Metabolic Reprogramming of Macrophages upon In Vitro Incubation with Aluminum-Based Adjuvant.

Aluminum-based adjuvants have been extensively used in vaccines. Despite their widespread use, the mechanism behind the immune stimulation properties of these adjuvants is not fully understood. Needless to say, extending the knowledge of the immune-stimulating properties of aluminum-based adjuvants is of utmost importance in the development of new, safer, and efficient vaccines. To further our knowledge of the mode of action of aluminum-based adjuvants, the prospect of metabolic reprogramming of macrophages upon phagocytosis of aluminum-based adjuvants was investigated. Macrophages were differentiated and polarized in vitro from human peripheral monocytes and incubated with the aluminum-based adjuvant Alhydrogel®. Polarization was verified by the expression of CD markers and cytokine production. In order to recognize adjuvant-derived reprogramming, macrophages were incubated with Alhydrogel® or particles of polystyrene as control, and the cellular lactate content was analyzed using a bioluminescent assay. Quiescent M0 macrophages, as well as alternatively activated M2 macrophages, exhibited increased glycolytic metabolism upon exposure to aluminum-based adjuvants, indicating a metabolic reprogramming of the cells. Phagocytosis of aluminous adjuvants could result in an intracellular depot of aluminum ions, which may induce or support a metabolic reprogramming of the macrophages. The resulting increase in inflammatory macrophages could thus prove to be an important factor in the immune-stimulating properties of aluminum-based adjuvants.

Intratumoral administration of the antisecretory peptide AF16 cures murine gliomas and modulates macrophage functions.

Glioblastoma has remained the deadliest primary brain tumor while its current therapy offers only modest survival prolongation. Immunotherapy has failed to record notable benefits in routine glioblastoma treatment. Conventionally, immunotherapy relies on T cells as tumor-killing agents; however, T cells are outnumbered by macrophages in glioblastoma microenvironment. In this study, we explore the effect of AF16, a peptide from the endogenous antisecretory factor protein, on the survival of glioma-bearing mice, the tumor size, and characteristics of the tumor microenvironment with specific focus on macrophages. We elucidate the effect of AF16 on the inflammation-related secretome of human and murine macrophages, as well as human glioblastoma cells. In our results, AF16 alone and in combination with temozolomide leads to cure in immunocompetent mice with orthotopic GL261 gliomas, as well as prolonged survival in immunocompromised mice. We recorded decreased tumor size and changes in infiltration of macrophages and T cells in the murine glioma microenvironment. Human and murine macrophages increased expression of proinflammatory markers in response to AF16 treatment and the same effect was seen in human primary glioblastoma cells. In summary, we present AF16 as an immunomodulatory factor stimulating pro-inflammatory macrophages with a potential to be implemented in glioblastoma treatment protocols.

Autotolerant ceruloplasmin based biocathodes for implanted biological power sources.

High-performance autotolerant bioelectrodes should be ideally suited to design implantable bioelectronic devices. Because of its high redox potential and ability to reduce oxygen directly to water, human ceruloplasmin, HCp, the only blue multicopper oxidase present in human plasma, appears to be the ultimate biocatalyst for oxygen biosensors and also biocathodes in biological power sources. In comparison to fungal and plant blue multicopper oxidases, e.g. Myrothecium verrucaria bilirubin oxidase and Rhus vernicifera laccase, respectively, the inflammatory response to HCp in human blood is significantly reduced. Partial purification of HCp allowed to preserve the native conformation of the enzyme and its biocatalytic activity. Therefore, electrochemical studies were carried out with the partially purified enzyme immobilised on nanostructured graphite electrodes at physiological pH and temperature. Amperometric investigations revealed low reductive current densities, i.e. about 1.65 µA cm-2 in oxygenated electrolyte and in the absence of any mediator, demonstrating nevertheless direct electron transfer based O2 bioelectroreduction by HCp for the first time. The reductive current density obtained in the mediated system was about 12 µA cm-2. Even though the inflammatory response of HCp is diminished in human blood, inadequate bioelectrocatalytic performance hinders its use as a cathodic bioelement in a biofuel cell.

