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Januszewski AS, Xu D, Cho YH, Benitez-Aguirre PZ, O'Neal DN, Craig ME, Donaghue KC, Jenkins AJ. Skin autofluorescence in people with type 1 diabetes and people without diabetes: An eight-decade cross-sectional study with evidence of accelerated aging and associations with complications. Diabet Med 2021; 38:e14432. [PMID: 33078416 DOI: 10.1111/dme.14432] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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] [Received: 05/25/2020] [Revised: 09/28/2020] [Accepted: 10/15/2020] [Indexed: 02/03/2023]
Abstract
AIM To measure skin autofluorescence in youth (<18 y.o.) and adults (≥18 y.o.) and to assess its relationship with type 1 diabetes, chronic complications and smoking. METHODS In a cross-sectional study (n = 383) skin autofluorescence was measured in 269 people with type 1 diabetes (67 with vascular complications) and 114 people without diabetes, covering eight decades of age. Associations of skin autofluorescence with demographics and traditional risk factors were assessed. RESULTS Skin autofluorescence increased with age in people with diabetes: for those with complications it increased by a mean ± se of 0.029 ± 0.003 arbitrary units per year (r = 0.76) and, for those without complications, it increased by 0.028 ± 0.002 arbitrary units (r = 0.77). These increases were higher than for people without diabetes, whose skin autofluorescence increased by 0.022 ± 0.002 arbitrary units (r = 0.78) per year (p = 0.004). Mean ±se age-adjusted skin autofluorescence was higher in people with diabetes complications vs people without diabetes complications (1.85 ± 0.04 vs 1.66 ± 0.02 arbitrary units) and people without diabetes (1.48 ± 0.03 arbitrary units; all P < 0.0001). Age-adjusted skin autofluorescence was higher in current smokers and recent ex-smokers vs non-smokers and longer-term ex-smokers (1.86 ± 0.06 vs 1.63 ± 0.02 arbitrary units; P = 0.0005). Skin autofluorescence area under the receiver-operating characteristic curve was 0.89 (95% CI 0.85-0.94) for retinopathy and 0.56 (95% CI 0.47-0.65) for nephropathy. CONCLUSIONS Skin autofluorescence increases with age, but faster in people with diabetes, particularly in those with complications and in smokers, consistent with accelerated aging. Skin autofluorescence may facilitate complication screening and prediction. Longitudinal studies are merited.
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Affiliation(s)
- A S Januszewski
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, NSW, Australia
- Department of Medicine, University of Melbourne, Fitzroy, NSW, Australia
| | - D Xu
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, NSW, Australia
- Department of Engineering Science, University of Oxford, Visual Geometry Group, Oxford, UK
| | - Y H Cho
- Children's Hospital at Westmead, Sydney, NSW, Australia
| | | | - D N O'Neal
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, NSW, Australia
- Department of Medicine, University of Melbourne, Fitzroy, NSW, Australia
| | - M E Craig
- Children's Hospital at Westmead, Sydney, NSW, Australia
| | - K C Donaghue
- Children's Hospital at Westmead, Sydney, NSW, Australia
| | - A J Jenkins
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, NSW, Australia
- Department of Medicine, University of Melbourne, Fitzroy, NSW, Australia
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Benitez-Aguirre PZ, Januszewski AS, Cho YH, Craig ME, Jenkins AJ, Donaghue KC. Early changes of arterial elasticity in Type 1 diabetes with microvascular complications - A cross-sectional study from childhood to adulthood. J Diabetes Complications 2017; 31:1674-1680. [PMID: 28941950 DOI: 10.1016/j.jdiacomp.2017.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 08/09/2017] [Accepted: 08/14/2017] [Indexed: 01/01/2023]
Abstract
AIM To examine the trajectory of small artery elasticity (SAE) and pulse pressure (PP) in people with Type 1 diabetes and non-diabetic controls across the lifespan, and explore associations with microvascular complications (CX+). METHODS This cross-sectional study included 477 Type 1 diabetes patients (188 with CX+, 289 without CX-) and 515 controls. Relationships between SAE and PP and age were evaluated using segmented linear regression. Logistic regression was used to assess the associations between microvascular complications (retinopathy and/or nephropathy) and SAE and PP. RESULTS SAE peaked significantly later among controls than diabetic patients CX- vs. CX+ (21.2 vs. 20.4 vs. 17.6 years respectively, p < 0.001). In adults, mean SAE was significantly lower in CX+ vs. CX- vs. controls (6.8 vs. 7.8 vs. 8.0 ml/mm Hg × 10; p < 0.0001), and mean PP was significantly higher in CX+ vs CX- and controls (60 vs. 55 vs. 53 mm Hg; p < 0.0001). CONCLUSION Type 1 diabetes CX+ subjects have an earlier peak and decline in SAE relative to CX- and controls, who did not differ. Lower SAE and higher PP were associated with increased odds of Type 1 diabetes complications in adults. These clinically applicable techniques demonstrate an association between accelerated vascular aging and vascular complications in diabetes.
