Applications

Endothelial Function

The endothelium is the lining of blood vessels of the circulatory system, with a fundamental role in vasodilation. Endothelial function, and studies of endothelial dysfunction, are widespread and include a number of areas of both clinical and pre-clinical research.

Fundamental to such studies are the techniques of laser Doppler monitoring and imaging combined, for example, with iontophoresis and skin heating. This is a technique which is rapidly being adopted as a clinical measure of endothelial function in the microcirculation (Turner et al, 2008).

Over many years the technique of Iontophoresis has been applied in wide variety of areas of investigation involving endothelial vascular studies and it has not been limited to a single application. Other techniques such as skin heating and PORH have also be used for these studies. Fields of study, using Iontophoresis, skin heating, PORH in combination with laser Doppler imaging (or laser Doppler monitoring) are shown in the table below.

The most recent advance in the field of iontophoresis and laser Doppler has been the use of laser Doppler imaging (LDI) in place of monitoring (LDF). The advantage of imaging is that blood flow can be imaged and recorded over an area of interest rather than a single point measurement, thus results are both more reliable and show better reproducibility Turner et al., 2008.

Techniques	Field of study	Reference
Iontophoresis	Cardiovascular disease	Frank et al. 2010, George et al. 2009 Jadhav et al. 2007, Khan et al. 2008
	Diabetes	Beer et al. 2008, Franklin et al. 2008
	Peripheral neuropathy	Brooks et al, 2008
	Systemic sclerosis	Gunawardena et al 2007a, Murray et al. 2008
	Dermal microvascular blood flow	Agarwal et al. 2010
	Idiopathic inflammatory myopathy	Gunawardena et al 2007b
Skin heating & Iontophoresis	Vascular reactivity	Vascular reactivity Beed et al, 2009
PORH	Endothelial function	Yamamoto-Suganuma & Aso, 2009
	Endothelial function	Spaan et al, 2010
	Microvascular function - CVD	Shore et al, 2005

References

Agarwal S. C., Allen J., Murray A., Purcell I. F. (2010) Comparative reproducibility of dermal microvascular blood flow changes in response to acetylcholine iontophoresis, hyperthermia and reactive hyperaemia. Physiological Measurement, 31 (1)

Beed M., O’Connor M. B., Kaur J., Mahajan R. P., Moppett I. K. 2009 Transient hyperaemic response to assess skin vascular reactivity: effects of heat and iontophoresed norepinephrine. British Journal of Anaesthesia, 102, No. 2, pp 205-209

Beer S., Feihl F., Ruiz J., Juhan-Vague I., Aillaud M., Wetzel S. G., Liaudet L., Gaillard R. C., Waeber B. (2008) Comparison of skin microvascular reactivity with hemostatic markers of endothelial dysfunction and damage in type 2 diabetes. Vascular health and Risk Management, 4 (6), pp 1449-1458

Brooks B, Delaney-Robinson C., Molyneauxa L., Yuea D. K. Endothelial and neural regulation of skin microvascular blood flow in patients with diabetic peripheral neuropathy: effect of treatment with the isoform-specific protein kinase C β inhibitor, ruboxistaurin. Journal of Diabetes and Its Complications, 22, pp 88–95

Frank J., George T. W., Lodge J. K., Rodriguez-Mateos A. M., Spencer J. P. E., Minihane A. M., Rimbach G. (2009) Daily consumption of an aqueous green tea extract supplement does not impair liver function or alter cardiovascular disease risk biomarkers in healthy men. The Journal of Nutrition, 139 (1), pp 58-62

Franklin V. L., Khan F., Kennedy G., Belch J. J. F. (2007) Intensive insulin therapy improves endothelial function and microvascular reactivity in young people with type 1 diabetes. Diabetologia, 51, pp 353-360

Gunawardena H., Harris N. D., Carmichael C., McHugh N. J. (2007a) Maximum blood flow and microvascular regulatory responses in systemic sclerosis. Rheumatology, 46, pp 1079-1082

Gunawardena H., Harris N. D., Carmichael C., McHugh N. J. (2007b) Microvascular responses following digital thermal hyperaemia and iontophoresis measured by laser Doppler imaging in idiopathic inflammatory myopathy. Rheumatology, 46, pp 1483-1486

Jadhav S., Sattar N., Petrie J. R., Cobbe S. M., Ferrell W. R. (2007) Reproducibility and repeatability of peripheral microvascular assessment using iontophoresis in conjunction with laser Doppler imaging. Journal of Cardiovascular Pharmacology, 50 (3), pp 343-349

Khan F., George J., Wong K., McSwiggan S., Struthers A. D., Belch J. J. F. (2008) The association between serum urate levels and arterial stiffness/endothelial function in stroke survivors. Atherosclerosis, 200, pp 374-379

Murray A. K., Moore T. L., King, T. A., Herrick A. L. (2008) Concise Report: Vasodilator iontophoresis – a possible new therapy for digital ischaemia in systemic sclerosis? Rheumatology, 47, pp 76-79

Spaan J. J., Houben A. J. H. M., Musella A., Ekhart T. Spaanderman M. E. A., Peeters L. L. H. 2010 Insulin resistance relates to microvascular reactivity 23 years after preeclampsia Microvascular Research, 80(3), pp 417-21

Strain W. D., Chatuvedi N., Bulpitt, C. J., Shore A. C. 2005 Albumin excretion rate and cardiovascular risk: could the association be explained by early microvascular dysfunction? Diabetes, 54, pp 1816-1822

Turner J., Belch J. J. F., Khan F. (2008) Current concepts in assessment of microvascular endothelial function using laser Doppler imaging and iontophoresis. Trends in Cardiovascular Medicine, 18, (4), pp 109-116

Yamamoto-Suganuma R., Aso Y. 2009 Relationship between post-occlusive forearm skin reactive hyperaemia and vascular disease in patients with Type 2 diabetes – A novel index for detecting micro- and microvascular dysfunction using laser Doppler flowmetry. Diabetes Med, 26, pp 83-88

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