Enterovirus RNA in blood is linked to the development of type 1 diabetes

OBJECTIVE

To assess whether the detection of enterovirus RNA in blood predicts the development of clinical type 1 diabetes in a prospective birth cohort study. Further, to study the role of enteroviruses in both the initiation of the process and the progression to type 1 diabetes.

RESEARCH DESIGN AND METHODS

This was a nested case-control study where all case children (N = 38) have progressed to clinical type 1 diabetes. Nondiabetic control children (N = 140) were pairwise matched for sex, date of birth, hospital district, and HLA-DQ–conferred genetic susceptibility to type 1 diabetes. Serum samples, drawn at 3- to 12-month intervals, were screened for enterovirus RNA using RT-PCR.

RESULTS

Enterovirus RNA–positive samples were more frequent among the case subjects than among the control subjects. A total of 5.1% of the samples (17 of 333) in the case group were enterovirus RNA–positive compared with 1.9% of the samples (19 of 993) in the control group (P < 0.01). The strongest risk for type 1 diabetes was related to enterovirus RNA positivity during the 6-month period preceding the first autoantibody-positive sample (odds ratio 7.7 [95% CI 1.9–31.5]). This risk effect was stronger in boys than in girls.

CONCLUSIONS

The present study supports the hypothesis that enteroviruses play a role in the pathogenesis of type 1 diabetes, especially in the initiation of the β-cell damaging process. The enterovirus-associated risk for type 1 diabetes may be stronger in boys than in girls.Enterovirus infections are among the major candidates for environmental risk factors for type 1 diabetes. Previous studies have suggested that enterovirus epidemics associate with an increase in the incidence of type 1 diabetes, and an increased frequency of enterovirus antibodies has been reported in patients with type 1 diabetes (1,2). Several studies have detected enterovirus genome in the blood of diabetic patients, but it is unknown whether the finding reflects persistent or acute infection (3). Virus has been detected both in pancreas and in intestinal mucosa and has also shown a tropism for islets (4,5). On some occasions, coxsackievirus B and echoviruses have even been isolated from diabetic children (6). The recent discovery that genetic polymorphism in the IFIH1 gene (innate immune system sensor for enteroviruses) affects diabetes susceptibility has further supported the possible role of enteroviruses (7). Experimental data support these findings because enteroviruses can cause diabetes in mice and damage β-cells in human islet cell cultures in vitro (3).Type 1 diabetes–associated autoantibodies in peripheral blood reflect initiation of the β-cell–damaging processes. However, the progression toward clinical diabetes is usually slow, and possible triggering infections can occur long before the presentation of clinical type 1 diabetes. Consequently, prospective follow-up series are essential for the identification of such triggers. A few prospective studies have been carried out on the possible role of enterovirus infections, but the results have been conflicting (8–11).The aim of this study is to test risk effect of enterovirus RNA in blood for the development of type 1 diabetes in a prospective birth cohort study. Blood samples were collected with short intervals, which made it possible to detect enterovirus RNA directly from the serum in different stages of the disease process. We have previously documented the risk effect of enteroviruses in children who developed β-cell autoimmunity. Now, the aim is to confirm these findings in children who have developed type 1 diabetes and to study the role of these viruses in both the initiation of the process and its progression to diabetes.     

Higher prevalence of anemia with diabetes mellitus in moderate kidney insufficiency: The Kidney Early Evaluation Program

BACKGROUND: The Kidney Early Evaluation Program (KEEP 2.0) cross-sectional, community-based study, targeted individuals at increased risk for kidney disease and measured blood glucose, creatinine, and hemoglobin. METHODS: KEEP 2.0 screening data were used to determine the prevalence of anemia by level of kidney function and diabetes status. Estimated glomerular filtration rate (EGFR) was calculated using serum creatinine values, and categorized as > or =90, 60-89, 30-59 and <30 mL/min/1.73 m(2). Anemia was defined as hemoglobin <12 g/dL in men and in women aged >50 years, and <11 g/dL in women < or =50 years. Diabetes was defined as participant-reported diagnosis, fasting glucose >125 mg/dL, or nonfasting glucose >200 mg/dL. RESULTS: Data were available on 5380 participants screened from August 2000 through December 2001. Diabetes was present in 26.9% of participants, and anemia in 7.7%; 15.9% of participants had at least moderately reduced kidney function (EGFR <60 mL/min/1.73 m(2)). In participants with diabetes, anemia prevalence at the 4 levels of descending EGFR were 8.7%, 7.5%, 22.2%, and 52.4%, compared with 6.9%, 5.0%, 7.9%, and 50.0% in persons without diabetes. In a multivariable model, participants of non-white race/ethnicity, those with diabetes and those with EGFR <30 or 30-59 mL/min/1.73 m(2) had significantly increased odds of anemia. In addition, a significant sex-diabetes interaction was identified; odds of anemia were 4-fold greater in men than women with diabetes relative to sex-matched participants without diabetes. CONCLUSION: Diabetes was independently correlated with anemia, more so in men than women, and may be linked to premature expression of anemia in persons with moderate reductions in kidney function.     

