Impacts of medication adherence and home healthcare on the associations between polypharmacy and the risk of severe hypoglycemia among elderly diabetic patients in Taiwan from 2002 to 2012: A nationwide case-crossover study.

AIM: To assess how medication adherence and home healthcare support influence the role of polypharmacy in induced hypoglycemia events among elderly diabetic patients. METHODS: This case-crossover study retrieved records on diabetic patients >=65 years with severe hypoglycemia from 2002 to 2012 in Taiwan. Case period defined as 1-3 days before severe hypoglycemia was compared with a preceding control period of the same length, with an all-washout period of 30 days. Moreover, the modifiable effects of medication adherence and home healthcare service use were evaluated by stratified analysis. RESULTS: Totally 2,237 patients were identified. Polypharmacy use was associated with the risk of severe hypoglycemia. Patients receiving polypharmacy without home healthcare services (aOR: 1.34; 95 % CI: 1.16-1.54) and those with poor adherence to anti-diabetic medications (aOR: 1.48; 95 % CI: 1.24-1.77) were significantly associated with an elevated risk of severe hypoglycemia. In patients with good adherence, non-home healthcare users being prescribed with polypharmacy had a higher risk of severe hypoglycemia. In the group that received home healthcare services, patients with poor adherence using polypharmacy had a higher risk of severe hypoglycemia. CONCLUSIONS: Good adherence and receiving home healthcare services were associated with a decreased odds of severe hypoglycemic events in elderly diabetic patients, regardless of the fact whether they were prescribed with polypharmacy.

Metformin Treatment Is Associated with a Decreased Risk of Nonproliferative Diabetic Retinopathy in Patients with Type 2 Diabetes Mellitus: A Population-Based Cohort Study.

PURPOSE: To assess the relationship between metformin use and the severity of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM) and to investigate the effect of metformin dosage on reducing the incidence of DR. METHODS: The study population included patients with newly diagnosed T2DM, who were aged ≥20 years and prescribed with antidiabetic drug therapy lasting ≥90 days, as identified using the National Health Insurance Research Database between 2000 and 2012. We matched metformin users and nonusers by a propensity score. Cox proportional hazard regression analyses were used to compute and compare the risk of developing nonproliferative diabetic retinopathy (NPDR) in metformin users and nonusers. RESULTS: Overall, 10,044 T2DM patients were enrolled. Metformin treatment was associated with a lower risk of NPDR (aHR 0.76, 95% CI 0.68-0.87) and sight-threatening diabetic retinopathy (STDR, aHR 0.29, 95% CI 0.19-0.45); however, the reduction in risk was borderline significant for STDR progression among NPDR patients (aHR 0.54, 95% CI 0.28-1.01). Combination therapy of metformin and DPP-4i exhibited a stronger but inverse relationship with NPDR development (aHR 0.32, 95% CI 0.25-0.41), especially at early (<3 months) stages of metformin prescription. These inverse relationships were also evident at different metformin doses and in adapted Diabetes Complications Severity Index scores (aDCSI). Moreover, combination therapy of metformin with sulfonylureas was associated with an increased risk of NPDR. CONCLUSION: Metformin treatment in patients with T2DM was associated with a reduced risk of NPDR, and a potential trend was found for a reduced STDR risk in patients who had previously been diagnosed with NPDR. Combining metformin with DPP-4i seemingly had a significantly beneficial effect against NPDR risk, particularly when aDCSI scores were low, and when metformin was prescribed early after T2DM diagnosis. These results may recommend metformin for early treatment of T2DM.

The Therapeutic Potential of Human Umbilical Mesenchymal Stem Cells From Wharton's Jelly in the Treatment of Rat Peritoneal Dialysis-Induced Fibrosis.