Aluminium adjuvants in vaccines - A way to modulate the immune response.

Aluminium salts have been used as adjuvants in vaccines for almost a century, but still no clear understanding of the mechanisms behind the immune stimulating properties of aluminium based adjuvants is recognized. Aluminium adjuvants consist of aggregates and upon administration of a vaccine, the aggregates will be recognized and phagocytosed by sentinel cells such as macrophages or dendritic cells. The adjuvant aggregates will persist intracellularly, maintaining a saturated intracellular concentration of aluminium ions over an extended time. Macrophages and dendritic cells are pivotal cells of the innate immune system, linking the innate and adaptive immune systems, and become inflammatory and antigen-presenting upon activation, thus mediating the initiation of the adaptive immune system. Both types of cell are highly adaptable, and this review will discuss and highlight how the occurrence of intracellular aluminium ions over an extended time may induce the polarization of macrophages into inflammatory and antigen presenting M1 macrophages by affecting the: endosomal pH; formation of reactive oxygen species (ROS); stability of the phagosomal membrane; release of damage associated molecular patterns (DAMPs); and metabolism (metabolic re-programming). This review emphasizes that a persistent intracellular presence of aluminium ions over an extended time has the potential to affect the functionality of sentinel cells of the innate immune system, inducing polarization and activation. The immune stimulating properties of aluminium adjuvants is presumably mediated by several discrete events, however, a persistent intracellular presence of aluminium ions appears to be a key factor regarding the immune stimulating properties of aluminium based adjuvants.

Sequestering of damage-associated molecular patterns (DAMPs): a possible mechanism affecting the immune-stimulating properties of aluminium adjuvants.

Aluminium-based adjuvants (ABAs) have been used in human and veterinary vaccines for decades, and for a long time, the adjuvant properties were believed to be mediated by an antigen depot at the injection site, prolonging antigen exposure to the immune system. The depot hypothesis is today more or less abandoned, and instead replaced by the assumption that ABAs induce an inflammation at the injection site. Induction of an inflammatory response is consistent with immune activation initiated by recognition of molecular patterns associated with danger or damage (DAMPs), and the latter are derived from endogenous molecules that normally reside intracellularly. When extracellularly expressed, because of damage, stress or cell death, a sterile inflammation is induced. In this paper, we report the induction of DAMP release by viable cells after phagocytosis of aluminium-based adjuvants. Two of the most commonly used ABAs in pharmaceutical vaccine formulations, aluminium oxyhydroxide and aluminium hydroxyphosphate, induced a vigorous extracellular expression of the two DAMP molecules calreticulin and HMGB1. Concomitantly, extracellular adjuvant particles adsorbed the DAMP molecules released by the cells whereas IL-1ß, a previously reported inflammatory mediator induced by ABAs, was not absorbed by the adjuvants. Induction of extracellular expression of the two DAMP molecules was more prominent using aluminium hydroxyphosphate compared to aluminium oxyhydroxide, whereas the extracellular adsorption of the DAMP molecules was more pronounced with the latter. Furthermore, it is hypothesised how induction of DAMP expression by ABAs and their concomitant adsorption by extracellular adjuvants may affect the inflammatory properties of ABAs.

Myeloperoxidase-immunoreactive cells are significantly increased in brain areas affected by neurodegeneration in Parkinson's and Alzheimer's disease.