The importance of serum transferrin receptor level in the diagnosis of functional iron deficiency due to recombinant human erythropoietin treatment in haemodialysis patients

In haemodialysis (HD) patients, functional iron deficiency frequently appears due to recombinant human erythropoietin (r-HuEPO) treatment. However, the diagnosis of iron deficiency is not always easy in such patients. Recent studies have shown that the serum transferrin receptor (s-TfR) level is a sensitive, quantitative measure of tissue iron deficiency. In this study, we examined the changes in s-TfR levels in patients with iron deficiency anaemia due to r-HuEPO treatment. We compared s-TfR levels of 24 patients with i.v. administered r-HuEPO 50–70 U/kg/dose) at the end of each dialysis session (three times a week) and diagnosed as having iron deficiency anaemia by routine laboratory methods (ferritin<50 μg/l and transferrin saturation<16%) with s-TfR levels of 32 patients not receiving r-HuEPO and without iron deficiency anaemia. Also, 40 healthy volunteer subjects were included in the study as a control group. Serum ferritin and transferrin receptor levels were measured with ELISAs using monoclonal reagents. There were no differences between the two groups with and without iron deficiency anaemia with respect to mean age, body weight, haemodialysis duration, haemoglobin and serum creatinine levels (p>0.05). For s-TfR levels, while no difference was present between the control and the non-iron deficiency groups (p>0.05), the iron deficiency group had higher s-TfR values than those of both the control and non-iron deficiency groups (p<0.001). Besides, there was an inverse correlation between haemoglobin and s-TfR levels in patients with iron deficiency anaemia (r=?0.85, p<0.0001). We conclude that the measurement of s-TfR levels may be useful in the diagnosis of functional iron deficiency in haemodialysis patients receiving r-HuEPO.     

Glycated albumin is a better glycemic indicator than glycated hemoglobin values in hemodialysis patients with diabetes: effect of anemia and erythropoietin injection

The significance of glycated albumin (GA), compared with casual plasma glucose (PG) and glycated hemoglobin (HbA(1c)), was evaluated as an indicator of the glycemic control state in hemodialysis (HD) patients with diabetes. The mean PG, GA, and HbA(1c) levels were 164.5 +/- 55.7 mg/dl, 22.5 +/- 7.5%, and 5.85 +/- 1.26%, respectively, in HD patients with diabetes (n = 538), which were increased by 51.5, 31.6, and 17.7%, respectively, compared with HD patients without diabetes (n = 828). HbA(1c) levels were significantly lower than simultaneous PG and GA values in those patients in comparison with the relationship among the three parameters in patients who had diabetes without renal dysfunction (n = 365), as reflected by the significantly more shallow slope of regression line between HbA(1c) and PG or GA. A significant negative correlation was found between GA and serum albumin (r = -0.131, P = 0.002) in HD patients with diabetes, whereas HbA(1c) correlated positively and negatively with hemoglobin (r = 0.090, P = 0.036) and weekly dose of erythropoietin injection (r = -0.159, P < 0.001), respectively. Although PG and GA did not differ significantly between HD patients with diabetes and with and without erythropoietin injection, HbA(1c) levels were significantly higher in patients without erythropoietin. Categorization of glycemic control into arbitrary quartile by HbA(1c) level led to better glycemic control in a significantly higher proportions of HD patients with diabetes than those assessed by GA. Multiple regression analysis demonstrated that the weekly dose of erythropoietin, in addition to PG, emerged as an independent factor associated with HbA(1c) in HD patients with diabetes, although PG but not albumin was an independent factor associated with GA. In summary, it is suggested that GA provides a significantly better measure to estimate glycemic control in HD patients with diabetes and that the assessment of glycemic control by HbA(1c) in these patients might lead to underestimation likely as a result of the increasing proportion of young erythrocyte by the use of erythropoietin.     

