Population pharmacokinetics of cefazolin before, during and after cardiopulmonary bypass in adult patients undergoing cardiac surgery.

PURPOSE: The aims of the present study were to establish a population pharmacokinetic (PPK) model of cefazolin for adult patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) and to assess the probability of target attainment (PTA) for the prophylaxis of surgical site infection (SSI) using cefazolin. METHODS: Adult patients who underwent cardiac surgery with CPB were enrolled in the prospective study. Blood samples for plasma cefazolin assay were collected, and total and unbound drug concentrations were measured and analysed using the nonlinear mixed-effects modelling (NONMEM) software considering saturable plasma protein binding. Using the PPK model, plasma unbound cefazolin concentration-time courses with current prophylaxis protocols were simulated, and the PTA for common SSI pathogens was estimated. RESULTS: A total of 199 blood samples were obtained from 27 patients. A one-compartment model with first-order elimination plus an on/off CPB compartment best described the data. The population mean for systemic drug clearance (CL) was reduced and that for the volume of distribution (V) was increased during CPB compared with the pre-CPB values. CPB-induced hypoalbuminemia was associated with reduced maximum protein binding (Bmax). The simulation studies suggested that the current dosing protocols are insufficient for attaining PTA > 0.9 throughout surgery against pathogens with minimum inhibitory concentrations (MICs) >8 mg/L. A new dosing protocol that achieves a PTA > 0.9 for pathogens with a MIC of 16 mg/L was proposed. CONCLUSION: PPK modelling with simulation may be valuable for devising a cefazolin prophylaxis protocol for patients undergoing cardiac surgery with CPB.

The activation of G protein-coupled receptor 30 increases pro-opiomelanocortin gene expression through cAMP/PKA/NR4A pathway in mouse pituitary corticotroph AtT-20 cells.

G protein-coupled receptor 30 (GPR30) signaling plays an important role in many regulatory pathways, such as gene expression, cell proliferation and migration. However, whether GPR30 is involved in transcription of the pro-opiomelanocortin (Pomc) gene in pituitary corticotroph cells is currently unknown. Here, we report that GPR30 signaling, activated by the GPR30 specific agonist G-1, increases Pomc expression in the mouse corticotroph cell line AtT-20. G-1 also increased nuclear receptor subfamily 4 group A member 1- and 2-dependent transcription activity and phosphorylation of cyclic adenosine monophosphate response element binding protein. Furthermore, protein kinase A inhibitors strongly attenuated G-1-mediated transactivation. The findings suggest that G-1 stimulates GPR30-mediated mechanisms via cyclic adenosine monophosphate/protein kinase A/nuclear receptor subfamily 4 group A members activity in the regulation of Pomc in corticotroph cells.

Presence of aberrant adrenocorticotropic hormone precursors in two cases of McCune-Albright syndrome.

McCune-Albright syndrome (MAS) is a rare disorder. MAS is classically defined by the occurrence of fibrous dysplasia, café-au-lait skin macules, and precocious puberty. In addition to precocious puberty, other hyperfunctioning endocrinopathies may occur. We evaluated hypothalamic-pituitary-adrenal function in two cases of typical MAS associated with fibrous dysplasia and growth hormone excess. Pituitary adenoma or hyperplasia was not detected by magnetic resonance imaging. Hormonal data showed normal or low cortisol levels, despite high ACTH levels in the blood. A high ratio of circulating ACTH to cortisol was found in the two cases. Insulin tolerance and CRH tests showed hyper-responses of ACTH and an insufficient increase in cortisol levels. No involvement of 11ß-HSD1 by GH excess was suggested because basal levels of ACTH and cortisol showed no changes, even after therapy for acromegaly by somatostatin analogues. Patients with Cushing's disease cases of pituitary macroadenoma can have high circulating ACTH precursor levels, and elevated ACTH precursors have been observed in ectopic ACTH syndrome. Autonomous cortisol excess was excluded by the level of midnight cortisol and the level of cortisol after a low-dose dexamethasone suppression test in the two cases. Finally, the gel filtration profiles of immunoreactive ACTH contents showed the presence of aberrant ACTH precursors. To the best of our knowledge, there have been no reports of MAS associated with aberrant ACTH precursors. Our findings in these cases emphasize that attention should be to secretion of inactive ACTH precursors in MAS.

Effects of alveolar recruitment maneuver on end-expiratory lung volume during one-lung ventilation.

