Mutational and biophysical analyses reveal a TFIIIC binding region in the TFIIF-related Rpc53 subunit of RNA polymerase III.

The TFIIF-like Rpc53/Rpc37 heterodimer of RNA polymerase (pol) III is involved in various stages of transcription. The C-terminal region of Rpc53 dimerizes with Rpc37 to anchor on the lobe domain of the pol III cleft. However, structural and functional features of the Rpc53 N-terminal region had not been characterized previously. Here, we conducted site-directed alanine replacement mutagenesis on the Rpc53 N-terminus, generating yeast strains that exhibited a cold-sensitive growth defect and severely compromised pol III transcriptional activity. Circular dichroism and NMR spectroscopy revealed a highly disordered 57-amino acid polypeptide in the Rpc53 N-terminus. This polypeptide is a versatile protein-binding module displaying nanomolar-level binding affinities for Rpc37 and the Tfc4 subunit of the transcription initiation factor TFIIIC. Accordingly, we denote this Rpc53 N-terminus polypeptide as the TFIIIC-binding region or CBR. Alanine replacements in the CBR significantly reduced its binding affinity for Tfc4, highlighting its functional importance to cell growth and transcription in vitro. Our study reveals the functional basis for Rpc53's CBR in assembly of the pol III transcription initiation complex.

Site-directed biochemical analyses reveal that the switchable C-terminus of Rpc31 contributes to RNA polymerase III transcription initiation.

Rpc31 is a subunit in the TFIIE-related Rpc82/34/31 heterotrimeric subcomplex of Saccharomyces cerevisiae RNA polymerase III (pol III). Structural analyses of pol III have indicated that the N-terminal region of Rpc31 anchors on Rpc82 and further interacts with the polymerase core and stalk subcomplex. However, structural and functional information for the C-terminal region of Rpc31 is sparse. We conducted a mutational analysis on Rpc31, which uncovered a functional peptide adjacent to the highly conserved Asp-Glu-rich acidic C-terminus. This C-terminal peptide region, termed 'pre-acidic', is important for optimal cell growth, tRNA synthesis, and stable association of Rpc31 in the pre-initiation complex (PIC). Our site-directed photo-cross-linking to map protein interactions within the PIC reveal that this pre-acidic region specifically targets Rpc34 during transcription initiation, but also interacts with the DNA entry surface in free pol III. Thus, we have uncovered a switchable Rpc31 C-terminal region that functions in an initiation-specific protein interaction for pol III transcription.

Sporadic zonular cataract found by scleral penetration.

PURPOSE: To present a case of bilateral zonular cataract without visual deterioration. OBSERVATION: A 41-year-old Taiwanese Han male presented with severe left ocular pain after being hit by iron filings while working. The iron dust was removed in a local hospital but due to a scleral laceration diagnosis he was referred to our hospital for further management. On examination, best-corrected visual acuity (BCVA) of 20/25 in the right eye and 20/200 in the left eye were obtained, while the before BCVA was 20/25 in the both eyes. The slit-lamp biomicroscopy demonstrated bilateral zonular cataract and left scleral full-thickness laceration with vitreous prolapse. The scleral suture procedure was then performed smoothly and the patient discharged three days later with BCVA in the left eye recovered to 20/30. CONCLUSION AND IMPORTANCE: The bilateral zonular cataract without associated systemic disorder is a rare form, which may be found incidentally with no visual symptoms.

PRAP1 is a novel lipid-binding protein that promotes lipid absorption by facilitating MTTP-mediated lipid transport.

