Prevalence of diabetic retinopathy in women with pregestational diabetes during pregnancy and the postpartum

BACKGROUND: Diabetic retinopathy (DR) may be affected by pregnancy. The majority of prevalence data regarding DR in pregnancy predate the advent of contemporary guidelines for diabetes management during pregnancy. This study reports DR prevalence and associated risk factors in women with pregestational diabetes during pregnancy and the postpartum in Australia. METHODS: A total of 172 pregnant women with type 1 (T1DM) or type 2 diabetes diagnosed pre-pregnancy were prospectively recruited from two obstetrics hospitals in Melbourne (November 2017-March 2020). Eye examinations were scheduled in each trimester, at 3-, 6-, and 12-months postpartum. DR severity was graded from two-field fundus photographs by an independent grader utilising the Airlie House Classification. Sight-threatening DR (STDR) was defined as the presence of diabetic macular oedema or proliferative DR. RESULTS: Overall, 146 (84.9%) women had at least one eye examination during pregnancy. The mean age was 33.8 years (range 19-51), median diabetes duration was 7.0 years (IQR 3.0-17.0), 71 women (48.6%) had T1DM. DR and STDR prevalence during pregnancy per 100 eyes was 24.3 (95% CI 19.7-29.6) and 9.0 (95% CI 6.1-12.9); while prevalence in the postpartum was 22.2 (95% CI 16.5-29.3) and 10.0 (95% CI 5.4-17.9), respectively. T1DM, longer diabetes duration, higher HbA1c in early pregnancy, and pre-existing nephropathy were significant risk factors. CONCLUSIONS: The prevalence of DR in pregnant women was similar to the non-pregnant diabetic population in Australia. One in nine participants had STDR during pregnancy and the postpartum, highlighting the need to optimise DR management guidelines in pregnancy given the significant risk of vision loss

Progression of diabetic retinopathy in women with pregestational diabetes during pregnancy and postpartum

BACKGROUND: Diabetic retinopathy (DR) may worsen during pregnancy, but its course in the postpartum remains poorly understood. Understanding the natural history of DR during and after pregnancy can help determine when sight-threatening DR treatment should be administered. METHODS: A prospective longitudinal cohort study recruited pregnant women with pre-existing type 1 (T1D) or type 2 diabetes from two tertiary Diabetes Antenatal Clinics in Melbourne, Australia. Eye examination results in early pregnancy, late pregnancy, and up to 12-months postpartum were compared to determine DR changes. Two-field fundus photographs and optical coherence tomography scans were used to assess DR severity. RESULTS: Overall, 105 (61.4%) women had at least two eye examinations during the observation period. Mean age was 33.5 years (range 19-51); 54 women (51.4%) had T1D; 63% had HbA1c <7% in early pregnancy. DR progression rate was 23.8% (95% CI 16.4-32.6). Having T1D (RR 4.96, 95% CI 1.83-13.46), pre-existing DR in either eye (RR 4.54, 95% CI 2.39-8.61), and elevated systolic blood pressure (adjusted RR 2.49, 95% CI 1.10-5.66) were associated with increased risk of progression. Sight-threatening progression was observed in 9.5% of women. Among the 19 eyes with progression during pregnancy, 15 eyes remained stable, three eyes progressed, and only one eye regressed in the postpartum. CONCLUSIONS: Nearly 1 in 4 women had DR progression from conception through to 12-months postpartum; almost half of these developing sight-threatening disease. DR progression occurring during pregnancy was found to predominantly remain unchanged, or worsen, after delivery, with very few eyes spontaneously improving postpartum

Optimization of Isolated Perfused/Ventilated Mouse Lung to Study Hypoxic Pulmonary Vasoconstriction

Hypoxic pulmonary vasoconstriction (HPV) is a compensatory physiological mechanism in the lung that optimizes the matching of ventilation to perfusion and thereby maximizes gas exchange. Historically, HPV has been primarily studied in isolated perfused/ventilated lungs; however, the results of these studies have varied greatly due to different experimental conditions and species. Therefore, in the present study, we utilized the mouse isolated perfused/ventilated lung model for investigation of the role of extracellular Ca(2+) and caveolin-1 and endothelial nitric oxide synthase expression on HPV. We also compared HPV using different perfusate solutions: Physiological salt solution (PSS) with albumin, Ficoll, rat blood, fetal bovine serum (FBS), or Dulbecco's Modified Eagle Medium (DMEM). After stabilization of the pulmonary arterial pressure (PAP), hypoxic (1% O(2)) and normoxic (21% O(2)) gases were applied via a ventilator in five-minute intervals to measure HPV. The addition of albumin or Ficoll with PSS did not induce persistent and strong HPV with or without a pretone agent. DMEM with the inclusion of FBS in the perfusate induced strong HPV in the first hypoxic challenge, but the HPV was neither persistent nor repetitive. PSS with rat blood only induced a small increase in HPV amplitude. Persistent and repetitive HPV occurred with PSS with 20% FBS as perfusate. HPV was significantly decreased by the removal of extracellular Ca(2+) along with addition of 1 mM EGTA to chelate residual Ca(2+) and voltage-dependent Ca(2+) channel blocker (nifedipine 1 μM). PAP was also reactive to contractile stimulation by high K(+) depolarization and U46619 (a stable analogue of thromboxane A(2)). In summary, optimal conditions for measuring HPV were established in the isolated perfused/ventilated mouse lung. Using this method, we further confirmed that HPV is dependent on Ca(2+) influx