ORCID Profile
0000-0001-5200-7640
Current Organisation
Loughborough University
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Publisher: Elsevier BV
Date: 12-2020
Publisher: Informa UK Limited
Date: 08-01-2023
Publisher: Informa UK Limited
Date: 29-07-2018
Publisher: Wiley
Date: 19-02-2023
DOI: 10.1113/EP090721
Abstract: What is the central question of this study? Does non‐freezing cold injury (NFCI) alter normal peripheral vascular function? What is the main finding and its importance? In iduals with NFCI were more cold sensitive (rewarmed more slowly and felt more discomfort) than controls. Vascular tests indicated that extremity endothelial function was preserved with NFCI and that sympathetic vasoconstrictor response might be reduced. The pathophysiology underpinning the cold sensitivity associated with NFCI thus remains to be identified. The impact of non‐freezing cold injury (NFCI) on peripheral vascular function was investigated. In iduals with NFCI (NFCI group) and closely matched controls with either similar (COLD group) or limited (CON group) previous cold exposure were compared ( n = 16). Peripheral cutaneous vascular responses to deep inspiration (DI), occlusion (PORH), local cutaneous heating (LH) and iontophoresis of acetylcholine and sodium nitroprusside were investigated. The responses to a cold sensitivity test (CST) involving immersion of a foot in 15°C water for 2 min followed by spontaneous rewarming, and a foot cooling protocol (footplate cooled from 34°C to 15°C), were also examined. The vasoconstrictor response to DI was lower in NFCI compared to CON (toe: 73 (28)% vs. 91 (17)% P = 0.003). The responses to PORH, LH and iontophoresis were not reduced compared to either COLD or CON. During the CST, toe skin temperature rewarmed more slowly in NFCI than COLD or CON (10 min: 27.4 (2.3)°C vs. 30.7 (3.7)°C and 31.7 (3.9)°C, P 0.05, respectively) however, no differences were observed during the footplate cooling. NFCI were more cold‐intolerant ( P 0.0001) and reported colder and more uncomfortable feet during the CST and footplate cooling than COLD and CON ( P 0.05). NFCI showed a decreased sensitivity to sympathetic vasoconstrictor activation than CON and greater cold sensitivity (CST) compared to COLD and CON. None of the other vascular function tests indicated endothelial dysfunction. However, NFCI perceived their extremities to be colder and more uncomfortable ainful than the controls.
Publisher: Wiley
Date: 20-02-2023
DOI: 10.1113/EP090722
Abstract: What is the central question of this study? Are biomarkers of endothelial function, oxidative stress and inflammation altered by non‐freezing cold injury (NFCI)? What is the main finding and its importance? Baseline plasma [interleukin‐10] and [syndecan‐1] were elevated in in iduals with NFCI and cold‐exposed control participants. Increased [endothelin‐1] following thermal challenges might explain, in part, the increased pain/discomfort experienced with NFCI. Mild to moderate chronic NFCI does not appear to be associated with either oxidative stress or a pro‐inflammatory state. Baseline [interleukin‐10] and [syndecan‐1] and post‐heating [endothelin‐1] are the most promising candidates for diagnosis of NFCI. Plasma biomarkers of inflammation, oxidative stress, endothelial function and damage were examined in 16 in iduals with chronic NFCI (NFCI) and matched control participants with (COLD, n = 17) or without (CON, n = 14) previous cold exposure. Venous blood s les were collected at baseline to assess plasma biomarkers of endothelial function (nitrate, nitrite and endothelin‐1), inflammation [interleukin‐6 (IL‐6), interleukin‐10 (IL‐10), tumour necrosis factor alpha and E‐selectin], oxidative stress [protein carbonyl, 4‐hydroxy‐2‐nonenal (4‐HNE), superoxide dismutase and nitrotyrosine) and endothelial damage [von Willebrand factor, syndecan‐1 and tissue type plasminogen activator (TTPA)]. Immediately after whole‐body heating and separately, foot cooling, blood s les were taken for measurement of plasma [nitrate], [nitrite], [endothelin‐1], [IL‐6], [4‐HNE] and [TTPA]. At baseline, [IL‐10] and [syndecan‐1] were increased in NFCI ( P 0.001 and P = 0.015, respectively) and COLD ( P = 0.033 and P = 0.030, respectively) compared with CON participants. The [4‐HNE] was elevated in CON compared with both NFCI ( P = 0.002) and COLD ( P 0.001). [Endothelin‐1] was elevated in NFCI compared with COLD ( P 0.001) post‐heating. The [4‐HNE] was lower in NFCI compared with CON post‐heating ( P = 0.032) and lower than both COLD ( P = 0.02) and CON ( P = 0.015) post‐cooling. No between‐group differences were seen for the other biomarkers. Mild to moderate chronic NFCI does not appear to be associated with a pro‐inflammatory state or oxidative stress. Baseline [IL‐10] and [syndecan‐1] and post‐heating [endothelin‐1] are the most promising candidates for diagnosing NFCI, but it is likely that a combination of tests will be required.