Microsomal triglyceride transfer protein (MTTP) is an endoplasmic reticulum resident protein that is essential for the assembly and secretion of triglyceride (TG)-rich, apoB-containing lipoproteins. Although the function and structure of mammalian MTTP have been extensively studied, how exactly MTTP transfers lipids to lipid acceptors and whether there are other biomolecules involved in MTTP-mediated lipid transport remain elusive. Here we identify a role in this process for the poorly characterized protein PRAP1. We report that PRAP1 and MTTP are partially colocalized in the endoplasmic reticulum. We observe that PRAP1 directly binds to TG and facilitates MTTP-mediated lipid transfer. A single amino acid mutation at position 85 (E85V) impairs PRAP1's ability to form a ternary complex with TG and MTTP, as well as impairs its ability to facilitate MTTP-mediated apoB-containing lipoprotein assembly and secretion, suggesting that the ternary complex formation is required for PRAP1 to facilitate MTTP-mediated lipid transport. PRAP1 is detectable in chylomicron/VLDL-rich plasma fractions, suggesting that MTTP recognizes PRAP1-bound TG as a cargo and transfers TG along with PRAP1 to lipid acceptors. Both PRAP1-deficient and E85V knock-in mutant mice fed a chow diet manifested an increase in the length of their small intestines, likely to compensate for challenges in absorbing lipid. Interestingly, both genetically modified mice gained significantly less body weight and fat mass when on high-fat diets compared with littermate controls and were prevented from hepatosteatosis. Together, this study provides evidence that PRAP1 plays an important role in MTTP-mediated lipid transport and lipid absorption.

Accelerated corneal endothelial cell loss in two patients with granulomatosis with polyangiitis following phacoemulsification.

BACKGROUND: Generally, the loss rate of human endothelial cells (HCEC) in routine cataract surgery is 8.5%. When the corneal endothelial cells density (ECD) drops, the HCEC may decompensate to keep cornea dehydration which leads to corneal edema. Granulomatosis with polyangiitis (GPA) is an uncommon autoimmune disease involving multiple organs including eyes such as conjunctivitis, scleritis, uveitis, and corneal ulcer. In this study, we report two cases of GPA whose corneal ECD decreased significantly after phacoemulsification cataract surgery. CASE PRESENTATION: In the first case of 69-year-old male with GPA, the ECD dropped 39.6% (OD) four months after phacoemulsification and 38.1% (OS) six months postoperatively respectively. At the final follow-up, the residual ECD was only 55% in the right eye in the 49th month, and 56% remained in the left eye in the 39th month. In the second case of 54-year old female, left ECD dropped 63.9% at the 4th month after surgery and 69.6% ECD remained at the 15th month postoperatively while similar ECD of right eye before and after left eye surgery. CONCLUSION: Extensive preoperative ophthalmic evaluation and meticulous postoperative inflammation control should be applied to prevent severe loss of HCEC in GPA patients.

Corneal Sensitivity and Tear Function in Recurrent Corneal Erosion Syndrome.

Purpose: To determine the association of corneal sensitivity and tear functions on the prognosis of eyes after posttraumatic recurrent corneal erosion syndrome (RCES). Methods: Patients were enrolled retrospectively and had unilateral RCES and a history of ocular surface trauma. A corneal sensitivity test and tear function test (tear break-up time and Schirmer test) were performed at three time points (month 1 to month 3, month 3 to month 6, and month 6 to month 12). Depending on the number of recurrences during the follow-up, patients were divided into group A (n > 2) or group B (n = 2). A comparison between diseased and normal fellow eyes in each patient was performed. Results: A total of 31 patients were enrolled and divided into group A (n = 14) and group B (n = 17). The mean age was 40.3 ± 12.2 years, whereas the mean follow-up was 28.0 ± 3.6 months. During the study period, corneal sensitivity, tear break-up time, and the Schirmer test results were all lower in diseased eyes than in normal fellow eyes in both groups. Compared to the first time point, recovery of corneal sensitivity and the Schirmer test values were observed in diseased eyes in group B at the second and third time points. Conclusions: Poor corneal sensitivity and tear function are associated with posttraumatic RCES. Recovery of corneal sensitivity and tear function may be associated with a reduction of recurrence in eyes with posttraumatic RCES.

Perioperative topical ascorbic acid for the prevention of phacoemulsification-related corneal endothelial damage: Two case reports and review of literature.