Myeloperoxidase (MPO) is a key enzyme in inflammatory and degenerative processes, although conflicting reports have been presented concerning its expression in the brain. We studied the cellular localization of MPO and compared numbers of MPO cells in various brain regions between neurologically healthy individuals and patients with Parkinson's disease (PD) or Alzheimer's disease (AD; n = 10-25). We also investigated two rodent PD models. MPO immunoreactivity (ir) was detected in monocytes, perivascular macrophages and amoeboid microglia in the human brain parenchyma, whereas no co-localization with glial fibrillary acidic protein (GFAP) ir was observed. In the midbrain, caudate and putamen, we found a significant increase of MPO-immunoreactive cells in PD compared with control brains, whereas in the cerebellum, no difference was apparent. MPO ir was detected neither in neurons nor in occasional small beta-amyloid-immunoreactive plaques in PD or control cases. In the frontal cortex of AD patients, we found significantly more MPO-immunoreactive cells compared with control cases, together with intense MPO ir in extracellular plaques. In the hippocampus of several AD cases, MPO-like ir was observed in some pyramidal neurons. Neither rapid dopamine depletion in the rat PD model, nor slow degeneration of dopamine neurons in MitoPark mice induced the expression of MPO ir in any brain region. MPO mRNA was not detectable with radioactive in situ hybridization in any human or rodent brain area, although myeloid cells from bone marrow displayed clear MPO signals. Our results indicate significant increases of MPO-immunoreactive cells in brain regions affected by neurodegeneration in PD and AD, supporting investigations of MPO inhibitors in novel treatment strategies.

Al adjuvants can be tracked in viable cells by lumogallion staining.

The mechanism behind the adjuvant effect of aluminum salts is poorly understood notwithstanding that aluminum salts have been used for decades in clinical vaccines. In an aqueous environment and at a nearly neutral pH, the aluminum salts form particulate aggregates, and one plausible explanation of the lack of information regarding the mechanisms could be the absence of an efficient method of tracking phagocytosed aluminum adjuvants and thereby the intracellular location of the adjuvant. In this paper, we want to report upon the use of lumogallion staining enabling the detection of phagocytosed aluminum adjuvants inside viable cells. Including micromolar concentrations of lumogallion in the culture medium resulted in a strong fluorescence signal from cells that had phagocytosed the aluminum adjuvant. The fluorescence appeared as spots in the cytoplasm and by confocal microscopy and co-staining with probes presenting fluorescence in the far-red region of the spectrum, aluminum adjuvants could to a certain extent be identified as localized in acidic vesicles, i.e., lysosomes. Staining and detection of intracellular aluminum adjuvants was achieved not only by diffusion of lumogallion into the cytoplasm, thereby highlighting the presence of the adjuvant, but also by pre-staining the aluminum adjuvant prior to incubation with cells. Pre-staining of aluminum adjuvants resulted in bright fluorescent particulate aggregates that remained fluorescent for weeks and with only a minor reduction of fluorescence upon extensive washing or incubation with cells. Both aluminum oxyhydroxide and aluminum hydroxyphosphate, two of the most commonly used aluminum adjuvants in clinical vaccines, could be pre-stained with lumogallion and were easily tracked intracellularly after incubation with phagocytosing cells. Staining of viable cells using lumogallion will be a useful method in investigations of the mechanisms behind aluminum adjuvants' differentiation of antigen-presenting cells into inflammatory cells. Information will be gained regarding the phagosomal pathways and the events inside the phagosomes, and thereby the ultimate fate of phagocytosed aluminum adjuvants could be resolved.

Unequivocal identification of intracellular aluminium adjuvant in a monocytic THP-1 cell line.

Aluminium-based adjuvants (ABA) are the predominant adjuvants used in human vaccinations. While a consensus is yet to be reached on the aetiology of the biological activities of ABA several studies have identified shape, crystallinity and size as critical factors affecting their adjuvanticity. In spite of recent advances, the fate of ABA following their administration remains unclear. Few if any studies have demonstrated the unequivocal presence of intracellular ABA. Herein we demonstrate for the first time the unequivocal identification of ABA within a monocytic T helper 1 (THP-1) cell line, using lumogallion as a fluorescent molecular probe for aluminium. Use of these new methods revealed that particulate ABA was only found in the cell cytoplasm. Transmission electron microscopy revealed that ABA were contained within vesicle-like structures of approximately 0.5-1 µm in diameter.

