Mouse models of polycystic kidney disease induced by defects of ciliary proteins

Polycystic kidney disease (PKD) is a common hereditary disorder which is characterized by fluid-filled cysts in the kidney. Mutation in either PKD1, encoding polycystin-1 (PC1), or PKD2, encoding polycystin-2 (PC2), are causative genes of PKD. Recent studies indicate that renal cilia, known as mechanosensors, detecting flow stimulation through renal tubules, have a critical function in maintaining homeostasis of renal epithelial cells. Because most proteins related to PKD are localized to renal cilia or have a function in ciliogenesis. PC1/PC2 heterodimer is localized to the cilia, playing a role in calcium channels. Also, disruptions of ciliary proteins, except for PC1 and PC2, could be involved in the induction of polycystic kidney disease. Based on these findings, various PKD mice models were produced to understand the roles of primary cilia defects in renal cyst formation. In this review, we will describe the general role of cilia in renal epithelial cells, and the relationship between ciliary defects and PKD. We also discuss mouse models of PKD related to ciliary defects based on recent studies. [BMB Reports 2013; 46(2): 73-79]

Inactivation of max-interacting protein 1 induces renal cilia disassembly through reduction in levels of intraflagellar transport 20 in polycystic kidney

Cilia in ciliated cells consist of protruding structures that sense mechanical and chemical signals from the extracellular environment. Cilia are assembled with variety molecules via a process known as intraflagellar transport (IFT). What controls the length of cilia in ciliated cells is critical to understand ciliary disease such as autosomal dominant polycystic kidney disease, which involves abnormally short cilia. But this control mechanism is not well understood. Previously, multiple tubular cysts have been observed in the kidneys of max-interacting protein 1 (Mxi1)-deficient mice aged 6 months or more. Here, we clarified the relationship between Mxi1 inactivation and cilia disassembly. Cilia phenotypes were observed in kidneys of Mxi1-deficient mice using scanning electron microscopy to elucidate the effect of Mxi1 on renal cilia phenotype, and cilia disassembly was observed in Mxi1-deficient kidney. In addition, genes related to cilia were validated in vitro and in vivo using quantitative PCR, and Ift20 was selected as a candidate gene in this study. The length of cilium decreased, and p-ERK level induced by a cilia defect increased in kidneys of Mxi1-deficient mice. Ciliogenesis of Mxi1-deficient mouse embryonic fibroblasts (MEFs) decreased, and this abnormality was restored by Mxi1 transfection in Mxi1-deficient MEFs. We confirmed that ciliogenesis and Ift20 expression were regulated by Mxi1 in vitro. We also determined that Mxi1 regulates Ift20 promoter activity via Ets-1 binding to the Ift20 promoter. These results indicate that inactivating Mxi1 induces ciliary defects in polycystic kidney.

Differential Expression of PKD2-Associated Genes in Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by formation of multiple fluid-filled cysts that expand over time and destroy renal architecture. The proteins encoded by the PKD1 and PKD2 genes, mutations in which account for nearly all cases of ADPKD, may help guard against cystogenesis. Previously developed mouse models of PKD1 and PKD2 demonstrated an embryonic lethal phenotype and massive cyst formation in the kidney, indicating that PKD1 and PKD2 probably play important roles during normal renal tubular development. However, their precise role in development and the cellular mechanisms of cyst formation induced by PKD1 and PKD2 mutations are not fully understood. To address this question, we presently created Pkd2 knockout and PKD2 transgenic mouse embryo fibroblasts. We used a mouse oligonucleotide microarray to identify messenger RNAs whose expression was altered by the overexpression of the PKD2 or knockout of the Pkd2. The majority of identified mutations was involved in critical biological processes, such as metabolism, transcription, cell adhesion, cell cycle, and signal transduction. Herein, we confirmed differential expressions of several genes including aquaporin-1, according to different PKD2 expression levels in ADPKD mouse models, through microarray analysis. These data may be helpful in PKD2-related mechanisms of ADPKD pathogenesis.