BACKGROUND: The current case report describes successful phacoemulsification with the aid of perioperative topical ascorbic acid (AA) in two patients with corneal endothelial disorders to prevent postoperative corneal endothelial decompensation. CASE SUMMARY: Two eyes of two patients underwent phacoemulsification with pre-existing corneal endothelial disorders including Fuchs corneal endothelial dystrophy (Patient 1) and endotheliitis (Patient 2). Topical AA was applied to both patients at least one month before and after with a frequency of four times per day. After the surgery, both eyes improved best-corrected visual acuity (BCVA) and there was limited human corneal endothelial cell loss without signs of corneal endothelial decompensation, such as deteriorated BCVA or persistent corneal edema during the follow-up of at least two years. CONCLUSION: Perioperative administration of topical AA may be an alternative therapy to the triple procedure in patients expecting to undergo cataract surgery.

Deriving a sub-nanomolar affinity peptide from TAP to enable smFRET analysis of RNA polymerase II complexes.

Our capability to visualize protein complexes such as RNA polymerase II (pol II) by single-molecule imaging techniques has largely been hampered by the absence of a simple bio-orthogonal approach for selective labeling with a fluorescent probe. Here, we modify the existing calmodulin-binding peptide (CBP) in the widely used Tandem Affinity Purification (TAP) tag to endow it with a high affinity for calmodulin (CaM) and use dye-CaM to conduct site-specific labeling of pol II. To demonstrate the single molecule applicability of this approach, we labeled the C-terminus of the Rpb9 subunit of pol II with donor-CaM and a site in TFIIF with an acceptor to generate a FRET (fluorescence resonance energy transfer) pair in the pol II-TFIIF complex. We then used total internal reflection fluorescence microscopy (TIRF) with alternating excitation to measure the single molecule FRET (smFRET) efficiency between these two sites in pol II-TFIIF. We found they exhibited a proximity consistent with that observed in the transcription pre-initiation complex by cryo-electron microscopy (cryo-EM). We further compared our non-covalent labeling approach with an enzyme-enabled covalent labeling method. The virtually indistinguishable results validate our smFRET approach and show that the observed proximity between the two sites represents a hallmark of the pol II-TFIIF complex. Taken together, we present a simple and versatile bio-orthogonal method derived from TAP to enable selective labeling of a protein complex. This method is suitable for analyzing dynamic relationships among proteins involved in transcription and it can be readily extended to many other biological processes.

Changes in corneal endothelial density following scleral buckling surgery for rhegmatogenous retinal detachment: a retrospective cross-sectional study.

BACKGROUND: To investigate the effect of scleral buckling (SB) on the morphology and density of human corneal endothelial cells (HCEC). METHODS: In this retrospective cross-sectional study, 26 patients who had undergone SB due to rhegmatogenous retinal detachment were enrolled, in which 15 patients received encircling while the other 11 segment types of SB. The postoperative status of affected eye, preoperative status of affected eye, and the contralateral healthy eye was served as the study, control and contralateral groups. The images of the corneal endothelium was obtained by specular microscopy at least three months postoperatively and analyzed. RESULTS: Postoperative best-corrected visual acuity of the study group was worse than that of another two groups (P < 0.001) while intraocular pressure and biometry data were similar. The mean cell area and standard deviation were larger in the study group while the coefficient of variation revealed no difference. The study group manifested a lower endothelial cell density than that of the control and the contralateral (P < 0.001) groups. Concerning the percentage of hexagonal cells, the study group showed a lower hexagonality than the control group (P = 0.04). No difference of the endothelial morphology was found between the segmental subgroup and the encircling subgroup, nor was a significant difference about endothelial cell loss found in the study group with different measurement interval. CONCLUSIONS: Scleral buckling leads to short-term decreased endothelial cell density and hexagonality, while the rest of morphological features remain unchanged. Moreover, both the segmental and encircling SB procedures yield similar postoperative HCEC status.

Functions of the TFIIE-Related Tandem Winged-Helix Domain of Rpc34 in RNA Polymerase III Initiation and Elongation.

