Effects of Chronic and Acute Protein Administration on Renal Function in Patients with Chronic Renal Insufficiency

Abstract

In 6 volunteers with normal renal function, we investigated the effects of various kinds of protein (soy, lactoprotein and beef) and various amounts of an intravenously administered amino acid solution on glomerular filtration (GFR) and effective renal plasma flow (ERPF). As for the protein-induced changes in renal function, rises in GFR and ERPF were lowest with soy protein, and highest with beef (baseline GFR, 110 ± 5; soy, 122 ± 5; beef, 131 ± 5 ml/min/1.73 m²; mean ± SEM). High doses of intravenous amino acids induced arise in GFR comparable to that after beef (132 ± 5 ml/min/1.73 m²). In a combined test a liquid mixed meal together with intravenously administered amino acids induced a comparable increase of the GFR (baseline 114 ± 5 versus 129 ± 5 ml/min/1.73 m²). When investigating 9 patients with chronic renal insufficiency after 4 weeks of low protein intake (LP) and after 4 weeks of high protein intake (HP), GFR and ERPF rose significantly under baseline conditions (GFR-LP 41 ± 9 versus GFR-HP 45 ± 9 ml/min/1.73 m², p < 0.02; ERPF-LP 169 ± 39 versus ERPF-HP 180 ± 40 ml/min/1.73 m², p < 0.02; paired Wilcoxon). At the end of both dietary periods a comparable rise in renal function could be induced through acute stimulation (GFR-LP 20 ± 5, GFR-HP 16 ± 4; ERPF-LP 23 ± 7, ERPF-HP 22 ± 3%). Glucagon levels tended to fall during a HP diet (glucagon-LP 69 ± 11 versus glucagon HP 50 ± 12 ng/l), whereas an acute rise in glucagon levels could be induced by acute stimulation at the end of both dietary periods (glucagon-LP 163 ± 18, glucagon-HP 173 ± 58%). We conclude that renal function remains variable even in patients with moderate to severe renal insufficiency and that acute stimulation remains possible to the same extent after LP and HP intake. Our results also suggest different underlying mechanisms for the acute and chronic stimulation of renal function.

Protein intake, calcium balance and health consequences

“…Indeed, as shown previously, HP diets cause elevation of glomerular filtration rate and hyperfiltration (Kim and Linkswiler, 1979;Schuette et al, 1980;Zemel et al, 1981;Brenner et al, 1982;Bilo et al, 1989;Metges and Barth, 2000;Tuttle et al, 2002;Frank et al, 2009;Burodom, 2010). In animal models, HP diets induce a renal hypertrophy (Addis, 1926;Wilson, 1933;Hammond and Janes, 1998) but not systematically (Robertson et al, 1986;Collins et al, 1990;Lacroix et al, 2004), and to our knowledge, the link between protein-induced renal hypertrophy or hyperfiltration and the initiation of renal disease in healthy individuals has not been clearly shown.…”

Renal Functional Reserve in Children with and without Renal Disease

“…However, in the study of Bilo et al [31], an acute protein load stimulated comparable levels of renal reserve both on high and low protein diets. By contrast, Wetzels et al [33] have reported on the stability of the renal reserve both with high and low protein regimens of 4-week duration (0.6 versus 1.8 g/kg BW).…”

“…In adult patients with renal disease, high protein in takes were associated with higher GFR [31,32]. However, in the study of Bilo et al [31], an acute protein load stimulated comparable levels of renal reserve both on high and low protein diets.…”

Renal Function and Renal Function Reserve in Insulin-Dependent Diabetic Patients during (Near) Normoglycaemia

“…The Netherlands). In an earlier study [22] in non-diabetic subjects, this combined testing procedure was as effective as the ingestion of 500 g red lean meat to stimulate renal function. Again, three consecutive clearances were calculated and the last two measurements averaged and used as the S values for GFR.…”