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Affiliation(s)
- P Z Benitez-Aguirre
- Discipline of Paediatrics and Child Health, University of Sydney, Australia; Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Sydney, Australia
| | - A S Januszewski
- NHMRC Clinical Trials Centre, University of Sydney, Australia; Department of Medicine, University of Melbourne, Australia
| | - Y H Cho
- Discipline of Paediatrics and Child Health, University of Sydney, Australia; Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Sydney, Australia
| | - M E Craig
- Discipline of Paediatrics and Child Health, University of Sydney, Australia; Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Sydney, Australia; School of Women's and Children's Health, University of New South Wales, Australia
| | - A J Jenkins
- NHMRC Clinical Trials Centre, University of Sydney, Australia; Department of Medicine, University of Melbourne, Australia
| | - K C Donaghue
- Discipline of Paediatrics and Child Health, University of Sydney, Australia; Institute of Endocrinology and Diabetes, The Children's Hospital at Westmead, Sydney, Australia.
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Traill CL, Januszewski AS, Larkins R, Keech AC, Jenkins AJ. Time to research Australian physician-researchers. Intern Med J 2017; 46:550-8. [PMID: 26909676 DOI: 10.1111/imj.13043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 02/01/2016] [Accepted: 02/05/2016] [Indexed: 11/27/2022]
Abstract
BACKGROUND Concerns have been expressed 'that the physician-researcher is a dying breed'. As yet there are few Australian data. AIMS To compare over time: (i) research progress of Sydney Medical School (SMS) medical practitioner - PhD awardees; (ii) National Health and Medical Research Council (NHMRC) project grant success rates for physician-researchers; and (iii) compare current NHMRC, NSW University and NSW Public Hospital pay scales for physician-researchers. METHODS We evaluated 303 medical practitioners awarded a University of Sydney/SMS PhD in 1989-2012 and their publications. We assessed 1990-2014 NHMRC grants to physicians and non-physicians (nationally) and compared physician salaries from NHMRC, the University of Sydney and NSW public hospitals. RESULTS SMS PhD completions by clinicians increased ≈2.4-fold since 1989, with a recent decline, whilst non-medical PhD awardees rose 10-fold. The median time of PhD award after medical degree completion was stable at 13 years. A lower percentage of the more recent physician-researchers had completed specialty training at PhD award (34% in 2011-2012 vs 71% in 1989-1990, P = 0.017). Publication rates were stable, but low. Although NHMRC funding increased >10-fold since 1990, national project grant success rates declined (35% in 1990, 17% in 2013 and 15% in 2014, P < 0.0001), with physician-led funded grants declining from 29% in 1989 to 21% in 2013, P = 0.002. Current NHMRC and University salaries are less than comparable-stage public hospital salaries. CONCLUSION Since 1989, more medical graduates are completing SMS PhDs, although more often prior to completing clinical Fellowships, and many have ongoing, albeit low, research activity. Nationally NHMRC project grant success rates have declined significantly, as has the proportion of funded physician-led projects. Medical practitioner salaries from NHMRC and from Universities are less than in public hospitals. The Australian physician-researcher is at-risk. Knowledge and actions are needed to protect our medical research capacity.