Rpc34 is a subunit of the Rpc82/34/31 subcomplex residing on the DNA-binding cleft of RNA polymerase (Pol) III. Rpc34 contains a structurally flexible N-terminal tandem winged-helix (tWH) domain related to the TFIIE transcription factor. While the second WH (WH2) fold of the tWH domain is known to function in DNA melting activity during transcription initiation, the functional role of the WH1 fold is unknown. In this study, we generated a series of new Rpc34 tWH mutants conferring a cold-sensitive growth phenotype. We found that the tWH mutations severely compromised in vitro transcription activity due to destabilization of the preinitiation complex (PIC). Site-specific protein photo-cross-linking analysis indicated that the tWH domain persistently interacts with protein subunits of the Pol III cleft in the PIC and the ternary elongation complex (TEC). Furthermore, purified Pol III proteins with tWH mutations also showed reduced efficiency in RNA elongation. Our study results suggest that the tWH domain is an important protein module above the Pol III cleft that integrates protein and nucleic acid interactions for initiation and elongation.

The TFIIE-related Rpc82 subunit of RNA polymerase III interacts with the TFIIB-related transcription factor Brf1 and the polymerase cleft for transcription initiation.

Rpc82 is a TFIIE-related subunit of the eukaryotic RNA polymerase III (pol III) complex. Rpc82 contains four winged-helix (WH) domains and a C-terminal coiled-coil domain. Structural resolution of the pol III complex indicated that Rpc82 anchors on the clamp domain of the pol III cleft to interact with the duplex DNA downstream of the transcription bubble. However, whether Rpc82 interacts with a transcription factor is still not known. Here, we report that a structurally disordered insertion in the third WH domain of Rpc82 is important for cell growth and in vitro transcription activity. Site-specific photo-crosslinking analysis indicated that the WH3 insertion interacts with the TFIIB-related transcription factor Brf1 within the pre-initiation complex (PIC). Moreover, crosslinking and hydroxyl radical probing analyses revealed Rpc82 interactions with the upstream DNA and the protrusion and wall domains of the pol III cleft. Our genetic and biochemical analyses thus provide new molecular insights into the function of Rpc82 in pol III transcription.

Asymptomatic Meibomian Gland Dysfunction and Cardiovascular Disease Risk Factors in a Middle-Aged Population in Taiwan - A Cross-sectional Analysis.

Managing cardiovascular disease (CVD) risk factors is the key to prevent CVD. This study aimed to prevent CVD by introducing asymptomatic meibomian gland dysfunction (MGD), a condition associated with various CVD risk factors, as an early indicator for CVD in middle-aged population. Participants with and without asymptomatic MGD underwent standardized questionnaires, physical examinations, and laboratory investigations. One ophthalmologist completed the identification and grading of MGD by using slit-lamp biomicroscopy examination on the eyelid margins, meibomian gland orifices, and meibomian gland secretions. Standardized techniques were used to measure the CVD risk factor parameters. After adjusted for age and gender, CVD risk factors including elevated uric acid (P = 0.01), total cholesterol (Total-C, P < 0.001), low-density lipoprotein cholesterol (LDL-C, P < 0.001), fasting triglyceride (Fasting TG, P < 0.001), decreased high-density lipoprotein cholesterol (HDL-C, P = 0.04), and presence of hepatic steatosis (P = 0.008) were significantly associated with asymptomatic MGD. Stepwise logistic regression analysis revealed that LDL-C (OR: 1.03, 95% CI: 1.02-1.04) and Fasting TG (OR: 1.01; 95% CI: 1.00-1.01) levels were risk factors for having asymptomatic MGD (P < 0.001). Together, the results suggest that asymptomatic MGD may serve as an indicator for CVD.

Dual Antiplatelet Therapy and Clinical Outcomes after Coronary Drug-Eluting Stent Implantation in Patients on Hemodialysis.