Use of human recombinant erythropoietin to correct severe preoperative anemia

The risks of homologous blood transfusion are well known. Herein, we describe the successful preoperative use of human recombinant erythropoietin to correct severe anemia in a patient refusing transfusion. This case report emphasizes the important perioperative role human recombinant erythropoietin may play in the future.     

Insulin resistance and type 2 diabetes in high-fat-fed mice are linked to high glycotoxin intake

Dietary advanced glycosylation end products (AGEs) have been linked to insulin resistance in db/db(++) mice. To test whether dietary AGEs play a role in the progression of insulin resistance in normal mice fed high-fat diets, normal C57/BL6 mice were randomly assigned to high-fat diets (35% g fat), either high (HAGE-HF group; 995.4 units/mg AGE) or low (by 2.4-fold LAGE-HF group; 329.6 units/mg AGE) in AGE content for 6 months. Age-matched C57/BL6 and db/db(++) mice fed regular diet (5% g fat, 117.4 units/mg AGE) served as controls. After 6 months, 75% of HAGE-HF mice were diabetic and exhibited higher body weight (P < 0.001), fasting glucose (P < 0.001), insulin (P < 0.001), and serum AGEs (P < 0.01) than control mice, while none of the LAGE-HF mice were diabetic despite a similar rise in body weight and plasma lipids. The HAGE-HF group displayed markedly impaired glucose and insulin responses during glucose tolerance tests and euglycemic and hyperglycemic clamps and altered pancreatic islet structure and function compared with those of LAGE-HF mice, in which findings resembled those of control mice. The HAGE-HF group had more visceral fat (by two- and fourfold) and more AGE-modified fat (by two- and fivefold) than LAGE-HF and control mice, respectively. In the HAGE-HF group, plasma 8-isoprostane was higher (P < 0.01) and adiponectin lower (P < 0.001) than control mice, while in the LAGE-HF group, these were more modestly affected (P < 0.05). These results demonstrate that the development of insulin resistance and type 2 diabetes during prolonged high-fat feeding are linked to the excess AGEs/advanced lipoxidation end products inherent in fatty diets.     

The role of aluminum in the functional iron deficiency of patients treated with erythropoietin: case report of clinical characteristics and response to treatment

The quantitative variation among patients in their response to erythropoietin can be explained, in part, by factors that can independently cause anemia in patients with end-stage renal disease. Aluminum can blunt the effect of erythropoietin, in part by interfering with iron bioavailability. This inhibitory effect cannot be completely overcome by aggressive ferrotherapy, but can be reversed with aluminum chelation therapy. A patient is described who developed hematological evidence of aluminum excess after being treated with erythropoietin. The biochemical evidence of functional iron deficiency and the response to aluminum chelation therapy support the hypothesis that the inhibitory effect of aluminum on erythropoiesis is mediated by the interference of aluminum with the bioavailability of iron.     

Vascular effects of erythropoietin and anemia correction

Since its introduction for clinical use a decade ago, recombinant human erythropoietin (rHuEPO) has revolutionized the management of the anemia of end-stage renal disease. Soon after its release, it became evident that the biological targets of rHuEPO were not limited to the erythroid progenitor cells. Instead, numerous clinical and laboratory studies have shown the modulatory action of rHuEPO on a wide array of cell types and organ systems. The present article is intended to provide an overview of the modulatory actions of rHuEPO on the production and action of vasoregulatory factors and its direct and indirect effects on vascular function and structure.     

