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1.
AIDS Care ; 35(10): 1542-1554, 2023 10.
Article in English | MEDLINE | ID: mdl-36912678

ABSTRACT

With advances in the treatment of HIV, people living with HIV (PLWH) are now expected to have a near-normal life expectancy, but challenges remain in the form of substantially poorer health-related quality of life (HRQoL) than the general population. Being overweight or obese may pose an additional burden in PLWH, but few studies have evaluated the relationship between body mass index (BMI) and HRQoL in PLWH. This study aimed to evaluate and describe the association between HRQoL and BMI among PLWH in the US. Data were obtained from the 2018 and 2019 US National Health and Wellness Survey, an online, self-reported, general population survey. Analyses included 575 PLWH who self-reported a physician diagnosis and prescription use for the treatment of HIV, as well as 1725 propensity score matched non-HIV controls. After adjusting for age, sex, race, and comorbidities, higher BMI was associated with poorer physical (ß = -0.18, p = 0.005) and general (ß = -0.42, p = 0.014) HRQoL among PLWH. Additionally, PLWH reported poorer mental, physical, and general HRQoL than non-HIV controls; these relationships were not moderated by BMI. The potential negative impact of higher BMI on patients' humanistic outcomes should be considered in HIV management, including selection of treatment.


Subject(s)
HIV Infections , Quality of Life , Humans , Body Mass Index , HIV Infections/epidemiology , HIV Infections/complications , Obesity/complications , Obesity/epidemiology , Surveys and Questionnaires
2.
JIMD Rep ; 64(1): 104-113, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36636593

ABSTRACT

Acute hepatic porphyria (AHP) is a group of rare genetic diseases of heme biosynthesis resulting in severe neurovisceral attacks and chronic complications that negatively impact patients' well-being. This study evaluated the impacts of AHP on patients' physical and emotional health from a global perspective. Adult patients from the United States, Italy, Spain, Australia, Mexico, and Brazil with AHP with >1 porphyria attack within the past 2 years or receiving intravenous hemin and/or glucose for attack prevention completed an online survey assessing demographics, health characteristics, and patient-reported outcomes. Results were analyzed collectively and by patient subgroups. Ninety-two patients with AHP across the six countries completed the survey. More than 70% of patients reported that their physical, emotional, and financial health was fair or poor. Among patients who reported pain, fatigue, and muscle weakness, 94.3%, 95.6%, and 91.4%, respectively, reported that these symptoms limited daily activities. Moderate to severe depression was present in 58.7% of patients, and moderate to severe anxiety in 48.9% of patients. Of the 47% of patients who were employed, 36.8% reported loss in productivity while at work. Among patients, 85.9% reported that they had to change or modify goals that were important to them because of AHP. Aside from differences in healthcare utilization and pain severity, scores did not significantly vary with attack rate or use of hemin or glucose prophylactic treatments. AHP substantially impacts patients' physical and emotional well-being, regardless of hemin or glucose prophylactic treatment or frequency of attacks. This multinational study demonstrates that there is substantial disease burden for patients with AHP, even among those experiencing sporadic attacks or using prophylactic treatment.

3.
Hematology ; 27(1): 1140-1151, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36165770

ABSTRACT

OBJECTIVES: To assess the clinical and healthcare resource burden among C5 inhibitor (C5i)-treated patients with paroxysmal nocturnal haemoglobinuria (PNH), using patient-reported data. METHODS: This web-based, cross-sectional survey (01FEB2021-31MAR2021) of adults with PNH treated with eculizumab (France, Germany, UK) or ravulizumab (Germany) included: patient characteristics; treatment patterns/dosage; haematological outcomes (haemoglobin [Hb] levels, transfusions, thrombotic events, breakthrough haemolysis); and medical encounters. Treatment and Hb-level subgroup differences were assessed with statistical significance tests. RESULTS: Among 71 patients, 98.6% were C5i-treated for ≥3 months. The majority (with reported Hb levels) had levels ≤12.0 g/dL (85.7%; n = 54/63). The mean Hb level was 10.2 g/dL (standard deviation [SD]: 2.0; median 10.0 g/dL). Treatment with above label-recommended doses was reported by 30.4% (eculizumab) and 5.3% (ravulizumab) of patients. Within the past 12 months among patients treated with C5i for ≥1 year: 24.1% had ≥1 transfusion; 3.2% had ≥1 thrombosis; and 28.6% had ≥1 breakthrough haemolysis. Among all patients, 26.8% and 31.0% reported emergency department/room [ER] and inpatient visits, respectively. Mean annual, per-patient all-cause medical encounters were: 0.5 (ER); 1.9 (inpatient); and overall outpatient visits ranged by setting from 2.0 to 6.4. Most encounters were PNH-related, with means of 0.4 (ER); 1.8 (inpatient); and 1.6-5.4 (outpatient). Primary haematological and medical encounter outcomes were similar between treatment as well as Hb-level subgroups, with almost no statistically significant differences. CONCLUSIONS: Despite at least 3 months of C5i treatment, high proportions of patients with PNH reported low haemoglobin levels and required transfusions and hospitalizations, which suggests remaining unmet needs.