Training of public health personnel in handling CBRN emergencies: a table-top exercise card concept.

There is a large concern in the society today about the threat posed from releases of chemical, biological, radiological or nuclear (CBRN) materials, whether accidental or malicious. A rapid and adapted response to a CBRN incident combined with a thorough public communication is believed to decrease the detrimental impacts on health and to reduce the psychosocial effects. To facilitate CBRN exercises, which often can be regarded by non-specialists as rather complicated, a tool in the form of a set of Exercise cards for CBRN emergency response table-top exercises has been developed. The exercise tool is a generic tool intended for an exercise director and consists of a set of adaptable scenarios with supporting instructions and questions that deal with preparedness, acute response and mitigation efforts. The exercise tool was tested in three different settings with positive results and has been assessed to be a cost-efficient means to train and test public health response to CBRN incidents.

Potent reversible inhibition of myeloperoxidase by aromatic hydroxamates.

The neutrophil enzyme myeloperoxidase (MPO) promotes oxidative stress in numerous inflammatory pathologies by producing hypohalous acids. Its inadvertent activity is a prime target for pharmacological control. Previously, salicylhydroxamic acid was reported to be a weak reversible inhibitor of MPO. We aimed to identify related hydroxamates that are good inhibitors of the enzyme. We report on three hydroxamates as the first potent reversible inhibitors of MPO. The chlorination activity of purified MPO was inhibited by 50% by a 5 nm concentration of a trifluoromethyl-substituted aromatic hydroxamate, HX1. The hydroxamates were specific for MPO in neutrophils and more potent toward MPO compared with a broad range of redox enzymes and alternative targets. Surface plasmon resonance measurements showed that the strength of binding of hydroxamates to MPO correlated with the degree of enzyme inhibition. The crystal structure of MPO-HX1 revealed that the inhibitor was bound within the active site cavity above the heme and blocked the substrate channel. HX1 was a mixed-type inhibitor of the halogenation activity of MPO with respect to both hydrogen peroxide and halide. Spectral analyses demonstrated that hydroxamates can act variably as substrates for MPO and convert the enzyme to a nitrosyl ferrous intermediate. This property was unrelated to their ability to inhibit MPO. We propose that aromatic hydroxamates bind tightly to the active site of MPO and prevent it from producing hypohalous acids. This mode of reversible inhibition has potential for blocking the activity of MPO and limiting oxidative stress during inflammation.

Aluminium based adjuvants and their effects on mitochondria and lysosomes of phagocytosing cells.

Aluminium oxyhydroxide, Al(OH)3 is one of few compounds approved as an adjuvant in human vaccines. However, the mechanism behind its immune stimulating properties is still poorly understood. In vitro co-culture of an aluminium adjuvant and the human monocytic cell line THP-1 resulted in reduced cell proliferation. Inhibition occurred at concentrations of adjuvant several times lower than would be found at the injection site using a vaccine formulation containing an aluminium adjuvant. Based on evaluation of the mitochondrial membrane potential, THP-1 cells showed no mitochondrial rupture after co-culture with the aluminium adjuvant, instead an increase in mitochondrial activity was seen. The THP-1 cells are phagocytosing cells and after co-culture with the aluminium adjuvant the phagosomal pathway was obstructed. Primary or early phagosomes mature into phagolysosomes with an internal pH of 4.5 - 5 and carry a wide variety of hydrolysing enzymes. Co-culture with the aluminium adjuvant yielded a reduced level of acidic vesicles and cathepsin L activity, a proteolytic enzyme of the phagolysosomes, was almost completely inhibited. THP-1 cells are an appropriate in vitro model in order to investigate the mechanism behind the induction of a phagocytosing antigen presenting cell into an inflammatory cell by aluminium adjuvants. Much information will be gained by investigating the phagosomal pathway and what occurs inside the phagosomes and to elucidate the ultimate fate of phagocytosed aluminium particles.