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Affiliation(s)
- C L Traill
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
| | - A S Januszewski
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
| | - R Larkins
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - A C Keech
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia.,Royal Prince Alfred Hospital, University of Sydney, Sydney, New South Wales, Australia
| | - A J Jenkins
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
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Cho YH, Craig ME, Januszewski AS, Benitez-Aguirre P, Hing S, Jenkins AJ, Donaghue KC. Higher skin autofluorescence in young people with Type 1 diabetes and microvascular complications. Diabet Med 2017; 34:543-550. [PMID: 27770590 DOI: 10.1111/dme.13280] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [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] [Accepted: 10/19/2016] [Indexed: 01/06/2023]
Abstract
AIM To test the hypothesis that non-invasive skin autofluorescence, a measure of advanced glycation end products, would provide a surrogate measure of long-term glycaemia and be associated with early markers of microvascular complications in adolescents with Type 1 diabetes. METHODS Forearm skin autofluorescence (arbitrary units) was measured in a cross-sectional study of 135 adolescents with Type 1 diabetes [mean ± sd age 15.6 ± 2.1 years, diabetes duration 8.7 ± 3.5 years, HbA1c 72 ± 16 mmol/mol (8.7 ± 1.5%)]. Retinopathy, assessed using seven-field stereoscopic fundal photography, was defined as ≥1 microaneurysm or haemorrhage. Cardiac autonomic function was measured by standard deviation of consecutive RR intervals on a 10-min continuous electrocardiogram recording, as a measure of heart rate variability. RESULTS Skin autofluorescence was significantly associated with age (R2 = 0.15; P < 0.001). Age- and gender-adjusted skin autofluorescence was associated with concurrent HbA1c (R2 = 0.32; P < 0.001) and HbA1c over the previous 2.5-10 years (R2 = 0.34-0.43; P < 0.002). Age- and gender-adjusted mean skin autofluorescence was higher in adolescents with retinopathy vs those without retinopathy [mean 1.38 (95% CI 1.29, 1.48) vs 1.22 (95% CI 1.17, 1.26) arbitrary units; P = 0.002]. In multivariable analysis, retinopathy was significantly associated with skin autofluorescence, adjusted for duration (R2 = 0.19; P = 0.03). Cardiac autonomic dysfunction was also independently associated with skin autofluorescence (R2 = 0.11; P = 0.006). CONCLUSIONS Higher skin autofluorescence is associated with retinopathy and cardiac autonomic dysfunction in adolescents with Type 1 diabetes. The relationship between skin autofluorescence and previous glycaemia may provide insight into metabolic memory. Longitudinal studies will determine the utility of skin autofluorescence as a non-invasive screening tool to predict future microvascular complications.
