Structural and Functional Changes in Human Kidneys with Healthy Aging

Abstract

Aging is associated with significant changes in structure and function of the kidney, even in the absence of age-related comorbidities. On the macrostructural level, kidney cortical volume decreases, surface roughness increases, and the number and size of simple renal cysts increase with age. On the microstructural level, the histologic signs of nephrosclerosis (arteriosclerosis/arteriolosclerosis, global glomerulosclerosis, interstitial fibrosis, and tubular atrophy) all increase with age. The decline of nephron number is accompanied by a comparable reduction in measured whole-kidney GFR. However, single-nephron GFR remains relatively constant with healthy aging as does glomerular volume. Only when glomerulosclerosis and arteriosclerosis exceed that expected for age is there an increase in single-nephron GFR. In the absence of albuminuria, age-related reduction in GFR with the corresponding increase in CKD (defined by an eGFR<60 ml/min per 1.73 m) has been shown to associate with a very modest to no increase in age-standardized mortality risk or ESRD. These findings raise the question of whether disease labeling of an age-related decline in GFR is appropriate. These findings also emphasize the need for a different management approach for many elderly individuals considered to have CKD by current criteria.

Association of renal arteriosclerosis and hypertension with renal and cardiovascular outcomes in Japanese type 2 diabetes patients with diabetic nephropathy

“…Although renal AS might be associated with concurrent HT, it is sometimes found even in patients without HT. Previous studies showed that renal AS was associated with aging, postprandial hyperglycemia and hyperinsulinemia, low serum high‐density lipoprotein cholesterol, hyperuricemia, and chronic inflammation. In contrast, a BP <140/90 mmHg is recommended to reduce ESRD and cardiovascular disease among people with diabetes in clinical practice.…”

Peripheral arterial stiffness is correlated with intrarenal arteriolosclerosis according to biopsies from patients with kidney disease

“…Intrarenal arteriolosclerosis, which is thought to result in glomerulosclerosis with atrophy of the attached tubules and adjacent interstitial fibrosis, is a common vascular lesion in patients with kidney disease and is significantly correlated with age . In a study that analyzed 1450 renal biopsies, the incidence of vascular lesions among 222 patients under 40 years of age was 20.3% compared to 6.2% in controls of similar age; in patients aged 40 to 65 years and those older than 65, vascular lesions were found in 50% to 60% and 80.8% of the patients, respectively .…”

“…Intrarenal arteriolosclerosis, defined as fibrous and/or hyalinosis thickening of the intima, is observed in many different situations, including aging, hypertension, diabetes mellitus, idiopathic membranous nephropathy and focal segmental glomerulosclerosis . For patients with immunoglobulin A (IgA) nephropathy, intrarenal vascular sclerosis is present in 1 of 3 of initial biopsies .…”

“…For patients with immunoglobulin A (IgA) nephropathy, intrarenal vascular sclerosis is present in 1 of 3 of initial biopsies . An arteriolar lesion, leading to ischemia, plays an important role in the progression of glomerulopathies to renal insufficiency …”

Retrospective analysis of simple and stage II renal cysts: Pediatric nephrology point of view

“…Simple cysts are considered to be part of the regular aging process and are common in adults . The number of cysts may also increase with age.…”