Cervical intervertebral disc disease in 307 small-breed dogs (2000-2021): Breed-characteristic features and disc-associated vertebral instability

OBJECTIVE

To evaluate the breed-characteristic features of cervical intervertebral disc disease (C-IVDD) and associated vertebral instability in small-breed dogs and to present the concept of intervertebral disc degeneration and associated instability stage, method of diagnosis, treatment and outcomes.

ANIMALS

In total, 307 client-owned dogs with C-IVDD treated with spinal cord decompression with or without vertebral stabilization (2000-2021).

METHODS

Information on age, sex, affected sites, stabilized sites, diagnostic methods for vertebral instability and outcomes were retrieved. The patient's age, affected sites (cranial vs caudal discs), and frequency of vertebral stabilization were compared in six CD and five NCD breed. Multivariable analyses of the chondrodystrophic (CD) vs non-CD (NCD) groups, and vertebral stabilization (dogs stabilized vs dogs not stabilized) were performed.

RESULTS

In total, 222 (72.3%) and 77 (25.1%) were CD and NCD breeds, respectively. Vertebral instabilities were diagnosed based on the survey radiographs with computed tomography/magnetic resonance imaging (n = 2), dynamic myelography (n = 29), intraoperative spinal manipulation (n = 11) or second surgery in dogs with persistent postoperative paraspinal pain (n = 3). Of these dogs, 295 (96.1%) recovered (median follow-up: 8.5 [range, 1-119] months). Significant differences in age, affected sites and frequency of stabilization were noted among the breeds. Older age and frequent vertebral stabilization were the associated factors for the NCD breed dogs. Male dogs, caudal discs affected (C5-T1) and the NCD breed dogs were risk factors for the dogs with vertebral stabilization.

CONCLUSION

Vertebral stabilization is indicated for small-breed dogs with cervical disc-associated vertebral instability.

Thoracic Vertebral Canal Stenosis and Vertebral Instability in a Young Minuet Cat

This report describes a unique case of thoracic vertebral canal stenosis and vertebral instability in a 1 yr old Minuet cat. The cat presented with a history of chronic progressive nonambulatory paraparesis. Myelography with neutral and stress positions revealed dynamic compression at T1-4. Computed tomography and MRI revealed multiple sites of vertebral endplate osteolysis, adjacent bone sclerosis, intervertebral disk space narrowing, and spondylotic bridging within the cervical and cranial thoracic vertebral bodies and pedicles, particularly at C6-T4. The cat underwent a right-sided T1-4 hemilaminectomy and C7-T4 vertebral stabilization using positively threaded profile pins and polymethylmethacrylate. The cat fully recovered without any complication. The case highlights the potential for young cats, especially those with a chondrodysplastic condition, to develop vertebral canal stenosis and vertebral instability. The surgical treatment described herein resulted in an excellent outcome.

Vertebral stabilisation for thoracolumbar vertebral instability associated with cranial and caudal articular process anomalies in pugs: Seven cases (2010-2019)

OBJECTIVES

To describe the diagnostic findings, surgical technique and outcomes in seven pugs with thoracolumbar vertebral instability due to articular process anomalies.

MATERIALS AND METHODS

Records (2010 to 2019) of pugs with thoracolumbar vertebral instability associated with articular process anomalies that underwent decompressive laminectomy and vertebral stabilisation were reviewed. Data on preoperative and postoperative neurologic status, diagnostic findings, surgical techniques and outcomes were retrieved.

RESULTS

Seven dogs were presented with ambulatory or non-ambulatory paraparesis. Caudal articular process anomalies (three dogs) and concomitant cranial and caudal articular process anomalies (four dogs) were noted. Myelography (six dogs) or magnetic resonance imaging (one dog) showed none to severe spinal cord compression. Dynamic myelography in six dogs demonstrated nine distinct sites of spinal cord dimension reduction positioned in extension and/or flexion (mean reduction: 16.0%, range: 8.5 to 24.0%). These dynamic compressions were located at sites with articular process anomalies (seven sites) and sites with no articular process anomalies (two sites). Vertebral instability was confirmed by intraoperative spinal manipulation in all dogs. All dogs remained ambulatory with improved (five dogs) or static (two dogs) neurological deficits at the last follow-up (median: 16 months; range: 1.5 to 66 months).

CLINICAL SIGNIFICANCE

Dynamic myelography and/or intraoperative spinal manipulation demonstrated vertebral instabilities at sites with or without articular process anomalies on imaging. Decompressive laminectomy with vertebral stabilisation resulted in long-term neurological improvement in most dogs.

Insulin-mediated regulation of decidual protein induced by progesterone (DEPP) in adipose tissue and liver

We analyzed the profile of the genes expressed in human adipose tissue and identified the fat-derived molecules, adiponectin and aquaporin 7, which modulate glucose and lipid metabolism. The same Bodymap analysis revealed abundant expression of the decidual protein induced by progesterone (DEPP) in the white adipose tissue. Northern blot analysis confirmed that human DEPP mRNA was highly expressed in white adipose tissue. Mouse DEPP mRNA was detected in heart, lung, skeletal muscle, and white adipose tissue under feeding state. In contrast, under fasting state, mouse DEPP mRNA was enhanced in lung, skeletal muscle, and white adipose tissue and it appeared also in the liver and kidney, suggesting up regulation of DEPP by fasting. Because fasting-induced DEPP expression was observed in insulin-sensitive organs, we investigated the regulation of DEPP in white adipose tissue and liver. During adipogenesis of mouse 3T3-L1 cells, DEPP mRNA increased in a differentiation-dependent manner similar to adiponectin and aquaporin 7. Treatment of cultured 3T3-L1 mature adipocytes, rat H4IIE, and human HepG2 hepatoma cells with insulin significantly decreased DEPP mRNA levels in dose- and time-dependent manners. IN VIVO experiments showed significant decrease of hepatic and adipose DEPP mRNA levels in refed mice, compared to fasted animals, and also showed significant increase in DEPP mRNA in streptozotocin-induced insulin-deficient diabetic mice. These results indicate that DEPP is a novel insulin-regulatory molecule expressed abundantly in insulin-sensitive tissues including white adipose tissue and liver.

Adiponectin plays a protective role in caerulein-induced acute pancreatitis in mice fed a high-fat diet

BACKGROUND

Obesity is a risk factor for acute pancreatitis (AP), but the molecular mechanism remains unclear. Adiponectin, an adipose tissue-derived secretory factor, has anti-inflammatory properties in addition to various biological functions, and its plasma concentrations are reduced in obese subjects. However, the role of adiponectin in AP has not been investigated.