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Affiliation(s)
- Y H Cho
- Institute of Endocrinology and Diabetes, Children's Hospital at Westmead, Westmead, Australia
- Discipline of Child and Adolescent Health, University of Sydney, Westmead, Australia
| | - M E Craig
- Institute of Endocrinology and Diabetes, Children's Hospital at Westmead, Westmead, Australia
- Discipline of Child and Adolescent Health, University of Sydney, Westmead, Australia
- School of Women's and Children's Health, University of New South Wales, Sydney, Australia
| | - A S Januszewski
- NHMRC Clinical Trials Centre, University of Sydney, Camperdown, NSW, Australia
| | - P Benitez-Aguirre
- Institute of Endocrinology and Diabetes, Children's Hospital at Westmead, Westmead, Australia
- Discipline of Child and Adolescent Health, University of Sydney, Westmead, Australia
| | - S Hing
- Institute of Endocrinology and Diabetes, Children's Hospital at Westmead, Westmead, Australia
| | - A J Jenkins
- NHMRC Clinical Trials Centre, University of Sydney, Camperdown, NSW, Australia
| | - K C Donaghue
- Institute of Endocrinology and Diabetes, Children's Hospital at Westmead, Westmead, Australia
- Discipline of Child and Adolescent Health, University of Sydney, Westmead, Australia
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Ogle GD, Abdullah M, Mason D, Januszewski AS, Besançon S. Insulin storage in hot climates without refrigeration: temperature reduction efficacy of clay pots and other techniques. Diabet Med 2016; 33:1544-1553. [PMID: 27472257 DOI: 10.1111/dme.13194] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [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] [Accepted: 07/26/2016] [Indexed: 12/21/2022]
Abstract
AIM Insulin loses potency when stored at high temperatures. Various clay pots part-filled with water, and other evaporative cooling devices, are used in less-resourced countries when home refrigeration is unavailable. This study examined the cooling efficacy of such devices. METHODS Thirteen devices used in Sudan, Ethiopia, Tanzania, Mali, India, Pakistan and Haiti (10 clay pots, a goat skin, a vegetable gourd and a bucket filled with wet sand), and two identical commercially manufactured cooling wallets were compared. Devices were maintained according to local instructions. Internal and ambient temperature and ambient humidity were measured by electronic loggers every 5 min in Khartoum (88 h), and, for the two Malian pots, in Bamako (84 h). Cooling efficacy was assessed by average absolute temperature difference (internal vs. ambient), and % maximal possible evaporative cooling (allowing for humidity). RESULTS During the study period, mean ambient temperature and humidity were 31.0°C and 32.0% in Khartoum and 32.9°C and 39.8% in Bamako. All devices reduced the temperature (P < 0.001) with a mean (sd) reduction from 2.7 ± 0.5°C to 8.3 ± 1.0°C, depending on the device. When expressed as % maximal cooling, device efficacy ranged from 20.5% to 71.3%. On cluster analysis, the most efficacious devices were the goat skin, two clay pots (from Ethiopia and Sudan) and the suspended cooling wallet. CONCLUSIONS Low-cost devices used in less-resourced countries reduce storage temperatures. With more efficacious devices, average temperatures at or close to standard room temperature (20-25°C) can be achieved, even in hot climates. All devices are more efficacious at lower humidity. Further studies are needed on insulin stability to determine when these devices are necessary.
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Affiliation(s)
- G D Ogle
- International Diabetes Federation Life for a Child Program, Sydney, NSW, Australia.
- Diabetes NSW, Glebe, NSW, Australia.
| | - M Abdullah
- Sudan Childhood Diabetes Centre, Khartoum, Sudan
| | - D Mason
- International Diabetes Federation Life for a Child Program, Sydney, NSW, Australia
- Macquarie University, Sydney, NSW, Australia
| | - A S Januszewski
- NHMRC Clinical Trials Centre, University of Sydney, Sydney, NSW, Australia
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Traill CL, Januszewski AS, Larkins RG, Keech AC, Jenkins AJ. Time to research Australian female physician-researchers. Intern Med J 2015; 46:412-9. [PMID: 26692102 DOI: 10.1111/imj.12986] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 12/13/2015] [Accepted: 12/14/2015] [Indexed: 11/29/2022]
Abstract
