Hemichorea due to ipsilateral thalamic infarction: A case report

BACKGROUND

Hemichorea usually results from vascular lesions of the basal ganglia. Most often, the lesion is contralateral to the affected limb but rarely, it may be ipsilateral. The pathophysiology of ipsilateral hemichorea is still poorly understood. We review the literature on hemichorea due to ipsilateral cerebral infarction and explore possible mechanisms for its occurrence.

CASE SUMMARY

A 72-year-old woman presented with complaints of involuntary movements of the muscles of the left side of the face and mild weakness of the right limbs. Her symptoms had started suddenly 1 d earlier. After admission to the hospital, the involuntary movements spread to involve the left limbs also. Magnetic resonance imaging revealed a left thalamic infarction. The patient’s hemichorea subsided after treatment with haloperidol (2 mg per time, 3 times/d) for 3 d; the hemiparesis resolved with rehabilitation physiotherapy. She is presently symptom free and on treatment for prevention of secondary stroke. We review the literature on the occurrence of ipsilateral hemichorea following thalamic infarction and discuss the possible pathomechanisms of this unusual presentation.

CONCLUSION

Ipsilateral hemichorea following a thalamic stroke is rare but it can be explained by structure of the extrapyramidal system. The thalamus is a relay station that exerts a bilateral control of motor function.

Hyperglycemic hemianopia: A case report

BACKGROUND

Nonketotic hyperglycemia (NKH) is characterized by hyperglycemia with little or no ketoacidosis. Diverse neurological symptoms have been described in NKH patients, including choreoathetosis, hemiballismus, seizures, and coma in severe cases. Homonymous hemianopia, with or without occipital seizures, caused by hyperglycemia is less readily recognized.

CASE SUMMARY

We describe a 54-year-old man with NKH, who reported seeing round, colored flickering lights with right homonymous hemianopia. Cranial magnetic resonance imaging demonstrated abnormalities in the left occipital lobe, with decreased T2 signal of the white matter, restricted diffusion, and corresponding low signal intensity in the apparent diffusion coefficient map. He responded to rehydration and a low-dose insulin regimen, with improvements of his visual field defect.

CONCLUSION

Patients with NKH may present focal neurologic signs. Hyperglycemia should be taken into consideration when making an etiologic diagnosis of homonymous hemianopia.

Bibliometric analysis of top 100 cited articles in nonalcoholic fatty liver disease research

AIM

To identify and assess the research situation of top 100 cited articles in nonalcoholic fatty liver disease (NAFLD).

METHODS

The global scientific research articles in the Science Citation Index-Expanded relevant to NAFLD were retrieved and listed according to their citation times from the most to the least. The 100 most frequently cited original articles were selected to systematically evaluate their bibliometric parameters including times cited, publication year, journals, subject categories, and the highly related concepts of NAFLD, which reflected the history and current situation, publication distribution of leading countries and institutes as well as the research hotspots of NAFLD.

RESULTS

Top 100 cited articles in NAFLD were published from 1965 to 2015 with a citation ranging of 227 to 2151 times since publication, in which the United States was the most predominant country and Mayo Clin was the most productive institution. The majority of the top 100 cited articles were concentrated in SCI subject category of Gastroenterology and Hepatology. Hepatology and Gastroenterology is the top journal that published over half 100 top-cited articles. The significant peak of top cited articles present in the first half of the 2000s while the highest mean number of citation presents in first half of the 1980s. In addition, concepts related to pathology characteristics, epidemiology and medicalization, metabolic syndrome and its combination of symptoms including insulin resistance, biomarkers of lipid metabolism and obesity are listed as the highly related concepts.

CONCLUSION

The 100 top-cited articles marked with the leading countries, institutions, journals, hotspots and development trend in NAFLD field that could provide the foundation for further investigations.

