Microvascular disease

Abstract

A healthy renal microcirculation is crucial to ensure adequate tissue perfusion, filtration and removal of toxins from the general circulation. Emerging evidence supports a role of renal microvascular (MV) disease in possibly determining the turning point between reversible and irreversible renal injury. Indeed, previous studies have shown that renal MV rarefaction correlates with the progressive deterioration of renal hemodynamics, filtration, and, tubular function. Furthermore, dysfunctional or damaged microvessels can compromise adequate renal perfusion and nutrition leading to tissue ischemia, which may in turn activate pro-inflammatory and pro-fibrotic factors that could promote renal parenchymal injury. This chapter will discuss the changes in renal MV function and structure and the role of MV disease on the initiation and progression of renal injury. Either as a causative mechanism or a consequence of renal injury, increasing experimental and clinical evidence showed that pathological changes in the renal microvasculature accompany the development and progression of renal injury associated to hypertension, diabetes, obesity, and atherosclerosis. Previous studies have shown that systemic and renal MV disease is associated to cardiovascular risk factors even in the absence of major deterioration of renal function, implying that early changes in renal MV function could later serve as instigator of renal injury. Hence, this chapter will also focus on the development, progression, and mechanisms of renal MV disease in hypertension, diabetes, obesity, and atherosclerosis.