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Davidson CT, Dover AR, McVicar CM, Megaw R, Glenn JV, Hadoke PWF, Stitt AW, Walker BR. Inhibition or deletion of 11β-HSD1 does not increase angiogenesis in ischemic retinopathy. Diabetes Metab 2017; 43:480-483. [PMID: 28089372 DOI: 10.1016/j.diabet.2016.12.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 11/24/2016] [Accepted: 12/01/2016] [Indexed: 11/27/2022]
Affiliation(s)
- C T Davidson
- University/BHF Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, 47, Little France Crescent, Edinburgh EH16 4TJ, Scotland, UK
| | - A R Dover
- University/BHF Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, 47, Little France Crescent, Edinburgh EH16 4TJ, Scotland, UK
| | - C M McVicar
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - R Megaw
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, Scotland, UK
| | - J V Glenn
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - P W F Hadoke
- University/BHF Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, 47, Little France Crescent, Edinburgh EH16 4TJ, Scotland, UK
| | - A W Stitt
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - B R Walker
- University/BHF Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of Edinburgh, 47, Little France Crescent, Edinburgh EH16 4TJ, Scotland, UK.
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Curtis TM, Hamilton R, Yong PH, McVicar CM, Berner A, Pringle R, Uchida K, Nagai R, Brockbank S, Stitt AW. Müller glial dysfunction during diabetic retinopathy in rats is linked to accumulation of advanced glycation end-products and advanced lipoxidation end-products. Diabetologia 2011; 54:690-8. [PMID: 21116609 DOI: 10.1007/s00125-010-1971-x] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 10/14/2010] [Indexed: 01/01/2023]
Abstract
AIMS/HYPOTHESIS The impact of AGEs and advanced lipoxidation end-products (ALEs) on neuronal and Müller glial dysfunction in the diabetic retina is not well understood. We therefore sought to identify dysfunction of the retinal Müller glia during diabetes and to determine whether inhibition of AGEs/ALEs can prevent it. METHODS Sprague-Dawley rats were divided into three groups: (1) non-diabetic; (2) untreated streptozotocin-induced diabetic; and (3) diabetic treated with the AGE/ALE inhibitor pyridoxamine for the duration of diabetes. Rats were killed and their retinas were evaluated for neuroglial pathology. RESULTS AGEs and ALEs accumulated at higher levels in diabetic retinas than in controls (p < 0.001). AGE/ALE immunoreactivity was significantly diminished by pyridoxamine treatment of diabetic rats. Diabetes was also associated with the up-regulation of the oxidative stress marker haemoxygenase-1 and the induction of glial fibrillary acidic protein production in Müller glia (p < 0.001). Pyridoxamine treatment of diabetic rats had a significant beneficial effect on both variables (p < 0.001). Diabetes also significantly altered the normal localisation of the potassium inwardly rectifying channel Kir4.1 and the water channel aquaporin 4 to the Müller glia end-feet interacting with retinal capillaries. These abnormalities were prevented by pyridoxamine treatment. CONCLUSIONS/INTERPRETATION While it is established that AGE/ALE formation in the retina during diabetes is linked to microvascular dysfunction, this study suggests that these pathogenic adducts also play a role in Müller glial dysfunction.
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Affiliation(s)
- T M Curtis
- Centre for Vision and Vascular Science, Queen's University Belfast, Royal Victoria Hospital, Belfast BT12 6BA, Northern Ireland, UK
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Bennetts LE, De Iuliis GN, Nixon B, Kime M, Zelski K, McVicar CM, Lewis SE, Aitken RJ. Impact of estrogenic compounds on DNA integrity in human spermatozoa: evidence for cross-linking and redox cycling activities. Mutat Res 2008; 641:1-11. [PMID: 18342339 DOI: 10.1016/j.mrfmmm.2008.02.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 02/02/2008] [Indexed: 05/26/2023]
Abstract
A great deal of circumstantial evidence has linked DNA damage in human spermatozoa with adverse reproductive outcomes including reduced fertility and high rates of miscarriage. Although oxidative stress is thought to make a significant contribution to DNA damage in the male germ line, the factors responsible for creating this stress have not been elucidated. One group of compounds that are thought to be active in this context are the estrogens, either generated as a result of the endogenous metabolism of androgens within the male reproductive tract or gaining access to the latter as a consequence of environmental exposure. In this study, a wide variety of estrogenic compounds were assessed for their direct effects on human spermatozoa in vitro. DNA integrity was assessed using the Comet and TUNEL assays, lesion frequencies were quantified by QPCR using targets within the mitochondrial and nuclear (beta-globin) genomes, DNA adducts were characterized by mass spectrometry and redox activity was monitored using dihydroethidium (DHE) as the probe. Of the estrogenic and estrogen analogue compounds evaluated, catechol estrogens, quercetin, diethylstilbestrol and pyrocatechol stimulated intense redox activity while genistein was only active at the highest doses tested. Other estrogens and estrogen analogues, such as 17beta-estradiol, nonylphenol, bisphenol A and 2,3-dihydroxynaphthalene were inactive. Estrogen-induced redox activity was associated with a dramatic loss of motility and, in the case of 2-hydroxyestradiol, the induction of significant DNA fragmentation. Mass spectrometry also indicated that catechol estrogens were capable of forming dimers that can cross-link the densely packed DNA strands in sperm chromatin, impairing nuclear decondensation. These results highlight the potential importance of estrogenic compounds in creating oxidative stress and DNA damage in the male germ line and suggest that further exploration of these compounds in the aetiology of male infertility is warranted.