BACKGROUND AND OBJECTIVES: We aimed to investigate the benefits and risks of dual antiplatelet therapy (DAPT) after coronary drug-eluting stent (DES) implantation in patients undergoing hemodialysis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A nested case-control analysis of patients on hemodialysis after receipt of DES and DAPT treatment was conducted using data from Taiwan's National Health Insurance Research Database for the period 2007-2011. Cases of myocardial infarction or death within 1 year after DES implantation were matched one-to-one with control patients. Odds ratios were calculated to compare DAPT continuation with discontinuation. Additionally, a propensity score-adjusted 6-month landmark cohort analysis was also conducted to evaluate the long-term benefits and risks of prolonged (>6 months) compared with ≤6 months of DAPT use. The primary outcomes were death and myocardial infarction. The secondary outcomes were ischemic stroke, revascularization, and major bleeding. RESULTS: In the nested case-control analysis, patients who continued DAPT had a lower rate of death or myocardial infarction within 1 year after receipt of a DES (adjusted odds ratio, 0.54; 95% confidence interval, 0.36 to 0.81; P=0.003), whereas this association became statistically nonsignificant when compared with patients who discontinued DAPT for the period between 6 and 12 months after receipt of a DES (adjusted odds ratio, 1.51; 95% confidence interval, 0.75 to 3.04). In the propensity score-adjusted cohort analysis, >6 months of DAPT use was not associated with different primary or secondary outcomes than shorter-term use. CONCLUSIONS: Our findings support that the clinical effectiveness of extended DAPT in a hemodialysis population may be tempered after 6 months post-DES implantation.

Dipeptidyl peptidase-4 inhibitors and cardiovascular risks in patients with pre-existing heart failure.

BACKGROUND: Although recent clinical trials raised concerns about the risk for heart failure (HF) in dipeptidyl peptidase-4 (DPP-4) inhibitor use, data on the cardiovascular risks in the patients with pre-existing HF are still lacking. METHODS: We used Taiwan's National Health Insurance Research Database to identify 196 986 patients diagnosed with type 2 diabetes mellitus (T2DM) who had previous history of HF between 2009 and 2013. This population included 30 204 DPP-4 inhibitor users and 166 782 propensity score-matched DPP-4 inhibitor non-users. The outcomes of interest were all-cause mortality, combination of myocardial infarction (MI) and ischaemic stroke, and hospitalisation for HF. RESULTS: The incidence in DPP-4 users compared with non-users was 67.02 vs 102.85 per 1000 person-years for all-cause mortality, 37.89 vs 47.54 per 1000 person-years for the combination of MI and ischaemic stroke, 12.70 vs 16.18 per 1000 person-years for MI and 26.37 vs 32.46 per 1000 person-years for ischaemic stroke. The risk of all-cause mortality was lower in DPP-4 inhibitor users (HR 0.67, 95% CI 0.64 to 0.70), combination of MI and stroke (HR 0.81, 95% CI 0.76 to 0.87), MI (HR 0.80, 95% CI 0.71 to 0.89) and ischaemic stroke (HR 0.83, 95% CI 0.76 to 0.89) than in non-users. Notably, the risk of hospitalisation for HF did not differ significantly between groups. The results were similar after accounting for death as a competing risk. CONCLUSIONS: In this nationwide T2DM cohort, the risks of mortality and the combination of MI and ischaemic stroke were lower for patients receiving DPP-4 inhibitors than for those who did not receive such treatment. DPP-4 inhibitor use was not associated with a higher risk of hospitalisation for HF even in patients with pre-existing HF.

Severity of dry eye syndrome is related to anti-dsDNA autoantibody in systemic lupus erythematosus patients without secondary Sjogren syndrome: A cross-sectional analysis.

There are as many as one-third of the systemic lupus erythematosus (SLE) patients who suffer from dry eye syndrome. To this date, dry eye syndrome in SLE patients is believed to be caused by secondary Sjogren syndrome (sSS). However, there is increasing evidence for possible independency of dry eye syndrome and sSS in patients suffering from autoimmune diseases. The purpose of this retrospective observational case series was to identify SLE patients without sSS who had dry eye syndrome, examine the correlation of different autoantibodies and dry eye severity, and determine the cause of dry eye in these patients.We included 49 consecutive SLE patients with dry eye who visited our dry eye clinic. In order to rule out sSS, these patients were all negative for anti-Sjogren's-syndrome-related antigen A and B (anti-SSA/SSB) and had no oral symptoms. Each patient's lupus activity was determined by serological tests including antidouble-stranded DNA antibody (anti-dsDNA), complement levels (C3, C4), erythrocyte sedimentation rate (ESR), and antinuclear antibody (ANA). Severity of dry eye syndrome was determined by corneal sensation (KSen), superficial punctuate keratopathy (SPK), Schirmer-I test (Schirmer), and tear film break-up time (TBUT). The autoantibodies and the dry eye parameters in each group were tested using the χ test or the Mann-Whitney U test for normally distributed or skewed data, respectively.The anti-dsDNA showed significant correlations with KSen (P < 0.001), SPK (P < 0.001), and Schirmer (P = 0.042) but not TBUT. The C3 showed significant correlations with KSen (P < 0.001), SPK (P < 0.001), and Schirmer (P = 0.014) but not TBUT. No correlations of dry eye parameters were observed between C4, ESR, and ANA.The major finding of this study was that the severity of dry eye syndrome in SLE patients without sSS was strongly correlated with anti-dsDNA and C3 but not with C4, ESR, and ANA.

