Dynapenia is an independent predictor of cardio-cerebrovascular events in patients undergoing hemodialysis.

The number of patients on maintenance hemodialysis (HD) diagnosed with sarcopenia has been increasing through as individuals age. Recent focus is on the condition termed, "dynapenia," which reduces only muscle function, as opposed to sarcopenia, which reduces both muscle mass and function. However, the association between dynapenia and cardio-cerebrovascular (CV) events in patients undergoing HD is largely unknown. The purpose of this study was to evaluate whether sarcopenia and dynapenia are associated with the onset of CV events in patients undergoing HD. We retrospectively analyzed 342 patients undergoing HD between January and December 2018. Patients who underwent HD thrice per week for > 3 months were included in the analysis. We adopted the Asian Working Group on Sarcopenia criteria for the diagnosis of sarcopenia and dynapenia. In this study, 244 patients undergoing HD were enrolled. The prevalence of sarcopenia was 38.5%. Sarcopenia was determined to be an independent contributor to CV events in patients undergoing HD. To investigate the clinical relevance of dynapenia in patients with HD, patients without sarcopenia were further divided into dynapenia and non-dynapenia groups. Among 150 patients without sarcopenia, 46 were diagnosed with dynapenia. In the Kaplan-Meier analysis, the rate of CV events was significantly different among the three groups in a stratified manner, with the highest rate in the sarcopenia group and the lowest rate in the non-sarco-dynapenia group. Both patients with sarcopenia and dynapenia had significantly increased CV events compared to those with non-sarco-dynapenia (HR 8.00; 95% CI 2.73-34.1; p < 0.0001 vs. HR 4.85; 95% CI 1.28-23.0; p < 0.02). Both sarcopenia and dynapenia resulted in significantly higher CV events than non-sarco-dynapenia in patients undergoing HD. Therefore, clinicians should evaluate muscle function in addition to muscle quantity to estimate CV events in patients undergoing HD.

Suppression of thyrotropin secretion during roxadustat treatment for renal anemia in a patient undergoing hemodialysis.

BACKGROUND: Inhibition of hypoxia-inducible factor prolyl hydroxylase (HIF-PH) is a novel choice for the treatment of renal anemia, and an oral HIF-PH inhibitor roxadustat was approved for renal anemia. Roxadustat has high affinity to thyroid hormone receptor beta, which may affect thyroid hormone homeostasis. CASE PRESENTATION: We present here a patient undergoing hemodialysis with primary hypothyroidism receiving levothyroxine replacement, who showed decreased free thyroxine (FT4) and thyroid stimulating hormone (TSH) after starting roxadustat. Pituitary stimulation test revealed selective suppression of TSH secretion. Recovery of TSH and FT4 levels after stopping roxadustat suggested the suppression of TSH was reversible. CONCLUSIONS: Physicians should pay special attention to thyroid hormone abnormalities in treatment with roxadustat.

High Coronary Heart Disease Risk in Hemodialysis Patients with Central Sleep Apnea: A Pilot Study.

BACKGROUND: The high prevalence of sleep apnea is reported in hemodialysis patients despite the low prevalence of obesity. The present study compared the occurrence of central sleep apnea (CSA) in hemodialysis patients with that in non-hemodialysis patients, and its association with new-onset coronary heart disease (CHD) events. METHODS: Seventy-three hemodialysis and 444 non-hemodialysis patients were examined for CSA and obstructive sleep apnea (OSA) occurrence using polysomnography. Hemodialysis patients were monitored for the occurrence of new-onset CHD events. RESULTS: Hemodialysis patients had a significantly higher central apnea-hypopnea index (AHI; 0.7, range 0.2-3.1) than age-, sex- and obstructive AHI-matched non-hemodialysis patients (0.1, range 0-1.0; p < 0.001), in contrast with an insignificant difference for obstructive AHI. Furthermore, the prevalence of CSA was significantly higher in the hemodialysis (21.9%) than in the non-hemodialysis group (9.7%; p = 0.004). A significant and negative association existed between log (central AHI + 1) and Kt/V in hemodialysis patients. In the Kaplan-Meier analysis, hemodialysis patients with CSA had a significantly higher rate of new-onset CHD events than those without CSA. Cox proportional-hazards regression analysis identified CSA prevalence as an independent risk factor for the development of a new-onset CHD event, independent of OSA. CONCLUSIONS: The present study demonstrated that hemodialysis patients had a significantly higher CSA prevalence than non-hemodialysis patients despite similar obstructive AHI, and that hemodialysis patients with CSA had a significantly higher risk for new-onset CHD events than those without CSA independent of obstructive AHI, suggesting CSA as a potential CHD risk specifically in hemodialysis patients.

