclusion. ANG II+Salt-induced acute decompensation in Balb/CJ is genetically linked to several QTLs, indicating a multifaceted phenotype. The present study identified potential candidate genes that may represent important pathways in acute decompensated heart failure.
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| 10. |
- Blackwell, TA, et al.
(författare)
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Transcriptomic analysis of the development of skeletal muscle atrophy in cancer-cachexia in tumor-bearing mice
- 2018
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Ingår i: Physiological genomics. - : American Physiological Society. - 1531-2267 .- 1094-8341. ; 50:12, s. 1071-1082
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Tidskriftsartikel (refereegranskat)abstract
- Cancer-cachexia (CC) is a wasting condition directly responsible for 20–40% of cancer-related deaths. The mechanisms controlling development of CC-induced muscle wasting are not fully elucidated. Most investigations focus on the postcachectic state and do not examine progression of the condition. We recently demonstrated mitochondrial degenerations precede muscle wasting in time course progression of CC. However, the extent of muscle perturbations before wasting in CC is unknown. Therefore, we performed global gene expression analysis in CC-induced muscle wasting to enhance understanding of intramuscular perturbations across the development of CC. Lewis lung carcinoma (LLC) was injected into the hind-flank of C57BL6/J mice at 8 wk of age with tumor allowed to develop for 1, 2, 3, or 4 wk and compared with PBS-injected control. Muscle wasting was evident at 4 wk LLC. RNA sequencing of gastrocnemius muscle samples showed widespread alterations in LLC compared with PBS animals with largest differences seen in 4 wk LLC, suggesting extensive transcriptomic alterations concurrent to muscle wasting. Commonly altered pathways included: mitochondrial dysfunction and protein ubiquitination, along with other less studied processes in this condition regulating transcription/translation and cytoskeletal structure. Current findings present novel evidence of transcriptomic shifts and altered cellular pathways in CC-induced muscle wasting.
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