BACKGROUND Given the concerns that physician-researchers are 'at risk', and ≈50% of Australian medical students are female, the evaluation of female physician-researchers is important. AIMS To compare over time (i) research-related metrics of male and female physician-researchers from Sydney Medical School; and (ii) National Health and Medical Research Council (NHMRC) Project grant leadership by gender. METHODS The Sydney Medical School (SMS) PhD award lists from 1989 to 2012 were cross-referenced with the Australian Health Practitioner Regulation Agency database, and registered medical practitioners were searched for in the Scopus database for publications and H-indexes. The gender of medical-practitioner Chief Investigator A (CIA) in Australia on funded NHMRC Project grants in 1990 to 2014 was also compared. RESULTS Of the medical practitioners awarded University of Sydney PhD, females increased from 14 to 55% in 1989-1990 and 2009-2010 and decreased to 38% in 2011-2012 (overall increase, P = 0.047). PhD award timings relative to MBBS and clinical fellowship completions were similar for both genders (P > 0.05). Post-PhD, as many women as men publish and have similar H-indexes, but women publish fewer papers (0.7 vs 1.0 publications per year, P = 0.028). On medical practitioner-led, funded NHMRC project grants between 1999 and 2014, female CIA increased from 7.5 to 19.5%, P < 0.0001. For the 17% of project grant applications funded to commence in 2014, 21% were medical practitioner-led, of whom 19.5% were female. CONCLUSIONS Since 1989, more female medical practitioners are completing SMS PhD at similar times in their careers to males. However, relative to their male peers, they publish less. Fewer female than male medical practitioner-researchers hold NHMRC Project Grant CIA status nationally, although the rates are increasing. In addressing physician-researcher workforce issues, including retention, attention should be given to factors impacting females.
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Affiliation(s)
- C L Traill
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
| | - A S Januszewski
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
| | - R G Larkins
- Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - A C Keech
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia.,Royal Prince Alfred Hospital, University of Sydney, Sydney, New South Wales, Australia
| | - A J Jenkins
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia.,NHMRC Clinical Trials Centre, University of Sydney, Sydney, New South Wales, Australia
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Kar P, Plummer MP, Bellomo R, Jenkins AJ, Januszewski AS, Lange K, Chapman MJ, Horowitz M, Deane AM. Personalised glucose therapy: glucose targets in critically ill patients with pre-existing poorly controlled type 2 diabetes. Intensive Care Med Exp 2015. [PMCID: PMC4797823 DOI: 10.1186/2197-425x-3-s1-a290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Januszewski AS, Sachithanandan N, Karschimkus C, O'Neal DN, Yeung CK, Alkatib N, Jenkins AJ. Non-invasive measures of tissue autofluorescence are increased in Type 1 diabetes complications and correlate with a non-invasive measure of vascular dysfunction. Diabet Med 2012; 29:726-33. [PMID: 22211881 DOI: 10.1111/j.1464-5491.2011.03562.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [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: 11/26/2022]
Abstract
OBJECTIVE To determine if ocular and skin autofluorescence, reflecting advanced glycation end-products, and vascular stiffness correlate in non-diabetic and Type 1 diabetic subjects and if levels differ by diabetes status. RESEARCH DESIGN AND METHODS Patients with Type 1 diabetes (n = 69, 19 with and 50 without vascular complications) and 60 subjects without diabetes (control) had ocular and skin autofluorescence and pulse-wave analysis performed in the fasted state. Correlations between measures within groups used the Pearson or Spearman correlation-coefficient and measures between groups were compared by ANOVA. RESULTS Lens and skin autofluorescence correlated in control (r = 0.58, P = 0.0001) and in Type 1 diabetes (r = 0.53, P = 0.001). Corneal autofluorescence correlated with lens (r = 0.53, r = 0.52, P = 0.0001) and skin autofluorescence (r = 0.34, P = 0.01 and r = 0.49, P = 0.00001) in control and Type 1 diabetes respectively. In Type 1 diabetes, small and large artery elasticity correlated inversely and systemic vascular resistance correlated positively with skin autofluorescence (all P = 0.001), and with lens and corneal autofluorescence (all P < 0.03). In Type 1 diabetes tissue advanced glycation end-products correlated with C-reactive protein and inversely with the estimated glucose disposal rate and with circulating advanced glycation end-product levels. Relative to non-diabetic subjects, lens, corneal and skin fluorescence were increased (all P < 0.001) and small artery elasticity was decreased in diabetes (P = 0.04). Lens, corneal and skin autofluorescence were greater (all P = 0.0001) in patients with Type 1 diabetes with complications compared to those without complications, but small artery elasticity did not differ significantly. CONCLUSIONS Ocular and skin autofluorescence and vascular stiffness correlate in non-diabetic and Type 1 diabetes subjects and are increased in Type 1 diabetes. Tissue advanced glycation end-products correlate with vascular risk factors, including circulating advanced glycation end-products.
