Blog
About

21
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Early Progressive Renal Decline Precedes the Onset of Microalbuminuria and Its Progression to Macroalbuminuria

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          OBJECTIVE

          Progressive decrease in the glomerular filtration rate (GFR), or renal decline, in type 1 diabetes (T1D) is observed in patients with macroalbuminuria. However, it is unknown whether this decline begins during microalbuminuria (MA) or normoalbuminuria (NA).

          RESEARCH DESIGN AND METHODS

          The study group (second Joslin Kidney Study) comprises patients with T1D and NA ( n = 286) or MA ( n = 248) who were followed for 4–10 years (median 8 years). Serial measurements (median 6, range 3–16) of serum creatinine and cystatin C were used jointly to estimate GFR (eGFRcr-cys) and assess its trajectories during follow-up.

          RESULTS

          Renal decline (progressive eGFRcr-cys loss of at least 3.3% per year) occurred in 10% of the NA and 35% of the MA ( P < 0.001). In both groups, the strongest determinants of renal decline were baseline serum concentrations of uric acid ( P < 0.001) and tumor necrosis factor receptor 1 or 2 (TNFR-1 or -2, P < 0.001). Other significant risk factors included baseline HbA 1c, age/diabetes duration, and systolic blood pressure. Relative impacts of these determinants were similar in NA and MA. Renal decline was not associated with sex or baseline serum concentration of TNF-α, IL-6, IL-8, IP-10, MCP-1, VCAM, ICAM, Fas, or FasL.

          CONCLUSIONS

          Renal decline in T1D begins during NA and it is determined by multiple factors, similar to MA. Thus, this early decline is the primary disease process leading to impaired renal function in T1D. Changes in albumin excretion rate, such as the onset of MA or its progression to macroalbuminuria, are either caused by or develop in parallel to the early renal decline.

          Related collections

          Most cited references 20

          • Record: found
          • Abstract: found
          • Article: not found

          A role for uric acid in the progression of renal disease.

          Hyperuricemia is associated with renal disease, but it is usually considered a marker of renal dysfunction rather than a risk factor for progression. Recent studies have reported that mild hyperuricemia in normal rats induced by the uricase inhibitor, oxonic acid (OA), results in hypertension, intrarenal vascular disease, and renal injury. This led to the hypothesis that uric acid may contribute to progressive renal disease. To examine the effect of hyperuricemia on renal disease progression, rats were fed 2% OA for 6 wk after 5/6 remnant kidney (RK) surgery with or without the xanthine oxidase inhibitor, allopurinol, or the uricosuric agent, benziodarone. Renal function and histologic studies were performed at 6 wk. Given observations that uric acid induces vascular disease, the effect of uric acid on vascular smooth muscle cells in culture was also examined. RK rats developed transient hyperuricemia (2.7 mg/dl at week 2), but then levels returned to baseline by week 6 (1.4 mg/dl). In contrast, RK+OA rats developed higher and more persistent hyperuricemia (6 wk, 3.2 mg/dl). Hyperuricemic rats demonstrated higher BP, greater proteinuria, and higher serum creatinine than RK rats. Hyperuricemic RK rats had more renal hypertrophy and greater glomerulosclerosis (24.2 +/- 2.5 versus 17.5 +/- 3.4%; P < 0.05) and interstitial fibrosis (1.89 +/- 0.45 versus 1.52 +/- 0.47; P < 0.05). Hyperuricemic rats developed vascular disease consisting of thickening of the preglomerular arteries with smooth muscle cell proliferation; these changes were significantly more severe than a historical RK group with similar BP. Allopurinol significantly reduced uric acid levels and blocked the renal functional and histologic changes. Benziodarone reduced uric acid levels less effectively and only partially improved BP and renal function, with minimal effect on the vascular changes. To better understand the mechanism for the vascular disease, the expression of COX-2 and renin were examined. Hyperuricemic rats showed increased renal renin and COX-2 expression, the latter especially in preglomerular arterial vessels. In in vitro studies, cultured vascular smooth muscle cells incubated with uric acid also generated COX-2 with time-dependent proliferation, which was prevented by either a COX-2 or TXA-2 receptor inhibitor. Hyperuricemia accelerates renal progression in the RK model via a mechanism linked to high systemic BP and COX-2-mediated, thromboxane-induced vascular disease. These studies provide direct evidence that uric acid may be a true mediator of renal disease and progression.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Use of allopurinol in slowing the progression of renal disease through its ability to lower serum uric acid level.