Subject(s)
Hemoglobinuria, Paroxysmal , Adult , Cost of Illness , Cross-Sectional Studies , Hemoglobins , Hemoglobinuria, Paroxysmal/drug therapy , Hemolysis , Humans
4.
Eur J Haematol ; 109(4): 351-363, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35746830

ABSTRACT

OBJECTIVES: To assess the clinical, humanistic and economic burden of paroxysmal nocturnal haemoglobinuria (PNH) among C5 inhibitor (C5i)-treated patients with PNH. METHODS: This was a web-based, cross-sectional survey (01FEB2021-31MAR2021) of adults with PNH treated with eculizumab (France, Germany, United Kingdom) or ravulizumab (Germany). Self-reported outcomes included: patient characteristics; patient-reported symptoms; and standardised patient-reported outcomes (e.g. Functional Assessment of Chronic Illness Therapy [FACIT]-Fatigue, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 [EORTC QLQ-C30]). RESULTS: Among 71 included patients, 98.6% were C5i-treated for ≥3 months (88.7% ≥12 months); among those with self-reported haemoglobin (Hb) levels (n = 63), most (85.7%) were anaemic (defined as ≤12.0 g/dL). Fatigue was the most common symptom at both diagnosis (73.2%) and survey time (63.4%); there were no statistically significant differences in symptom prevalence between treatment subgroups (eculizumab vs. ravulizumab). Total FACIT-Fatigue and EORTC QLQ-C30 scores were substantially lower than European general population references, but there were no statistically significant differences between treatment subgroups. Hb-level subgroups (<10.5 g/dL vs. ≥10.5 d/dL) followed similar trends for all measures, with few significant subgroup differences. CONCLUSIONS: Results suggest that there remains a considerable burden and unmet need among C5i-treated patients with PNH that requires improved therapies.


Subject(s)
Hemoglobinuria, Paroxysmal , Adult , Cost of Illness , Cross-Sectional Studies , Fatigue/drug therapy , Fatigue/epidemiology , Fatigue/etiology , Germany/epidemiology , Hemoglobinuria, Paroxysmal/complications , Hemoglobinuria, Paroxysmal/diagnosis , Hemoglobinuria, Paroxysmal/drug therapy , Humans , Patient Reported Outcome Measures , Quality of Life
5.
Brain Sci ; 12(2)2022 Jan 26.
Article in English | MEDLINE | ID: mdl-35203927

ABSTRACT

BACKGROUND: The study provides real-world data on the impact of Huntington's disease (HD) from the perspective of individuals with HD (IHD) and care partners (HD-CP) and contextualizes these results relative to Parkinson's disease (PD) and the general population (GP). METHODS: Cross-sectional survey of IHD and HD-CP in the US (July 2019-August 2019) conducted using the Rare Patient Voice panel. Data for individuals with Parkinson's Disease (IPD), the general population (GP), and respective care partners (PD-CP; GP-CP) came from the 2018 US National Health and Wellness Survey. Outcomes included demographics, mental health, clinical characteristics, and health-related quality of life (HRQoL). RESULTS: IHD had greater comorbid anxiety (IHD = 51.2%, IPD = 28.8%, GP = 2.0%), and HD-CP had greater comorbid anxiety (HD-CP = 52.5%, PD-CP = 28.6%, GP-CP = 19.6%) and depression (HD-CP = 65.0%, PD-CP = 29.9%, GP-CP = 19.6%), relative to other cohorts (p < 0.05). Respective of their GP cohorts, IHD exhibited lower HRQoL (EQ-5D: 0.66 ± 0.21 vs. 0.81 ± 0.17) and greater depression (PHQ-9: 11.59 ± 7.20 vs. 5.85 ± 6.71), whereas HD-CP exhibited greater depression only (PHQ-9: 6.84 ± 6.38 vs. 4.15 ± 5.58) (p < 0.001). No differences were observed between HD/HD-CP and PD/PD-CP cohorts on PHQ-9 or HRQoL. CONCLUSIONS: HD has a significant burden on patients and care partners, which is higher than GP. Notably, anxiety and depression were greater among HD vs. PD, despite similar HRQoL.