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Affiliation(s)
- L E Bennetts
- ARC Centre of Excellence in Biotechnology and Development and Discipline of Biological Sciences, University of Newcastle, NSW, Australia
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Agbaje IM, Rogers DA, McVicar CM, McClure N, Atkinson AB, Mallidis C, Lewis SEM. Insulin dependant diabetes mellitus: implications for male reproductive function. Hum Reprod 2007; 22:1871-7. [PMID: 17478459 DOI: 10.1093/humrep/dem077] [Citation(s) in RCA: 295] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Diabetes mellitus (DM) is increasing in men of reproductive age. Despite this, the prevalence of diabetes in men attending fertility clinics is largely unknown. Furthermore, studies examining the effects of DM on sperm fertility potential have been limited to conventional semen analysis. METHODS Conventional semen analysis (semen volume, sperm count, motility and morphology) was performed for 27 diabetic (mean age 34+/-2 years) and 29 non-diabetic subjects (control group, men undergoing routine infertility investigations, mean age 33+/-1 years). Nuclear DNA (nDNA) fragmentation was assessed using the alkaline Comet assay and mitochondrial DNA (mtDNA) deletions by Long-PCR. RESULTS Other than a small, but significant, reduction in semen volume in diabetic men (2.6 versus 3.3 ml; P<0.05), conventional semen parameters did not differ significantly from control subjects. Diabetic subjects had significantly higher mean nDNA fragmentation (53 versus 32%; P<0.0001) and median number of mtDNA deletions (4 versus 3; P<0.05) compared with control subjects. CONCLUSIONS Diabetes is associated with increased sperm nuclear and mtDNA damage that may impair the reproductive capability of these men.
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Affiliation(s)
- I M Agbaje
- Reproductive Medicine Research Group, Centre for Clinical and Population Sciences, Queen's University of Belfast, Institute of Clinical Science, and Regional Centre for Endocrinology and Diabetes, Royal Victoria Hospital, UK.
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McVicar CM, O'Neill DA, McClure N, Clements B, McCullough S, Lewis SEM. Effects of vasectomy on spermatogenesis and fertility outcome after testicular sperm extraction combined with ICSI. Hum Reprod 2005; 20:2795-800. [PMID: 15958397 DOI: 10.1093/humrep/dei138] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Each year 40,000 men have a vasectomy in the UK whilst another 2400 request a reversal to begin a second family. Sperm can now be obtained by testicular biopsy and subsequently used in assisted conception with ICSI. The study aims were to compare sperm yields of men post-vasectomy or with obstructive azoospermia (OA) of unknown aetiology with yields of fertile men and to assess any alteration in the clinical pregnancy rates after ICSI. METHODS Testicular tissue was obtained by Trucut needle from men who had undergone a vasectomy >5 years previously or had OA from other causes and from fertile men during vasectomy. Seminiferous tubules were milked to measure sperm yields. Numbers of Sertoli cells and spermatids and thickness of the seminiferous tubule walls were assessed using quantitative computerized analysis. RESULTS AND CONCLUSIONS Sperm yields/g testis were significantly decreased in men post-vasectomy and in men with OA, relative to fertile men. Significant reductions were also observed in early (40%) and mature (29%) spermatid numbers and an increase of 31% was seen in the seminiferous tubule wall (basal membrane and collagen thickness) of vasectomized men compared with fertile men. Clinical pregnancy rates in couples who had had a vasectomy were also significantly reduced.
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Affiliation(s)
- C M McVicar
- Obstetrics and Gynaecology, School of Medicine, Queen's University Belfast, Institute of Clinical Science, UK.