The 100 most cited articles in ectopic pregnancy: a bibliometric analysis

Ectopic pregnancy (EP) remains a major gynecological emergency and is a cause of morbidity or even mortality in women. As a consequence, top citation analysis of EP research in database of the Science Citation Index Expanded is needed to assess the publication trends of leading countries/territories and institutes as well as the research hotspots of EP. A total of 4881 articles relevant to EP were retrieved in the database of the Science Citation Index Expanded from 1965 to present, in which the 100 top-cited articles were selected for further analysis. The number of citations ranged from 81 to 482 (131.57 ± 69.76), with a time span of 40 years between 1969 and 2009. These citation classics came from 14 countries, and 65 of the articles came from the United States. Yale University in Connecticut led the list of classics with six papers. The 100 top-cited articles were published in 32 journals, in which the journal of Fertility and Sterility published the most (23 papers). Stovall TG and Ling FW published the highest number of studies (6 papers each). Articles that originated in the United States and that were published in high-impact journals were most likely to be cited in the field of EP research. Bibliometric analysis was used to provide a historical perspective on the progress in EP research over the past 50 years. Citation analysis is a feasible tool to comprehensively recognize the advances of EP research in the past and future research.

Potential Signaling Pathways Involved in the Clinical Application of Oxymatrine

Oxymatrine, an alkaloid component extracted from the roots of Sophora species, has been shown to have antiinflammatory, antifibrosis, and antitumor effects and the ability to protect against myocardial damage, etc. The potential signaling pathways involved in the clinical application of oxymatrine might include the TGF-β/Smad, toll-like receptor 4/nuclear factor kappa-light-chain-enhancer of activated B cells, toll-like receptor9/TRAF6, Janus kinase/signal transduction and activator of transcription, phosphatidylinositol-3 kinase/Akt, delta-opioid receptor-arrestinl-Bcl-2, CD40, epidermal growth factor receptor, nuclear factor erythroid-2-related factor 2/heme oxygenase-1 signaling pathways, and dimethylarginine dimethylaminohydrolase/asymmetric dimethylarginine metabolism pathway. In this review, we summarize the recent investigations of the signaling pathways related to oxymatrine to provide clues and references for further studies on its clinical application. Copyright © 2016 John Wiley & Sons, Ltd.

Global publication trends and research hotspots of nonalcoholic fatty liver disease: a bibliometric analysis and systematic review

With the globally increasing prevalence, nonalcoholic fatty liver disease (NAFLD) becomes the predominant cause of chronic liver disease. A global look at the publication trends and the research hotspots of NAFLD are urgently needed to assess the situation of NAFLD research. The global scientific research in the Science Citation Index-Expanded covered articles relevant to NAFLD was retrieved and its bibliometric parameters and research hotspots of NAFLD were systematically evaluated. To sum up, 6356 articles were published in 994 different journals covering 93 SCI subject categories during 1986–2013, in which English was the most predominant language used. Starting from the late 1980s, the publication on NAFLD grew slowly and entered into a highly developing period in the 21st century, especially in the last decade. Besides hepatic steatosis, metabolic syndrome and its combination of symptoms such as obesity, insulin resistance are listed as the top frequent keywords. Bibliometric results suggest that the obviously rapid growth of the articles in recent years appears to be associated with the accelerating incidence of NAFLD and its cofactors such as metabolic syndrome. In addition, epidemiology focusing on comparing different regions and population is attracting ever-growing attention. Meantime, pathology plays an important role in NAFLD research.

Effect of oxymatrine on lipopolysaccharide induced expression of NF-κB in pancreatic stellate cells

AIM: To investigate the effect of oxymatrine (OM) on lipopolysaccharide (LPS) induced expression of nuclear factor κB (NF-κB) in pancreatic stellate cells (LTC-14).

METHODS: LTC-14 cells were cultured with suitable concentrations of LPS as well as the corresponding concentrations of OM. Cell proliferation was detected by MTT assay. The expression of cytoplasmic and nuclear NF-κB was detected by immunohistochemistry. The expression of NF-κB mRNA was evaluated by Q-PCR. The protein expression of NF-κB was measured by Western blot.

