Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Anticardiolipin antibodies in hemodialysis patients with hepatitis C and their role in fistula failure

BACKGROUND/AIMS

Several conflicting results are presently reported regarding raised IgG and IgM-anticardiolipin antibodies (ACA) titers in hemodialysis (HD) patients and their role in vascular access dysfunction. We aimed to determine the prevalence of both IgM and IgG-ACA titers and to analyze retrospectively their role in primary and secondary arteriovenous fistula (AVF) failure in a homogeneous group of HD patients with chronic hepatitis C.

METHODS

This study included 103 adults on maintenance hemodialysis with chronic hepatitis C infection. All participants had blood samples drawn predialysis and after an overnight fast. Analysis included biochemistry, IgG and IgM ACA, Anti-HCV, HBsAg, serum HCV RNA and HCV genotyping.

RESULTS

The prevalence of IgG-ACA was 14.6% (15/103). No patient had a positive value of the IgM-ACA test. HCV replication was detected in 52 of 76 patients. The most common HCV genotype was genotype 1 (90%). The percentage of females was higher in ACA(+) group (p = 0.038). There were no significant differences between subjects with and without ACA-IgG regarding other parameters studied. No difference in regard to AVF survival was detected between ACA(+) and ACA(-) groups (p > 0.05).

CONCLUSION

We found no significant differences in primary or secondary AVF failure between patients with elevated and normal ACA. Therefore, we conclude that AVFF may be caused by factors other than ACA in these patients. More prospective studies are needed to confirm this observation.

Parathyroid Hormone as a Marker for the Differential Diagnosis of Acute and Chronic Renal Failure

It is often difficult to distinguish acute renal failure clinically from chronic renal failure, especially in patients who do not have records of their medical history. We investigated the magnitude of iPTH increase in ARF and the potential role of iPTH as a marker for differential diagnosis of ARF and CRF in new patients referred to our renal unit. We prospectively analyzed 122 (ARF n = 64, CRF n = 58) patients referred to our renal unit with serum creatinine higher than 2 mg/dL. ROC curve analysis was performed to investigate role of iPTH for differentiating ARF from CRF. The sensitivity, specificity, and positive predictive value of iPTH in discrimination of ARF and CRF were calculated. There was no statistically significant difference regarding the means of age, sex distribution, and serum chemistry between patients with ARF or CRF. But serum iPTH (p < 0.0001) levels were lower in patients with ARF than in those with CRF. A cutoff, set at 170 pg/mL for iPTH to discriminate patients with CRF, yielded a sensitivity of 88% and a specificity of 89%. This study confirms that the iPTH measurement is of clinical value in differentiating acute from chronic renal failure.

Clinical significance of elevated antinuclear antibody test in patients with Hodgkin's and Non-Hodgkin's lymphoma: a single center experience

AIM

There is an increased risk of lymphoma subsequent to autoimmune conditions. Autoimmune disorders may occur in the course of lymphomas. In this study, the association of autoimmunity and related autoantibodies within non-Hodgkin's (NHL) and Hodgkin's lymphoma (HL) patients has been investigated.

METHODS

The study enrolled 119 patients affected by NHL and 60 patients affected by HL for the presence of autoantibodies and autoimmune diseases. Afterwards, the results between the two lymphoma groups have been confronted.

RESULTS

Autoimmune diseases were diagnosed in eight (6.7%) patients with NHL and three patients with HL (5%) (P=0.651). Thirty-four (28.5%) patients with NHL and 14 (23.3%) patients with HL displayed autoantibody positivity (P=0.083). As regards HL cases, antinuclear antibodies (ANA) were detected in 12 (20%) and anti PM-Scl in two patients (3.3%). None the patients had anti Jo-1, anti Scl-70, anti Sm, anti nRNP/Sm, anti single-stranded DNA (anti-ssDNA), anti double-stranded DNA (anti-dsDNA), antihistones, antinucleosomes, anti SS-A, anti SS-B or anti CENP-B autoantibodies. In patients affected by NHL ANA was detected in 16 (13.4%), anti SS-A and anti SS-B in two (1.7%), anti CENP-B in eight (6.7%) and anti PM-Scl in eight patients (6.7%). None of the patients had anti Jo-1, anti Scl-70, anti Sm, anti nRNP/Sm, anti ssDNA, antihistones or antinucleosome antibodies. There was a statistically significant difference between patients with HL and NHL in terms of anti CENP-B positivity (P=0.040).

CONCLUSION

In conclusion, ANA and related autoantibodies can frequently be detected during lymphoma treatment. However, the majority of lymphoma patients with positive ANA did not display autoimmune diseases, demonstrating the lack of a strict correlation between the presence of ANA and autoimmune diseases.

Randomized trial of peribulbar triamcinolone acetonide with and without focal photocoagulation for mild diabetic macular edema: a pilot study

OBJECTIVE

To provide pilot data on the safety and efficacy of anterior and posterior sub-Tenon injections of triamcinolone either alone or in combination with focal photocoagulation in the treatment of mild diabetic macular edema (DME).

DESIGN

Prospective, phase II, multicenter, randomized clinical trial.

PARTICIPANTS

One hundred nine patients (129 eyes) with mild DME and visual acuity 20/40 or better.

