Dataset Information

Carbohydrate ingestion induces differential autonomic dysregulation in normal-tension glaucoma and primary open angle glaucoma.

ABSTRACT:

Background

It is reported that glaucoma may be associated with vascular dysregulation. Normal tension glaucoma (NTG) and primary open angle glaucoma (POAG), which feature different intraocular pressure levels, may manifest differential features of systemic autonomic dysregulation.

Methods and results

We investigated autonomic regulation to carbohydrate ingestion and postural change in 37 glaucoma patients (19 NTG and 18 POAG) and 36 controls. Subjects were age and gender-matched, normotensive, and had normal comparable insulin sensitivity. Continuous finger arterial pressure and ECG was recorded in supine and standing positions before and after carbohydrate ingestion. Low frequency (LF, 0.04-0.15Hz) and high frequency (HF, 0.15-0.4Hz) spectral power of heart rate and systolic blood pressure variability (HRV and SBPV) were calculated to estimate sympathovagal function. Overall comparison glaucoma (N = 37) and controls (N = 36) showed an increased sympathetic excitation, vagal withdrawal and unstable mean arterial pressure after carbohydrate ingestion in glaucoma patients. Glaucoma severity by retinal nerve fibre layer (RNFL) thickness is positively correlated to autonomic responses (HRV LF power and HF power in normalised units (nu), and HRV LF/HF ratio) after carbohydrate ingestion. Early (30 minutes) following carbohydrate ingestion, SBP LF power and HRV parameters remained unchanged in controls; while POAG showed abnormal autonomic responses, with a paradoxical vagal enhancement (increased HRV HF power in nu) and sympathetic inhibition (decreased HRV LF power nu and HRV LF/HF ratio), and associated hypotension. Later (60-120 minutes) following carbohydrate ingestion, HRV parameters remained unaltered in controls; whereas NTG manifested vagal withdrawal (reduced HRV HF power nu) and sympathetic hyper-responsiveness (increased HRV LF power nu and HRV LF/HF ratio), despite increased SBP LF power in both controls and NTG. Both NTG and POAG exhibited attenuated autonomic responses to postural stress.

Conclusions

NTG and POAG both manifest some systemic autonomic cardiovascular dysregulation. However, the two forms of glaucoma respond differentially to carbohydrate ingestion, irrespective of insulin resistance.

SUBMITTER: Cao L

PROVIDER: S-EPMC5991678 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Publications

Carbohydrate ingestion induces differential autonomic dysregulation in normal-tension glaucoma and primary open angle glaucoma.

Cao Lei L Graham Stuart L SL Pilowsky Paul M PM

PloS one 20180607 6

<h4>Background</h4>It is reported that glaucoma may be associated with vascular dysregulation. Normal tension glaucoma (NTG) and primary open angle glaucoma (POAG), which feature different intraocular pressure levels, may manifest differential features of systemic autonomic dysregulation.<h4>Methods and results</h4>We investigated autonomic regulation to carbohydrate ingestion and postural change in 37 glaucoma patients (19 NTG and 18 POAG) and 36 controls. Subjects were age and gender-matched, ...[more]