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Affiliation(s)
- A S Januszewski
- Department of Medicine, University of Melbourne, St Vincent's Hospital, Melbourne, Australia.
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9
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Jenkins AJ, Zhang SX, Rowley KG, Karschimkus CS, Nelson CL, Chung JS, O'Neal DN, Januszewski AS, Croft KD, Mori TA, Dragicevic G, Harper CA, Best JD, Lyons TJ, Ma JX. Increased serum pigment epithelium-derived factor is associated with microvascular complications, vascular stiffness and inflammation in Type 1 diabetes. Diabet Med 2007; 24:1345-51. [PMID: 17971181 DOI: 10.1111/j.1464-5491.2007.02281.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [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] [Indexed: 02/06/2023]
Abstract
AIMS To determine in Type 1 diabetes patients if levels of pigment epithelium-derived factor (PEDF), an anti-angiogenic, anti-inflammatory and antioxidant factor, are increased in individuals with complications and positively related to vascular and renal dysfunction, body mass index, glycated haemoglobin, lipids, inflammation and oxidative stress. METHODS Serum PEDF levels were measured by ELISA in a cross-sectional study of 123 Type 1 diabetic patients (71 without and 52 with microvascular complications) and 31 non-diabetic control subjects. PEDF associations with complication status, pulse-wave analysis and biochemical results were explored. RESULTS PEDF levels [geometric mean (95% CI)] were increased in patients with complications 8.2 (7.0-9.6) microg/ml, vs. complication-free patients [5.3 (4.7-6.0) microg/ml, P < 0.001] and control subjects [5.3 (4.6-6.1) microg/ml, P < 0.001; anova between three groups, P < 0.001], but did not differ significantly between control subjects and complication-free patients (P > 0.05). In diabetes, PEDF levels correlated (all P < 0.001) with systolic blood pressure (r = 0.317), pulse pressure (r = 0.337), small artery elasticity (r = -0.269), glycated haemoglobin (r = 0.245), body mass index (r = 0.362), renal dysfunction [including serum creatinine (r = 0.491), cystatin C (r = 0.500)], triglycerides (r = 0.367), and inflammation [including log(e)C-reactive protein (CRP; r = 0.329), and soluble vascular cell adhesion molecule-1 (r = 0.363)]. Age, blood urea nitrogen, systolic blood pressure, pulse pressure and log(e)CRP correlated with PEDF levels in control subjects (all P < 0.04). PEDF levels were not significantly correlated with measures of oxidative stress: isoprostanes, oxidized low-density lipoprotein or paraoxonase-1 activity. On stepwise linear regression analysis (all subjects), independent determinants of PEDF levels were renal function, triglycerides, inflammation, small artery elasticity and age (r(2) = 0.427). CONCLUSIONS In Type 1 diabetes, serum PEDF levels are associated with microvascular complications, poor vascular health, hyperglycaemia, adiposity and inflammation.
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Affiliation(s)
- A J Jenkins
- University of Melbourne, Department of Medicine, St Vincent's Hospital, Melbourne, Australia.