AIM

To determine the effects of adiponectin on AP.

METHODS

We investigated the effects of adiponectin on experimental AP by using adiponectin-knockout (APN-KO) mice and adenovirus-mediated adiponectin over-expression. AP was induced by 10 hourly intraperitoneal injections of low-dose caerulein (10 microg/kg) after 2 week feeding of normal chow or a high-fat diet (HFD) in wild-type (WT) and APN-KO mice. We evaluated the severity of AP biochemically and morphologically.

RESULTS

Low-dose caerulein treatment did not induce pancreatic damage in either WT or APN-KO mice under normal chow feeding. APN-KO mice, but not WT mice, fed a HFD and then treated with caerulein developed pancreatic damage and inflammation, accompanied by increased macrophage/neutrophil infiltration and upregulation of pro-inflammatory mediators such as tumour necrosis factor alpha in the pancreas. Adenovirus-mediated over-expression of adiponectin attenuated the severity of HFD/caerulein-induced AP in APN-KO mice.

CONCLUSIONS

Adiponectin plays a protective role in caerulein-induced AP in HFD-fed mice.

[Dissection of descending aorta with spinal paralysis]

A 56-year-old man had undergone ascending aorta and total arch replacement because of aortic dissection (Stanford type A) in 1997. He had onset of diplegia of the lower limb and vesicorectal disability. Computed tomography (CT) showed serpentine aneurysm in the descending aorta, it was seen between the left subclavian artery and diaphragm level. It was 80 mm of maximum diameter. Magnetic resonance imaging (MRI) was performed for identified Adamkiewicz artery, but we could not identify it. We performed a graft replacement. The 8th intercostal artery was reconstructed with a branch graft. The postoperative course was uneventful. We conclude that graft replacement for spinal ischemia can be effective.

Blockade of Angiotensin II type-1 receptor reduces oxidative stress in adipose tissue and ameliorates adipocytokine dysregulation

Dysregulated production of adipocytokines may be involved in the development of atherosclerotic cardiovascular disease in metabolic syndrome and chronic kidney disease (CKD) associated with metabolic syndrome. The aim of this study was to determine the effects of treatment with angiotensin II (Ang II) type-1 receptor blocker (ARB) on the regulation of adipocytokines. Olmesartan, an ARB, significantly blunted the age- and body weight-associated falls in plasma adiponectin both in genetically and diet-induced obese mice, without affecting body weight, but had no effect on plasma adiponectin levels in lean mice. Olmesartan also ameliorated dysregulation of adipocytokines in obesity, such as tumor necrosis factor-alpha, plasminogen activator inhibitor-1, monocyte chemotactic protein-1, and serum amyloid A3. Olmesartan significantly reduced reactive oxygen species originating from accumulated fat and attenuated the expression of nicotinamide adenine dinucleotide phospho hydrogenase oxidase subunits in adipose tissue. In cultured adipocytes, olmesartan acted as an antioxidant and improved adipocytokine dysregulation. Our results indicate that blockade of Ang II receptor ameliorates adipocytokine dysregulation and that such action is mediated, at least in part, by targeting oxidative stress in obese adipose tissue. Ang II signaling and subsequent oxidative stress in adipose tissue may be potential targets for the prevention of atherosclerotic cardiovascular disease in metabolic syndrome and also in metabolic syndrome-based CKD.

Production of adiponectin, an anti-inflammatory protein, in mesenteric adipose tissue in Crohn's disease

BACKGROUND AND AIMS

A characteristic feature of Crohn's disease (CD) is mesenteric adipose tissue hypertrophy. Mesenteric adipocytes or specific proteins secreted by them may play a role in the pathogenesis of CD. We recently identified adiponectin as an adipocyte specific protein with anti-inflammatory properties. Here we report on expression of adiponectin in mesenteric adipose tissue of CD patients.

METHODS AND RESULTS

Mesenteric adipose tissue specimens were obtained from patients with CD (n = 22), ulcerative colitis (UC) (n = 8) and, for controls, colon carcinoma patients (n = 28) who underwent intestinal resection. Adiponectin concentrations were determined by enzyme linked immunosorbent assay, and adiponectin mRNA levels were determined by real time quantitative reverse transcription-polymerase chain reaction. Tissue concentrations and release of adiponectin were significantly increased in hypertrophied mesenteric adipose tissue of CD patients compared with normal mesenteric adipose tissue of CD patients (p = 0.002, p = 0.040, respectively), UC patients (p = 0.002, p = 0.003), and controls (p<0.0001, p<0.0001). Adiponectin mRNA levels were significantly higher in hypertrophied mesenteric adipose tissue of CD patients than in paired normal mesenteric adipose tissue from the same subjects (p = 0.024). Adiponectin concentrations in hypertrophied mesenteric adipose tissue of CD patients with an internal fistula were significantly lower than those of CD patients without an internal fistula (p = 0.003).

CONCLUSIONS

Our results suggest that adipocytes in hypertrophied mesenteric adipose tissue produce and secrete significant amounts of adiponectin, which could be involved in the regulation of intestinal inflammation associated with CD.

Maternal soluble tumour necrosis factor receptor type 2 (sTNFR2) and adiponectin are both related to blood pressure during gestation and infant's birthweight

OBJECTIVE

Tumour necrosis factor alpha (TNF-alpha) and adiponectin are strongly related to insulin sensitivity; insulin resistance of pregnancy is a major determinant of infant's birthweight. We aimed to study the contributions of maternal serum concentrations of soluble TNF-alpha receptors (sTNFR1 and sTNFR2) and adiponectin to infant's birthweight.

DESIGN

Cross-sectional, hospital-based study of insulin sensitivity during gestation.

PATIENTS

Fifty-one healthy women with uncomplicated pregnancy and delivery (except for elective Caesarian section) and their healthy newborn infants. measurements Maternal blood levels of glucose, insulin, glycosylated haemaglobin (HbA1c), sTNFR1, sTNFR2 and adiponectin at delivery; cord-blood levels of sTNFR1, sTNFR2 and adiponectin.

RESULTS

At delivery, maternal sTNFR2 correlated with systolic blood pressure (SBP; r = 0.38, P = 0.005). In multiple regression analyses, SBP and HbA1c were independent predictors of sTNFR2, explaining 18 and 7% of its variance, respectively; insulin resistance index (HOMA-IR), body mass index at delivery and SBP were independent predictors of adiponectin, explaining 15, 8 and 7% of its variance, respectively. Both maternal sTNFR2 and SBP were negatively correlated with infant's birthweight (r = -0.28, P = 0.04 and r = -0.36, P = 0.01 respectively, adjusted for sex and gestational age). In multivariate regression analyses, infant's sex and either maternal sTNFR2 or adiponectin were independent predictors of infant's birthweight, each explaining between 6 and 9% of birthweight variance. Further addition of maternal SBP to these models revealed that this variable was the main predictor of infant's birthweight, explaining 13% of its variance.