Comparison of the Estimated Glomerular Filtration Rate (eGFR) in Diabetic Patients, Non-Diabetic Patients and Living Kidney Donors.

BACKGROUND/AIMS: We have reported that the eGFR overestimates renal function when glycemic control is poor. It has been reported that eGFR calculated by serum creatinine underestimates GFR in living kidney donors. We compared the utility of the eGFR in diabetic patients, non-diabetic patients and living kidney donors. Forty diabetic patients, 40 non-diabetic patients, and 40 living kidney donors were enrolled. METHODS: GFR was measured by inulin clearance (C(in)). eGFR was calculated based on serum creatinine (eGFR(cr)) or serum cystatin C (eGFR(cys)). We compared the agreements between each of the eGFR and C(in) in each group. RESULTS: There were significant and positive correlations between each eGFR and C(in) in diabetic patients and non-diabetic patients. However, the intraclass correlation coefficients (ICC) between each eGFR and C(in) in diabetic patients (ICC: eGFR(cr) 0.699, eGFR(cys) 0.604) were weaker than those in non-diabetic patients (ICC: eGFR(cr) 0.865, eGFR(cys) 0.803). The correlation coefficients between each eGFR and C(in) (eGFR(cr); r = 0.422, p = 0.0067 and eGFR(cys); r = 0.358, p = 0.0522) in living kidney donors were significantly weaker than those in non-diabetic patients. The ICCs between each eGFR and C(in) (ICC: eGFR(cr) 0.340, eGFR(cys) 0.345) in living kidney donors were significantly weaker than those in non-diabetic patients. CONCLUSIONS: Based on C(in), eGFR was accurate in non-diabetic patients. However, eGFR was inaccurate in living kidney donors and relatively inaccurate in diabetic patients.

Relationship between serum uric acid levels and intrarenal hemodynamic parameters.

BACKGROUND/AIMS: Hyperuricemia has been reported to affect renal hemodynamics in rat models. We evaluate the relationship between serum uric acid and intrarenal hemodynamic parameters in humans, utilizing the plasma clearance of para-aminohippurate (CPAH ) and inulin (Cin). METHODS: Renal and glomerular hemodynamics were assessed by simultaneous measurement of CPAH and Cin in 58 subjects. Of these, 19 subjects were planned to provide a kidney for transplantation; 26 had diabetes without proteinuria; and 13 had mild proteinuria. Renal and glomerular hemodynamics were calculated using Gomez`s formulae. RESULTS: Cin was more than 60 ml/min/1.73m(2) in all subjects. Serum uric acid levels correlated significantly with vascular resistance at the afferent arteriole (Ra) (r = 0.354, p = 0.006) but not with that of the efferent arteriole (Re). Serum uric acid levels (ß = 0.581, p = <0.001) were significantly and independently associated with Ra after adjustment for several confounders (R(2) = 0.518, p = <0.001). CONCLUSIONS: These findings suggest, for the first time in humans, that higher serum uric acid levels are associated significantly with Ra in subjects with Cin > 60 ml/min/1.73m(2). The increase in Ra in subjects with higher uric acid levels may be related to dysfunction of glomerular perfusion.

Greater potency of darbepoetin-α than erythropoietin in suppression of serum hepcidin-25 and utilization of iron for erythropoiesis in hemodialysis patients.