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Nobecourt E, Davies MJ, Brown BE, Curtiss LK, Bonnet DJ, Charlton F, Januszewski AS, Jenkins AJ, Barter PJ, Rye KA. The impact of glycation on apolipoprotein A-I structure and its ability to activate lecithin:cholesterol acyltransferase. Diabetologia 2007; 50:643-53. [PMID: 17216278 DOI: 10.1007/s00125-006-0574-z] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [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] [Received: 05/02/2006] [Accepted: 11/21/2006] [Indexed: 11/28/2022]
Abstract
AIMS/HYPOTHESIS Hyperglycaemia, one of the main features of diabetes, results in non-enzymatic glycation of plasma proteins, including apolipoprotein A-I (apoA-I), the most abundant apolipoprotein in HDL. The aim of this study was to determine how glycation affects the structure of apoA-I and its ability to activate lecithin:cholesterol acyltransferase (LCAT), a key enzyme in reverse cholesterol transport. MATERIALS AND METHODS Discoidal reconstituted HDL (rHDL) containing phosphatidylcholine and apoA-I ([A-I]rHDL) were prepared by the cholate dialysis method and glycated by incubation with methylglyoxal. Glycation of apoA-I was quantified as the reduction in detectable arginine, lysine and tryptophan residues. Methylglyoxal-AGE adduct formation in apoA-I was assessed by immunoblotting. (A-I)rHDL size and surface charge were determined by non-denaturing gradient gel electrophoresis and agarose gel electrophoresis, respectively. The kinetics of the LCAT reaction was investigated by incubating varying concentrations of discoidal (A-I)rHDL with a constant amount of purified enzyme. The conformation of apoA-I was assessed by surface plasmon resonance. RESULTS Methylglyoxal-mediated modifications of the arginine, lysine and tryptophan residues in lipid-free and lipid-associated apoA-I were time- and concentration-dependent. These modifications altered the conformation of apoA-I in regions critical for LCAT activation and lipid binding. They also decreased (A-I)rHDL size and surface charge. The rate of LCAT-mediated cholesterol esterification in (A-I)rHDL varied according to the level of apoA-I glycation and progressively decreased as the extent of apoA-I glycation increased. CONCLUSIONS/INTERPRETATION It is concluded that glycation of apoA-I may adversely affect reverse cholesterol transport in subjects with diabetes.
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Affiliation(s)
- E Nobecourt
- Lipid Research Group, The Heart Research Institute, 145 Missenden Road, Camperdown, Sydney, NSW, 2050, Australia
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Januszewski AS, Thomas MC, Chung SJ, Karschimkus CS, Rowley KG, Nelson C, O'Neal D, Wang Z, Best JD, Jenkins AJ. Plasma low-molecular weight fluorescence in type 1 diabetes mellitus. Ann N Y Acad Sci 2005; 1043:655-61. [PMID: 16037289 DOI: 10.1196/annals.1333.074] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [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]
Abstract
Characteristic tissue fluorescence is associated with advanced glycation end product (AGE) accumulation in experimental diabetes models, but its utility in patients with type 1 diabetes remains to be established. We studied 148 patients with type 1 diabetes and 77 healthy age-matched control subjects. Low-molecular weight (LMW) fluorophore levels were estimated in plasma samples obtained after an overnight fast. Intra- and interassay coefficients of variation were 4.7% and 6.4%, respectively. LMW fluorophore levels were significantly higher in patients with diabetes than in control subjects (6.3 +/- 0.6 AU/mL vs. 4.1 +/- 0.3; P = 0.007). However, all of this difference came from patients with microvascular complications (n = 67, 7.5 +/- 1.3). There was no significant difference in LMW fluorescence between complication-free patients (4.4 +/- 0.2) and control subjects (P > 0.05). On multivariate analysis, LMW fluorophores correlated with measures of renal function (P < 0.05) but not with diabetes per se. In addition, there was no correlation between LMW fluorophores and the markers of oxidative stress or systemic inflammation. Longitudinal and interventional studies are required to determine whether the association between LMW fluorophores and nephropathy is cause or effect.