6.
Ann Hematol ; 101(2): 251-263, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34973099

ABSTRACT

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare and life-threatening disease with symptoms of hemolysis and thrombosis. Current therapies for this complement-mediated disease rely predominantly on inhibition of the C5 complement protein. However, data on treatment responses and quality of life in C5-inhibitor (C5i)-treated PNH patients are scarce. The objective of this study was to determine C5i treatment effects on clinical parameters, PNH symptoms, quality of life, and resource use for PNH patients. This cross-sectional study surveyed 122 individuals in the USA receiving treatment for PNH with C5-targeted monoclonal antibodies, eculizumab (ECU) or ravulizumab (RAV). Despite most patients receiving C5i therapy for ≥ 3 months (ECU 100%, n = 35; RAV 95.4%, n = 83), many patients remained anemic with hemoglobin levels ≤ 12 g/dL in 87.5% (n = 28/32) and 82.9% (n = 68/82) of ECU and RAV recipients, respectively. A majority of patients on ECU (88.6%; n = 31/35) and RAV (74.7%; n = 65/87) reported fatigue symptoms. Among PNH patients receiving C5i therapy for ≥ 12 months, some still reported thrombotic events (ECU, 10.0%, n = 1/10; RAV, 23.5%, n = 4/17) and required transfusions within the past year (ECU, 52.2%, n = 12/23; RAV, 22.6%, n = 7/31). Other patient-reported PNH symptoms included breakthrough hemolysis, shortness of breath, and headaches. Patients reported scores below the average population norms on the Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) scales. Overall, this study found that PNH patients receiving ECU or RAV therapy demonstrated a significant burden of illness, highlighting the need for improved PNH therapies.


Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Complement Inactivating Agents/therapeutic use , Hemoglobinuria, Paroxysmal/drug therapy , Adult , Aged , Antibodies, Monoclonal, Humanized/economics , Complement Inactivating Agents/economics , Cost of Illness , Cross-Sectional Studies , Female , Hemoglobinuria, Paroxysmal/economics , Hemoglobinuria, Paroxysmal/epidemiology , Humans , Male , Middle Aged , Quality of Life , Surveys and Questionnaires , United States/epidemiology
7.
Patient Prefer Adherence ; 15: 1061-1073, 2021.
Article in English | MEDLINE | ID: mdl-34054292

ABSTRACT

BACKGROUND AND OBJECTIVE: Treatment for attention deficit hyperactivity disorder (ADHD) requires a multifaceted approach including psychosocial interventions and pharmacological treatment. This study evaluates preferences for specific attributes associated with different long-acting stimulant treatment among US adults with ADHD. METHODS: Patients completed an online, cross-sectional survey, incorporating a discrete choice experiment to assess preferences for attributes. RESULTS: Analyses included 200 adults with ADHD (mean age 33.0 years; 60% self-reporting moderate severity); the mean (SD) Adult ADHD Self-Report Scale-v1.1 score was 45.9 (12.4). Overall, patients valued speed of onset most and risk of rebound least. Three population groups with distinct preferences were identified: side effect-driven (n=69, 35%), quick onset-driven (n=47, 24%) and quick onset and long duration-driven (n=84, 42%). CONCLUSION: This study shows differences in how adults with ADHD value and assess benefit-risk trade-offs when considering the desired attributes of stimulant treatments, highlighting the importance of patient-physician shared decision-making to optimize the desired benefits of individualized treatment.