RESULTS: OM inhibited the proliferation of LTC-14 cells in a time- and dose-dependent manner. The expression of NF-κB mRNA and protein was significantly increased in LTC-14 cells incubated with LPS (10 μg/mL), which could be down-regulated by OM. The nuclear translocation of NF-κB could also be inhibited by OM.

CONCLUSION: The reduction of NF-κB mRNA and protein as well as the inhibition of NF-κB nuclear translocation might be involved in the therapeutic effects of OM on pancreatic fibrosis.

Genomewide analysis of rat periaqueductal gray-dorsal horn reveals time-, region- and frequency-specific mRNA expression changes in response to electroacupuncture stimulation

Electroacupuncture (EA) has been widely applied for illness prevention, treatment or rehabilitation in the clinic, especially for pain management. However, the molecular events that induce these changes remain largely uncharacterized. The periaqueductal gray (PAG) and the spinal dorsal horn (DH) have been verified as two critical regions in the response to EA stimulation in EA analgesia. In this study, a genetic screen was conducted to delineate the gene expression profile in the PAG-DH regions of rats to explore the molecular events of the analgesic effect induced by low-frequency (2-Hz) and high-frequency (100-Hz) EAs. Microarray analysis at two different time points after EA stimulation revealed time-, region- and frequency-specific gene expression changes. These expression differences suggested that modulation of neural-immune interaction in the central nervous system played an important role during EA analgesia. Furthermore, low-frequency EA could regulate gene expression to a greater degree than high-frequency EA. Altogether, the present study offers, for the first time, a characterized transcriptional response pattern in the PAG-DH regions followed by EA stimulation and, thus, provides a solid experimental framework for future in-depth analysis of the mechanisms underlying EA-induced effects.

Potential role of NADPH oxidase in pathogenesis of pancreatitis

Studies have demonstrated that reactive oxygen species (ROS) are closely related to inflammatory disorders. Nicotinamide adenine dinucleotide phosphate oxidase (NOX), originally found in phagocytes, is the main source of ROS in nonphagocytic cells. Besides directly producing the detrimental highly reactive ROS to act on biomolecules (lipids, proteins, and nucleic acids), NOX can also activate multiple signal transduction pathways, which regulate cell growth, proliferation, differentiation and apoptosis by producing ROS. Recently, research on pancreatic NOX is no longer limited to inflammatory cells, but extends to the aspect of pancreatic acinar cells and pancreatic stellate cells, which are considered to be potentially associated with pancreatitis. In this review, we summarize the literature on NOX protein structure, activation, function and its role in the pathogenesis of pancreatitis.

Low- and high-frequency transcutaneous electrical acupoint stimulation induces different effects on cerebral μ-opioid receptor availability in rhesus monkeys

Although systematic studies have demonstrated that acupuncture or electroacupuncture (EA) analgesia is based on their accelerating endogenous opioid release to activate opioid receptors and that EA of different frequencies is mediated by different opioid receptors in specific areas of the central nervous system, there is little direct, real-time evidence to confirm this in vivo. The present study was designed to investigate the effects of transcutaneous electrical acupoint stimulation (TEAS), an analogue of EA, at low and high frequencies on μ-opioid receptor (MOR) availability in the brain of rhesus monkeys. Monkeys underwent 95-min positron emission tomography (PET) with (11) C-carfentanil three times randomly while receiving 0, 2, or 100 Hz TEAS, respectively. Each TEAS was administered in the middle 30 min during the 95-min PET scan, and each session of PET and TEAS was separated by at least 2 weeks. The results revealed that 2 Hz but not 100 Hz TEAS evoked a significant increase in MOR binding potential in the anterior cingulate cortex, the caudate nucleus, the putamen, the temporal lobe, the somatosensory cortex, and the amygdala compared with 0 Hz TEAS. The effect remained after the end of TEAS in the anterior cingulate cortex and the temporal lobe. The selective increase in MOR availability in multiple brain regions related to pain and sensory processes may play a role in mediating low-frequency TEAS efficacy.