Mxi1 influences cyst formation in three-dimensional cell culture

Cyst formation is a major characteristic of ADPKD and is caused by the abnormal proliferation of epithelial cells. Renal cyst formation disrupts renal function and induces diverse complications. The mechanism of cyst formation is unclear. mIMCD-3 cells were established to develop simple epithelial cell cysts in 3-D culture. We confirmed previously that Mxi1 plays a role in cyst formation in Mxi1-deficient mice. Cysts in Mxi1 transfectanted cells were showed by collagen or mebiol gels in 3-D cell culture system. Causative genes of ADPKD were measured by q RT-PCR. Herein, Mxi1 transfectants rarely formed a simple epithelial cyst and induced cell death. Overexpression of Mxi1 resulted in a decrease in the PKD1, PKD2 and c-myc mRNA relating to the pathway of cyst formation. These data indicate that Mxi1 influences cyst formation of mIMCD-3 cells in 3-D culture and that Mxi1 may control the mechanism of renal cyst formation.

Mxi1 regulates cell proliferation through insulin-like growth factor binding protein-3

Mxi1, a member of the Myc-Max-Mad network, is an antagonist of the c-Myc oncogene and is associated with excessive cell proliferation. Abnormal cell proliferation and tumorigenesis are observed in organs of Mxi1-/- mice. However, the Mxi1-reltaed mechanism of proliferation is unclear. The present study utilized microarray analysis using Mxi1 mouse embryonic fibroblasts (MEFs) to identify genes associated with cell proliferation. Among these genes, insulin-like growth factor binding protein-3 (IGFBP-3) was selected as a candidate gene for real-time PCR to ascertain whether IGFBP-3 expression is regulated by Mxi1. Expression of IGFBP-3 was decreased in Mxi1-/- MEFs and Mxi1-/- mice, and the gene was regulated by Mxi1 in Mxi1 MEFs. Furthermore, proliferation pathways related to IGFBP-3 were regulated in Mxi1-/- mice compared to Mxi1+/+ mice. To determine the effect of Mxi1 inactivation on the induction of cell proliferation, a proliferation assay is performed in both Mxi1 MEFs and Mxi1 mice. Cell viability was regulated by Mxi1 in Mxi1 MEFs and number of PCNA-positive cells was increased in Mxi1-/- mice compared to Mxi1+/+ mice. Moreover, the IGFBP-3 level was decreased in proliferation defect regions in Mxi1-/- mice. The results support the suggestion that inactivation of Mxi1 has a positive effect on cell proliferation by down-regulating IGFBP-3.

Up-regulation of Idh3alpha causes reduction of neuronal differentiation in PC12 cells

The PC12 is the widely used cell line to study neuronal differentiation. We had extensively investigated the details of protein expression in differentiated PC12 cells by proteomic analysis. The cells were incubated at the presence of nerve growth factor. We had analyzed the expression changes in the differentiating PC12 cells by 2-dimensional electrophoresis and the identification of the proteins using MALDI-TOF MS. By comparing expression pattern in the time course, we identified the candidate genes which are associated with neuronal differentiation. Among these genes, we performed real-time PCR analysis to validate Idh3alpha expression by the time course. To identify the function of Idh3alpha in neuronal differentiation stage, the transfection of Idh3alpha to PC12 cells was performed. As a result, we proved that up-regulation of Idh3alpha causes reduction in neural differentiation of PC12 cells. Based on these data, we suggest that Idh3alpha plays a role to the neuronal differentiation.

Extracorporeal shockwave for hip necrosis in systemic lupus erythematosus

Patients with systemic lupus erythematosus (SLE) frequently received corticosteroid therapy, resulting in osteonecrosis of the femoral head (ONFH). Prior studies demonstrated the effectiveness of extracorporeal shockwave treatment (ESWT) for ONFH.. This study evaluated the effectiveness of ESWT for ONFH in patients with SLE. We studied 39 patients, including 15 patients with SLE (26 hips) and 24 controls (29 hips). To each affected hip we applied ESWT (6000 impulses at 28 kV in a single session). Patients were ambulated with partial weight bearing for 4-6 weeks. The primary endpoint was the need for hip replacement. The secondary endpoints were improvement in hip pain and function and image changes on X-ray and MRI. Patients received total hip replacement in 12% of patients with SLE and in 14% of controls (P = 0.802). There was no statistically significant difference in pain scores (0.86 vs. 0.89; P = 0.467) and function scores (89% vs. 91%; P = 0.194) between patients with SLE and controls. SLE response to ESWT for ONFH is comparable with ONFH in patients without SLE.