8.
Eur J Haematol ; 107(1): 3-23, 2021 Jul.
Article in English | MEDLINE | ID: mdl-33715214

ABSTRACT

Myelodysplastic syndromes (MDS) are a group of malignant hematologic diseases characterized by ineffective hematopoiesis, which may lead to chronic anemia and transfusion dependency, with up to 30% of patients progressing to acute myeloid leukemia (AML). Studies suggest transfusion dependency may impact overall survival (OS); however, there is a lack of evidence concerning the association between transfusion status (TS) and OS in patients with MDS who become transfusion independent (TI) after treatment. In addition, the holistic impact of TS on other clinical, economic, and humanistic outcomes has not been well understood. We conducted a systematic literature review (SLR) to understand this impact. Ten studies were included and showed consistent decrease in OS in transfusion dependent (TD) compared with TI patients. These findings were confirmed by a meta-analysis (MA) reporting better OS prognosis for TI patients. A second SLR was conducted to understand the association between TS and other clinical, economic, and humanistic outcomes. Twenty-eight studies were included and showed better prognosis for other outcomes, including AML progression and leukemia-free survival for TI patients. Risk of AML progression and cumulative non-leukemic death assessed by the MA showed a trend toward worse prognosis and higher risk of AML progression for TD patients. Lower healthcare resource utilization, better quality of life, and reduced non-leukemic death for TI patients were observed. Studies not eligible for MA also showed better clinical, economic, and humanistic outcomes for TI patients. These findings contribute to understanding the association between transfusion dependence and OS among other outcomes in patients with MDS.


Subject(s)
Erythrocyte Transfusion/methods , Erythrocytes/cytology , Leukemia, Myeloid, Acute/complications , Myelodysplastic Syndromes/therapy , Anemia/complications , Bayes Theorem , Disease Progression , Disease-Free Survival , Female , Humans , Male , Monte Carlo Method , Myelodysplastic Syndromes/complications , Phenotype , Prognosis , Quality of Life , Risk , Treatment Outcome
9.
Womens Health Rep (New Rochelle) ; 2(1): 622-632, 2021.
Article in English | MEDLINE | ID: mdl-35141710

ABSTRACT

Introduction: This study aimed to understand women's preferences regarding the subdermal contraceptive implant and to assess the proportion of women who would be underserved (with increased unintended pregnancies as the consequence) by not providing implant access equal to that of uterine-based long-acting reversible contraceptive methods (LARCs). Methods: A total of 1,200 women aged 18-44 years old (mean: 30.42 ± 7.67 years) participated in a U.S. cross-sectional online survey. To qualify for the study, women had to be sexually active with a male and not pregnant or trying to get pregnant at the time of the study. Women who had undergone a hysterectomy, a bilateral salpingo-oophorectomy, or a tubal ligation, and women with general infertility or those with a vasectomized partner were excluded. Descriptive analyses were conducted and weighted estimates, projecting to the total U.S. population were also provided. Results: The majority of women (72.6%) reported that they would be willing to switch to a LARC, should it be readily available to them. Considering those women who already use an implant and those who would be willing to switch to it, 58% of women would be underserved by not being provided equal access to the subdermal implant. This reduced availability of this type of LARC may alone elevate the number of unintended pregnancies in the United States by ∼8% of all pregnancies per year. Conclusion: Thus, making all the available contraceptive methods and maintaining access to LARCs would help reduce unintended pregnancies and better serve women and their family planning needs.