Publisher: Elsevier BV
Date: 07-2020
Publisher: Springer Science and Business Media LLC
Date: 04-04-2015
DOI: 10.1007/S00421-015-3164-2
Abstract: In iduals of African descent (AFD) are more susceptible to non-freezing cold injury than Caucasians (CAU) which may be due, in part, to differences in the control of skin blood flow. We investigated the skin blood flow responses to transdermal application of vasoactive agents. Twenty-four young males (12 CAU and 12 AFD) undertook three tests in which iontophoresis was used to apply acetylcholine (ACh 1 w/v %), sodium nitroprusside (SNP 0.01 w/v %) and noradrenaline (NA 0.5 mM) to the skin. The skin sites tested were: volar forearm, non-glabrous finger and toe, and glabrous finger (pad) and toe (pad). In response to SNP on the forearm, AFD had less vasodilatation for a given current application than CAU (P = 0.027-0.004). ACh evoked less vasodilatation in AFD for a given application current in the non-glabrous finger and toe compared with CAU (P = 0.043-0.014) with a lower maximum vasodilatation in the non-glabrous finger (median [interquartile], AFD n = 11, 41[234] %, CAU n = 12, 351[451] %, P = 0.011) and non-glabrous toe (median [interquartile], AFD n = 9, 116[318] %, CAU n = 12, 484[720] %, P = 0.018). ACh and SNP did not elicit vasodilatation in the glabrous skin sites of either group. There were no ethnic differences in response to NA. AFD have an attenuated endothelium-dependent vasodilatation in non-glabrous sites of the fingers and toes compared with CAU. This may contribute to lower skin temperature following cold exposure and the increased risk of cold injuries experienced by AFD.
Publisher: Wiley
Date: 20-02-2023
DOI: 10.1113/EP090720
Abstract: What is the central question of this study? Is peripheral sensory function impaired in the chronic phase of non‐freezing cold injury (NFCI)? What is the main finding and its importance? Warm and mechanical detection thresholds are elevated and intraepidermal nerve fibre density is reduced in in iduals with NFCI in their feet when compared to matched controls. This indicates impaired sensory function in in iduals with NFCI. Interin idual variation was observed in all groups, and therefore a diagnostic cut‐off for NFCI has yet to be established. Longitudinal studies are required to follow NFCI progression from formation to resolution The aim of this study was to compare peripheral sensory neural function of in iduals with non‐freezing cold injury (NFCI) with matched controls (without NFCI) with either similar (COLD) or minimal previous cold exposure (CON). Thirteen in iduals with chronic NFCI in their feet were matched with the control groups for sex, age, race, fitness, body mass index and foot volume. All undertook quantitative sensory testing (QST) on the foot. Intraepidermal nerve fibre density (IENFD) was assessed 10 cm above the lateral malleolus in nine NFCI and 12 COLD participants. Warm detection threshold was higher at the great toe in NFCI than COLD (NFCI 45.93 (4.71)°C vs. COLD 43.44 (2.72)°C, P = 0.046), but was non‐significantly different from CON (CON 43.92 (5.01)°C, P = 0.295). Mechanical detection threshold on the dorsum of the foot was higher in NFCI (23.61 (33.59) mN) than in CON (3.83 (3.69) mN, P = 0.003), but was non‐significantly different from COLD (10.49 (5.76) mN, P 0.999). Remaining QST measures did not differ significantly between groups. IENFD was lower in NFCI than COLD (NFCI 8.47 (2.36) fibre/mm 2 vs. COLD 11.93 (4.04) fibre/mm 2 , P = 0.020). Elevated warm and mechanical detection thresholds may indicate hyposensitivity to sensory stimuli in the injured foot for in iduals with NFCI and may be due to reduced innervation given the reduction in IENFD. Longitudinal studies are required to identify the progression of sensory neuropathy from the formation of injury to its resolution, with appropriate control groups employed.
