IL18 and metabolic syndrome: In the current study, we found that: (1) Il18−/− mice showed renal impairment in their youth-6 weeks of age, but improved naturally as they aged; (2) even though no renal damage was observed at 48 weeks of age, Il18−/− mice showed diabetes mellitus, dyslipidemia, and arteriosclerosis; (3) several molecules related to renal function were affected by a lack of IL-18; and (4) the administration of IL-18 exerted few effects on the kidney regardless of short or long-term administration.