Roles of BN52021 in platelet-activating factor pathway in inflammatory MS1 cells

AIM: To determine the effects of BN52021 on platelet-activating factor receptor (PAFR) signaling molecules under lipopolysaccharide (LPS)-induced inflammatory conditions in MS1 cells.

METHODS: MS1 cells (a mouse pancreatic islet endothelial cell line) were grown in Dulbecco’s modified Eagle’s medium supplemented with 10% fetal bovine serum, 2 mmol/L glutamine and 100 μg/mL penicillin/streptomycin in 5% CO₂ at 37 °C. After growth to confluency in media, the cells were processed for subsequent studies. The MS1 cells received 0, 0.1, 1 and 10 μg/mL LPS in this experiment. The viability/proliferation of the cells induced by LPS was observed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assay. Apoptosis and necrosis of the cells under the inflammatory condition described previously were observed using Hoechst 33342-propidium iodide staining. Adenylate cyclase (AC), phospholipase A₂ (PLA₂), phospholipase Cβ (PLCβ), protein tyrosine kinase (PTK), G protein-coupled receptor kinases (GRK) and p38-mitogen-activated protein kinase (p38 MAPK) mRNA in the PAFR signaling pathway were measured by real-time polymerase chain reaction. The protein expression level of phosphorylated AC (p-AC), phosphorylated PLA₂ (p-PLA₂), phosphorylated PTK (p-PTK), phosphorylated p38 MAPK (p-p38 MAPK), PLCβ and GRK was measured using Western blotting analysis.

RESULTS: The activity of MS1 cells incubated with different concentrations of LPS for 6 h decreased significantly in the 1 μg/mL LPS group (0.49 ± 0.10 vs 0.67 ± 0.13, P < 0.05) and 10 μg/mL LPS group (0.44 ± 0.10 vs 0.67 ± 0.13, P < 0.001), but not in 0.1 μg/mL group. When the incubation time was extended to 12 h (0.33 ± 0.05, 0.32 ± 0.03 and 0.25 ± 0.03 vs 0.69 ± 0.01) and 24 h (0.31 ± 0.01, 0.29 ± 0.03 and 0.25 ± 0.01 vs 0.63 ± 0.01), MS1 cell activity decreased in all LPS concentration groups compared with the blank control (P < 0.001). BN52021 significantly improved the cell activity when its concentration reached 50 μmol/L compared with the group that received LPS treatment alone, which was consistent with the results obtained from fluorescence staining. The mRNAs levels of AC (4.02 ± 0.14 vs 1.00 ± 0.13), GRK (2.63 ± 0.03 vs 1.00 ± 0.12), p38 MAPK (3.87 ± 0.07 vs 1.00 ± 0.17), PLA₂ (3.31 ± 0.12 vs 1.00 ± 0.12), PLCβ (2.09 ± 0.08 vs 1.00 ± 0.06) and PTK (1.85 ± 0.07 vs 1.00 ± 0.11) were up-regulated after LPS stimulation as compared with the blank control (P < 0.05). The up-regulated mRNAs including AC (2.35 ± 0.13 vs 3.87 ± 0.08), GRK (1.17 ± 0.14 vs 2.65 ± 0.12), p38 MAPK (1.48 ± 0.18 vs 4.30 ± 0.07), PLCβ (1.69 ± 0.10 vs 2.41 ± 0.13) and PLA₂ (1.87 ± 0.11 vs 2.96 ± 0.08) were significantly suppressed by BN52021 except for that of PTK. The level of p-AC (1.11 ± 0.12 vs 0.65 ± 0.08), GRK (0.83 ± 0.07 vs 0.50 ± 0.03), PLCβ (0.83 ± 0.16 vs 0.50 ± 0.10) and p-p38 MAPK (0.74 ± 0.10 vs 0.38 ± 0.05) was up-regulated after LPS stimulation as compared with the blank control (P < 0.05). The up-regulated proteins, including p-AC (0.65 ± 0.15 vs 1.06 ± 0.14), GRK (0.47 ± 0.10 vs 0.80 ± 0.06), PLCβ (0.47 ± 0.04 vs 0.80 ± 0.19) and p-p38 MAPK (0.30 ± 0.10 vs 0.97 ± 0.05), was significantly suppressed by BN52021, but p-PLA₂ and p-PTK protein level were not suppressed.