Myeloid blood dendritic cells and monocyte-derived dendritic cells differ in their endocytosing capability.

Human dendritic cells (DCs) constitute a heterogeneous population of antigen-presenting cells characterized by a unique capacity to stimulate naïve T cells. The functions of DCs depend on the particular subset and in this study we compare two types of myeloid DCs: freshly isolated blood mDCs and in vitro generated monocyte-derived DCs (MoDCs), in their ability to accomplish endocytosis. In our hands, these two DC subtypes showed similarities in the expression of surface markers, but displayed clear differences in endocytic capacity. Freshly isolated blood mDCs showed a high propensity to capture and endocytose particles compared to in vitro generated MoDCs. The blood mDCs also showed a clear receptor-enhanced endocytosis when zeolite particles were co-adsorbed with IgG. On the other hand, the MoDCs differed remarkably compared to blood mDCs in the capture of ovalbumin and immune complexes. Interestingly, the MoDCs showed low endocytosis of IgG-coated particles but an efficient capture of immune complexes. The MoDCs also showed a high capacity to capture ovalbumin although with a relatively low degree of internalization. These data indicate distinct differences in the early process of endocytosis featured by mDCs and MoDCs, which is important to consider when choosing DC populations for future functional or clinical applications.

First and second generation γ-secretase modulators (GSMs) modulate amyloid-ß (Aß) peptide production through different mechanisms.

γ-Secretase-mediated cleavage of amyloid precursor protein (APP) results in the production of Alzheimer disease-related amyloid-ß (Aß) peptides. The Aß42 peptide in particular plays a pivotal role in Alzheimer disease pathogenesis and represents a major drug target. Several γ-secretase modulators (GSMs), such as the nonsteroidal anti-inflammatory drugs (R)-flurbiprofen and sulindac sulfide, have been suggested to modulate the Alzheimer-related Aß production by targeting the APP. Here, we describe novel GSMs that are selective for Aß modulation and do not impair processing of Notch, EphB2, or EphA4. The GSMs modulate Aß both in cell and cell-free systems as well as lower amyloidogenic Aß42 levels in the mouse brain. Both radioligand binding and cellular cross-competition experiments reveal a competitive relationship between the AstraZeneca (AZ) GSMs and the established second generation GSM, E2012, but a noncompetitive interaction between AZ GSMs and the first generation GSMs (R)-flurbiprofen and sulindac sulfide. The binding of a (3)H-labeled AZ GSM analog does not co-localize with APP but overlaps anatomically with a γ-secretase targeting inhibitor in rodent brains. Combined, these data provide compelling evidence of a growing class of in vivo active GSMs, which are selective for Aß modulation and have a different mechanism of action compared with the original class of GSMs described.

Myeloperoxidase inhibition ameliorates multiple system atrophy-like degeneration in a transgenic mouse model.

Multiple system atrophy (MSA) is a rare and fatal α-synucleinopathy characterized by a distinctive oligodendrogliopathy with glial cytoplasmic inclusions and associated neuronal multisystem degeneration. The majority of patients presents with a rapidly progressive parkinsonian disorder and atypical features such as early autonomic failure and cerebellar ataxia. We have previously reported that complete MSA pathology can be modeled in transgenic mice overexpressing oligodendroglial α-synuclein under conditions of oxidative stress induced by 3-nitropropionic acid (3-NP) including striatonigral degeneration, olivopontocerebellar atrophy, astrogliosis, and microglial activation. Here, we show that myeloperoxidase (MPO), a key enzyme involved in the production of reactive oxygen species by phagocytic cells, is expressed in both human and mouse MSA brains. We also demonstrate that in the MSA mouse model, MPO inhibition reduces motor impairment and rescues vulnerable neurons in striatum, substantia nigra pars compacta, cerebellar cortex, pontine nuclei, and inferior olives. MPO inhibition is associated with suppression of microglial activation but does not affect 3-NP induced astrogliosis in the same regions. Finally, MPO inhibition results in reduced intracellular aggregates of α-synuclein. This study suggests that MPO inhibition may represent a novel candidate treatment strategy against MSA-like neurodegeneration acting through its anti-inflammatory and anti-oxidative properties.

