Elevated sympathetic nerve activity (SNA) coupled with dysregulated b-adrenoceptor (b-AR) signaling is postulated as a major driving force for cardiac dysfunction in patients with type 2 diabetes; however, cardiac SNA has never been assessed directly in diabetes. Our aim was to measure the sympathetic input to and the b-AR responsiveness of the heart in the type 2 diabetic heart. In vivo recording of SNA of the left efferent cardiac sympathetic branch of the stellate ganglion in Zucker diabetic fatty rats revealed an elevated resting cardiac SNA and doubled firing rate compared with nondiabetic rats. Ex vivo, in isolated denervated hearts, the intrinsic heart rate was markedly reduced. Contractile and relaxation responses to b-AR stimulation with dobutamine were compromised in externally paced diabetic hearts, but not in diabetic hearts allowed to regulate their own heart rate. Protein levels of left ventricular b 1 -AR and G s (guanine nucleotide binding protein stimulatory) were reduced, whereas left ventricular and right atrial b 2 -AR and G i (guanine nucleotide binding protein inhibitory regulatory) levels were increased. The elevated resting cardiac SNA in type 2 diabetes, combined with the reduced cardiac b-AR responsiveness, suggests that the maintenance of normal cardiovascular function requires elevated cardiac sympathetic input to compensate for changes in the intrinsic properties of the diabetic heart.

BackgroundSevere obstetric hemorrhage caused by placenta accreta results in significant maternal morbidity and mortality. As a new technology, abdominal aortic balloon occlusion (AABO) is becoming an important treatment for patients with placenta accreta. To evaluate the safety and efficacy of AABO, we conducted a systematic review and meta-analysis of previous studies.MethodsWe used a three-check subset including placenta accreta (placenta previa, percreta, increta, etc.), balloon, and aortic (aortas, aorta, etc.) to form a retrieval formula and searched in MEDLINE, EMBASE, the Cochrane Library, clinicaltrials.gov and Web of Science. All articles regarding placenta previa or placenta accreta and including the use of abdominal aortic balloon occlusion were included in our screening. Two researchers selected articles and extracted data independently. Finally, the Newcastle-Ottawa Quality Assessment Scale was used for quality assessments.ResultsWe retrieved 776 articles and eventually included 11 clinical studies. Meta-analysis showed that AABO significantly reduced the blood loss volume (MD − 1480 ml, 95% CI -1806 to − 1154 ml, P < 0.001) and blood transfusion volume (MD − 1125 ml, 95% CI -1264 to − 987 ml, P < 0.001). Similarly, obvious reductions in the hysterectomy rate (OR 0.30, 95% CI 0.19 to 0.48, P < 0.001), hospitalization duration (MD − 1.35 days, 95% CI -2.40 to − 0.31 days, P = 0.01), and operative time (MD − 29.23 min, 95% CI -46.04 to − 12.42 min, P < 0.001) were observed in the AABO group.ConclusionThe prophylactic use of AABO in patients with placenta accreta is safe and effective.

BackgroundDiastolic dysfunction is a key factor in the development and pathology of cardiac dysfunction in diabetes, however the exact underlying mechanism remains unknown, especially in humans. We aimed to measure contraction, relaxation, expression of calcium-handling proteins and fibrosis in myocardium of diabetic patients with preserved systolic function.MethodsRight atrial appendages from patients with type 2 diabetes mellitus (DM, n = 20) and non-diabetic patients (non-DM, n = 36), all with preserved ejection fraction and undergoing coronary artery bypass grafting (CABG), were collected. From appendages, small cardiac muscles, trabeculae, were isolated to measure basal and β-adrenergic stimulated myocardial function. Expression levels of calcium-handling proteins, sarcoplasmic reticulum Ca2+ ATPase (SERCA2a) and phospholamban (PLB), and of β1-adrenoreceptors were determined in tissue samples by Western blot. Collagen deposition was determined by picro-sirius red staining.ResultsIn trabeculae from diabetic samples, contractile function was preserved, but relaxation was prolonged (Tau: 74 ± 13 ms vs. 93 ± 16 ms, non-DM vs. DM, p = 0.03). The expression of SERCA2a was increased in diabetic myocardial tissue (0.75 ± 0.09 vs. 1.23 ± 0.15, non-DM vs. DM, p = 0.007), whereas its endogenous inhibitor PLB was reduced (2.21 ± 0.45 vs. 0.42 ± 0.11, non-DM vs. DM, p = 0.01). Collagen deposition was increased in diabetic samples. Moreover, trabeculae from diabetic patients were unresponsive to β-adrenergic stimulation, despite no change in β1-adrenoreceptor expression levels.ConclusionsHuman type 2 diabetic atrial myocardium showed increased fibrosis without systolic dysfunction but with impaired relaxation, especially during β-adrenergic challenge. Interestingly, changes in calcium-handling protein expression suggests accelerated active calcium re-uptake, thus improved relaxation, indicating a compensatory calcium-handling mechanism in diabetes in an attempt to maintain diastolic function at rest despite impaired relaxation in the diabetic fibrotic atrial myocardium. Our study addresses important aspects of the underlying mechanisms of diabetes-associated diastolic dysfunction, which is crucial to developing new therapeutic treatments.

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