CONCLUSION: BN52021 could effectively inhibit LPS-induced inflammation by down-regulating the mRNA and protein levels of AC, GRK, p38 MAPK, PLA₂ and PLCβ in the PAFR signaling pathway.

Electroacupuncture frequency-related transcriptional response in rat arcuate nucleus revealed region-distinctive changes in response to low- and high-frequency electroacupuncture

Electroacupuncture (EA) has been clinically applied for treating different medical conditions, such as pain, strain, and immune diseases. Low- and high-frequency EAs have distinct therapeutic effects in clinical practice and experimental studies. However, the molecular mechanism of this difference remains obscure. The arcuate nucleus (Arc) is a critical region of the hypothalamus and is responsible for the effect of EA stimulation to remote acupoints. Gene expression profiling provides a powerful tool with which to explore the basis of physiopathological responses to external stimulus. In this study, using cDNA microarray, we investigated gene expressions in the rat Arc region induced by low-frequency (2-Hz) and high-frequency (100-Hz) EAs to two remote acupoints, zusanli (ST36) and sanyinjiao (SP6). We have found that more genes were differentially regulated by 2-Hz EA than 100-Hz EA (154 vs. 66 regulated genes/ESTs) in Arc, especially those related to neurogenesis, which was confirmed by qRT-PCR. These results demonstrate that the expression level of genes in the Arc region could be effectively regulated by low-frequency EA, compared with high-frequency EA, helping to uncover the mechanisms of the therapeutic effects of the low-frequency EA. Our results also indicate different-frequency EAs are spatially specific.

Transcriptome profiling analysis reveals region-distinctive changes of gene expression in the CNS in response to different moderate restraint stress

It is generally believed that temporary moderate stress to a living organism has protective and adaptive effects, but little is known about the responses of CNS to the moderate stresses at molecular level. This study aims to investigate the gene expression changes induced by moderate stress in CNS stress- and nociception-related regions of rats. Moderate restraint was applied to rats for 50 min and cDNA microarrays were used to detect the differential gene expression in different CNS regions. Transcriptome profiling analysis showed that at acute stage stress-related genes were up-regulated in arcuate nucleus; fight-or-flight behavior-related genes were up-regulated in periaqueductal gray, while nitric oxide and GABA signal transmission-related genes were up-regulated in spinal dorsal horn. In addition, immune-related genes were broadly regulated, especially at the late stage. These results suggested that specific genes of certain gene ontology categories were spatiotemporally regulated in specific CNS regions related to relevant functions under moderate external stimuli at acute stage, while immune response was broadly regulated at the late stage. The co-regulated genes among the three different CNS regions may play general roles in CNS when exposed to moderate stress. Furthermore, these results will help to elucidate the physiological processes involved in moderate stress in CNS.

Ethological analysis of scopolamine treatment or pretreatment in morphine dependent rats

Although scopolamine is currently used to treat morphine addiction in humans, its extensive actions on behaviors have not been systematically analyzed yet, and the underlying mechanisms of its effects still remain ambiguous. The present study was carried out to clarify the possible mechanisms by evaluating the effects of scopolamine pretreatment and treatment on naloxone-precipitated withdrawal signs and some of other general behaviors in morphine dependent rats. Our results showed that scopolamine pretreatment and treatment attenuated naloxone-precipitated withdrawal signs including jumping, writhing posture, weight loss, genital grooming, teeth-chattering, ptosis, diarrhea and irritability, except for wet dog shakes, while general behaviors such as water intake, urine volume and morphine excretion in urine were increased. Our findings suggest that scopolamine has significant actions in the treatment of opiate addiction, which might result from increasing morphine excretion from urine.