PURPOSE: To investigate the effects of alveolar recruitment maneuver (ARM) during one-lung ventilation (OLV) on end-expiratory lung volume (EELV) of the dependent lung. METHODS: Patients who were planned to undergo lung resection surgery for lung tumors and needed OLV for at least 1 h were included in the study. After turning the patients into the lateral position under total intravenous anesthesia, OLV was commenced using a double-lumen endobronchial tube. EELV was measured using the nitrogen washout technique at 20 min after OLV started (baseline) and 15, 30, 45, 60 min after ARM was performed on the dependent lung. RESULTS: Among 42 patients who completed the study, EELV increased at 15 min after ARM by 20% or greater compared with baseline in 21 patients (responders). Responders were significantly shorter in height (158 vs. 165 cm, p = 0.01) and had smaller preoperative functional residual capacity (2.99L vs. 3.65L, p = 0.02) than non-responders. Before ARM, responders had significantly higher driving pressure (14.2 vs. 12.4 cmH2O, p = 0.01) and lower respiratory system compliance (23.6 vs. 31.4 ml/cmH2O, p = 0.0002) than non-responders. Driving pressure temporarily dropped after ARM in responders, while no significant change was observed in non-responders. Fourteen out of 21 responders kept EELV 20% or more increased EELV than baseline at 60 min after ARM. CONCLUSION: EELV of the dependent lung was increased by 20% or greater in half of the patients responding to ARM. The increased volume of the dependent lung caused by ARM was maintained for 60 min in two-thirds of the responders.

Progression of Hypopituitarism and Hypothyroidism after Treatment with Pembrolizumab in a Patient with Adrenal Metastasis from Non-small-cell Lung Cancer.

Pembrolizumab, or anti-programmed death receptor 1 antibody, is an immune checkpoint inhibitor that can cause immune-related adverse events. We herein report for the first time the progression of hypopituitarism and hypothyroidism after treatment with pembrolizumab in a patient with adrenal metastasis of non-small-cell lung cancer. Severe primary hypothyroidism occurred three weeks after the first administration of pembrolizumab. Four months after the discontinuation of pembrolizumab, isolated adrenocorticotropic hormone (ACTH) deficiency was noted. Corticotropin-releasing hormone and rapid ACTH tests performed repeatedly showed that the patient's pituitary and adrenal function had been gradually deteriorating. It is important to diagnose adrenal insufficiency without delay in order to prevent adrenal crisis.

O-linked ß-N-acetylglucosamine transferase is involved in pro-opiomelanocortin gene expression in mouse pituitary corticotroph AtT-20 cells.

Glucocorticoids and glucocorticoid receptors (GRs) suppress pituitary pro-opiomelanocortin (Pomc) gene expression. O-linked ß-N-acetylglucosamine (O-GlcNAc) modification, mediated by O-GlcNAc transferase (OGT), plays an important role during gene transcription. However, whether OGT is involved in the GR-mediated transrepression that occurs in pituitary corticotroph cells is currently unknown. Here, we report that OGT regulates Pomc expression in the mouse corticotroph cell line AtT-20. The overexpression of OGT has an additive effect on the GR-mediated negative transcription pathway. Both the knockdown of OGT by RNA interference and the use of a chemical OGT inhibitor abolished the repressive effects of Pomc expression induced by GRs. OGT inhibition leads to both the decreased recruitment of GRs and the increased recruitment of RNA polymerase II to the Pomc locus. O-GlcNAc modification is involved in the negative regulation of Pomc transcription in corticotroph cells. OGT may be a promising therapeutic target for the treatment of Cushing's disease.

Effects of cardiopulmonary bypass on the disposition of cefazolin in patients undergoing cardiothoracic surgery.