Publisher: Public Library of Science (PLoS)
Date: 22-01-2018
Publisher: Elsevier BV
Date: 05-2020
Publisher: Springer Science and Business Media LLC
Date: 08-2014
DOI: 10.1007/S00421-014-2962-2
Abstract: Cold injuries are more prevalent in in iduals of African descent (AFD). Therefore, we investigated the effect of extremity cooling on skin blood flow (SkBF) and temperature (T sk) between ethnic groups. Thirty males [10 Caucasian (CAU), 10 Asian (ASN), 10 AFD] undertook three tests in 30 °C air whilst digit T sk and SkBF were measured: (i) vasomotor threshold (VT) test--arm immersed in 35 °C water progressively cooled to 10 °C and rewarmed to 35 °C to identify vasoconstriction and vasodilatation (ii) cold-induced vasodilatation (CIVD) test--hand immersed in 8 °C water for 30 min followed by spontaneous warming (iii) cold sensitivity (CS) test--foot immersed in 15 °C water for 2 min followed by spontaneous warming. Cold sensory thresholds of the forearm and finger were also assessed. In the VT test, vasoconstriction and vasodilatation occurred at a warmer finger T sk in AFD during cooling [21.2 (4.4) vs. 17.0 (3.1) °C, P = 0.034] and warming [22.0 (7.9) vs. 12.1 (4.1) °C, P = 0.002] compared with CAU. In the CIVD test, average SkBF during immersion was greater in CAU [42 (24) %] than ASN [25 (8) %, P = 0.036] and AFD [24 (13) %, P = 0.023]. Following immersion, SkBF was higher and rewarming faster in CAU [3.2 (0.4) °C min(-1)] compared with AFD [2.5 (0.7) °C min(-1), P = 0.037], but neither group differed from ASN [3.0 (0.6) °C min(-1)]. Responses to the CS test and cold sensory thresholds were similar between groups. AFD experienced a more intense protracted finger vasoconstriction than CAU during hand immersion, whilst ASN experienced an intermediate response. This greater sensitivity to cold may explain why AFD are more susceptible to cold injuries.
Publisher: Elsevier BV
Date: 02-1201
DOI: 10.1016/J.JTHERBIO.2017.07.006
Abstract: The importance of using infrared thermography (IRT) to assess skin temperature (t
Publisher: Frontiers Media SA
Date: 09-11-2017
Publisher: Elsevier BV
Date: 05-2017
DOI: 10.1016/J.MVR.2017.01.005
Abstract: In iduals of African descent (AFD) are more susceptible to non-freezing cold injury (NFCI) compared with Caucasian in iduals (CAU). Vasodilatation to acetylcholine (ACh) is lower in AFD compared with CAU in the non-glabrous foot and finger skin sites the reason for this is unknown. Prostanoids are responsible, in part, for the vasodilator response to ACh, however it is not known whether the contribution differs between ethnicities. 12 CAU and 12 AFD males received iontophoresis of ACh (1 w/v%) on non-glabrous foot and finger skin sites following placebo and then aspirin (600mg, single blinded). Aspirin was utilised to inhibit prostanoid production by inhibiting the cyclooxygenase (COX) enzyme. Laser Doppler flowmetry was utilised to measure changes in skin blood flow. Not all participants could receive iontophoresis charge due to high skin resistance these participants were therefore excluded from the analyses. Foot: ACh elicited greater maximal vasodilatation in CAU than AFD following placebo (P=0.003) and COX inhibition (COXib) (P<0.001). COXib did not affect blood flow responses in AFD, but caused a reduction in the area under the curve for CAU (P=0.031). Finger: ACh elicited a greater maximal vasodilatation in CAU than AFD following placebo (P=0.013) and COXib (P=0.001). COXib tended to reduce the area under the curve in AFD (P=0.053), but did not affect CAU. CAU have a greater endothelial reactivity than AFD in both foot and finger skin sites irrespective of COXib. It is concluded that the lower ACh-induced vasodilatation in AFD is not due to a compromised COX pathway.
Publisher: Springer Science and Business Media LLC
Date: 14-06-2019
Publisher: Springer Science and Business Media LLC
Date: 14-09-2015
Publisher: Wiley
Date: 06-2017
DOI: 10.1113/EP086186
Publisher: Public Library of Science (PLoS)
Date: 22-03-2019
Publisher: Frontiers Media SA
Date: 12-04-2019
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Matthew J Maley.