2-thioxanthines are mechanism-based inactivators of myeloperoxidase that block oxidative stress during inflammation.

Myeloperoxidase (MPO) is a prime candidate for promoting oxidative stress during inflammation. This abundant enzyme of neutrophils uses hydrogen peroxide to oxidize chloride to highly reactive and toxic chlorine bleach. We have identified 2-thioxanthines as potent mechanism-based inactivators of MPO. Mass spectrometry and x-ray crystal structures revealed that these inhibitors become covalently attached to the heme prosthetic groups of the enzyme. We propose a mechanism whereby 2-thioxanthines are oxidized, and their incipient free radicals react with the heme groups of the enzyme before they can exit the active site. 2-Thioxanthines inhibited MPO in plasma and decreased protein chlorination in a mouse model of peritonitis. They slowed but did not prevent neutrophils from killing bacteria and were poor inhibitors of thyroid peroxidase. Our study shows that MPO is susceptible to the free radicals it generates, and this Achilles' heel of the enzyme can be exploited to block oxidative stress during inflammation.

Tree and shrub expansion over the past 34 years at the tree-line near Abisko, Sweden.

Shrubs and trees are expected to expand in the sub-Arctic due to global warming. Our study was conducted in Abisko, sub-arctic Sweden. We recorded the change in coverage of shrub and tree species over a 32- to 34-year period, in three 50 x 50 m plots; in the alpine-tree-line ecotone. The cover of shrubs and trees (<3.5 cm diameter at breast height) were estimated during 2009-2010 and compared with historical documentation from 1976 to 1977. Similarly, all tree stems (> or =3.5 cm) were noted and positions determined. There has been a substantial increase of cover of shrubs and trees, particularly dwarf birch (Betula nana), and mountain birch (Betula pubescens ssp. czerepanovii), and an establishment of aspen (Populus tremula). The other species willows (Salix spp.), juniper (Juniperus communis), and rowan (Sorbus aucuparia) revealed inconsistent changes among the plots. Although this study was unable to identify the causes for the change in shrubs and small trees, they are consistent with anticipated changes due to climate change and reduced herbivory.

Multi-decadal changes in tundra environments and ecosystems: synthesis of the International Polar Year-Back to the Future project (IPY-BTF).

Understanding the responses of tundra systems to global change has global implications. Most tundra regions lack sustained environmental monitoring and one of the only ways to document multi-decadal change is to resample historic research sites. The International Polar Year (IPY) provided a unique opportunity for such research through the Back to the Future (BTF) project (IPY project #512). This article synthesizes the results from 13 papers within this Ambio Special Issue. Abiotic changes include glacial recession in the Altai Mountains, Russia; increased snow depth and hardness, permafrost warming, and increased growing season length in sub-arctic Sweden; drying of ponds in Greenland; increased nutrient availability in Alaskan tundra ponds, and warming at most locations studied. Biotic changes ranged from relatively minor plant community change at two sites in Greenland to moderate change in the Yukon, and to dramatic increases in shrub and tree density on Herschel Island, and in subarctic Sweden. The population of geese tripled at one site in northeast Greenland where biomass in non-grazed plots doubled. A model parameterized using results from a BTF study forecasts substantial declines in all snowbeds and increases in shrub tundra on Niwot Ridge, Colorado over the next century. In general, results support and provide improved capacities for validating experimental manipulation, remote sensing, and modeling studies.

Results of surgery for sporadic primary hyperparathyroidism in patients with preoperatively negative sestamibi scintigraphy and ultrasound.