BACKGROUND: The potency of darbepoetin-α (DPO-α) to improve anemia in hemodialysis (HD) patients is greater than that of recombinant human erythropoietin (rHuEPO). DESIGN AND METHODS: To assess the potency of DPO-α to mobilize iron from body stores in comparison with rHuEPO in HD patients without apparent inflammation or infection, serum iron, transferrin saturation (TSAT), ferritin, and hepcidin-25 were measured serially. This study included (i) a long-term crossover study for 3 yr to compare the effects of the two erythropoiesis-stimulating agents (ESA) on serum iron, TSAT, and ferritin, and (ii) a short-term crossover study for 8 wk to examine their effects on serum hepcidin-25 in HD patients. RESULTS: The long-term crossover study demonstrated that the change of ESA from rHuEPO to DPO-α significantly decreased serum ferritin while serum iron and TSAT remained unchanged, while DPO-α as well as rHuEPO maintained hemoglobin level in the target range between 10.0 and 11.0 g/dL. Furthermore, in the short-term crossover study, area under the percent suppression of serum hepcidin-25 time curve for the first 7 d during the DPO-α treatment period was significantly greater than that during the rHuEPO period (348.0 ± 92.4 vs. 178.4 ± 131.5%.day P = 0.030). The greater suppression of hepcidin-25 by DPO-α may facilitate iron mobilization, resulting in diminution of body iron stores without any significant effect on serum iron utilizable for erythropoiesis. CONCLUSION: This study demonstrated that DPO-α has a greater advantage than rHuEPO in that it facilitates iron mobilization from body stores into bone marrow to induce effective erythropoiesis and thus could protect against possible harmful effects caused by excessive iron stores in the body.

Quantitative analysis of abdominal aortic calcification in CKD patients without dialysis therapy by use of the Agatston score.

BACKGROUND/AIM: The aim of the present study was to quantitatively examine factors associated with aortic calcification in non-dialysis CKD patients. METHODS: We quantitatively investigated aortic calcification from the renal artery to the bifurcation in 149 non-dialysis CKD patients (58±16 years; 96 males and 53 females, 48 diabetics; eGFR 40.3 ± 29.3 ml/min), and measured Agatston scores using multi-slice computed tomography. RESULT: Of 149 patients, aortic calcification was present in 117. In patients with aortic calcification, age (p<0.001), C-reactive protein (p<0.001), and intact-PTH (p < 0.001) were significantly higher, estimated glomerular filtration rate (eGFR) was significantly lower (p<0.001), and diabetes was observed more often (p<0.05). In regards to the degree of aortic calcification, the Agatston scores correlated significantly and positively with age (ρ=0.438, p<0.001) and serum phosphate (ρ=0.208, p=0.024), and correlated significantly but negatively with e-GFR (ρ=-0.353, p<0.001). In multiple regression analysis, eGFR was associated significantly and independently with the log [Agatston score] (ß=-0.346, p<0.01), after adjustment for several confounders including serum phosphate and the presence of diabetes. CONCLUSIONS: Hyperphospatemia, chronic inflammation, diabetes, and decreased GFR are associated significantly with the presence of aortic calcification in non-dialysis CKD patients. Decreased eGFR was associated significantly and independently with the quantitative degree of aortic calcification.

Reduced Risk of Progression from Non-Severe to Severe COVID-19 in Hospitalized Dialysis Patients by Full COVID-19 Vaccination.