A major complication in continuous, ambulatory peritoneal dialysis in patients with end-stage renal disease who are undergoing long-term peritoneal dialysis (PD) is peritoneal fibrosis, which can result in peritoneal structural changes and functional ultrafiltration failure. Human umbilical mesenchymal stem cells (HUMSCs) in Wharton's jelly possess stem cell properties and are easily obtained and processed. This study focuses on the effects of HUMSCs on peritoneal fibrosis in in vitro and in vivo experiments. After 24-hour treatment with mixture of Dulbecco's modified Eagle's medium and PD solution at a 1:3 ratio, primary human peritoneal mesothelial cells became susceptible to PD-induced cell death. Such cytotoxic effects were prevented by coculturing with primary HUMSCs. In a rat model, intraperitoneal injections of 20 mM methylglyoxal (MGO) in PD solution for 3 weeks (the PD/MGO 3W group) markedly induced abdominal cocoon formation, peritoneal thickening, and collagen accumulation. Immunohistochemical analyses indicated neoangiogenesis and significant increase in the numbers of ED-1- and α-smooth muscle actin (α-SMA)-positive cells in the thickened peritoneum in the PD/MGO 3W group, suggesting that PD/MGO induced an inflammatory response. Furthermore, PD/MGO treatment for 3 weeks caused functional impairments in the peritoneal membrane. However, in comparison with the PD/MGO group, intraperitoneal administration of HUMSCs into the rats significantly ameliorated the PD/MGO-induced abdominal cocoon formation, peritoneal fibrosis, inflammation, neoangiogenesis, and ultrafiltration failure. After 3 weeks of transplantation, surviving HUMSCs were found in the peritoneum in the HUMSC-grafted rats. Thus, xenografts of HUMSCs might provide a potential therapeutic strategy in the prevention of peritoneal fibrosis. Significance: This study demonstrated that direct intraperitoneal transplantation of human umbilical mesenchymal stem cells into the rat effectively prevented peritoneal dialysis/methylglyoxal-induced abdominal cocoon formation, ultrafiltration failure, and peritoneal membrane alterations such as peritoneal thickening, fibrosis, and inflammation. These findings provide a basis for a novel approach for therapeutic benefits in the treatment of encapsulating peritoneal sclerosis.

Computational solution of spike overlapping using data-based subtraction algorithms to resolve synchronous sympathetic nerve discharge.

Sympathetic nerves conveying central commands to regulate visceral functions often display activities in synchronous bursts. To understand how individual fibers fire synchronously, we establish "oligofiber recording techniques" to record "several" nerve fiber activities simultaneously, using in vitro splanchnic sympathetic nerve-thoracic spinal cord preparations of neonatal rats as experimental models. While distinct spike potentials were easily recorded from collagenase-dissociated sympathetic fibers, a problem arising from synchronous nerve discharges is a higher incidence of complex waveforms resulted from spike overlapping. Because commercial softwares do not provide an explicit solution for spike overlapping, a series of custom-made LabVIEW programs incorporated with MATLAB scripts was therefore written for spike sorting. Spikes were represented as data points after waveform feature extraction and automatically grouped by k-means clustering followed by principal component analysis (PCA) to verify their waveform homogeneity. For dissimilar waveforms with exceeding Hotelling's T(2) distances from the cluster centroids, a unique data-based subtraction algorithm (SA) was used to determine if they were the complex waveforms resulted from superimposing a spike pattern close to the cluster centroid with the other signals that could be observed in original recordings. In comparisons with commercial software, higher accuracy was achieved by analyses using our algorithms for the synthetic data that contained synchronous spiking and complex waveforms. Moreover, both T(2)-selected and SA-retrieved spikes were combined as unit activities. Quantitative analyses were performed to evaluate if unit activities truly originated from single fibers. We conclude that applications of our programs can help to resolve synchronous sympathetic nerve discharges (SND).

Glutamatergic activities in neonatal rat spinal cord heterogeneously regulate single-fiber splanchnic nerve discharge.