CONCLUSIONS

Maternal sTNFR2 and adiponectin are independently related to both maternal blood pressure and infant's birthweight in uncomplicated pregnancy. The contributions of the TNF-alpha system and adiponectin to hypertensive disorders of pregnancy and fetal growth merit further studies.

[Selection of surgical strategy for abdominal aortic aneurysm coexisting with coronary artery disease; one-stage versus two-stage, and off-pump versus on-pump]

BACKGROUND

In patients having a combination of severe coronary artery disease (CAD) and expanding abdominal aortic aneurysm (AAA), one-stage operation of simultaneous coronary artery bypass grafting (CABG) and AAA repair has been recommended.

METHODS AND RESULTS

Of 96 patients (94 men, average 65 year) with AAA and CAD, 21 patients underwent one-stage operation of simultaneous CABG and AAA repair (Group A-1: off-pump CABG in 10 and on-pump in 11), and 75 underwent two-stage operation of CABG followed by AAA with an interval of less than 6 months in 23 patients (Group A-2) and more than 6 months in 52 patients (Group B). Baseline characteristics were similar between the one-stage and two-stage groups, and off-pump and on-pump subgroups, except the proportion of single vessel disease. Mean number of distal anastomoses was significantly lower in the off-pump subgroup than in the on-pump subgroup (p = 0.011) and the two-stage group (p = 0.0057). There was 1 hospital death among on-pump patients but none among off-pump patients. Mortality rate was 4.8% in the one-stage group. Two patients (8.7 &) in the two-stage group, who had AAA was 7.0 cm and 7.5 cm diameter, died of AAA rupture prior to repair. The 10-year all death free rates were 44% in Group A (A-1 and A-2), and 86% in Group B (p = 0.0004).

CONCLUSIONS

Our data suggest that one-stage operation with off-pump CABG is an attractive option in selected patients with a large AAA (> 7 cm).

[Off-pump versus standard on-pump reoperative coronary artery bypass grafting]

BACKGROUND

Using standard on-pump procedures, repeat coronary artery bypass grafting (re-CABGs) are associated with a higher morbidity and mortality than first-time CABGs. This retrospective study assessed the clinical outcomes of off-pump re-CABG versus on-pump re-CABG.

METHODS

From 1983, 2nd CABG and 3rd CABGs were performed in 162 patients at our institute. The early and late results of 142 patients who received standard on-pump re-CABGs and 20 patients who received off-pump re-CABGs were evaluated. The 2 groups were similar in age, sex, preoperative ejection fraction (EF) and number of coronary lesions. However, mean number of distal anastomoses per patient was significantly higher in on-pump (2.0 +/- 0.8) than in off-pump re-CABG (1.4 +/- 0.6) [p = 0.0009].

RESULTS

Hospital mortality tended to be higher in the on-pump group (5.6%) than in the off-pump group (0%) [p = 0.6]. Morbidity in term of total postoperative complications tended to be higher for on-pump (14.1%) than in off-pump (0%) [p = 0.14]. The 5-year survival rate tended to be higher in the off-pump group (100%) than in the on-pump group (80.8 +/- 3.5%) [p = 0.096].

CONCLUSIONS

In selected patients, off-pump re-CABG can be a reliable and safe option. The mid-term survival and event-free survival rates achievable with the off-pump option are encouraging.

Hemodynamic responses among three tracheal intubation devices in normotensive and hypertensive patients

We compare hemodynamic responses in normotensive and hypertensive anesthetized paralyzed patients among three intubation devices: the Macintosh laryngoscope (LS), the Trachlight lightwand (LW), and the intubating laryngeal mask airway Fastrach (ILM). Seventy-five normotensive and 75 hypertensive patients were randomly assigned to each intubation device (n = 25). Noninvasive systolic blood pressure (SBP) and diastolic blood pressure (DBP) and heart rate (HR) were recorded immediately preinduction, immediately preintubation, and every minute for the first 5 min after the successful intubation. The number of intubation attempts, the time to successful intubation, and any airway injuries were recorded. Pharyngolaryngeal morbidity was assessed 18-24 h after surgery by a blinded investigator. In all groups, there was a reduction in SBP and DBP but no change in HR immediately preintubation compared with baseline values. In all groups, HR increased, but there were no increases in SBP and DBP other than in DBP in the LS/hypertensive group after intubation compared with baseline values. In normotensive patients, there were no differences in any hemodynamic variables among the three devices. In hypertensive patients, SBP and DBP in the LS group were significantly higher than the ILM and LW groups for 2 min after intubation, but there were no differences in HR among the devices. The number of intubation attempts was similar among groups, but intubation time was longer for the ILM group. The incidence of airway injury was more frequent for the ILM than the LS and LW groups (16% versus 0% versus 0%). There were no differences in pharyngolaryngeal morbidity among groups. We conclude that both the ILM and the LW attenuated the hemodynamic stress response to tracheal intubation compared with the LS in hypertensive, but not in normotensive, anesthetized paralyzed patients.

IMPLICATIONS

Both the intubating laryngeal mask airway Fastrach and the Trachlight lightwand attenuate the hemodynamic stress response to tracheal intubation compared with the Macintosh laryngoscope in hypertensive, but not in normotensive, anesthetized paralyzed patients.

Novel LPL mutation (L303F) found in a patient associated with coronary artery disease and severe systemic atherosclerosis

BACKGROUND

Patients with lipoprotein lipase (LPL) deficiency had been generally thought to be spared accelerated atherosclerosis in spite of a marked elevation of plasma triglyceride levels. However, it has been recently reported that some heterozygous and homozygous LPL-deficient patients are associated with premature atherosclerosis. In this paper, we report a 55-year-old type I hyperlipidaemic patient with a novel missense mutation in the LPL gene.