Ionotropic glutamatergic neurotransmission in the ventral tegmental area modulates ΔFosB expression in the nucleus accumbens and abstinence syndrome in morphine withdrawal rats

The present study sought to assess whether the blockade of ionotropic glutamate receptors in the ventral tegmental area could modulate morphine withdrawal in morphine-dependent rats and the expression of stable DeltaFosB isoforms in the nucleus accumbens during morphine withdrawal. Rats were injected (i.p.) with increasing doses of morphine for 1 week to develop physical dependence, and withdrawal was then precipitated by one injection of naloxone (2 mg/kg, i.p.). Abstinence signs such as jumping, wet-dog shake, writhing posture, weight loss, and Gellert-Holtzman scale score were recorded to evaluate naloxone-induced morphine withdrawal. Two ionotropic glutamate receptor antagonists, dizocilpine (MK-801) and 6, 7-dinitroquinnoxaline-2, 3-dione (DNQX), were microinjected unilaterally into the ventral tegmental area 30 min before naloxone precipitation. A second injection of naloxone (2 mg/kg i.p.) was given 1 h after the first naloxone injection to sustain a maximal level of withdrawal so that the expression of stable DeltaFosB isoforms in the nucleus accumbens could be measured. This would enable determination of the correlation between the MK-801 or DNQX-induced decrease in somatic withdrawal signs and the change in neuronal activity in the nucleus accumbens. The results showed that both MK-801 and DNQX significantly alleviated all symptoms of morphine withdrawal except for weight loss and reduced the expression of stable DeltaFosB isoforms within the nucleus accumbens. These data suggest that ionotropic glutamatergic neurotransmission in the ventral tegmental area regulates the levels of stable DeltaFosB isoforms in the nucleus accumbens, which play a very important role in modulating opiate withdrawal.

Blockade of ionotropic glutamatergic transmission in the ventral tegmental area attenuates the physical signs of morphine withdrawal in rats

The present study sought to assess whether the blockade of ionotropic glutamate receptors in the ventral tegmental area (VTA) could modulate the morphine withdrawal in male Sprague-Dawley rats. The effects of dizocilpine (MK-801) or 6,7-dinitroquinnoxaline-2,3-dione (DNQX), ionotropic glutamate receptor antagonists, microinjected unilaterally into the VTA 30 min before naloxone [2 mg/kg, intraperitoneally (i.p.)] administration on the morphine withdrawal were assessed. Morphine dependence was developed with increasing morphine injection (i.p.), and morphine withdrawal was induced by injection of naloxone (2 mg/kg, i.p.). Jumping, wet-dog shakes, writhing posture, wall clamber, weight loss and Gellert-Holtzman scale were used as the indices to evaluate the intensity of morphine withdrawal. The results showed that unilateral microinjection of MK-801 or DNQX into the VTA significantly increased the incidence of wall clamber, had no effect on weight loss, and reduced all other symptoms of morphine withdrawal. These data suggest that the ionotropic glutamate receptors in the VTA are involved in mediating naloxone-precipitated opiate withdrawal.

Targeted disruption of the catalytic subunit of the DNA-PK gene in mice confers severe combined immunodeficiency and radiosensitivity

The DNA-dependent protein kinase is a mammalian protein complex composed of Ku70, Ku80, and DNA-PKcs subunits that has been implicated in DNA double-strand break repair and V(D)J recombination. Here, by gene targeting, we have constructed a mouse with a disruption in the kinase domain of DNA-PKcs, generating an animal model completely devoid of DNA-PK activity. Our results demonstrate that DNA-PK activity is required for coding but not for signal join formation in mice. Although our DNA-PKcs defective mice closely resemble Scid mice, they differ by having elevated numbers of CD4+CD8+ thymocytes. This suggests that the Scid mice may not represent a null phenotype and may retain some residual DNA-PKcs function.