Comparison of echocardiography and electron beam tomography in differentiating the etiology of heart failure

BACKGROUND

The clinical manifestations in patients with ischemic cardiomyopathy are often indistinguishable from those in patients with primary dilated cardiomyopathy (DCM). Clinicians often base work-up of patients with heart failure on echocardiographic wall motion abnormalities; however misclassification can lead to unnecessary coronary angiography.

HYPOTHESIS

The study was undertaken to evaluate the diagnostic ability of echocardiography and electron beam tomography (EBT) to differentiate between ischemic and nonischemic cardiomyopathy.

METHODS

The accuracy of EBT and echocardiography was compared in 111 patients undergoing coronary angiography for the evaluation of heart failure. The presence of coronary calcification (CC) by EBT or segmental wall motion abnormalities by echocardiography was used as evidence of coronary-induced cardiomyopathy.

RESULTS

Of 63 patients, 61 (97%) with obstructive coronary artery disease had CC by EBT. This sensitivity was significantly higher compared with 43 of 63 patients (68%) with segmental wall motion abnormalities by echocardiography (p < 0.001). Of 48 patients without obstructive coronary artery disease by angiography, 39 (81%) had no CC by EBT and 35 (73%) had no segmental wall motion (global hypokinesis) by echocardiography (p = 0.33). The overall accuracy of EBT to differentiate ischemic from nonischemic cardiomyopathy was 90%, significantly higher than echocardiography (70%, p < 0.001).

CONCLUSION

This double-blind study demonstrates that the presence of CC by EBT is superior to that of segmental wall motion abnormalities by echocardiography to distinguish ischemic from nonischemic cardiomyopathy. This modality may prove to be an important diagnostic tool when the etiology of the cardiomyopathy is not clinically evident.

Induction chemotherapy with mitomycin, epirubicin, cisplatin, fluorouracil, and leucovorin followed by radiotherapy in the treatment of locoregionally advanced nasopharyngeal carcinoma

PURPOSE

Survival in advanced nasopharyngeal carcinoma (NPC) is compromised by distant metastasis. Because mitomycin is active against hypoxic and G0 cells, which may help to eradicate micrometastasis, we investigated the effect of mitomycin-containing cisplatin-based induction chemotherapy.

PATIENTS AND METHODS

Recruited for this study were American Joint Committee on Cancer (AJCC) 1992 staging system stage IV NPC patients with the following adverse features: obvious intracranial invasion, supraclavicular or bilateral neck lymph node metastasis, large neck node (> 6 cm), or elevated serum lactate dehydrogenase (LDH) level. Patients were given three cycles of chemotherapy before radiotherapy. The chemotherapy comprised a 3-week cycle of mitomycin, epirubicin, and cisplatin on day 1 and fluorouracil and leucovorin on day 8 (MEPFL).

RESULTS

From January 1994 to December 1997, 111 patients were recruited. The median follow-up period was 43 months. The actuarial 5-year overall survival rate was 70% (95% confidence interval [CI], 60% to 80%; n = 111). For patients having completed radiotherapy (n = 100), the 5-year locoregional control rate was 70% (95% CI, 55% to 84%) and the distant metastasis-free rate was 81% (95% CI, 73% to 89%). The 5-year distant metastasis-free rate of N3a and N3b disease of AJCC 1997 staging system were 79% (95% CI, 62% to 95%) and 74% (95% CI, 60% to 89%), respectively. By Cox multivariate analysis, high pretreatment serum LDH level (P = .04) and neck nodal enlargement before radiotherapy (P = .001) were adverse prognostic factors of survival.