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Affiliation(s)
- A S Januszewski
- University of Melbourne, Department of Medicine, St. Vincent's Hospital, Princes & Regent Streets, Fitzroy, 3065 Melbourne, Australia
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Januszewski AS, Alderson NL, Metz TO, Thorpe SR, Baynes JW. Role of lipids in chemical modification of proteins and development of complications in diabetes. Biochem Soc Trans 2004; 31:1413-6. [PMID: 14641077 DOI: 10.1042/bst0311413] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hyperglycaemia is the major risk factor for the development of complications in both Type I and Type II diabetes; however, there is growing evidence from several clinical trials that dyslipidaemia, including hypertriglyceridaemia, is a significant and independent risk factor for diabetic complications. In this paper, we propose that chemical modification of proteins by lipids may be a underlying pathogenic mechanism linking dyslipidaemia to diabetic complications. Thus the major AGEs (advanced glycation end-products) in tissues, such as carboxymethyl-lysine, carboxyethyl-lysine and hydroimidazolones, may, in fact, be ALEs (advanced lipoxidation end-products), derived from lipids. Increased lipid peroxidation and accelerated ALE formation, possibly catalysed by hyperglycaemia and oxidative stress, may be the mechanistic link between dyslipidaemia and diabetic complications. If correct, this proposal would suggest that inhibition or reversal of glycation, which is a central theme of this symposium, may not be sufficient for protection against diabetic complications.
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Affiliation(s)
- A S Januszewski
- Department of Chemistry and Biochemistry, Graduate Science Research Center, University of South Carolina, 631 Sumter Street, Columbia, SC 29208, U.S.A
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Alderson NL, Chachich ME, Frizzell N, Canning P, Metz TO, Januszewski AS, Youssef NN, Stitt AW, Baynes JW, Thorpe SR. Effect of antioxidants and ACE inhibition on chemical modification of proteins and progression of nephropathy in the streptozotocin diabetic rat. Diabetologia 2004; 47:1385-95. [PMID: 15309289 DOI: 10.1007/s00125-004-1474-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [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: 01/15/2004] [Accepted: 04/30/2004] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS This study was designed to determine whether inhibition of formation of AGE and advanced lipoxidation end-products (ALE) is a mechanism of action common to a diverse group of therapeutic agents that limit the progress of diabetic nephropathy. We compared the effects of the ACE inhibitor enalapril, the antioxidant vitamin E, the thiol compound lipoic acid, and the AGE/ALE inhibitor pyridoxamine on the formation of AGE/ALE and protection against nephropathy in streptozotocin diabetic rats. METHODS Renal function and AGE/ALE formation were evaluated in rats treated with the agents listed above. Plasma was monitored monthly for triglycerides, cholesterol, creatinine and TNF-alpha, and 24-h urine samples were collected for measurement of albumin and total protein excretion. After 29 weeks, renal expression of mRNA for extracellular matrix proteins was measured, and AGE/ALE were quantified in skin and glomerular and tubular collagen. RESULTS Diabetic animals were both hyperglycaemic and dyslipidaemic, and showed evidence of early nephropathy (albuminuria, creatinaemia). All interventions limited the progression of nephropathy, without affecting glycaemia. The order of efficacy was: pyridoxamine (650 mg.kg(-1).day(-1)) > vitamin E (200 mg.kg(-1).day(-1)) > lipoic acid (93 mg.kg(-1).day(-1)) approximately enalapril (35 mg.kg(-1).day(-1)). Pyridoxamine also significantly inhibited AGE/ALE accumulation in tissues; effects of other agents were mixed, but the degree of renoprotection was consistent with their effects on AGE/ALE formation. CONCLUSIONS/INTERPRETATION All interventions inhibited the progression of nephropathy at the doses studied, but the maximal benefit was achieved with pyridoxamine, which also limited dyslipidaemia and AGE/ALE formation. These experiments indicate that the more effective the renoprotection, the greater the inhibition of AGE/ALE formation. For optimal protection of renal function, it would be beneficial to select drugs whose mechanism of action includes inhibition of AGE/ALE formation.
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Affiliation(s)
- N L Alderson
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina, USA
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