            Hyperuricemia is associated strongly with the development of hypertension, renal disease, and progression. Allopurinol decreases serum uric acid levels by inhibiting the enzyme xanthine oxidase. We hypothesized that administrating allopurinol to decrease serum uric acid levels to the normal range in hyperuricemic patients with chronic kidney disease may be of benefit in decreasing blood pressure and slowing the rate of renal disease progression in these patients. We conducted a prospective, randomized, controlled trial of 54 hyperuricemic patients with chronic kidney disease. Patients were randomly assigned to treatment with allopurinol, 100 to 300 mg/d, or to continue the usual therapy for 12 months. Clinical, hematologic, and biochemical parameters were measured at baseline and 3, 6, and 12 months of treatment. We define our study end points as: (1) stable kidney function with less than 40% increase in serum creatinine level, (2) impaired renal function with creatinine level increase greater than 40% of baseline value, (3) initiation of dialysis therapy, and (4) death. One patient in the treatment group dropped out because of skin allergy to allopurinol. Serum uric acid levels were significantly decreased in subjects treated with allopurinol, from 9.75 +/- 1.18 mg/dL (0.58 +/- 0.07 mmol/L) to 5.88 +/- 1.01 mg/dL (0.35 +/- 0.06 mmol/L; P < 0.001). There were no significant differences in systolic or diastolic blood pressure at the end of the study comparing the 2 groups. There was a trend toward a lower serum creatinine level in the treatment group compared with controls after 12 months of therapy, although it did not reach statistical significance (P = 0.08). Overall, 4 of 25 patients (16%) in the allopurinol group reached the combined end points of significant deterioration in renal function and dialysis dependence compared with 12 of 26 patients (46.1%) in the control group (P = 0.015). Allopurinol therapy significantly decreases serum uric acid levels in hyperuricemic patients with mild to moderate chronic kidney disease. Its use is safe and helps preserve kidney function during 12 months of therapy compared with controls. Results of this study need to be confirmed with an additional prospective trial involving a larger cohort of patients to determine the long-term efficacy of allopurinol therapy and in specific chronic kidney disease subpopulations.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Intensive diabetes therapy and glomerular filtration rate in type 1 diabetes.

              An impaired glomerular filtration rate (GFR) leads to end-stage renal disease and increases the risks of cardiovascular disease and death. Persons with type 1 diabetes are at high risk for kidney disease, but there are no interventions that have been proved to prevent impairment of the GFR in this population. In the Diabetes Control and Complications Trial (DCCT), 1441 persons with type 1 diabetes were randomly assigned to 6.5 years of intensive diabetes therapy aimed at achieving near-normal glucose concentrations or to conventional diabetes therapy aimed at preventing hyperglycemic symptoms. Subsequently, 1375 participants were followed in the observational Epidemiology of Diabetes Interventions and Complications (EDIC) study. Serum creatinine levels were measured annually throughout the course of the two studies. The GFR was estimated with the use of the Chronic Kidney Disease Epidemiology Collaboration formula. We analyzed data from the two studies to determine the long-term effects of intensive diabetes therapy on the risk of impairment of the GFR, which was defined as an incident estimated GFR of less than 60 ml per minute per 1.73 m(2) of body-surface area at two consecutive study visits. Over a median follow-up period of 22 years in the combined studies, impairment of the GFR developed in 24 participants assigned to intensive therapy and in 46 assigned to conventional therapy (risk reduction with intensive therapy, 50%; 95% confidence interval, 18 to 69; P=0.006). Among these participants, end-stage renal disease developed in 8 participants in the intensive-therapy group and in 16 in the conventional-therapy group. As compared with conventional therapy, intensive therapy was associated with a reduction in the mean estimated GFR of 1.7 ml per minute per 1.73 m(2) during the DCCT study but during the EDIC study was associated with a slower rate of reduction in the GFR and an increase in the mean estimated GFR of 2.5 ml per minute per 1.73 m(2) (P<0.001 for both comparisons). The beneficial effect of intensive therapy on the risk of an impaired GFR was fully attenuated after adjustment for glycated hemoglobin levels or albumin excretion rates. The long-term risk of an impaired GFR was significantly lower among persons treated early in the course of type 1 diabetes with intensive diabetes therapy than among those treated with conventional diabetes therapy. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others; DCCT/EDIC ClinicalTrials.gov numbers, NCT00360815 and NCT00360893.).
                Bookmark

                Author and article information

                Journal
                Diabetes Care
                Diabetes Care
                diacare
                dcare
                Diabetes Care
                Diabetes Care
                American Diabetes Association
                0149-5992
                1935-5548
                January 2014
                11 December 2013
                : 37
                : 1
                : 226-234
                Affiliations
                1Research Division of Joslin Diabetes Center, Boston, MA
                2Department of Medicine, Harvard Medical School, Boston, MA
                3Department of Metabolic Diseases, Jagiellonian University Medical College, Krakow, Poland
                4Division of Nephrology, Department of Internal Medicine, Juntendo University School of Medicine, Tokyo, Japan
                5Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN
                Author notes
                Corresponding author: Andrzej S. Krolewski, andrzej.krolewski@ 123456joslin.harvard.edu .
                Article
                0985
                10.2337/dc13-0985
                3867993
                23939543
                © 2014 by the American Diabetes Association.

                Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.

                Page count
                Pages: 9
                Product
                Categories
                Pathophysiology/Complications

                Endocrinology & Diabetes

                Comments

                Comment on this article