Coronavirus disease 2019 (COVID-19) vaccination reduces the risk of progression to severe COVID-19 in the general population. To examine that preventive effect in dialysis patients, the association of vaccination status with severe COVID-19 progression was investigated in this retrospective observational study conducted from December 2020 to May 2022 of 100 such patients hospitalized for non-severe COVID-19 at Inoue Hospital (Suita, Japan). Fifty-seven were fully vaccinated, defined as receiving a COVID-19 vaccine second dose at least 14 days prior to the onset of COVID-19, while 43 were not. Among all patients, 13 (13.0%) progressed to severe COVID-19 with a median (interquartile range) time of 6 (2.5-9.5) days, while 87 (87.0%) were discharged after 11 (8-16) days. Kaplan-Meier analysis showed that fully vaccinated patients had a significantly lower rate of progression to severe COVID-19 (p = 0.001, log-rank test). Cox proportional hazard analysis also indicated that full COVID-19 vaccination was significantly associated with reduced instances of progression to severe COVID-19 (hazard ratio 0.104, 95% confidence interval 0.022 to 0.483; p = 0.004) after balancing patient background characteristics using an inverse probability of treatment weight method. These results suggest that full vaccination status contributes to reducing the risk of progression from non-severe to severe COVID-19 in dialysis patients.

Nutritional Status Association With Sarcopenia in Patients Undergoing Maintenance Hemodialysis Assessed by Nutritional Risk Index.

Background: Malnutrition and sarcopenia are frequently observed in patients undergoing maintenance hemodialysis (MHD). To elucidate whether malnutrition is associated with sarcopenia in those cases, the relationship of nutritional status with sarcopenia was investigated. Methods: Nutritional status was assessed using a nutritional risk index (NRI) developed for patients undergoing MHD. This retrospective cross-sectional study included 315 MHD patients (199 males, 116 females), who were divided into low-risk (score 0-7) and medium-/high-risk (score 8-13) groups. Sarcopenia and severe sarcopenia, along with low muscle mass, low muscle strength, and low physical performance were defined using the Asian Working Group for Sarcopenia 2019 criteria. Results: The median NRI score was 5.0, while the prevalence of medium-/high-risk cases among the patients was 31.1%. Additionally, the rates of those with low muscle mass, low muscle strength, and low physical performance were 55.9, 60.6, and 31.4%, respectively, while those of sarcopenia and severe sarcopenia were 44.1 and 20.0%, respectively. Multivariable logistic regression analyses revealed a significant (P < 0.001) association of NRI score with sarcopenia [odds ratio (OR) 1.255, 95% confidence interval (CI) 1.143-1.377] and severe sarcopenia (OR 1.257, 95% CI 1.122-1.407), as well as low muscle mass (OR 1.260, 95% CI 1.157-1.374), low muscle strength (OR 1.310, 95% CI 1.178-1.457), and low physical performance (OR 1.216, 95% CI 1.104-1.339). Furthermore, medium-/high-risk status showed a significant (P < 0.05) association with sarcopenia (OR 2.960, 95% CI 1.623-5.401) and severe sarcopenia (OR 2.241, 95% CI 1.151-4.362), as well as low muscle mass (OR 2.141, 95% CI 1.219-3.760), low muscle strength (OR 7.665, 95% CI 3.438-17.091), and low physical performance (OR 2.570, 95% CI 1.401-4.716). Conclusions: These results suggest that malnutrition contributes to sarcopenia/severe sarcopenia in MHD patients by reducing muscle mass and strength, and physical performance.

Decreased kidney function is a significant factor associated with silent cerebral infarction and periventricular hyperintensities.

BACKGROUND/AIMS: Silent cerebral lacunar infarction (SCI) and periventricular hyperintensities (PVH) have been reported to be markers of ischemic cerebral small-vessel disease and risk factors for future cerebrovascular events in the general population. The relationship between CKD and SCI/PVH is examined. METHODS: In this cross-sectional study, brain magnetic resonance imaging was performed with a 1.5-T system in 324 predialysis CKD patients and in 60 normal subjects. RESULTS: SCI was found in 103 CKD patients (31.8%), and PVH was found in 174 CKD patients (53.7%). SCI/PVH were more prevalent in patients with higher blood pressure, advanced age and decreased kidney function. There was a significant association between the prevalence of SCI/PVH and the CKD stage, with greater prevalence of SCI/PVH as the CKD stage advanced (p < 0.0001). PVH grade also advanced as the CKD stage advanced. The estimated glomerular filtration rate was a significant factor associated with the presence of SCI/PVH, independent of any other factors. There was a strong association between the prevalence of SCI/PVH (p < 0.0001). CONCLUSION: In CKD patients, decreased kidney function is a significant factor associated with SCI/PVH, both of which are significantly associated with each other. These results suggest that CKD patients with SCI/PVH are at greater risk of future cerebrovascular events.