Comparative effectiveness of angiotensin-converting-enzyme inhibitors and angiotensin II receptor blockers in patients with type 2 diabetes and retinopathy.

BACKGROUND: Angiotensin-converting-enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) are effective treatments for diabetic retinopathy, but randomized trials and meta-analyses comparing their effects on macrovascular complications have yielded conflicting results. We compared the effectiveness of these drugs in patients with pre-existing diabetic retinopathy in a large population-based cohort. METHODS: We conducted a propensity score-matched cohort study using Taiwan's National Health Insurance Research Database. We included adult patients prescribed an ACE inhibitor or ARB within 90 days after diagnosis of diabetic retinopathy between 2000 and 2010. Primary outcomes were all-cause death and major adverse cardiovascular events (myocardial infarction, ischemic stroke or cardiovascular death). Secondary outcomes were hospital admissions with acute kidney injury or hyperkalemia. RESULTS: We identified 11 246 patients receiving ACE inhibitors and 15 173 receiving ARBs, of whom 9769 patients in each group were matched successfully by propensity scores. In the intention-to-treat analyses, ARBs were similar to ACE inhibitors in risk of all-cause death (hazard ratio [HR] 0.94, 95% confidence interval [CI] 0.87-1.01) and major adverse cardiovascular events (HR 0.95, 95% CI 0.87-1.04), including myocardial infarction (HR 1.03, 95% CI 0.88-1.20), ischemic stroke (HR 0.94, 95% CI 0.85-1.04) and cardiovascular death (HR 1.01, 95% CI 0.88-1.16). They also did not differ from ACE inhibitors in risk of hospital admission with acute kidney injury (HR 1.01, 95% CI 0.91-1.13) and hospital admission with hyperkalemia (HR 1.01, 95% CI 0.86-1.18). Results were similar in as-treated analyses. INTERPRETATION: Our study showed that ACE inhibitors were similar to ARBs in risk of all-cause death, major adverse cardiovascular events and adverse effects among patients with pre-existing diabetic retinopathy.

Ty1 Integrase Interacts with RNA Polymerase III-specific Subcomplexes to Promote Insertion of Ty1 Elements Upstream of Polymerase (Pol) III-transcribed Genes.

Retrotransposons are eukaryotic mobile genetic elements that transpose by reverse transcription of an RNA intermediate and are derived from retroviruses. The Ty1 retrotransposon of Saccharomyces cerevisiae belongs to the Ty1/Copia superfamily, which is present in every eukaryotic genome. Insertion of Ty1 elements into the S. cerevisiae genome, which occurs upstream of genes transcribed by RNA Pol III, requires the Ty1 element-encoded integrase (IN) protein. Here, we report that Ty1-IN interacts in vivo and in vitro with RNA Pol III-specific subunits to mediate insertion of Ty1 elements upstream of Pol III-transcribed genes. Purification of Ty1-IN from yeast cells followed by mass spectrometry (MS) analysis identified an enrichment of peptides corresponding to the Rpc82/34/31 and Rpc53/37 Pol III-specific subcomplexes. GFP-Trap purification of multiple GFP-tagged RNA Pol III subunits from yeast extracts revealed that the majority of Pol III subunits co-purify with Ty1-IN but not two other complexes required for Pol III transcription, transcription initiation factors (TF) IIIB and IIIC. In vitro binding studies with bacterially purified RNA Pol III proteins demonstrate that Rpc31, Rpc34, and Rpc53 interact directly with Ty1-IN. Deletion of the N-terminal 280 amino acids of Rpc53 abrogates insertion of Ty1 elements upstream of the hot spot SUF16 tRNA locus and abolishes the interaction of Ty1-IN with Rpc37. The Rpc53/37 complex therefore has an important role in targeting Ty1-IN to insert Ty1 elements upstream of Pol III-transcribed genes.