METHODS

The participants were assigned randomly to receive either focal photocoagulation (n = 38), a 20-mg anterior sub-Tenon injection of triamcinolone (n = 23), a 20-mg anterior sub-Tenon injection followed by focal photocoagulation after 4 weeks (n = 25), a 40-mg posterior sub-Tenon injection of triamcinolone (n = 21), or a 40-mg posterior sub-Tenon injection followed by focal photocoagulation after 4 weeks (n = 22). Follow-up visits were performed at 4, 8, 17, and 34 weeks.

MAIN OUTCOME MEASURES

Change in visual acuity and retinal thickness measured with optical coherence tomography (OCT).

RESULTS

At baseline, mean visual acuity in the study eyes was 20/25 and mean OCT central subfield thickness was 328 mum. Changes in retinal thickening and in visual acuity were not significantly different among the 5 groups at 34 weeks (P = 0.46 and P = 0.94, respectively). There was a suggestion of a greater proportion of eyes having a central subfield thickness less than 250 mum at 17 weeks when the peribulbar triamcinolone was combined with focal photocoagulation. Elevated intraocular pressure and ptosis were adverse effects attributable to the injections.

CONCLUSIONS

In cases of DME with good visual acuity, peribulbar triamcinolone, with or without focal photocoagulation, is unlikely to be of substantial benefit. Based on these results, a phase III trial to evaluate the benefit of these treatments for mild DME is not warranted.

Retinal blood flow indices in patients infected with human immunodeficiency virus

AIMS/BACKGROUND

Abnormal blood flow dynamics are believed to contribute to the development of retinal microvascular disease in patients infected with human immunodeficiency virus (HIV). In this study, the scanning laser ophthalmoscope (SLO) was used, combined with fluorescein angiography, to measure retinal blood flow indices in HIV seropositive patients.

METHODS

Arteriovenous passage time (AVP) and perifoveal capillary blood flow velocity (CFV) were measured in 23 HIV infected patients and 23 control subjects with SLO fluorescein angiography.

RESULTS

No significant difference in AVP was found between the two groups. However, CFV was significantly reduced in HIV infected patients (p = 0.013).

CONCLUSION

Patients infected with HIV show abnormal haemodynamics at the level of the perifoveal capillaries.

Retinal blood flow during dynamic exercise

BACKGROUND

Exercise acutely lowers intraocular pressure (IOP) and raises arterial pressure. We wondered whether the resultant increase in ocular perfusion pressure would alter retinal blood flow.

METHODS

To investigate this question, 11 healthy volunteers each performed progressive cycle ergometer exercise until exhaustion was reached in 5-10 min. Immediately after exercise, retinal blood flow and arteriovenous passage time were determined by video fluorescein angiography. Ten other volunteers performed repeated episodes of cycle ergometer exercise at approximately 60% of the maximal aerobic capacity, immediately prior to estimates of macular leukocyte velocity and density via blue-field stimulation.

RESULTS

Progressive exercise lowered IOP and elevated calculated ocular perfusion pressure. Within the retinal circulation, this exercise tended to raise mean dye velocity, as it significantly narrowed the superior temporal artery and vein; as a result, calculated retinal blood flow was unchanged. Simultaneously, retinal arteriovenous passage time was substantially shortened. Blue-field simulation showed that exercise increased macular leukocyte velocity while leaving leukocyte density unchanged.

CONCLUSIONS

These results show that the normal retinal hemodynamic response to increases in perfusion pressure on dynamic exercise includes vasoconstriction that normalizes flow and faster capillary and overall retinal blood transit.

Sodium homeostasis in infants with biliary drainage procedures

We studied biliary excretion of sodium and chloride in 17 infants with external bile drainage through a "biliostomy" and describe four additional children who became ill from sodium depletion following external biliary drainage procedures for biliary tract anomalies. In the 17 infants, the mean +/- SD bile sodium concentration was 122 +/- 15 mEq/L. The mean +/- SD serum sodium concentration was low (132 +/- 7 mEq/L) (normal, 138 to 145 mEq/L). The mean +/- SD bile volume was 388 +/- 317 mL/day at one year following surgery (range, 40 to 1,000 mL/day). In the four children, clinical manifestations of sodium depletion (lethargy, anorexia, dehydration, and malnutrition) necessitated hospital admission. At that time, the serum sodium concentration ranged from 109 to 129 mEq/L, and the simultaneous urinary sodium concentration ranged from 0 to 5 mEq/L. Although dietary sodium was normal, biliary losses exceeded dietary intake, resulting in salt and water depletion despite renal conservation. Children with biliary drainage procedures are at risk for sodium depletion and should be monitored closely and supplemented accordingly until biliostomy closure is performed.

Optic atrophy and the Wyburn-Mason syndrome

A 14-year-old girl developed impaired vision and optic atrophy of the left eye as a manifestation of an orbital and parachiasmal arteriovenous malformation. Despite the lack of a retinal arteriovenous malformation, this condition appears to be a variant of the Wyburn -Mason syndrome, representing a vascular dysgenesis of the orbit and midbrain resulting in focal arteriovenous communications without interposed capillaries.