10.
Curr Med Res Opin ; 36(3): 377-386, 2020 03.
Article in English | MEDLINE | ID: mdl-31771370

ABSTRACT

Objective: Type 2 diabetes (T2D) is a prevalent health problem. Oral agents, with the exception of metformin, are often discontinued with the initiation of insulin. The objective was to understand the proportion of patients discontinuing dipeptidyl peptidase-4 inhibitors (DPP-4is) and the reasons for the decision to discontinue.Methods: A retrospective study using a health claims database investigated discontinuation of DPP-4i in adult patients on a dual therapy of metformin and DPP-4i who initiated insulin (n = 3391). An online survey administered to 406 physicians in the US examined reasons for discontinuation. Physicians surveyed included endocrinologists (34.5%), general practitioners (32.5%), internal medicine specialists (30.5%), and diabetologists (2.5%), treating a monthly average of 154 patients.Results: Among patients treated with metformin and DPP-4is who were newly prescribed insulin, 33.3 and 57.3% discontinued DPP-4i therapy within 3 and 12 months, respectively. Patients who discontinued DPP-4i therapy had higher out-of-pocket costs and a greater proportion of renal and liver disease. Top 3 responses for discontinuation included adverse events/tolerability issues (58.9%), lack of efficacy/treatment goals not being met (55.4%) and additional cost of DPP-4i with insulin (48.5%). Top 3 responses for continuing DPP-4i included meeting treatment goals (70.7%), using a lower dose of insulin (65.3%) and good tolerability (48.0%). Physician characteristics, such as physician specialty, age, gender and location impacted to some extent the reasons for treatment decisions.Conclusions: A large proportion of patients discontinue DPP-4is in the real world when initiating insulin. The impact of physician characteristics in treatment decisions highlights the need for enhanced physician training and support as new clinical data emerges and therapy options are available.


Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Dipeptidyl-Peptidase IV Inhibitors/therapeutic use , Hypoglycemic Agents/therapeutic use , Insulin/therapeutic use , Aged , Cohort Studies , Female , Humans , Male , Metformin/therapeutic use , Middle Aged , Retrospective Studies , Treatment Outcome
11.
Reprod Biol Endocrinol ; 13: 60, 2015 Jun 12.
Article in English | MEDLINE | ID: mdl-26066493

ABSTRACT

BACKGROUND: In cryopreservation, oocytes are subjected to extreme hyperosmotic conditions, inducing large volume changes that, along with an abrupt temperature drop, interfere with their developmental competence. Our objectives in this work were to find conditions enabling an increase in oocyte cryosurvival and subsequent development. METHODS: Abattoir-derived bovine oocytes were cultured without (Control group) or with trans-10,cis-12 conjugated linoleic acid isomer (CLA group). Comparative observations were made for 1) the oocyte developmental competence after exposure to cryoprotectants followed or not by vitrification/warming, 2) the oocyte membrane permeability to water (using the non-permeant cryoprotectant sucrose) and 3) the oocyte membrane permeability to two cryoprotectants (ethylene glycol, EG, and dimethyl sulfoxide, DMSO). Mature oocytes cultured with or without CLA and vitrified/warmed or only exposed to cryoprotectants without vitrification were subjected to in vitro fertilization; embryo culture proceeded until the blastocyst stage. The oocyte membrane permeabilities to water and cryoprotectants were estimated using mature oocytes subjected to hyperosmotic challenges. For water permeability, 200 mM sucrose was used, whereas for the cryoprotectant permeability, a 10 % solution of both EG and DMSO was used. The data were analyzed using the MIXED procedure and Student's T-test. RESULTS: CLA supplementation improves the developmental competence of vitrified/warmed and cryoprotectants exposed oocytes (p < 0.01) and reduces their membrane permeability to water (37 %, p < 0.001) and to cryoprotectants (42 %, p < 0.001). CONCLUSIONS: By slowing the fluxes of water and of permeant cryoprotectants, CLA contributed to improved oocyte cryosurvival and post-thawed viability. This isomer supplementation to the maturation media should be considered when designing new protocols for oocyte cryopreservation.


Subject(s)
Cryopreservation/methods , Cryoprotective Agents/pharmacology , Linoleic Acids, Conjugated/pharmacology , Oocytes/cytology , Animals , Cattle , Cell Membrane Permeability , Female , Fertilization in Vitro , Oocytes/drug effects
12.
Trends Biochem Sci ; 35(11): 643-51, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20561791

ABSTRACT

Several neurodegenerative diseases are characterized by the accumulation of misfolded and aggregated proteins, which lead to neurotoxicity. However, the nature of those toxic species is controversial. Developments in optical microscopy and live-cell imaging are essential in providing crucial insight into the molecular mechanisms involved. In particular, the technique of bimolecular fluorescence complementation (BiFC) represents a remarkable improvement for observing protein-protein interactions within living cells. Unlike other techniques, BiFC provides spatial and temporal resolution and can be carried out in a physiological environment. Among other applications, BiFC has been used to study molecular determinants of oligomerization in neurodegenerative disorders, thereby promising to unveil novel targets for therapeutics. We review the applicability of BiFC for investigating the molecular basis of neurodegenerative diseases associated with protein misfolding and aggregation.