CONCLUSION

The good 5-year survival of N3 disease supports the effectiveness of induction MEPFL in the primary treatment of advanced NPC. Further investigation to incorporate concurrent chemoradiotherapy is warranted.

Topiramate treatment of bipolar spectrum disorders: a retrospective chart review

The objective of this paper was to determine if topiramate is effective as treatment for bipolar spectrum disorders in a naturalistic setting. All charts of outpatients treated with topiramate (n = 76) were reviewed, and clinical response was assessed retrospectively using the Clinical Global Impressions Scale for Improvement. Mild improvement was seen in 47% (n = 36) and moderate-to-marked improvement in 13% (n = 10). Responders received a higher mean dose (180 mg/day) than did nonresponders (83.2 mg/day, p = 0.002). Topiramate dose was also higher in those who lost weight (138.3 mg/day) than in those who did not (70 mg/day, p = 0.007). Weight loss was experienced by 50% of the sample, with a mean loss of 14.2 lbs. Side effects were reported by 82% (n = 62) of the population, including cognitive effects, sedation, parasthesias, nausea, insomnia, headache, and dizziness. Adverse effects led 36% (n = 27) of the total sample to discontinue treatment with topiramate. Topiramate led to significant weight loss in about half of this bipolar population, while also improving mood symptoms at least mildly in most patients. Topiramate response and weight loss were both dose-related, with efficacy, in particular, associated with higher doses (mean = 180 mg/day) than frequently used in current clinical practice.

Information circulation in a two-mode solid-state laser with optical feedback

A two-mode solid-state laser subjected to a delayed optical feedback is studied. Simultaneous random switchings between stable and chaotic antiphase spiking oscillations featuring the establishment of causal (drive response) relationships among modes have been demonstrated by a proposed information circulation analysis of an experimental time series. The observed phenomenon has been well reproduced by numerical simulations of two-mode laser equations with uncorrelated modal phase fluctuations.

Acute septic arthritis of the hip in children

Thirty-three cases of acute septic arthritis of the hip in children were treated at our hospital from 1986 to 1997. The average follow-up period was 6 years (range 2-11 years). In 17 cases the right hip was affected, and in 16 the left hip. The average duration of symptoms was 5 days (range 1-14 days). Microorganisms were isolated from the blood, joint aspirate, or surgical specimens in 25 cases (76%). Staphylococcus aureus was the most common bacteria found (44%). Those patients with S. aureus infection were older than 1 year of age. There was no significant difference in the final outcome between the younger and the older age groups. Twenty-six out of 33 patients (89%) had a satisfactory outcome. Satisfactory results can also be expected with arthrocentesis and medical treatment if the diagnosis is made early, and antibiotic treatment affords a good clinical response. Four out of 7 cases with an unsatisfactory result were associated with osteomyelitis of the proximal femur. The two most important factors associated with poor results included a delay of definite treatment lasting longer than 5 days and the presence of osteomyelitis of the proximal femur.

The bipolar spectrum and the antidepressant view of the world

Whereas much progress has been made in the diagnosis and treatment of schizophrenia and depression in recent years, bipolar disorder continues to be frequently misunderstood, leading to its inconsistent diagnosis and treatment. In this article, we seek to identify the causes of this problem and suggest possible solutions, based on a critical review of studies concerning the nosology of bipolar disorder and the effects of antidepressant agents. Bipolar disorder appears to be underdiagnosed as well as frequently misdiagnosed as unipolar major depressive disorder. Underdiagnosis can stem from patients' impaired insight into mania and failure to involve family members in the diagnostic process and also from clinicians' inadequate understanding of manic symptoms. Underdiagnosis may also reflect disagreement about the breadth of the bipolar spectrum. We therefore propose a heuristic definition of "bipolar spectrum disorder," a diagnosis that gives greater weight to family history and antidepressant-induced manic symptoms. This diagnosis would include all forms of bipolar illness that are not type I or II . The evidence also suggests that antidepressants are probably overused and mood stabilizers underused. We consequently recommend aggressive use of mood stabilizers and less emphasis on antidepressants. In summary, the state of diagnosis and treatment in bipolar disorder is suboptimal. More diagnostic attention to the criteria for mania is necessary. In addition, the current pattern of antidepressant use in bipolar disorder does not appear to be evidence-based.