The aim of the study was to evaluate the disposition of plasma unbound cefazolin in patients undergoing cardiothoracic surgery with cardiopulmonary bypass (CPB). Adult patients undergoing cardiothoracic surgery with CPB were enrolled in the study. Cefazolin sodium was given intravenously before skin incision (1 g) and at the beginning of CPB (2 g). Thereafter, an additional dose (1 g) was given every 4 hours. Seven to ten blood samples were collected before and during surgery. Plasma total and unbound (ultrafiltrated) cefazolin concentrations were analyzed using an HPLC-UV method. Plasma protein binding was analyzed with the Langmuir model. Twenty-seven patients (aged 70 ± 12 years, body weight 62 ± 12 kg, mean ± SD) with GFR >30 mL min-1 completed the study. There was a significant (P < 0.001) increase in median plasma unbound fraction of cefazolin from 21% before skin incision to 45% during CPB (P < 0.001), which was accompanied by a significant (P < 0.001) reduction in median plasma albumin concentration from 36 to 27 g L-1. Plasma concentrations of unbound cefazolin exceeded the assumed target thresholds of 2 µg mL-1 in all samples and of 8 µg mL-1 in all but one of 199 samples. The increased plasma unbound fraction of cefazolin would be attributable to dilutional reduction of serum albumin at the beginning of CPB and to saturable plasma protein binding of cefazolin. These data reveal CPB may alter the plasma protein binding and possibly distribution of cefazolin. Further studies are warranted to reappraise the protocol of antimicrobial prophylaxis with cefazolin in patients undergoing surgery with CPB.

Neonatal Sevoflurane Exposure Induces Adulthood Fear-induced Learning Disability and Decreases Glutamatergic Neurons in the Basolateral Amygdala.

BACKGROUND: Neonatal mice exposed to sevoflurane show certain cognitive and behavioral impairments in adulthood. However, the mechanisms underlying long-term cognitive deficits induced by sevoflurane exposure remain unknown. The present study was performed to investigate whether there is differential neuronal activation between naive mice and sevoflurane-exposed neonates in fear-conditioning tests based on immediate early gene (c-Fos) expression. METHODS: Male mice were exposed to 3% sevoflurane (SEVO group) or carrier gas alone (no anesthesia, NA group) for 6 hours on postnatal day 6. The mice were allowed to mature before performing the contextual fear-conditioning test. A reduced freezing response was confirmed in the SEVO group. Neural activation in the regions of the medial prefrontal cortex, hippocampus, and amygdala was investigated using c-Fos immunostaining 2 hours after the test. The types of neurons activated were also identified. RESULTS: The number of c-Fos-positive cells decreased by 27% in the basolateral amygdala in the SEVO group, while no significant changes were observed in other regions. Furthermore, glutamatergic, but not γ-aminobutyric acid (GABA)ergic, neurons expressed c-Fos after the contextual fear-conditioning test in both groups. The number of glutamatergic neurons in the basolateral amygdala in the SEVO group was reduced by 27%. CONCLUSIONS: Decreased neural activation in the basolateral amygdala may be associated with reduced freezing time in neonatal sevoflurane-exposed mice. Fewer glutamatergic neurons responding to fear stimuli in the basolateral amygdala may contribute to decreased neural activation and learning deficits in mice exposed to sevoflurane as neonates.

Cytotoxicity of propofol in human induced pluripotent stem cell-derived cardiomyocytes.

PURPOSE: Propofol infusion syndrome (PRIS) is a lethal condition caused by propofol overdose. Previous studies suggest that pathophysiological mechanisms underlying PRIS involve mitochondrial dysfunction; however, these mechanisms have not been fully elucidated. This study aimed to establish an experimental model of propofol-induced cytotoxicity using cultured human induced pluripotent stem cell (iPSC)-derived cardiomyocytes to determine the mechanisms behind propofol-induced mitochondrial dysfunction, and to evaluate the protective effects of coenzyme Q10 (CoQ10). METHODS: Human iPSC-derived cardiomyocytes were exposed to propofol (0, 2, 10, or 50 µg/ml) with or without 5 µM CoQ10. Mitochondrial function was assessed by measuring intracellular ATP, lactate concentrations in culture media, NAD+/NADH ratio, and the mitochondrial membrane potential. Propofol-induced cytotoxicity was evaluated by analysis of cell viability. Expression levels of genes associated with mitochondrial energy metabolism were determined by PCR. Intracellular morphological changes were analyzed by confocal microscopy. RESULTS: Treatment with 50 µg/ml propofol for 48 h reduced cell viability. High concentrations of propofol (≥ 10 µg/ml) induced mitochondrial dysfunction accompanied by downregulation of gene expression of PGC-1alpha and its downstream targets (NDUFS8 and SDHB, which are involved in the respiratory chain reaction; and CPT1B, which regulates beta-oxidation). Cardiomyocytes co-treated with 5 µM CoQ10 exhibited resistance to propofol-induced toxicity through recovery of gene expression. CONCLUSIONS: Propofol-induced cytotoxicity in human iPSC-derived cardiomyocytes may be associated with mitochondrial dysfunction via downregulation of PGC-1alpha-regulated genes associated with mitochondrial energy metabolism. Co-treatment with CoQ10 protected cardiomyocytes from propofol-induced cytotoxicity.