PURPOSE: The purpose of this study is to investigate the results of first-time surgery for sporadic primary hyperparathyroidism (pHPT) in patients with preoperatively negative sestamibi scintigraphy and ultrasound. METHODS: Data were gathered prospectively in a multicenter database for quality control in parathyroid surgery. Between 2004 and 2008, 3,158 patients underwent first-time surgery for sporadic pHPT. A total of 984 patients were subjected to preoperative localization with ultrasound and sestamibi scintigraphy, and in 173 patients, both investigations were negative. Intraoperative findings and early outcome are reported. RESULTS: One hundred and fifty-five of 173 patients underwent bilateral neck exploration. The median weight of excised parathyroid tissue was 350 mg. In 23 patients (13.3%), the exploration was negative. A total of 112 patients (64.7%) had a histological diagnosis of parathyroid adenoma and 38 patients (22%) had multiglandular disease. Six weeks after operation, 164 patients were available for analysis, and 30 patients (18%) had persistent pHPT. The risk for persistent pHPT increased for patients with few intraoperatively identified (p = 0.001) and excised (p = 0.024) parathyroid glands. Patients operated with intraoperative parathyroid hormone (iOPTH) had lower risk for persistent pHPT 7/79 (9%) compared with 23/85 patients (27%) operated without iOPTH (p = 0.003). CONCLUSIONS: Negative localization with sestamibi and ultrasound in pHPT infers a highly selected patient population with small parathyroid adenomas, an alarmingly high rate of negative exploration, and an increased risk for persistent disease. The use of iOPTH influences cure rate favorably.

The immunobiology of aluminium adjuvants: how do they really work?

Aluminium adjuvants potentiate the immune response, thereby ensuring the potency and efficacy of typically sparingly available antigen. Their concomitant critical importance in mass vaccination programmes may have prompted recent intense interest in understanding how they work and their safety. Progress in these areas is stymied, however, by a lack of accessible knowledge pertaining to the bioinorganic chemistry of aluminium adjuvants, and, consequently, the inappropriate application and interpretation of experimental models of their mode of action. The objective herein is, therefore, to identify the many ways that aluminium chemistry contributes to the wide and versatile armoury of its adjuvants, such that future research might be guided towards a fuller understanding of their role in human vaccinations.

Impact of modern techniques on short-term outcome after surgery for primary hyperparathyroidism: a multicenter study comprising 2,708 patients.

PURPOSE: Preoperative localization procedures and the use of intraoperative parathyroidism (iOPTH) have led to a shift of paradigm from bilateral neck exploration to focused parathyroidectomy in primary hyperparathyroidism (pHPT). However, only a small number of randomized trials from specialized centers have been published. The main purpose of the study was to analyze the impact of localization procedures and iOPTH on short-term outcome after pHPT surgery in a multi-institutional setting. METHODS: An audit for quality assurance in pHPT surgery was performed in 23 Scandinavian departments in 2004-2008. Data were gathered prospectively in a database. Two thousand seven hundred and eight patients were registered and 78% were females. The median serum calcium level was 2.79 mmol/l. RESULTS: Localization procedures were performed in 1,831 patients (68%), (sestamibi in 54% and ultrasound in 41%) and iOPTH in 792 operations (29%). Bilateral exploration was performed in 61%, focused parathyroidectomy in 17%, and unilateral exploration in 22%. Histology showed parathyroid adenoma in 82%, with the median weight of 0.6 g. The alleviation of hypercalcemia at the first follow-up was 93% (94% for primary operation). In the multivariate logistic regression analysis, iOPTH increased cure rate (OR 1.70, 95% CI 1.14-2.53, p = 0.0092). The risk for postoperative medically treated hypocalcemia decreased with the use of localization procedures (OR 0.56, 95% CI 0.43-0.78, p = 0.0004) and iOPTH (OR 0.56, 95% CI 0.39-0.90, p = 0.0015). CONCLUSIONS: Localization procedures and iOPTH decreased the risk for hypocalcemia after pHPT surgery. Additionally, iOPTH influenced short-term cure rate favorably.