PATIENT AND RESULTS

The patient had suffered from coronary artery disease, abdominal aortic aneurysm, and stenoses of the bilateral renal arteries and superficial femoral arteries. Sequencing of the genomic DNA revealed that the patient was a homozygote for the mutation, a G to C transition at nucleotide position 1069 in the exon 6, resulting in an amino acid substitution of Phe for Leu303 (L303F). Approximately 6% and approximately 40% of normal LPL activity and LPL mass, respectively, were detected in the patient's postheparin plasma. An in vitro expression study demonstrated that COS7 cells transfected with L303F mutant cDNA produced a 40% amount of LPL protein in cell lysates compared with normal cDNA, but no protein was detected in the media. Lipoprotein lipase activity was completely absent in both lysates and media of the cells transfected with the mutant cDNA, suggesting that this mutation in the LPL gene results in the production of a functionally inactive protein.

CONCLUSION

This case suggests that the LPL missense mutation (L303F), which impairs lipolysis but preserves the LPL mass, is proatherogenic.

Effects of soy protein diet on the expression of adipose genes and plasma adiponectin

Many studies have reported the cholesterol-lowering, anti-lipogenic, anti-obesity and anti-hypertensive effects of soy protein. Adipose tissue-specific plasma protein, adiponectin, has anti-atherogenic and anti-insulin-resistance properties. Here, we investigated the effects of soy protein diet on body fat composition, plasma glucose, lipid and adiponectin levels and expression of genes involved in glucose and fatty acid metabolism in obese KK-A y mice. Body weights and adipose tissue weights of mesenteric, epididymal, and brown fat were lower in mice on calorie-restricted diet containing soy protein isolate. Plasma cholesterol, triglyceride, free fatty acid, and glucose levels were also decreased by this diet. Body fat content and plasma glucose levels in mice on a soy protein isolate diet were still lower than those treated with an isocaloric casein-protein-diet. Among the genes related to glucose and fatty acid metabolism, adiponectin mRNA levels in adipose tissue and adiponectin plasma concentrations were elevated in mice on a calorie-restricted diet, although there were no significant differences between soy protein and casein protein groups. Our results indicate that that soy protein diet decreased body fat content and plasma glucose levels more effectively than isocaloric casein-protein diet in obese mice.

Intubating laryngeal mask airway size selection: a randomized triple crossover study in paralyzed, anesthetized male and female adult patients

We determined the optimal size of intubating laryngeal mask airway (ILM) for ventilation and blind tracheal intubation in men and women. We also determined the distance the tracheal tube needs to protrude beyond the distal aperture to ensure that the cuff is through the vocal cords. Fifty male and 50 female anesthetized, paralyzed patients (ASA physical status I or II, aged 18-80 yr) were studied. Three operators (A, B, and C) were involved for the purposes of blinding. The size 3, 4, or 5 ILM was inserted into each patient in random order by Operator A, and the quality of ventilation was scored (adequate, suboptimal, or failed) by Operator B. The fiberoptic position (correct, too shallow, or too deep) and the distance between the distal aperture and the vocal cords was determined by Operator B. A single attempt at blind intubation was made by Operator C. Operators B and C were blinded to the size of the ILM. Operator C was also blinded to the information recorded by Operator B. All ILMs were inserted into the laryngopharynx at the first attempt. For men and women, the ventilation score was smaller for the Size 3 than the Size 4 or 5 (all: P < 0.002). For men, correct positioning was less common with the Size 3 than the Size 4 or 5 (both: P < 0.02). For women, correct positioning was similar among sizes. For men, tracheal intubation was successful less frequently with the Size 3 (84%) than the Size 4 (100%) or 5 (98%) (both: P < or = 0.01). For women, tracheal intubation success was similar among sizes (Size 3, 4, and 5: 86%, 96%, and 92%, respectively). Intubation was always successful if the ILM was correctly positioned and always failed if it was too shallow or deep. In both male and female patients, the distance between the distal aperture and the vocal cords increased with increasing ILM size (all: P < 0.04) and patient height (P < 0.0001) and was always longer for men (all: P < 0.0001). The overall mean distance (95% confidence interval) that the tracheal tube needed to protrude was 10-12 cm (8-13 cm) in men and 8-11 cm (8-12 cm) in women. We conclude that for men, the Size 4 and 5 ILMs are better than the Size 3 for ventilation and blind intubation. For women, the Size 4 and 5 ILMs are better than the Size 3 for ventilation, but there is no difference among sizes for blind intubation. The length the tracheal tube must protrude from the distal aperture to ensure that the cuff is completely through the vocal cords is 8-13 cm, depending on ILM size, the tracheal tube size, and the sex and height of the patient.

IMPLICATIONS

For men, the Size 4 and 5 intubating laryngeal mask airways are better than the Size 3 for ventilation and blind tracheal intubation. For women, the Size 4 and 5 are better than the Size 3 for ventilation, but there is no difference among sizes for blind intubation. The length the tracheal tube must protrude from the distal aperture of the intubating laryngeal mask airway to ensure that the cuff is completely through the vocal cords is 8-13 cm, depending on the size of the mask and tracheal tube and on the sex and height of the patient.

[Dissecting aneurysm of ventricular septum following acute inferior myocardial infarction]

Dissecting aneurysm of the ventricular septum as a complication after myocardial infarction (MI) is very rare. The patient was a 70-year-old women who was diagnosed with acute inferior MI. Three months after MI, catheterization showed a left ventricular aneurysm of the inferior wall, and left-to-right ventricular shunt flow was detected in the aneurysm. Echocardiography showed that the inferior left ventricular free wall was aneurysmal and dissected from the septal wall. Nine months after MI, chronic heart failure was uncontrollable by medication. At surgery, a tear (5 mm long) in the dissecting aneurysm of the ventricular septum was found and closed directly using 2 felt patches, and aneurysmectomy was performed using felt strips. The postoperative course was uneventful and she has been free from any complication for over 1 year.

Enhancement of the aquaporin adipose gene expression by a peroxisome proliferator-activated receptor gamma

The current study demonstrates that aquaporin adipose (AQPap), an adipose-specific glycerol channel (Kishida, K., Kuriyama, H., Funahashi, T., Shimomura, I., Kihara, S., Ouchi, N., Nishida, M., Nishizawa, H., Matsuda, M., Takahashi, M., Hotta, K., Nakamura, T., Yamashita, S., Tochino, Y., and Matsuzawa, Y. (2000) J. Biol. Chem. 275, 20896-20902), is a target gene of peroxisome proliferator-activated receptor (PPAR) gamma. The AQPap mRNA amounts increased following the induction of PPARgamma in the differentiation of 3T3-L1 adipocytes. The AQPap mRNA in the adipose tissue increased when mice were treated with pioglitazone (PGZ), a synthetic PPARgamma ligand, and decreased in PPARgamma(+/-) heterozygous knockout mice. In 3T3-L1 adipocytes, PGZ augmented the AQPap mRNA expression and its promoter activity. Serial deletion of the promoter revealed the putative peroxisome proliferator-activated receptor response element (PPRE) at -93/-77. In 3T3-L1 preadipocytes, the expression of PPARgamma by transfection and PGZ activated the luciferase activity of the promoter containing the PPRE, whereas the PPRE-deleted mutant was not affected. The gel mobility shift assay showed the direct binding of PPARgamma-retinoid X receptor alpha complex to the PPRE. DeltaPPARgamma, which we generated as the dominant negative PPARgamma lacking the activation function-2 domain, suppressed the promoter activity in 3T3-L1 cells, dose-dependently. We conclude that AQPap is a novel adipose-specific target gene of PPARgamma through the binding of PPARgamma-retinoid X receptor complex to the PPRE region in its promoter.