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McVicar CM, Cunningham RT, McClure N, Curry WJ. Chromogranin A proteolysis to generate beta-granin and WE-14 in the adenohypophysis during the rat oestrous cycle. Regul Pept 2003; 115:1-10. [PMID: 12873792 DOI: 10.1016/s0167-0115(03)00130-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Immunohistochemical analysis of the male and female rat adenohypophysis revealed that chromogranin A (CgA), beta-granin and WE-14 immunostaining was localised to follicle stimulating hormone (FSH) producing cells, while luteinizing hormone (LH) producing cells exhibited chromogranin A and beta-granin immunostaining. The intensity of chromogranin A, beta-granin and WE-14 immunostaining exhibited variation during the oestrous cycle; weak immunostaining was observed during proestrous and oestrous, corresponding with the lowest cellular concentration of luteinizing and follicle stimulating hormone. Chromogranin A and beta-granin immunostaining were similar in both the male and female (at dioestrous), however, a larger number of more intense WE-14 immunopositive cells were evident in the male adenohypophysis relative to the female at any stage of the cycle. The tissue and plasma concentrations of beta-granin and WE-14 immunoreactivity fluctuated throughout the oestrous cycle. Maximum and minimum beta-granin and WE-14 tissue concentration counterpoised the latent maximum and minimum plasma concentration. Chromatographic analysis of adenohypophysis extracts revealed the degree of chromogranin A proteolysis throughout the oestrous cycle; in contrast, plasma profiles consistently possessed a large chromogranin A-like immunoreactant. This data suggests that chromogranin A biosynthesis, proteolysis and the secretion of its derived peptides parallels that of the gonadotroph hormones throughout the oestrous cycle.
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Affiliation(s)
- Carmel Mary McVicar
- School of Medicine, Obstetrics and Gynaecology, Queen's University of Belfast, Institute of Clinical Science, Grosvenor Road, Belfast, BT12 6BJ, Northern Ireland, UK.
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Abstract
The neuropeptide WE-14 is derived from the posttranslational processing of chromogranin A (CgA). While CgA is expressed in a preponderance of neuroendocrine cells, WE-14 is generated in a distinct subpopulation of CgA-immunopositive cells, most notably in the adrenal, pituitary, and parathyroid glands. Physiological and pharmacological studies have demonstrated that CgA is cleaved to generate WE-14 in the adrenal chromaffin cell population and in the enterochromaffin-like (ECL) cells of the oxyntic mucosa. Pathological analyses of neuroendocrine tumors have revealed a heterogeneous pattern of WE-14 immunostaining, with variable concentrations quantified and chromatographically resolved in tissue extracts. Phylogenetic surveys have demonstrated that WE-14 exhibits an ancient lineage, while ontogenetic examination has shown that it is generated at an early stage during fetal development. Putative WE-14 receptor binding sites have been identified in several tissues; however, the physiological role of WE-14 remains enigmatic.
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Affiliation(s)
- W J Curry
- Department of Ophthalmology and School of Clinical Medicine, Queen's University, Belfast, Northern Ireland.
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McVicar CM, Cunningham RT, Harriott P, Johnston CF, Buchanan KD, Curry WJ. Analysis of the post-translational processing of chromogranin A in rat neuroendocrine tissue employing an N-terminal site-specific antiserum. J Neuroendocrinol 2001; 13:588-95. [PMID: 11442773 DOI: 10.1046/j.1365-2826.2001.00671.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Chromogranin A (CgA) is a complex prohormone expressed as a constituent of the regulated secretory pathway of numerous neuroendocrine cells. Recent investigations have demonstrated that CgA is selectively cleaved to generate distinct peptides in different neuroendocrine tissues. This investigation employed a site-specific antiserum that detects residues 98-106 rat CgA to examine the amino-terminal processing of CgA to generate beta-granin and related peptides in rat neuroendocrine tissues. Immunohistochemistry revealed moderate to intense beta-granin-like immunostaining in cells scattered throughout the anterior pituitary, thyroid, in the islets of Langerhans and in the mucosa of the gastrointestinal tract. Variable intensities of immunostaining were observed in distinct clusters of chromaffin cells. Quantitatively, the highest concentration of beta-granin-like immunoreactivity was detected in pituitary extracts. Significantly lower concentrations were detected in adrenal and thyroid glands, brain, ventral and dorsal pancreatic lobes and gastrointestinal tissue extracts. Chromatography resolved three distinct beta-granin-like immunoreactants; a large CgA-like form, an intermediate molecular form presumably corresponding to beta-granin (rat CgA1-128) and small immunoreactants that coeluted with the synthetic peptide. Two beta-granin-like immunoreactants, 21 and 22 kDa, were detected following immunoblot analysis of pituitary extracts. This study has demonstrated that chromogranin A is subject to distinct amino-terminal patterns of tissue-and cell-specific processing to generate a beta-granin-like immunoreactant which is additionally cleaved in pancreatic, fundic and colonic tissue to generate previously unidentified peptides.
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Affiliation(s)
- C M McVicar
- Department of Medicine, School of Biology and Biochemistry, The Queen's University of Belfast, UK
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