Sevoflurane preconditioning ameliorates lipopolysaccharide-induced cognitive impairment in mice.

Systemic inflammation induces brain neuronal inflammation, in turn causing acute cognitive disorders. Furthermore, neuronal inflammation is one cause of postoperative cognitive disorder (POCD) and delirium. However, no sufficiently established pharmacological treatment is available for neurocognitive inflammation. This study evaluated the possible neuroprotective effects of preconditioning with sevoflurane anesthesia on cognition and neuroinflammatory changes in an animal model of lipopolysaccharide (LPS)-induced systemic inflammation. Adult mice were randomly divided into (1) control, (2) 2% sevoflurane preconditioning for 1 h, (3) intraperitoneal 5 mg/kg LPS injection, and (4) 2% sevoflurane preconditioning for 1 h + LPS injection groups. At 24 h after 5 mg/kg LPS injection, microglial activation based on ionized calcium-binding adapter molecule 1 (Iba-1) expression in the hippocampus was determined using immunostaining and immunoblotting. IL-1ß and IL-6 immunoblotting were used as inflammation markers, and ß-site of amyloid precursor protein cleaving enzyme 1 (BACE1) immunoblotting was performed to evaluate amyloid ß-protein (Aß) accumulation. Long-term cognitive impairment was evaluated using fear conditioning tests. Intraperitoneal LPS increased levels of Iba-1 (150%), inflammation markers (160%), and Aß accumulation (350%), and sevoflurane preconditioning suppressed these increases. Systemic LPS caused learning deficits. Sevoflurane also maintained long-term memory in mice receiving LPS injection. Sevoflurane preconditioning prevented long-term memory impairment in the mouse model administered systemic LPS by decreasing excessive microglial activation, inflammation, and Aß accumulation. This study supports the hypothesis that sevoflurane preconditioning might also be beneficial for neuronal inflammation. Sevoflurane might be beneficial for reducing delirium and POCD.

Corrigendum to "Sugammadex-Enhanced Neuronal Apoptosis following Neonatal Sevoflurane Exposure in Mice".

[This corrects the article DOI: 10.1155/2016/9682703.].

Effects of acute kidney injury after liver resection on long-term outcomes.

BACKGROUND: To investigate the effects of acute kidney injury (AKI) after liver resection on the long-term outcome, including mortality and renal dysfunction after hospital discharge. METHODS: We conducted a historical cohort study of patients who underwent liver resection for hepatocellular carcinoma with sevoflurane anesthesia between January 2004 and October 2011, survived the hospital stay, and were followed for at least 3 years or died within 3 years after hospital discharge. AKI was diagnosed based on the Acute Kidney Injury Network classification within 72 hours postoperatively. In addition to the data obtained during hospitalization, serum creatinine concentration data were collected and the glomerular filtration rate (GFR) was estimated after hospital discharge. RESULTS: AKI patients (63%, P = 0.002) were more likely to reach the threshold of an estimated GFR (eGFR) of 45 ml/min/1.73 m2 within 3 years than non-AKI patients (31%) although there was no significant difference in mortality (33% vs. 29%). Cox proportional hazard regression analysis showed that postoperative AKI was significantly associated with the composite outcome of mortality or an eGFR of 45 ml/min/1.73 m2 (95% CI of hazard ratio, 1.05-2.96, P = 0.033), but not with mortality (P = 0.699), the composite outcome of mortality or an eGFR of 60 ml/min/1.73 m2 (P =0.347). CONCLUSIONS: After liver resection, AKI patients may be at higher risk of mortality or moderate renal dysfunction within 3 years. These findings suggest that even after discharge from the hospital, patients who suffered AKI after liver resection may need to be followed-up regarding renal function in the long term.

Perioperative airway management of a 16-year-old boy with progressive airway obstruction due to juvenile nasopharyngeal angiofibroma.

Juvenile nasopharyngeal angiofibroma (JNA) involves difficult anesthetic management because of the risk of massive bleeding, while airway management is rarely a problem in JNA. This report presents an unusual case of JNA causing airway obstruction.

Disrupted offset analgesia distinguishes patients with chronic pain from healthy controls.