PMID: 29879162

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Project description:The total RNA from control and POAG optic nerve lamina cribrosa region was isolated and subjected to analysis on U133A 2.0 affymetrix microarray chip. The results from these two analysis was compared to determine whether PAD II RNA level is altered. Purpose of the study. This study was done to determine which RNA transcripts undergo significant changes in the optic nerve between normal and cadaver primary open-angle glaucoma donors. Using donor tissues from NDRI we have performed proteomic analyses (which will be published shortly), we intend a comparison between the proteomic and RNA changes for select proteins in our study. Sample Collection and Preparation of Labeled Copy RNA; The total RNA from optic nerve was obtained using TRIZOL (Invitrogen Inc., Carlsbad, CA) with modification of recommended protocols. The optic nerve from donor eyes were carefully excised and minced into small pieces first using a scissor and then a scalpel. Prior to use tissue was washed with DEPC water and all solutions were prepared in DEPC water. The minced tissue was placed in a glass homogenizer with 1 ml TRIZOL per 100 mg of tissue and homogenized in a glass homogenizer DUALL 20 (Kimble Kontes Glass Co, Vineland, NJ) with 10 strokes cycles each at room temperature and after freezing with liquid nitrogen for 1 min for 40 cycles. This RNA was extracted with chloroform, isoamylalcohol and precipitated with sodium citrate/sodium chloride and isopropanol. The final air-dried RNA precipitate was suspended in DEPC water and stored in â??80oC prior to use. RNA was prepared for hybridization according to the GeneChip Expression Analysis Technical Manual (Affymetrix, Santa Clara, CA). The hybridization was performed at Gene Expression Array Core Facility at Case Western Reserve University (www.geacf.net). The RNA sample was cleaned using a column from a Qiagen RNeasy kit, (part # 74104 ) in accordance with the manufacturerâ??s instructions. The volume of DEPC water used to elute the RNA from the Qiagen column was dictated by the nominal mass of the loaded RNA sample. Samples were eluted in 100ml of water, precipitated with 0.5 volume of 7.5M Ammonium Acetate and 2.5 volumes of 100% ethanol at -20oC for 1 hr and centrifuged for 10 min at room temperature. The pellet was drained and washed twice in 500Âµl of 70% ethanol. Supernatant was aspirated. The pellet was dried briefly (less than 1 min) in a speeedvac (Savant) and re-suspended in a small volume (~ 12â??15ml) of DEPC water. A small aliquot (2ml) of the sample was used for quantitation. Cleaned RNA samples were annotated as â??clnRNAâ?? and stored at -20oC. cDNA Synthesis; The protocol recommended by Affymetrix Inc. for cDNA synthesis was used at all times. The reaction was primed by annealing an oligo-dT primer coupled to a T7 RNA polymerase promoter to the RNA sample. Whenever possible, 8 mg of clnRNA were reverse transcribed using Superscript II reverse transcriptase in a 20ml reaction at 42oC for 1 hr. Second strand synthesis was carried out immediately in a total reaction volume of 150ml in the presence of E. coli DNA polymerase I, RNAse H and DNA ligase. The reaction mixture incubated for 2 hrs at 16oC and for a further 5 min in the presence of T4 DNA pol.. The reaction was terminated by the addition of EDTA. The sample was cleaned with a Qiagen cDNA clean-up column according to the manufacturers directions. The elution buffer volume was 14ml. The eluted samples were stored overnight at -20oC. In-Vitro Transcription (IVT) reaction; In a 0.5ml microfuge tube, complementary RNA (cRNA) was generated in an IVT reaction using a BioArray High Yield ENZO kit (Affymetrix). The 40ml reaction contained 10ml of cDNA sample and was incubated at 37oC in the heating block for 4-5hrs. Samples were mixed by flicking, pulse-centrifuged and returned to the incubator once every 40 minutes. Upon completion of the reaction, IVT samples were adjusted to a volume of 100ml with DEPC-treated water and cleaned using Qiagen RNA clean-up columns. Samples were eluted in 45ml of DEPC-treated water. A 2ml-aliquot was used for quantitation. Corrected concentrations of cRNA (minus the input clnRNA) were determined. A standard fragmentation reaction volume was 40ml in a 0.5 ml microfuge tube and used 20mg of overall IVT RNA in 1X fragmentation buffer (40mM Tris acetate, pH 8.1, 100mM KOAc, 30mM MgOAc). The reaction was incubated at 94oC for 35min in a heat block. After the 35 min incubation the fragmented samples were placed on ice. 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Dataset Information

Carbohydrate ingestion induces differential autonomic dysregulation in normal-tension glaucoma and primary open angle glaucoma.

Background

Methods and results

Conclusions

Publications

Carbohydrate ingestion induces differential autonomic dysregulation in normal-tension glaucoma and primary open angle glaucoma.

Similar Datasets

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