Thiazolidinedione derivative improves fat distribution and multiple risk factors in subjects with visceral fat accumulation--double-blind placebo-controlled trial

BACKGROUND

It has been clarified that visceral fat accumulation leads to atherosclerosis through multiple risk factors such as insulin resistance, glucose intolerance, hyperlipidemia and hypertension. So far, it has been reported that a thaizolidinedione derivative, troglitazone, improves the insulin resistance in subjects with diabetes, glucose intolerance and obesity. However, it has not been reported yet that troglitazone affects fat distribution in subjects concomitant with visceral fat accumulation and multiple risk factors.

METHODS

Twenty-nine subjects with visceral fat accumulation who had at least two risk factors including glucose intolerance, hyperlipidemia and hypertension were investigated. They were randomly assigned to receive either 200 or 400 mg per day of troglitazone or placebo for 12 weeks. A 75 g oral glucose tolerance test (OGTT) was performed before and after the treatment for 12 weeks. Fasting plasma glucose, insulin, HbA(1c), total serum cholesterol (T-chol), triglyceride (TG), HDL-cholesterol (HDL-C), and blood pressure, as well as the number of risk factors were measured periodically during the treatment. The change of the abdominal fat distribution was evaluated using computed tomographic scanning (CT scan) at the umbilicus level.

RESULTS

After the treatment for 12 weeks, the area under the curve (AUC) of plasma glucose from a 75 g OGTT decreased dose-dependently. HbA(1c) and TG decreased significantly in the high-dose troglitazone group (400 mg per day) compared with the placebo group (P<0.05). Systolic blood pressure was significantly lower in subjects with hypertension in the pooled troglitazone group than in the placebo group (P<0.05). Therefore, the number of risk factors decreased with the troglitazone treatment. The ratio of visceral fat area (VFA) to subcutaneous fat area (SFA) (V/S ratio) decreased in the troglitazone groups due to decreased VFA and increased SFA.

CONCLUSION

These results suggest that thiazolidinedione derivative may be a useful drug to improve multiple risk factors by changing the fat distribution in subjects with visceral fat accumulation.

Initial experience with off-pump coronary artery bypass grafting

Off-pump coronary artery bypass grafting (OPCAB) is clearly preferable for patients with extracardiac complications. The aim of this study was to evaluate the initial outcome of OPCAB, and its validity for patients with extracardiac complications. One hundred and fifty-seven consecutive coronary artery bypass graft (CABG) patients were divided into two groups: 30 OPCAB patients and 127 on-pump CABG patients. The early outcomes of the two groups were compared. Preoperatively, OPCAB patients had more extracardiac risk factors than on-pump CABG patients. There were no differences in age or cardiac function between the groups, but the off-pump group had a higher incidence of previous surgery, cerebrovascular disease, and renal failure. There were no differences in graft patency, stroke, or mortality between the two groups, even though the OPCAB patients had more risk factors than the on-pump patients. Our initial experience with OPCAB showed that it is acceptable for high-risk patients in view of the serious nature of their extracardiac condition.

[Cardiovascular effects of colforsin daropate hydrochloride for acute heart failure after open heart surgery]

Colforsin daropate hydrochloride (COL) is a novel drug for the treatment of acute heart failure. COL stimulates adenylate cyclase directly and produces positive inotropic and vasodilator effects accompanied by the increase in cellular cAMP. We investigated its cardiovascular effects for 9 patients who showed low cardiac index (< 3.0 l/min/m2) after open-heart surgery in ICU. After 2 or 3 hours from administration of COL, heart rate and cardiac index increased, and pulmonary artery pressure and central venous pressure decreased significantly, but blood pressure and systemic venous oxygen saturation did not show significant change. In conclusion, COL improved hemodynamics through positive inotropic and vasodilator effects without hypotension. We should investigate more proper usage of this drug to avoid such side effects as tachycardia and arrhythmia, which occurred in some cases.

[A case report of extended thoracoabdominal graft repair for dissecting aneurysm (DeBakey Type IIIb) with visceral ischemia]

A 62-year-old man diagnosed as dissecting aneurysm (DeBakey type IIIb) with visceral is chemia was transferred to our hospital. He had suffered from abdominal pain and the absence of right femoral pulse. Emergent laparotomy revealed no evidence of visceral infarction. Right axillo-femoral bypass was performed. However, visceral ischemia gradually progressed. Enhanced CT and angiography showed that celiac artery and supramesenteric artery (SMA) were collapsed. He underwent graft replacement of thoracoabdominal aorta involving visceral arteries with femoro-femoral bypass with a centrifugal pump as an ajunct. The visceral arteries were reconstructed. Postoperative CT revealed sufficient flow of branch arteries. He recovered well without complication and then discharged.

Genomic structure and insulin-mediated repression of the aquaporin adipose (AQPap), adipose-specific glycerol channel

Aquaporin adipose (AQPap) is a putative glycerol channel in adipocytes (Kishida, K., Kuriyama, H., Funahashi, T., Shimomura, I., Kihara, S., Ouchi, N., Nishida, M., Nishizawa, H., Matsuda, M., Takahashi, M., Hotta, K., Nakamura, T., Yamashita, S., Tochino, Y., and Matsuzawa, Y. (2000) J. Biol. Chem. 275, 20896-20902). In the current study, we examined the genomic structure of the mouse AQPap gene and its regulation by insulin. The mouse AQPap gene spanned 12 kilobase pairs in chromosome 4 and consisted of 8 exons and 7 introns. The first two exons, designated exon 1 and exon 1', are alternatively spliced to common exon 2, and thus the AQPap gene possessed two potential promoters. The exon 1-derived transcript is dominant in both adipose tissues and adipocytes on the basis of RNase protection assay and promoter analysis. The mRNA increased after fasting and decreased with refeeding. Insulin deficiency generated by streptozotocin enhanced the mRNA in adipose tissue. Insulin down-regulated AQPap mRNA in 3T3-L1 adipocytes. The AQPap promoter contained heptanucleotide sequences, TGTTTTT at -443/-437, similar to the insulin-response element identified previously in the promoters of insulin-repressed genes. Deletion and single base pair substitution analysis of the promoter revealed that these sequences were required for insulin-mediated repression of AQPap gene transcription. The phosphatidylinositol 3-kinase pathway was involved in this inhibition. We conclude that insulin represses the transcription of AQPap gene via insulin response element in its promoter. Sustained up-regulation of AQPap mRNA in adipose tissue in the insulin-resistant condition may disturb glucose homeostasis by increasing plasma glycerol.