Offset analgesia (OA) represents a disproportionately large decrease of pain perception after a brief, temporary increment of thermal pain stimulus and was reported attenuated in patients with neuropathic pain. We examined whether OA depends on the increment duration before offset, and whether individual features of OA distinguish patients with chronic pain and healthy controls. We used a Peltier-type thermal stimulator and OA paradigms including 5-, 10-, or 15-s duration of 1°C-increment (T2) over 45°C. We first examined OA response, on the left volar forearm, at 3 different T2's in 40 healthy volunteers, and OA and constant stimulus responses in 12 patients with chronic pain and 12 matched healthy controls. We measured magnitude of OA ([INCREMENT]OA) and maximum visual analogue scale (VAS) latency (time to peak VAS) during constant stimulus for each individual. Pain perception kinetics were compared with analysis of variance and sought for correlations with psychophysical parameters with a significance threshold at P < 0.05. In healthy controls, longer T2 at 10 or 15 seconds resulted in larger [INCREMENT]OA compared with T2 at 5 seconds (P = 0.04). In patients, [INCREMENT]OA was significantly smaller than controls at T2 = 5 or 10 seconds (P < 0.05) but grew comparable at T2 = 15 seconds with controls. Maximum VAS latency was longer in patients than in controls and negatively correlated with [INCREMENT]OA in patients. An OA index ([INCREMENT]OA/[maximum VAS latency]) proved diagnostic of chronic pain with an area under the receiver operating characteristic curve at 0.897. Patients with chronic pain showed impairment of OA and reduced temporal sharpening of pain perception, which might imply possible disturbance of the endogenous pain modulatory system.

Apocynin preserves glutamatergic neurons in the basolateral amygdala in mice with neonatal sevoflurane exposure.

BACKGROUND: Neonatal exposure to anesthetics induces neuronal apoptosis and long-term cognitive dysfunction in rodents. We showed that the nicotinamide adenine dinucleotide phosphate-oxidase inhibitor apocynin not only reduces neurotoxicity by decreasing superoxide levels and preventing mitochondrial dysfunction but also improves long-term memory impairment in neonatal mice exposed to sevoflurane. We also found that after the contextual fear conditioning test, glutamatergic neurons expressed c-Fos (neural activation) regardless of previous exposure to sevoflurane. Moreover, there were fewer c-Fos-expressing glutamatergic neurons in the basolateral amygdala (BLA) after exposure to sevoflurane than after exposure to carrier gas. In this study, we investigated whether the administration of apocynin prior to sevoflurane exposure would preserve glutamatergic neurons in the BLA. METHODS: Apocynin (50 mg/kg) was injected intraperitoneally into six-day-old male mice 30 min before 6 h of exposure to 3% sevoflurane or carrier gas only. The mice were allowed to mature and then were subjected to the contextual fear conditioning test. The neural activation and neuron population in the BLA were investigated 2 h later. RESULTS: Administration of apocynin prior to neonatal sevoflurane exposure not only prevented learning deficits but also preserved c-Fos-expressing glutamatergic neurons in the BLA. CONCLUSIONS: Apocynin mitigates the cognitive impairment induced by neonatal sevoflurane exposure and preserves c-Fos-expressing glutamatergic neurons in the basolateral amygdala.

A low dose of droperidol decreases the desflurane concentration needed during breast cancer surgery: a randomized double-blinded study.

BACKGROUND: Droperidol (DHB) reportedly reduces the dose of propofol needed to achieve hypnosis when anesthesia is induced and decreases the bispectral index (BIS) in propofol-sedated patients during spinal anesthesia. We reported previously that supplemental DHB decreased the BIS after the administration of sevoflurane and remifentanil. This study investigated the effect of DHB on desflurane (DES) consumption in a clinical setting. METHODS: We conducted a prospective, randomized double-blinded study of 35 women with American Society of Anesthesiologist physical status I or II who underwent a mastectomy. Either DHB (20 µg/kg) or a saline placebo was administered to patients 30 min after the induction of anesthesia. A blinded anesthesiologist maintained a BIS value of 50 during anesthesia by modulating inhaled DES concentrations that changed 0.5% at 2.5 min intervals and maintained analgesia via the constant administration of remifentanil by referring to vital signs. The primary endpoint was the effect of DHB on DES consumption. The secondary endpoints included blood circulatory parameters, the time from the end of surgery to extubation, and discharge time between the groups. RESULTS: The characteristics of the patients did not differ between the groups. The DHB group used a mean of 27.2 ± 6.0 ml of DES compared with 41.4 ± 9.5 ml by the placebo group (P < 0.05). CONCLUSIONS: A small dose of DHB reduced the DES concentration needed to maintain a BIS of 50. Our results show that DHB reduced the consumption of DES without adverse effects.