[Membranous nephropathy with nephrotic syndrome developed after allogeneic hematopoietic stem cell transplantation for acute lymphoblastic leukemia].

A 38-year-old man was diagnosed with acute lymphoblastic leukemia. We performed myeloablative bone marrow transplantation from an unrelated donor during the patient's first complete remission. After engraftment, he developed acute graft-versus-host disease involving the gastrointestinal tract on day 32. Steroids and mycophenolate mofetil were initiated from day 39. His symptoms improved and the dose of immunosuppressants was tapered and then discontinued on day 421. On day 491, he developed nephrotic syndrome (NS). Based on renal biopsy, membranous nephropathy was diagnosed. There were no apparent symptoms or abnormal laboratory data suggestive of chronic graft-versus-host disease (cGVHD). Steroid therapy was initiated from day 518 and proteinuria improved significantly. NS is very rare following allogeneic hematopoietic stem cell transplantation (allo-HSCT). When there is no concomitant cGVHD, as in this case, allo-HSCT-associated NS is difficult to distinguish from idiopathic NS.

Decreases in parathyroid gland volume after cinacalcet treatment in hemodialysis patients with secondary hyperparathyroidism.

BACKGROUND/AIM: Cinacalcet, an allosteric modulator of the calcium-sensing receptor, effectively reduces serum parathyroid hormone (PTH). It was examined whether a regression of parathyroid glands in hemodialysis patients with secondary hyperparathyroidism was induced by cinacalcet treatment. METHODS: Ultrasonography of the parathyroid glands was performed to examine the changes in the parathyroid gland volumes after cinacalcet treatment in 58 patients. RESULTS: After cinacalcet treatment, serum calcium, phosphate, alkaline phosphatase, and intact PTH significantly decreased (p < 0.0001). The total volumes of the parathyroid glands were significantly decreased 6 months after cinacalcet treatment (942 +/- 747 vs. 708 +/- 550 mm(3), p < 0.0005). There was a significant positive correlation between the parathyroid gland volumes at the start of cinacalcet treatment and the volume reduction in parathyroid glands (r = 0.716, p < 0.0001). Of the 58 patients, the total parathyroid gland volume was decreased in 42 patients and increased in 16 although the doses of cinacalcet, phosphate binders or vitamin D were not significantly different. In both groups, the intact PTH serum levels were significantly decreased after cinacalcet treatment. CONCLUSION: Cinacalcet treatment in patients with secondary hyperparathyroidism significantly reduced the total parathyroid gland volume in a short 6-month period. This study suggests that cinacalcet treatment may postpone parathyroidectomy and/or reduce cases.

Significant association between glycemic status and increased estimated postglomerular resistance in nondiabetic subjects - study of inulin and para-aminohippuric acid clearance in humans.