Galectin-12, an Adipose-expressed Galectin-like Molecule Possessing Apoptosis-inducing Activity

Galectins constitute a family of proteins that bind to beta-galactoside residues and have diverse physiological functions. Here we report on the identification of a galectin-like molecule, galectin-12, in a human adipose tissue cDNA library. The protein contained two potential carbohydrate-recognition domains with the second carbohydrate-recognition domain being less conserved compared with other galectins. In vitro translated galectin-12 bound to a lactosyl-agarose column far less efficiently than galectin-8. Galectin-12 mRNA was predominantly expressed in adipose tissue of human and mouse and in differentiated 3T3-L1 adipocytes. Caloric restriction and treatment of obese animals with troglitazone increased galectin-12 mRNA levels and decreased the average size of the cells in adipose tissue. The induction of galectin-12 expression by the thiazolidinedione, troglitazone, was paralleled by an increase in the number of apoptotic cells in adipose tissue. Immunocytochemical analysis revealed that galectin-12 was localized in the nucleus of adipocytes, and transfection with galectin-12 cDNA induced apoptosis of COS-1 cells. These results suggest that galectin-12, an adipose-expressed galectin-like molecule, may participate in the apoptosis of adipocytes.

[A re-operative case of bentall operation and aortic arch replacement using a stent graft for a Marfan syndrome, post sternum turnover and post mitral valve replacement]

A 36-year-old male with Marfan syndrome succesfully underwent Bentall operation and aortic arch replacement using a stent graft as an elephant trunk. He had received MVR with sternum turn over 14 years previously. Median sternotomy was performed. Under circulatory arrest with rertograde cerebral perfusion we performed Bentall operation and aortic arch replacement using a stent graft. The sternum was cured well. Retractive breathing was not detected. This surgical procedure was effective for cardiovascular disease with Marfan syndrome.

The genetic basis of plasma variation in adiponectin, a global endophenotype for obesity and the metabolic syndrome

Here we present the first genetic analysis of adiponectin levels, a newly identified adipocyte-derived protein. Recent work has suggested that adiponectin may play a role in mediating the effects of body weight as a risk factor for coronary artery disease. For this analysis we assayed serum levels of adiponectin in 1100 adults of predominantly northern European ancestry distributed across 170 families. Quantitative genetic analysis of adiponectin levels detected an additive genetic heritability of 46%. The maximum LOD score detected in a genome wide scan for adiponectin levels was 4.06 (P = 7.7 x 10(-6)), 35 cM from pter on chromosome 5. The second largest LOD score (LOD = 3.2; P = 6.2 x 10(-5)) was detected on chromosome 14, 29 cM from pter. The detection of a significant linkage with a quantitative trait locus on chromosome 5 provides strong evidence for a replication of a previously reported quantitative trait locus for obesity-related phenotypes. In addition, several secondary signals offer potential evidence of replications for additional previously reported obesity-related quantitative trait loci on chromosomes 2 and 10. Not only do these results identify quantitative trait loci with significant effects on a newly described, and potentially very important, adipocyte-derived protein, they also reveal the emergence of a consistent pattern of linkage results for obesity-related traits across a number of human populations.

PPARgamma ligands increase expression and plasma concentrations of adiponectin, an adipose-derived protein

Insulin resistance and its dreaded consequence, type 2 diabetes, are major causes of atherosclerosis. Adiponectin is an adipose-specific plasma protein that possesses anti-atherogenic properties, such as the suppression of adhesion molecule expression in vascular endothelial cells and cytokine production from macrophages. Plasma adiponectin concentrations are decreased in obese and type 2 diabetic subjects with insulin resistance. A regimen that normalizes or increases the plasma adiponectin might prevent atherosclerosis in patients with insulin resistance. In this study, we demonstrate the inducing effects of thiazolidinediones (TZDs), which are synthetic PPARgamma ligands, on the expression and secretion of adiponectin in humans and rodents in vivo and in vitro. The administration of TZDs significantly increased the plasma adiponectin concentrations in insulin resistant humans and rodents without affecting their body weight. Adiponectin mRNA expression was normalized or increased by TZDs in the adipose tissues of obese mice. In cultured 3T3-L1 adipocytes, TZD derivatives enhanced the mRNA expression and secretion of adiponectin in a dose- and time-dependent manner. Furthermore, these effects were mediated through the activation of the promoter by the TZDs. On the other hand, TNF-alpha, which is produced more in an insulin-resistant condition, dose-dependently reduced the expression of adiponectin in adipocytes by suppressing its promoter activity. TZDs restored this inhibitory effect by TNF-alpha. TZDs might prevent atherosclerotic vascular disease in insulin-resistant patients by inducing the production of adiponectin through direct effect on its promoter and antagonizing the effect of TNF-alpha on the adiponectin promoter.

Staged coronary artery bypass grafting after percutaneous angioplasty for intracranial vascular stenosis

OBJECTIVE

Cerebrovascular disease is commonly associated with coronary artery disease and is a major risk factor for cardiac surgery. Concomitant coronary artery bypass grafting and carotid endarterectomy may reduce the risk of stroke; however, this staged operation is effective only for extracranial lesions. The strategy for on-pump coronary artery bypass grafting for patients with intracranial vascular stenosis is still controversial.

METHODS

The subjects were 157 consecutive candidates for coronary artery bypass grafting who underwent computed tomography and digital subtraction cerebral angiography preoperatively to check for cerebrovascular disease. Additional single-photon emission computed tomography was performed to evaluate cerebral ischemia, according to the neurologist's request. Patients with diffuse intracranial vascular stenosis impossible to treat with percutaneous transluminal angioplasty underwent off-pump coronary artery bypass grafting. Patients with a circumflex coronary artery lesion first underwent percutaneous transluminal angioplasty for cerebral vascular stenosis followed by secondary on-pump coronary artery bypass grafting.