A case of unexpected impaired oxygenation due to intraoperative pneumothorax: an adverse event associated with respiratory management with spontaneous respiration in a patient with esophagobronchial fistulae.

BACKGROUND: Respiratory management in patients with esophagobronchial fistulae is challenging since positive pressure ventilation (PPV) may not be feasible due to air leaks and possible risks for regurgitation and aspiration of gastric contents. We and others have previously reported that spontaneous respiration may be one of the good options of respiratory management during general anesthesia in those patients. However, adverse events associated with this respiratory strategy have not been reported previously. We experienced a 77-year-old male patient who suffered unexpected impairment of oxygenation due to intraoperative pneumothorax, which was assumed to have been exacerbated by spontaneous respiration during esophageal bypass surgery. CASE PRESENTATION: The patient was planned to undergo esophageal bypass surgery for esophagobronchial fistulae associated with malignant esophageal cancer. Both of two esophagobronchial fistulae were located in the proximal part of the left main bronchus. For the risks of air leaks and aspiration associated with PPV and further damage to the tissue around the fistulae, we decided to maintain spontaneous respiration under general anesthesia and obtain abdominal muscle relaxation with epidural anesthesia. After catheterization of epidural anesthesia, the patient was sedated with 35 mg of intravenous pethidine and was nasotracheally intubated under bronchoscopic guidance. We confirmed that the tip of the tracheal tube was located above the carina. Then anesthesia was induced and maintained with sevoflurane so that his spontaneous respiration could be maintained thereafter. His spontaneous respiration was assisted with 3 cmH2O of pressure support. Approximately 60 min into the surgery, percutaneous arterial oxygen saturation (SpO2) suddenly dropped from 99 to 89% with an inspiratory fraction of oxygen of 0.4. We assumed that lung atelectasis associated with airway secretion or pulmonary soiling was the most likely reason for impaired oxygenation; however, arterial oxygenation only partially regained even after they were suctioned. After the completion of the surgery, chest X-ray revealed right pneumothorax. After a chest drainage tube was inserted, right pneumothorax was ameliorated and SpO2 returned to the baseline level. CONCLUSIONS: Although spontaneous respiration may be useful in a patient with esophagobronchial fistulae, oxygenation can be impaired more seriously than PPV in case intraoperative pneumothorax occurs.

Dysfunction of Nucleus Accumbens Is Associated With Psychiatric Problems in Patients With Chronic Low Back Pain: A Functional Magnetic Resonance Imaging Study.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: The aim of this study was to evaluate activity of the nucleus accumbens (NAc) in response to lumbar mechanical stimulation in patients with chronic low back pain (cLBP) using functional magnetic resonance imaging (fMRI). SUMMARY OF BACKGROUND DATA: Although a modified activity of the NAc was characterized in cLBP patients, its pathological significance has yet to be determined. We hypothesized that NAc activation in response to pain might differ depending on the extent of psychiatric problems, which might be associated with the affective/motivational background of chronic pain. METHODS: Twenty-one patients with cLBP (four men, 17 women) were recruited. Subjects were divided into two groups on the basis of scores on the patient version of the Brief Scale for Psychiatric problems in Orthopaedic Patients (BS-POP) scores: ≥17 (High Score, HiS group) and <17 (non-High Score, non-HiS group). Each subject was placed in the prone position on a 3-Tesla magnetic resonance imaging (MRI) scanner and stimulated by mechanical stimulation on the left lower back. Three blocks of 30-second pain stimulus calibrated at either 3 or 5 on an 11-grade numerical rating scale (NRS) were applied with intervening 30-second rest conditions during whole-brain echo-planar imaging. Functional images were analyzed using a multisubject general linear model with Bonferroni multiple comparisons. RESULTS: Subjects in the HiS group had more intense daily pain and lower quality of life than those in the non-HiS group (P < 0.05). Catastrophic thinking in relation to pain experience did not differ between the groups. Activation at the NAc was smaller in the HiS group than in the non-HiS group (P < 0.001). CONCLUSION: The presence of psychiatric problems was associated with attenuated activity of the NAc in cLBP patients. Dysfunction of the NAc might potentially be involved in the affective/motivational factors in the chronification of LBP. LEVEL OF EVIDENCE: N/A.