We investigated whether glomerular hemodynamic parameters in nondiabetic subjects, including healthy subjects, are associated with glycemic status indices, by simultaneous measurement of inulin (Cin) and para-aminohippuric acid (CPHA) clearance. Twenty-six subjects (age 49.5 ± 13.3 years; 13 men and 13 women; 14 healthy subjects and 12 subjects with mild proteinuria) were enrolled. Cin and CPAH were measured simultaneously. All 26 subjects were nondiabetics. Estimated preglomerular resistance, estimated postglomerular resistance, and estimated glomerular hydrostatic pressure (Pglo) were calculated according to Gomez' formula. Pglo correlated significantly and positively with hemoglobin A1c (HbA1c) in both healthy subjects (r = 0.532, P = 0.0498) and subjects with mild proteinuria (r = 0.681, P = 0.015). While there was no significant correlation between estimated preglomerular resistance and HbA1c, estimated postglomerular resistance correlated significantly and positively with HbA1c both in healthy subjects (r = 0.643, P = 0.013) and subjects with mild proteinuria (r = 0.589, P = 0.044). Glomerular filtration fraction, estimated Pglo and estimated postglomerular resistance in total subjects were associated significantly with HbA1c after adjustment for age, gender, and body mass index. These results demonstrate that, even in nondiabetic subjects, glycemic status is associated with estimated postglomerular resistance, but not estimated preglomerular resistance. It is suggested that increased estimated postglomerular resistance associated with higher HbA1c levels, even within the normal range, causes increased estimated Pglo, leading to increased FF. Thus, hemodynamic abnormalities associated with higher HbA1c levels may be related to glomerular hypertension, even in nondiabetic subjects.

Relationship between serum sclerostin, bone metabolism markers, and bone mineral density in maintenance hemodialysis patients.

BACKGROUND: Sclerostin, which is secreted exclusively by osteocytes, is a negative regulator of bone formation. The role of sclerostin in chronic kidney disease-mineral and bone disorder is not well known. In the present study, we examined the relationship between serum sclerostin levels, bone turnover markers, and bone mineral density (BMD) of the radius in maintenance hemodialysis patients. METHODS: This was a cross-sectional study that analyzed sclerostin, bone alkaline phosphatase (a bone formation marker), and tartrate-resistant acid phosphatase 5b (a bone resorption marker) in stored serum samples from 181 hemodialysis patients (age, 68 ± 11 y; 105 males and 76 females; hemodialysis duration, 6.9 ± 5.9 y). The BMD in the distal one-third of the radius and in the ultradistal radius, which are enriched with cortical and cancellous bone, respectively, was examined by dual-energy x-ray absorptiometry. RESULTS: Serum sclerostin was 125 ± 53 pmol/L (mean ± SD). Serum sclerostin correlated significantly and negatively with serum bone alkaline phosphatase and tartrate-resistant acid phosphatase 5b (r = -0.265, P < .001; r = -0.218, P < .01, respectively). The BMD in the distal one-third of the radius and in the ultradistal radius both correlated significantly and positively with serum sclerostin levels (r = 0.454, P < .0001; r = 0.329, P < .0001, respectively). In multiple regression analysis, serum sclerostin was associated significantly and independently with BMD of both parts of the radius (ß = 0.200, P < .001; ß = 0.218, P < .05), after adjustment for age, hemodialysis duration, and bone metabolism markers. CONCLUSION: Serum sclerostin was associated significantly, independently, and positively with BMD of both cortical and cancellous bone. Sclerostin is considered to be one of the factors associated with chronic kidney disease-mineral and bone disorder in hemodialysis patients.

Poor glycemic control is a major factor in the overestimation of glomerular filtration rate in diabetic patients.

OBJECTIVE Serum creatinine levels are lower in diabetic patients compared with their nondiabetic counterparts. Therefore, estimated glomerular filtration rate (eGFR) is higher in the former than in the latter group. Factors associated with overestimation of renal function in diabetic patients were examined, and new formulae reflecting precise eGFR were created. RESEARCH DESIGN AND METHODS Eighty subjects (age 56.5 ± 15.4 years; 35 males [43.8%]; 40 patients with diabetes and 40 nondiabetic subjects) were enrolled. GFR was evaluated by inulin clearance (Cin). eGFR values were calculated based on serum creatinine and/or serum cystatin C levels. The factors related to the dissociation between eGFR and Cin in diabetic patients and the agreement among each of three eGFR and Cin were compared. RESULTS Although Cin was not significantly different between the diabetic and nondiabetic subjects (P = 0.2866), each of three eGFR measures from the diabetic patients was significantly higher than that of the nondiabetic subjects (P < 0.01). There were significant and positive correlations between the ratio of each eGFR/Cin, hemoglobin A1c, and glycated albumin. The intraclass correlation coefficients in diabetic patients were weaker than those in the nondiabetic subjects, and the intercepts of the regression lines between each eGFR measure and Cin in the diabetic patients were significantly higher than those of the nondiabetic subjects. New formulae for the calculation of eGFR corrected by the glycemic control indices were better than the original eGFR, particularly in diabetic patients. CONCLUSIONS eGFR overestimates Cin as glycemic controls worsen. eGFR corrected by hemoglobin A1c is considered to be clinically useful and feasible.

