Oral contraceptive progestins and angiotensin-dependent control of the renal circulation in humans

Oral contraceptive (OC) use is associated with increased intra-renal renin-angiotensin-aldosterone system (RAA System) activity and risk of nephropathy, though the contribution of progestins contained in the OC in the regulation of angiotensin-dependent control of the renal circulation has not been elucidated. Eighteen OC users (8 non-diabetic, 10 Type 1 diabetic) were studied in high salt balance, a state of maximal RAA System suppression. Progestational and androgenic activity of the progestin in each OC was standardized to that of the reference progestin norethindrone. Renal plasma flow (RPF) was measured by paraaminohippurate clearance at baseline and in response to angiotensin converting enzyme (ACE)-inhibition. There was a positive correlation between OC progestational activity and the RPF response to ACE-inhibition (r=0.52, p=0.03). Similar results were noted with OC androgenic activity (r=0.54, p=0.02). On subgroup analysis, only non-diabetic subjects showed an association between progestational activity and angiotensin-dependent control of the renal circulation (r=0.71, p=0.05 non-diabetic; r=0.14, p=0.7 diabetic; p=0.07 between groups). Similar results were noted with respect to androgenic activity (r=0.88, p=0.005 non-diabetic; r=−0.33, p=0.3 diabetic; p=0.002 between groups). Our results suggest that the OC progestin component is a significant influence on the degree of angiotensin-dependent control of the renal circulation, though these findings may not apply to women with diabetes

Cerebral blood flow response to flavanol-rich cocoa in healthy elderly humans

Farzaneh A Sorond1,2, Lewis A Lipsitz2,4, Norman K Hollenberg3,5, Naomi DL Fisher31Department of Neurology, Stroke Division; 2Institute for Aging Research, Hebrew SeniorLife, Boston, MA; 3Department of Medicine, Endocrine-Hypertension Division; 4Department of Medicine, Gerontology, Beth Israel Deaconess Medical Center, Boston, MA, USA; 5Department of Radiology, Brigham and Women’s Hospital, Boston, MABackground and Purpose: Cerebral ischemia is a common, morbid condition accompanied by cognitive decline. Recent reports on the vascular health benefits of flavanol-containing foods signify a promising approach to the treatment of cerebral ischemia. Our study was designed to investigate the effects of flavanol-rich cocoa (FRC) consumption on cerebral blood flow in older healthy volunteers.Methods: We used transcranial Doppler (TCD) ultrasound to measure mean blood flow velocity (MFV) in the middle cerebral artery (MCA) in thirty-four healthy elderly volunteers (72 ± 6 years) in response to the regular intake of FRC or flavanol-poor cocoa (FPC).Results: In response to two weeks of FRC intake, MFV increased by 8% ± 4% at one week (p = 0.01) and 10% ± 4% (p = 0.04) at two weeks. In response to one week of cocoa, significantly more subjects in the FRC as compared with the FPC group had an increase in their MFV (p < 0.05).Conclusions: In summary, we show that dietary intake of FRC is associated with a significant increase in cerebral blood flow velocity in the MCA as measured by TCD. Our data suggest a promising role for regular cocoa flavanol’s consumption in the treatment of cerebrovascular ischemic syndromes, including dementias and stroke.Keywords: cerebral blood flow, flavanol, cocoa, transcranial Doppler ultrasoun

ACE and non-ACE pathways in the renal vascular response to RAS interruption in type 1 diabetes mellitus

ACE and non-ACE pathways in the renal vascular response to RAS interruption in type 1 diabetes mellitus.BackgroundThe enormous contribution of renin-angiotensin system (RAS) interruption with ACE (angiotensin-converting enzyme) inhibitors and angiotensin II receptor blockers (ARB) in the treatment of diabetic nephropathy has led to interest in the factors involved in angiotensin II (Ang II) generation. In normal subjects, RAS interruption using an ARB produced a 50% greater renal plasma flow (RPF) rise than with an ACE inhibitor, suggesting a substantial contribution of non-ACE pathways. Moreover, immunohistochemistry studies in kidneys of overtly proteinuric diabetic subjects showed up-regulation of chymase, an alternative Ang II-generating enzyme. Our aim was to determine the degree to which the non-ACE pathways contribute to RAS activation in type 1 diabetes mellitus (DM).MethodsType 1DM patients (N = 37, 14 M/23 F; age 31 ± 2 years; DM duration 16 ± 1.7 years; HbA1c 7.7.0 ± 0.3%) were studied on a high-salt diet. They received captopril 25mg po one day and candesartan 16mg po the next day. RPF and glomerular filtration rate (GFR) were measured before and up to 4 hours after drug administration.ResultsBoth captopril and candesartan induced a significant rise in RPF (baseline vs. peak <0.0001 for both), and the rise was concordant for the 2 drugs (r = 0.77,P < 0.001). However, the RPF responses were not significantly different between the 2 drugs (captopril 72 ± 11mL/min/1.73m2, candesartan 75 ± 12,P = 0.841).ConclusionIn predominantly normoalbuminuric, normotensive type 1 DM, activation of the intrarenal RAS reflects a mechanism involving primarily the classic ACE pathway

Serum Calcium to Phosphorous (Ca/P) Ratio is a simple, inexpensive, and accurate tool in the diagnosis of primary hyperparathyroidism

Primary hyperparathyroidism (PHPT) diagnosis is challenging and is based on serum calcium (Ca) and parathyroid hormone (PTH). Because serum Ca and phosphorous (P) are inversely related in PHPT, we investigated the diagnostic value of the serum Ca/P ratio in the diagnosis of PHPT. We report a single-center, case-controlled, retrospective study including 97 patients with documented PHPT and compared them with those of 96 controls (C). The main outcome measures were: serum PTH, 25-OH vitamin D, Ca, P, albumin, and creatinine. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the serum Ca/P ratio were calculated. The results were verified using an independent, anonymous set of data extracted from a laboratory database containing over 900 million entries. A total of 35 (36.1%) PHPT patients had normocalcemic PHPT (NCHPT). Ca and PTH were significantly higher in PHPT than in C (p < 0.0001). P was significantly lower in PHPT than in C (p < 0.0001). The Ca/P ratio was significantly higher in PHPT than in C (p < 0.0001). Receiver-operating characteristic (ROC) curves analyses identified a cutoff of 2.71 (3.5 if Ca and P are expressed in mg/dL) for Ca/P ratio with a sensitivity and specificity of 86% and 87%, respectively (p < 0.0001), confirmed by the independent, big data approach. In conclusion, Ca/P is a valuable tool for the diagnosis of PHPT and is of superior value compared to serum Ca alone, especially in NCPHT. Because Ca/P is simple, inexpensive, and easily accessible worldwide, this ratio is useful for PHPT diagnosis, especially in laboratory/medical settings relying on limited resources, such as low-income countries. © 2017 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research

Funci\uf3n renal en el paciente con hipertensi\uf3n

El ri\uf1\uf3n es tanto una causa de hipertensi\uf3n como un \uf3rgano blanco mayor de da\uf1o en pacientes hipertensos. En este art\uedculo se insiste in\ue1s en el diagn\uf3stico de la enfermedad renal como causa de hipertensi\uf3n y el tratamiento de complicaciones seleccionadas de la hipertensi\uf3n que afectan el ri\uf1\uf3n