Kynurenic acid (KYN) is a metabolite of tryptophan and is involved in various neurological disorders. Using whole-bundle nerve recording techniques, we previously observed that applications of KYN to block endogenous ionotropic glutamate receptor activities in neonatal rat spinal cords in vitro cause a reversible fluctuation of splanchnic sympathetic nerve discharge (SND). We hypothesized that the SND fluctuation was due to a heterogeneous single-fiber response. To detail individual fiber activities, we used the so-called 'oligofiber recordings'. Spontaneous single-fiber activities were recorded from the collagenase-dissociated splanchnic nerve fascicles. Applications of KYN increased, decreased or did not change firing rates. The heterogeneous responses in spontaneous spiking activities were confirmed by applications of APV or CNQX, suggesting an effect mediated by endogenous NMDA- or non-NMDA receptor activities. In addition to changes in firing rates, apparent drug-induced changes in firing patterns were also observed in some fiber activities. Using the oligofiber recording techniques, we confirmed a differential role of endogenous ionotropic glutamate receptor activities in regulating sympathetic outflows from the spinal cord of neonatal rats. Fine-tuning of ionotropic glutamate receptor activities in the spinal cord may serve as a simple way for heterogeneous regulation of various sympathetic-targeting tissues.

Basal sympathetic activity generated in neonatal mouse brainstem-spinal cord preparation requires T-type calcium channel subunit 1H.

The T-type calcium channel (T-channel) is a low-voltage-activated channel. Whether T-channels are involved in sympathetic nerve discharge (SND), with subunits α1G and α1H differentially regulating SND genesis, was explored using in vitro brainstem-spinal cord-splanchnic sympathetic nerve preparations of wild-type and genetically modified B6 mice. Applications of 10-80 µm NNC 55-0396 to block T-channels in wild-type mice reduced SND in a concentration-dependent manner. Amounts of SND were measured in units of signal-to-noise ratio for objective comparisons between mouse groups. Comparable amounts of SND were observed in wild-type and α1G(-/-) mice. However, only ∼40% of the amount of SND of that in wild-type or α1G(-/-) mice was observed in α1H(-/-) mice. Whether a diminished excitatory drive originating in the brainstem could explain a low SND in α1H(-/-) mice was evaluated by cervical cord transections. Isolated spinal cord preparations of mice with different genetic backgrounds produced comparable amounts of SND. Excitability of the spinal circuitry was further explored by bath applications of 5 mm glutamate. Glutamate applications produced a prominent SND rise in all mouse groups. The ratios of glutamate-induced SND rise were similar between wild-type and α1H(-/-) mice, but significantly higher in α1G(-/-) mice. Taken together, these results suggest that α1H in mouse brainstem is essential for the genesis of presympathetic drive, whereas α1G in mouse spinal cord is functionally inhibitory for SND genesis. We conclude that α1H and α1G T-channel subunits may differentially regulate mouse SND genesis at different levels of the neuraxis.

Supraspinal contribution to splanchnic sympathetic activity in neonatal mouse and rat brainstem-spinal cord in vitro.

Under optimal in vitro conditions, isolated spinal cords of neonatal Sprague-Dawley (SD) rats spontaneously generate sympathetic nerve discharge (SND). To aid future studies involving genetically modified mice, we established a preparation to assess SND generation within the mouse spinal cord. Brainstem-spinal cord-splanchnic nerve preparations of neonatal 129S6/SvEvTac (129S6) mice, C57BL/6 (B6) mice, Long-Evan (LE) rats, and SD rats were used. The contributions of the brainstem to splanchnic SND (sSND) were not significantly affected by cervical cord transections in LE and SD rats. However, the transections caused approximately a 70% reduction in sSND in both mice species. Power spectral analyses characterized distinct features of sSND oscillations. With intact brainstem-spinal cord, comparable maximal power peaks at approximately 1-2Hz were observed in mouse and rat spectra, although the spectral peak widths were broader in mice. Cervical cord transections reduced the maximal peak powers and the peak widths in mice but not in rats. For comparisons across animal groups, the amounts of sSND were normalized to ambient current noise and expressed in signal/noise units. Similar amounts of normalized sSND were recorded from mice and rats with intact brainstem-spinal cords. However, the level of mouse sSND was reduced following cervical cord transection, whereas rat sSND was not. Our results demonstrate a species related difference in sSND recorded from neonatal rat and mouse spinal cord preparations in vitro. The current experimental model is applicable to evaluate the SND strength in neonatal rodents of various genetic backgrounds.