Cardiovascular Outcomes of Dipeptidyl Peptidase-4 Inhibitors in Elderly Patients With Type 2 Diabetes: A Nationwide Study.

OBJECTIVES: The elderly (aged ≥65 years) population with type 2 diabetes (T2D) is growing substantially, but evidence for associations between the use of dipeptidyl peptidase-4 inhibitors (DPP-4is), novel incretin-based antidiabetic drugs, and clinical hard endpoints in this group remains inconclusive. We aimed to assess the safety and cardiovascular effects of DPP-4i use in a nationally representative sample of elderly adults with T2D. DESIGN, SETTING, AND PARTICIPANTS: We conducted a nationwide, observational, propensity score-matched study using Taiwan's National Health Insurance Research Database. Of a total of 414,213 patients aged ≥65 years with T2D, 58,485 patients receiving initial DPP-4i prescriptions between March 1, 2009, and June 31, 2013, were included. Each DPP-4i user was matched with a nonuser control using propensity scores. The endpoints were all-cause mortality and major adverse cardiovascular events (MACEs), including ischemic stroke and myocardial infarction. Potential adverse effects of hospitalization for heart failure and hypoglycemia were also evaluated. RESULTS: Compared with the matched control cohort, the risks of all-cause mortality (hazard ratio [HR] 0.54, 95% confidence interval [CI] 0.52-0.56), MACEs (HR 0.79, 95% CI 0.75-0.83), myocardial infarction (HR 0.79, 95% CI 0.72-0.87), and ischemic stroke (HR 0.79, 95% CI 0.75-0.84) were lower in the DPP-4i cohort. DPP-4i use did not affect the risks of hospitalization for heart failure and hypoglycemia. Stratified analyses produced consistent results across age, sex, and comorbidity subgroups. CONCLUSIONS: Prescription of DPP-4is was associated with reduced risks of all-cause mortality and MACEs in patients aged ≥65 years with T2D.

Angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers and the risk of major adverse cardiac events in patients with diabetes and prior stroke: a nationwide study.

OBJECTIVE: Renin-angiotensin-aldosterone system blockers are the preferred antihypertensive medications in patients with diabetes and prior stroke. This study aimed to compare the effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) in terms of major adverse cardiac events (MACEs) in patients with diabetes who survived ischemic stroke. METHODS: We conducted an observational, nationwide, propensity score-matched cohort study using Taiwan's National Health Insurance Research Database. Patients aged at least 20 years with type 2 diabetes who initiated ACEI (n = 15,959) or ARB (n = 23,929) use within 90 days after discharge for first ischemic stroke between January 2000 and December 2011 were allocated to ACEI and ARB groups, respectively. The primary outcomes were MACEs (myocardial infarction, ischemic stroke, and cardiovascular mortality). The secondary outcomes were hospitalization for acute kidney injury and hyperkalemia. Intention-to-treat and as-treated models were used. RESULTS: Intention-to-treat analysis showed no significant difference between the ACEI and ARB groups in the outcomes of MACEs [hazard ratio (HR), 0.99; 95% confidence interval (CI), 0.95-1.04], including ischemic stroke (HR, 1.01; 95% CI, 0.97-1.06), myocardial infarction (HR, 1.06; 95% CI, 0.95-1.18), and cardiovascular mortality (HR, 0.98; 95% CI, 0.91-1.06). As-treated analysis produced similar results. Additionally, the groups showed no difference in the risk of hospitalization for acute kidney injury or hyperkalemia. CONCLUSION: Our study supports the hypothesis that the risks of MACEs and two additional secondary outcomes in patients with diabetes who survived ischemic stroke did not differ according to ACEI versus ARB use.