Heme induction with delta-aminolevulinic Acid stimulates an increase in water and electrolyte excretion

A Randomized Phase 2 Study of 5-Aminolevulinic Acid Hydrochloride and Sodium Ferrous Citrate for the Prevention of Nephrotoxicity Induced by Cisplatin-Based Chemotherapy of Lung Cancer

INTRODUCTION

Cisplatin-based chemotherapy was established in the 1980s, and it has been improved by the development of a short hydration protocol in lung cancer therapy. However, cisplatin-based chemotherapy is still associated with renal toxicity. Because 5-aminolevulinic acid (5-ALA) with sodium ferrous citrate (SFC) is known to be a mitochondrial activator and a heme oxygenase-1 (HO-1) inducer, 5-ALA with SFC is speculated to mitigate cisplatin-induced renal inflammation.

METHODS

We investigated the effects of oral administration of 5-ALA with SFC for preventing cisplatin-based nephrotoxicity in patients with lung cancer and evaluated its benefits for patients who received cisplatin-based chemotherapy. The primary endpoint was the significance of the difference between the serum creatinine (sCr) levels of the patients administered 5-ALA with SFC and those given placebo after course 1 of chemotherapy. The difference in the estimated glomerular filtration rate (eGFR) between the two groups was also evaluated as the secondary endpoint.

RESULTS

The double-blind, randomized two-arm studies were conducted at 15 medical facilities in Japan; 54 male and 20 female patients with lung cancer who received cisplatin-based chemotherapy between the ages of 42 and 75 years were included in the study. The compliance rate was greater than 94% in the primary assessment and subsequent drug administration periods. All enrolled patients completed the four cycles of cisplatin-based chemotherapy with short hydration. The average level of sCr on day 22 of course 1 was 0.707 mg/dL in the group treated with 5-ALA and SFC and 0.735 mg/dL in the placebo group, respectively, and the sCr in the test group was significantly lower than that in the placebo group (p = 0.038). In addition, the eGFR was significantly higher in the SPP-003 group than in the placebo group up to day 1 of course 3 (84.66 and 75.68 mL/min/1.73 m2, respectively, p = 0.02) and kept better even after the last administration of the study drug (82.37 and 73.49 mL/min/1.73 m2, respectively, p = 0.013).

CONCLUSIONS

The oral administration of 5-ALA with SFC is beneficial to patients undergoing cisplatin-based chemotherapy for lung cancer with short hydration.

(Pro)renin receptor contributes to regulation of renal epithelial sodium channel

BACKGROUND

Recent studies reported increased (Pro)renin receptor (PRR) expression during low-salt intake. We hypothesized that PRR plays a role in regulation of renal epithelial sodium channel (ENaC) through serum and glucocorticoid-inducible kinase isoform 1 (SGK-1)-neural precursor cell expressed, developmentally downregulated 4-2 (Nedd4-2) signaling pathway.

METHOD

Male Sprague-Dawley rats on normal-sodium diet and mouse renal inner medullary collecting duct cells treated with NaCl at 130  mmol/l (normal salt), or 63  mmol/l (low salt) were studied. PRR and α-ENaC expressions were evaluated 1 week after right uninephrectomy and left renal interstitial administration of 5% dextrose, scramble shRNA, or PRR shRNA (n = 6 each treatment).

RESULTS

In-vivo PRR shRNA significantly reduced expressions of PRR throughout the kidney and α-ENaC subunits in the renal medulla. In inner medullary collecting duct cells, low salt or angiotensin II (Ang II) augmented the mRNA and protein expressions of PRR (P < 0.05), SGK-1 (P < 0.05), and α-ENaC (P < 0.05). Low salt or Ang II increased the phosphorylation of Nedd4-2. In cells treated with low salt or Ang II, PRR siRNA significantly downregulated the mRNA and protein expressions of PRR (P < 0.05), SGK-1 (P < 0.05), and α-ENaC expression (P < 0.05).

CONCLUSION

We conclude that PRR contributes to the regulation of α-ENaC via SGK-1-Nedd4-2 signaling pathway.

Combination of 5-aminolevulinic acid and ferrous ion reduces plasma glucose and hemoglobin A1c levels in Zucker diabetic fatty rats

Mitochondrial dysfunction is associated with type 2 diabetes mellitus (T2DM). 5‐Aminolevulinic acid (ALA), a natural amino acid produced only in the mitochondria, is a precursor of heme. Cytochromes that contain heme play an important role in aerobic energy metabolism. Thus, ALA may help reduce T2DM‐associated hyperglycemia. In this study, we investigated the effect of ALA combined with sodium ferrous citrate (SFC) on hyperglycemia in Zucker diabetic fatty (ZDF) rats. We found that the gavage administration of ALA combined with SFC (ALA/SFC) for 6 weeks reduced plasma glucose and hemoglobin A1c (HbA1c) levels in rats without affecting plasma insulin levels. The glucose‐lowering effect depended on the amount of ALA/SFC administered per day. Furthermore, the glucose tolerance was also significantly improved by ALA/SFC administration. Although food intake was slightly reduced in the rats administered ALA/SFC, there was no effect on their body weight. Importantly, ALA/SFC administration induced heme oxygenase‐1 (HO‐1) expression in white adipose tissue and liver, and the induced expression levels of HO‐1 correlated with the glucose‐lowering effects of ALA/SFC. Taken together, these results suggest that ALA combined with ferrous ion is effective in reducing hyperglycemia of T2DM without affecting plasma insulin levels. HO‐1 induction may be involved in the mechanisms underlying the glucose‐lowering effect of ALA/SFC.

5-Aminolevulinic acid combined with ferrous iron induces carbon monoxide generation in mouse kidneys and protects from renal ischemia-reperfusion injury

Renal ischemia reperfusion injury (IRI) is a major factor responsible for acute renal failure. An intermediate in heme synthesis, 5-aminolevulinic acid (5-ALA) is fundamental in aerobic energy metabolism. Heme oxygenase (HO)-1 cleaves heme to form biliverdin, carbon monoxide (CO), and iron (Fe(2+)), which is used with 5-ALA. In the present study, we investigated the role of 5-ALA in the attenuation of acute renal IRI using a mouse model. Male Balb/c mice received 30 mg/kg 5-ALA with Fe(2+) 48, 24, and 2 h before IRI and were subsequently subjected to bilateral renal pedicle occlusion for 45 min. The endogenous CO concentration of the kidneys from the mice administered 5-ALA/Fe(2+) increased significantly, and the peak concentrations of serum creatinine and blood urea nitrogen decreased. 5-ALA/Fe(2+) treatments significantly decreased the tubular damage and number of apoptotic cells. IRI-induced renal thiobarbituric acid-reactive substance levels were also significantly decreased in the 5-ALA/Fe(2+) group. Furthermore, mRNA expression of HO-1, TNF-α, and interferon-γ was significantly increased after IRI. Levels of HO-1 were increased and levels of TNF-α and interferon-γ were decreased in the 5-ALA/Fe(2+)-pretreated renal parenchyma after IRI. F4/80 staining showed reduced macrophage infiltration, and TUNEL staining revealed that there were fewer interstitial apoptotic cells. These findings suggest that 5-ALA/Fe(2+) can protect the kidneys against IRI by reducing macrophage infiltration and decreasing renal cell apoptosis via the generation of CO.