RESULTS

Three patients were selected for staged operations. Percutaneous transluminal angioplasty was performed for 4 intracranial stenotic lesions. All lesions were dilated successfully, and no complications developed during or after the procedure. All patients tolerated staged coronary artery bypass grafting and were extubated within 1 day without any mental disturbance. No further neurologic complication occurred, and computed tomography performed postoperatively revealed no significant changes.

CONCLUSION

Staged on-pump coronary bypass after percutaneous transluminal angioplasty for cerebrovascular disease may reduce the risk of stroke during cardiopulmonary bypass, and it is useful especially in patients with intracranial cerebrovascular disease.

[Early and mid-term results of elephant trunk method using stent graft during total arch replacement]

Combined therapy of stent graft implantation and open surgery is an alternative method for aortic aneurysm. Seven patients with aortic aneurysm [annulo aortic ectasia (AAE) + Marfan syndrome (4), AAE + arch aneurysm + s/o Behçet disease (1), acute dissected aneurysm (type A) (1), thoracic aortic true aneurysm (1)] were successfully treated by means of elephant trunk method using a stent graft during total arch replacement. There was no complication related to the stent graft during the perioperative period. Postoperative computed tomographic scans were performed 1 and 6 months later. There was no endleak and no migration, and the aortic diameter around the stent graft was not changed in six patients. However, one patient showed thrombus around the stent graft, because of endleak 2 months after the operation. Such patients should therefore have careful long-term follow-up.

The expression of SPARC in adipose tissue and its increased plasma concentration in patients with coronary artery disease

OBJECTIVE

Adipocytes secrete various cytokines and matrix proteins. Several of them precipitate in obesity-associated diseases, including atherosclerosis. In the current study, we have examined the expression of secreted protein, acidic and rich in cysteine (SPARC) in adipose tissue and its significance in obesity and coronary artery disease (CAD).

RESEARCH METHODS AND PROCEDURES

The SPARC mRNA expressions both in vivo and in vitro were detected by Northern blot analysis. Plasma SPARC concentrations were measured by enzyme immunosorbent assay. First, we investigated the plasma SPARC levels of 88 unrelated adult Japanese subjects (62 men and 26 women; average age: [+/- SD] 50 +/- 12 years; body mass index [BMI]: 16 to 46 kg/m(2)). Additionally 31 subjects with CAD diagnosed by coronary angiography (20 men and 11 women) were also investigated.

RESULTS

Human adipose tissues expressed abundant SPARC mRNA. SPARC expression in adipose tissues was upregulated in obese db/db mice. Markedly enhanced expression of SPARC mRNA was observed in 3T3-L1 fibroblasts during adipocyte differentiation. Consistent with these results, plasma SPARC levels proved a positive correlation with BMI in humans (r = 0.27; p < 0.01). Interestingly, plasma SPARC concentrations were significantly elevated in age- and BMI-matched subjects with CAD (p < 0.05).

DISCUSSION

SPARC was expressed in adipose tissues and its expression was enhanced in obese mice. In human, plasma SPARC levels were elevated in obesity and CAD patients. This elevated SPARC may be involved in the progression of CAD.

Two new drainage tubes for minimally invasive cardiac surgery

BACKGROUND

The limited exposure typical of new minimally invasive surgical approaches to cardiac surgery makes it difficult to utilize traditional equipment such as temporary pacing electrodes or the placement of drainage tubes into the lateral pleural space. To overcome these difficulties, we have developed specialized drainage tubes just for limited access cardiac surgery.

METHODS

The first device is a drainage tube with temporary pacing function. It has three fixed electrodes and one free pacing wire incorporated into an elliptical, angled 28 Fr silicone drainage tube. This tube is placed in the space between the heart and the diaphragm. The two fixed electrodes provide epicardial contact for ventricular pacing. The third fixed electrode and one free pacing wire are for the purpose of atrial pacing (Japanese patent #2,701,135). The second device is a Y-shaped drainage tube. Frequently, the pleural space is opened during harvesting of an internal mammary graft and then insertion of a chest tube in the thoracic cavity becomes necessary. We developed a new Y-shaped tube where one segment is placed in the retrosternal space and one segment is placed in the pleural cavity. (Japanese Association of Intellectual Copyright #130,591)

RESULTS

The drainage-pacing device was used in 48 coronary artery bypass grafting (CABG) patients. Drainage function and pacing function were excellent in all patients. The bifurcated drainage device was used in 34 patients achieving effective drainage of both cavities without complication during or after removal.

CONCLUSIONS

Due to the limited surgical exposure provided by the newer minimally invasive procedures in cardiac surgery, specialized equipment that can be inserted through small incisions needs to be developed. We report the development of a new drainage-pacing device as well as a bifurcated drain for simultaneous drainage of the mediastinal and pleural cavities. These devices have facilitated minimally invasive cases and were free of complications.

[The intubating laryngeal mask: its advantages and limitations]

It has been hypothesized that the intubating laryngeal mask (ILM) has some advantages: (1) tracheal intubation is achieved with a neutral head-neck position and limited mouth opening, (2) intubation is not interfered with blood and secretion in the mouth, (3) ventilation via the device is possible, and (4) it is easy to use. Many studies have brought evidences for these points. Actually, cervical spine movement is unavoidable to a small extent although tracheal intubation is possible with a neutral head-neck position. Degree of hemodynamic changes and incidences of postoperative airway complications are similar between the ILM and the laryngoscope. ILM-users should pay attention to these limitations when they use the ILM.

Routine use of the intubating laryngeal mask airway results in increased upper airway morbidity

PURPOSE

The classic laryngeal mask airway (LMA) has a soft, silicone tube and the intubating laryngeal mask airway (ILM) has a rigid, silicone-coated steel tube. We compare postoperative pharyngolaryngeal morbidity in patients randomised to receive either device.

METHODS

Sixty-five female patients (ASA physical status class I or II, aged 18-80 yr) undergoing balanced regional anesthesia for gynecological laparotomy expected to last one to two hours were randomly assigned for airway management with the LMA or ILM. Intracuff pressure was maintained at 60 cm H20. Postoperative pharyngolaryngeal morbidity (sore throat, difficulty swallowing, sore mouth, sore neck/jaw, hoarseness) was assessed at two, 24 and 48 hr by blinded investigators.