Relationship between serum TSH levels and intrarenal hemodynamic parameters in euthyroid subjects.

OBJECTIVE: Low thyroid function may be associated with a reduced glomerular filtration rate (GFR) calculated on the basis of creatinine metabolism. Thyroid hormone directly affects serum creatinine in muscle and low thyroid function might exert a similar direct effect in the kidney. The goal of the study was to evaluate this possibility by assessment of the inulin-based GFR and to examine the mechanism underlying the reduction of GFR. PATIENTS AND METHODS: Renal and glomerular hemodynamics were assessed by simultaneous measurements of plasma clearance of para-aminohippurate (CPAH) and inulin (Cin) in 26 patients with serum creatinine <1.00 mg/dl and without thyroid disease. All subjects were normotensive with or without antihypertensive treatment and were kept in a sodium-replete state. Renal and glomerular hemodynamics were calculated using Gomez's formulae. RESULTS: Serum TSH, including within the normal range (0.69-4.30 µIU/ml), was positively correlated with vascular resistance at the afferent arteriole (Ra) (r=0.609, P=0.0010), but not at the efferent arteriole (Re). Serum TSH was significantly and negatively correlated with renal plasma flow (RPF), renal blood flow (RBF), and GFR (r=-0.456, P=0.0192; r=-0.438, P=0.0252; r=-0.505, P=0.0086 respectively). In multiple regression analysis, serum TSH was significantly positively associated with Ra after adjustment for age and mean blood pressure. CONCLUSIONS: These findings suggest that low thyroid function, even within the normal range, is associated with reduced RPF, RBF, and GFR, which might be caused by a preferential increase in Ra.

Impaired response of FGF-23 to oral phosphate in patients with type 2 diabetes: a possible mechanism of atherosclerosis.

BACKGROUND: Fibroblast growth factor (FGF)-23, secreted from osteocytes/osteoblasts, plays major roles in phosphate (Pi)-mediated stimulation of PTH secretion and consequently in regulation of serum Pi. Osteocyte/osteoblast dysfunction develops in patients with type 2 diabetes mellitus (DM). OBJECTIVE: Our objective was to examine whether increases in serum FGF-23 and PTH after oral Pi stimulation are impaired in type 2 DM. DESIGN AND METHODS: The subjects were 10 DM and 10 non-DM patients without chronic kidney disease stage 3-5. Serum FGF-23, intact PTH (iPTH), and Pi were measured serially after oral Pi administration at a daily dose of 2.0 g. RESULTS: Pi administration caused significant increases of FGF-23 by 2 h and iPTH by 4 h in non-DM patients. These increases were attenuated in DM patients. After 2 d of Pi stimulation, serum FGF-23 and iPTH remained elevated in non-DM patients but not in DM. In all subjects, initial changes of serum FGF-23 (0-2 h) and iPTH (0-4 h) were positively correlated (r = 0.528) and showed significant negative correlations with later changes in serum Pi (2-4 h) (r = -0.457 and r = -0.673, respectively). Serum Pi (2-4 h) significantly increased in DM patients, consistent with the lack of change in serum FGF-23 and iPTH, whereas serum Pi did not change significantly in non-DM patients. CONCLUSION: These results show that increases of serum FGF-23 and PTH in response to Pi stimulation are impaired in type 2 DM and that serum Pi is significantly increased thereafter. This may be a mechanism underlying advanced atherosclerosis in type 2 DM.