Subject(s)
Luminescent Proteins/analysis , Neurons/chemistry , Neurons/metabolism , Protein Multimerization , Proteins/analysis , Proteins/metabolism , Animals , Humans , Luminescent Proteins/metabolism , Protein Binding , Protein Folding
13.
Pflugers Arch ; 459(5): 645-56, 2010 Apr.
Article in English | MEDLINE | ID: mdl-20143237

ABSTRACT

Homeostatic control of plasma K+ is a necessary physiological function. The daily dietary K+ intake of approximately 100 mmol is excreted predominantly by the distal tubules of the kidney. About 10% of the ingested K+ is excreted via the intestine. K+ handling in both organs is specifically regulated by hormones and adapts readily to changes in dietary K+ intake, aldosterone and multiple local paracrine agonists. In chronic renal insufficiency, colonic K+ secretion is greatly enhanced and becomes an important accessory K+ excretory pathway. During severe diarrheal diseases of different causes, intestinal K+ losses caused by activated ion secretion may become life threatening. This topical review provides an update of the molecular mechanisms and the regulation of mammalian colonic K+ absorption and secretion. It is motivated by recent results, which have identified the K+ secretory ion channel in the apical membrane of distal colonic enterocytes. The directed focus therefore covers the role of the apical Ca2+ and cAMP-activated BK channel (KCa1.1) as the apparently only secretory K+ channel in the distal colon.


Subject(s)
Colon/physiology , Potassium/blood , Animals , Biological Transport , Intestinal Mucosa/physiology , Potassium/metabolism
14.
J Physiol ; 586(17): 4251-64, 2008 Sep 01.
Article in English | MEDLINE | ID: mdl-18617563

ABSTRACT

Mammalian K(+) homeostasis results from highly regulated renal and intestinal absorption and secretion, which balances the unregulated K(+) intake. Aldosterone is known to enhance both renal and colonic K(+) secretion. In mouse distal colon K(+) secretion occurs exclusively via luminal K(Ca)1.1 (BK) channels. Here we investigate if aldosterone stimulates colonic K(+) secretion via BK channels. Luminal Ba(2+) and iberiotoxin (IBTX)-sensitive electrogenic K(+) secretion was measured in Ussing chambers. In vivo aldosterone was augmented via a high K(+) diet. High K(+) diet led to a 2-fold increase of luminal Ba(2+) and IBTX-sensitive short-circuit current in distal mouse colonic mucosa. This effect was absent in BK alpha-subunit-deficient (BK(-/-)) mice. The resting and diet-induced K(+) secretion was stimulated by luminal ionomycin. In BK(-/-) mice luminal ionomycin did not stimulate K(+) secretion. In vitro addition of aldosterone likewise triggered a 2-fold increase in K(+) secretion, which was inhibited by the mineralocorticoid receptor antagonist spironolactone and the BK channel blocker IBTX. Semi-quantification of mRNA from colonic crypts showed up-regulation of BK alpha- and beta(2)-subunits in high K(+) diet mice. The BK channel could be detected luminally in colonic crypt cells by immunohistochemistry. The expression level of the channel in the luminal membrane was strongly up-regulated in K(+)-loaded animals. Taken together, these data strongly suggest that aldosterone-induced K(+) secretion occurs via increased expression of luminal BK channels.


Subject(s)
Aldosterone/metabolism , Colon/metabolism , Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/metabolism , Potassium/pharmacology , Aldosterone/blood , Aldosterone/pharmacology , Animals , Barium/pharmacology , Colon/drug effects , Female , Gene Deletion , Gene Expression Regulation , Immunohistochemistry , Ionomycin/pharmacology , Ionophores/pharmacology , Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/genetics , Male , Mice , Mineralocorticoid Receptor Antagonists/pharmacology , Peptides/pharmacology , Polymerase Chain Reaction , Potassium/administration & dosage , Spironolactone/pharmacology , Up-Regulation
15.
J Biol Chem ; 281(46): 35147-55, 2006 Nov 17.
Article in English | MEDLINE | ID: mdl-16980298