Cardiovascular effects of erythropoietin and anemia correction

Although recombinant erythropoietin has no short-acting pressor effect in vivo, its long-term administration frequently raises arterial pressure in humans and animals, with renal insufficiency. Contrary to the original view, erythropoietin-induced hypertension is not due to amelioration of anemia, because a similar rise in blood pressure occurs, despite persistent anemia, in erythropoietin-treated iron-deficient animals and humans. Moreover, multiple small blood transfusions administered to simulate the action of erythropoietin fail to increase blood pressure. Finally, iron repletion in severely anemic iron-deficient patients maintained on constant erythropoietin dosages does not raise blood pressure, despite a dramatic increase in hematocrit. Thus, chronic erythropoietin administration results in a hematocrit-independent, vasoconstriction-dependent hypertension that is marked by, and largely due to, elevated resting and agonist-stimulated cytoplasmic calcium concentration, leading to resistance to the vasodilatory action of nitric oxide. In addition, increased endothelin production, upregulation of tissue (but not circulating) renin and angiotensinogen expression, and a possible change in vascular tissue prostaglandin production have been variably demonstrated with erythropoietin administration in humans, intact animals and cultured endothelial cells. Erythropoietin has been shown to promote angiogenesis and stimulate endothelial and vascular smooth muscle cell proliferation. Finally, partial correction of anemia with erythropoietin therapy may partly prevent or reverse left ventricular hypertrophy in dialysis-dependent and dialysis-independent patients with chronic renal insufficiency. However, data on the risks and benefits of complete correction of anemia in this population are limited and inconclusive, and await future investigation.     

Low 1,25-dihydroxyvitamin D level is associated with erythropoietin deficiency and endogenous erythropoietin resistance in patients with chronic kidney disease

Purpose

Erythropoietin (EPO) deficiency and resistance to endogenous EPO is an important pathophysiological feature in anemia of chronic kidney disease (CKD). Low 1,25 dihydroxyvitamin D [1,25(OH)₂D] level is known to contribute to anemia of CKD. We aimed to investigate the associations between serum 1,25(OH)₂D and anemia, EPO deficiency, and endogenous EPO resistance in patients with CKD.

Methods

This study included 409 patients with CKD [glomerular filtration rate (GFR)?<?60 ml/min/1.73 m²] who were not on dialysis therapy. Patients on exogenous EPO therapy and patients with iron deficiencies were excluded. Endogenous EPO resistance was assessed by calculating the ratio of endogenous EPO to hemoglobin (Hb) (endogenous EPO/Hb ratio). The associations of Hb level, endogenous EPO level, and the endogenous EPO/Hb ratio with clinical and laboratory variables were investigated by univariate and multivariate analyses.

Results

In univariate analysis, serum 1,25(OH)₂D level was correlated with the Hb level, endogenous EPO level, and the endogenous EPO/Hb ratio. Multiple regression analysis revealed that the serum 1,25(OH)₂D level remained significantly associated with the Hb level (β?=?0.532, P?<?0.001), endogenous EPO level (β?=?0.149, P?=?0.010), and the endogenous EPO/Hb ratio (β?=???0.187, P?=?0.002), even after adjusting for other confounding factors, including the levels of parathyroid hormone and the inflammatory marker C-reactive protein.

Conclusion

The serum 1,25(OH)₂D level exhibited significant associations with anemia, EPO deficiency, and endogenous EPO resistance in CKD patients. These associations were independent of secondary hyperparathyroidism and inflammation status.

     

Possible role of soluble erythropoietin receptors in renal anemia

Recombinant human erythropoietin(rHuEpo) is effective for the treatment of renal anemia associated with chronic renal failure(CRF). However, we have encountered some patients with CRF who have sometimes developed a resistance to rHuEpo. This resistance can be due to iron or folate deficiency, aluminum toxicity, hyperparathyroidism, or auto-antibodies for rHuEpo. In this study, we focused on the soluble erythropoietin receptor(sEpoR), which can bind to rHuEpo. To demonstrate the possibility that the sweeping of rHuEpo by sEpoR results in resistance to rHuEpo, we performed a bioassay using the rHuEpo-dependent cell line, UT7/EPO. The results showed that recombinant mouse sEpoR(rmsEpoR) can reduce the proliferation of UT7/EPO induced by rHuEpo in a dose-dependent manner. We consider that this cell line could be a useful tool in a bioassay to detect the inhibitory factor(s) against Epo. We selected sera from three groups of patients with renal anemia associated with CRF who were receiving hemodialysis three times a week: the first was a patient group that needed a high dose of rHuEpo(7,500-9,000 unit/dialysis), the second was a patient group that needed an intermediate dose of rHuEpo (4,500 unit/dialysis), the third was a patient group that needed a low dose of rHuEpo(below 1,500 unit/dialysis). Interestingly, the proliferation of UT7/EPO determined with [3H]-thymidine incorporation was reduced by the addition of sera from the first group, but not by the addition of sera from the third group. These results suggested that serum sEpoR may play an important role in signal transduction via EpoR on erythroid progenitor in CRF patients.