Characterization of a sodium-response transcriptional mechanism

On the basis of paradigms in development wherein discrete transcriptional events are pivotal regulatory steps, we tested the hypothesis that transcriptional sodium (Na+)-response mechanisms are involved in in vivo Na+-induced responses relevant to normal (homeostatic) and pathophysiological (salt-sensitive hypertension) conditions. We used Na,K-ATPase alpha-subunit genes as molecular probes and the Na+ ionophore monensin to induce a dose-specific incremental increase in [Na+]i in rat A10 embryonic aortic smooth muscle cells. RNA blot analysis of rat A10 cells revealed a dose-specific (0.022 to 30 micromol/L monensin) upregulation of alpha1-, alpha2-, and beta1-subunit Na,K-ATPase RNA levels. Control beta-actin and alpha-tropomyosin RNA levels did not change. With the use of chloramphenicol acetyltransferase (CAT) as reporter gene, CAT assays of rat alpha1[-1288]CAT and human alpha2[-798]CAT promoter constructs exhibited induction of CAT activity in monensin (10 micromol/L)-treated A10 cells compared with untreated A10 cells. Promoter deletion constructs for rat alpha1[-1288]CAT defined a positive Na+-response regulatory region within -358 to -169 that is distinct from the basal transcriptional activation region of -155 to -49 previously defined. Similarly, a positive Na+-response regulatory region is delimited to within -301 in the human alpha2 Na,K-ATPase 5' flanking region. Analysis of transgenic TgH alpha2[-798]CAT rats demonstrated sodium activation of human alpha2[-798]CAT transgene expression in aorta parallel to observations made in rat A10 aortic tissue culture cells. Southwestern blot analysis of nuclear extracts from monensin (10 micromol/L)-treated and control untreated A10 cells revealed a nuclear DNA binding protein (approximately 95 kD) that is upregulated by increased [Na+]i. These data provide initial characterization of a transcriptional Na+-response mechanism delimiting a positive Na+-response regulatory region in two target genes (alpha1 and alpha2 Na,K-ATPase) as well as detection of a Na+-response nuclear DNA binding protein. The in vitro data are corroborated by in vivo experimental and transgenic promoter expression studies, thus validating the biological relevance of the observations.

Pressure-overload deinduction of human alpha 2 Na,K-ATPase gene expression in transgenic rats

The early and sustained deinduction of alpha 2 Na,K-ATPase gene expression in both cardiac left ventricle and aorta in various pressure-overload rat models and in hypertrophied human heart suggests a common transcriptional pressure response mechanism to pressure overload in both rats and humans. To test this hypothesis, we developed transgenic rat lines expressing the chloramphenicol acetyltransferase reporter gene regulated by the human alpha 2 Na,K-ATPase (-798 to +67) regulatory region, H alpha 2-CAT. Analysis of two homozygous transgenic rat lines revealed (1) parallel tissue-specific regulation of the H alpha 2-CAT transgene and rat alpha 2 Na,K-ATPase gene and (2) parallel load-induced deinduction of both cardiac and vascular (aortic) H alpha 2-CAT transgene and rat alpha 2 Na,K-ATPase gene expression in a 3-day model of induced pressure overload. Cardiac H alpha 2-CAT deinduction was detected at a systolic pressure greater than or equal to 150 mm Hg and correlated with the degree of systolic pressure elevation (r = .82, P < .0001). The data suggest a systolic pressure gradient-dependent coordinate pressure-overload transcriptional response mechanism in the heart and aorta, with one of its target genes being the alpha 2 Na,K-ATPase gene in both humans and rats.