ABSTRACT

Immune cell function is modulated by changes in extracellular nucleotide levels. Here we used reverse transcription-PCR analyses, single cell Ca2+ imaging, and knock-out mice to define the receptors mediating nucleotide-induced Ca2+ signaling in resident peritoneal macrophages. In Ca2+-free buffer, the potent (K0.5<1 microm) stimulatory effect of UTP (or ATP) on endoplasmic reticulum (ER) Ca2+ release was abolished in cells isolated from P2Y2/P2Y4 double knock-out mice. Moreover, P2Y4(0/-), but not P2Y2-/-, macrophages responded to UTP. In P2Y2-/- macrophages, we could elicit Ca2+ responses to "pure" P2X receptor activation by applying ATP in buffer containing Ca2+. Purified UDP and ADP were ineffective agonists, although modest UDP-induced Ca2+ responses could be elicited in macrophages after "activation" with lipopolysaccharide and interferon-gamma. Notably, in Ca2+-free buffer, UTP-induced Ca2+ transients decayed within 1 min, and there was no response to repeated agonist challenge. Measurements of ER [Ca2+] with mag-fluo-4 showed that ER Ca2+ stores were depleted under these conditions. When extracellular Ca2+ was available, ER Ca2+ stores refilled, but Ca2+ increased to only approximately 40% of the initial value upon repeated UTP challenge. This apparent receptor desensitization persisted in GRK2+/- and GRK6-/- macrophages and after inhibition of candidate kinases protein kinase C and calmodulin-dependent kinase II. Initial challenge with UTP also reduced Ca2+ mobilization by complement component C5a (and vice versa). In conclusion, homologous receptor desensitization is not the major mechanism that rapidly dampens Ca2+ signaling mediated by P2Y2, the sole Gq-coupled receptor for UTP or ATP in macrophages. UDP responsiveness (P2Y6 receptor expression) increases following macrophage activation.


Subject(s)
Macrophages, Peritoneal/metabolism , Receptors, Purinergic P2/metabolism , Adenosine Diphosphate/metabolism , Animals , Calcium Channels , Calcium Signaling , Calcium-Transporting ATPases/metabolism , G-Protein-Coupled Receptor Kinase 2 , G-Protein-Coupled Receptor Kinases , Gene Expression Regulation , Mice , Mice, Knockout , Nucleotides , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Receptors, Purinergic P2/genetics , Receptors, Purinergic P2Y2 , Uridine Diphosphate/metabolism , beta-Adrenergic Receptor Kinases/genetics , beta-Adrenergic Receptor Kinases/metabolism
16.
J Am Soc Nephrol ; 17(5): 1275-82, 2006 May.
Article in English | MEDLINE | ID: mdl-16571783

ABSTRACT

K(+) secretion in the kidney and distal colon is a main determinant of K(+) homeostasis. This study investigated the identity of the relevant luminal secretory K(+) ion channel in distal colon. An Ussing chamber was used to measure ion transport in the recently generated BK channel-deficient (BK(-/-)) mice. BK(-/-) mice display a significant colonic epithelial phenotype with (1) lack of Ba(2+)-sensitive resting K(+) secretion, (2) absence of K(+) secretion stimulated by luminal P2Y(2) and P2Y(4) receptors, (3) absence of luminal Ca(2+) ionophore (A23187)-stimulated K(+) secretion, (4) reduced K(+) and increased Na(+) contents in feces, and (5) an increased colonic Na(+) absorption. In contrast, resting and uridine triphosphate (UTP)-stimulated K(+) secretion was not altered in mice that were deficient for the intermediate conductance Ca(2+)-activated K(+) channel SK4. BK channels localize to the luminal membrane of crypt, and reverse transcription-PCR results confirm the expression of the BK channel alpha-subunit in isolated distal colonic crypts. It is concluded that BK channels are the responsible K(+) channels for resting and stimulated Ca(2+)-activated K(+) secretion in mouse distal colon.


Subject(s)
Colon/metabolism , Ion Channel Gating/physiology , Large-Conductance Calcium-Activated Potassium Channels/metabolism , Potassium/metabolism , Animals , Ion Transport/physiology , Large-Conductance Calcium-Activated Potassium Channels/genetics , Mice , Mice, Inbred C57BL , Mice, Knockout
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