RESULTS

The number of insertion attempts and duration of anesthesia was similar between groups. Sore throat was more common for the ILM at two hours (44 vs 15%, P=0.01), 24 hr (59 vs 21%, P=0.008) and 48 hr (34 vs 3%, P=0.005). Sore mouth was more common for the ILM at two hours (16 vs 0%, P=0.02) and 24 hr (12 vs 0%, P=0.04), but not at 48 hr (6 vs 3%). Difficulty swallowing was more common for the ILM at two hours (25 vs 0%, P=0.04), but not at 24 hr (31 vs 3%) and 48 hr (12 vs 9%). There were no differences in the incidence of sore jaw/neck (ILM, 3-12%; LMA, 0-3%) and hoarseness (ILM, 12-31%; LMA, 16-18%). There was no correlation between postoperative pharyngolaryngeal morbidity and duration of anesthesia.

CONCLUSION

Pharyngolaryngeal morbidity is more common with the ILM than the LMA following anesthesia lasting one to two hours.

Repeated administration of protamine does not attenuate circulatory changes caused by protamine reversal of heparin in dogs

OBJECTIVE

To determine whether repeated administration of protamine attenuates circulatory changes caused by protamine reversal of heparin and to evaluate the significance of nitric oxide generation.

DESIGN

Prospective, randomized, controlled, animal study.

SETTING

University research laboratory.

PARTICIPANTS

Twenty-seven adult mongrel dogs.

INTERVENTIONS

The animals were randomly assigned to 3 groups (n = 9 in each) according to the pretreatment. The control group was pretreated with normal saline, and the 2 other groups were given 2 different doses of protamine: protamine 0.1 (protamine, 0.1 mg/kg) and protamine 1.0 (protamine, 1.0 mg/kg). Under general anesthesia, all animals were anticoagulated with intravenous heparin, 200 IU/kg. Five minutes after heparin injection, preadministered saline (control) or protamine in saline was infused during 60 seconds. Five minutes after the pretreatment, protamine, 2.0 mg/kg in control, 1.9 mg/kg in protamine 0.1, or 1.0 mg/kg in protamine 1.0, was administered intravenously during 10 seconds.

MEASUREMENTS AND MAIN RESULTS

Percent changes in mean arterial blood pressure among the 3 groups at each period were not significantly different except 60 minutes after protamine infusion. Mean pulmonary arterial pressure in the protamine 1.0 group at 5, 15, 20, and 60 minutes was higher than in the control group. Serum nitrate concentration was not significantly different among the 3 groups at baseline and 10 minutes after protamine injection.

CONCLUSION

Repeated administration of protamine does not attenuate circulatory changes caused by protamine reversal of heparin in dogs. Nitric oxide generation does not appear to be responsible for the phenomenon.

Coronary artery bypass grafting in 105 patients with hemodialysis-dependent renal failure

This study was proposed to define early and long-term results of coronary artery bypass grafting (CABG) in dialysis-dependent renal failure (RF) patients, and preoperative patient characteristics. This study included 105 patients (87 males and 18 females; mean age 60.0 +/- 9.0 years, range 39-79) with RF on maintenance dialysis (hemodialysis 100, peritoneal dialysis 5) who underwent isolated CABG between August 1985 and April 2000. Postoperative follow-up was completed in 100% and averaged 3.1 years. There were 22 emergency and 2 re-CABG cases. Previous myocardial infarction (MI) was found in 55 patients (52%), and unstable angina was noted in 53 patients (50%). Diabetes mellitus was the cause of RF in 50 patients (48%; 24 patients required insulin). There was 1 case of single vessel disease, 31 cases of double vessel disease, 54 cases of triple vessel disease, and 19 cases of left main disease. Preoperative left ventriculography was performed in 92 patients (88%). Left ventricular ejection fraction (LVEF) was 48.3 +/- 15.8% (range 11-74%) and was 40% or less in 25 patients (27%). The mean number of distal anastomoses was 2.5 (range 1-5). Three patients received only vein grafts, but all were cases of emergency CABG. The remaining 102 patients (97%) received at least 1 arterial conduit. Among them, 64 patients received only arterial conduits, and 72 patients received 2 or more distal anastomoses with arterial conduits. Five patients (4.8%) died within 30 days after CABG (2 cardiac deaths and 3 noncardiac deaths), and 8 patients (7.6%) died beyond 30 days after CABG before discharge (all noncardiac deaths). The cause of 2 cardiac deaths was abrupt circulatory collapse during or after hemodialysis in patients with severe left ventricular dysfunction (LVEF; 11% and 28%) in the early postoperative period. The causes of 8 noncardiac deaths included infection in 4 and rupture of aortic aneurysm, stroke, sleep apnea syndrome, and mesenteric infarction. During the follow-up period, there were 29 late deaths (8 cardiac, 13 noncardiac, and 8 sudden death), 6 MIs, 13 percutaneous transluminal coronary angioplasty, and 1 re-CABG. The 5-year actuarial survival rate was 59.8%, the cardiac death-free rate was 83.0%, and the cardiac event-free rate was 62.4%. Although CABG in patients on hemodialysis is associated with high early and long-term mortality in terms of both cardiac and noncardiac deaths in proportion to the severity of the preoperative condition, long-term survival was still better than that of general dialysis patients. Meticulous perioperative management may be the key factor in the improvement of early results.

Immunohistochemical localization of Betacellulin, a member of epidermal growth factor family, in atherosclerotic plaques of human aorta

Betacellulin (BTC), a new member of the EGF family, has been reported to be a potent mitogen for rat vascular smooth muscle cells (SMCs). BTC mRNA is known to be expressed in several human organs. However, the localization of BTC in human vascular tissues has not yet been clarified. We investigated whether or not BTC protein is involved in the pathogenesis of human atherosclerosis. Recombinant human BTC showed a mitogenic activity on cultured human aortic SMCs by measuring [3H]thymidine incorporation. The immunohistochemical localization of BTC, SMCs, macrophages, EGF receptors and ErbB4 was examined in autopsied human aortas. BTC was detected in both intimal and medial SMCs of the aortic wall. The percentage of BTC-positive medial SMCs in early types of atherosclerotic lesions decreased with age, but in adult, it was significantly higher in advanced types than in early types of atherosclerotic lesions. BTC-positive SMCs were predominantly localized in the medial side of the intima. Furthermore, numerous BTC-positive SMCs and macrophages were observed around the core lesion of atherosclerotic plaques. Receptors for BTC, EGF receptor and ErbB4, were expressed on SMCs, suggesting that BTC is associated with EGF receptor family-mediated signaling. BTC is produced in human aortic tissue and might play important roles in atherogenesis.