Instability in a laser-diode-pumped microchip Nd:YAG laser in a n-ary product scheme

Dynamical instability, chaotic pulsations, and generalized bistability have been observed in a laser-diode-pumped microchip Nd:YAG laser operating in a double transition scheme in which lasing occurs on two transitions with overlapping gain profiles, F(3/2)(4)(2)? I(11/2)(4)(3) and F(3/2)(4)(1)? I(11/2)(4)(2), and simultaneously involves excited Nd atoms from different sublevels of the upper manifold. The modeling of the experimental results requires rate equations that include cross-gain coupling among oscillating modes that belong to different transitions whose population inversion densities are determined by the Boltzmann distribution.

Phase I clinical trial of curcumin, a chemopreventive agent, in patients with high-risk or pre-malignant lesions

Curcumin (diferuloylmethane), a yellow substance from the root of the plant Curcuma longa Linn., has been demonstrated to inhibit carcinogenesis of murine skin, stomach, intestine and liver. However, the toxicology, pharmacokinetics and biologically effective dose of curcumin in humans have not been reported. This prospective phase-I study evaluated these issues of curcumin in patients with one of the following five high-risk conditions: 1) recently resected urinary bladder cancer; 2) arsenic Bowen's disease of the skin; 3) uterine cervical intraepithelial neoplasm (CIN); 4) oral leucoplakia; and 5) intestinal metaplasia of the stomach. Curcumin was taken orally for 3 months. Biopsy of the lesion sites was done immediately before and 3 months after starting curcumin treament. The starting dose was 500 mg/day. If no toxicity > or = grade II was noted in at least 3 successive patients, the dose was then escalated to another level in the order of 1,000, 2,000, 4,000, 8,000, and 12,000 mg/day. The concentration of curcumin in serum and urine was determined by high pressure liquid chromatography (HPLC). A total of 25 patients were enrolled in this study. There was no treatment-related toxicity up to 8,000 mg/day. Beyond 8,000 mg/day, the bulky volume of the drug was unacceptable to the patients. The serum concentration of curcumin usually peaked at 1 to 2 hours after oral intake of crucumin and gradually declined within 12 hours. The average peak serum concentrations after taking 4,000 mg, 6,000 mg and 8,000 mg of curcumin were 0.51 +/- 0.11 microM, 0.63 +/- 0.06 microM and 1.77 +/- 1.87 microM, respectively. Urinary excretion of curcumin was undetectable. One of 4 patients with CIN and 1 of 7 patients with oral leucoplakia proceeded to develop frank malignancies in spite of curcumin treatment. In contrast, histologic improvement of precancerous lesions was seen in 1 out of 2 patients with recently resected bladder cancer, 2 out of 7 patients of oral leucoplakia, 1 out of 6 patients of intestinal metaplasia of the stomach, I out of 4 patients with CIN and 2 out of 6 patients with Bowen's disease. In conclusion, this study demonstrated that curcumin is not toxic to humans up to 8,000 mg/day when taken by mouth for 3 months. Our results also suggest a biologic effect of curcumin in the chemoprevention of cancer.

Factors affecting the overall survival after salvage surgery in patients with recurrent nasopharyngeal carcinoma at the primary site: experience with 60 cases

OBJECTIVE

To analyze the factors affecting overall survival after salvage surgery in patients with recurrent nasopharyngeal carcinoma at the primary site after a full course of radiotherapy.

DESIGN

Retrospective analysis of 60 consecutive patients treated by surgical resection of the recurrent tumors, with a mean follow-up of 43.1 months (range, 19-96 months).

SETTING

Academic tertiary referral center.

RESULTS

The overall survival and locoregional relapse-free survival were 56% and 60% at 2 years, respectively, and 30% and 40% at 5 years. Twenty-nine (81%) of 36 patients died with uncontrolled local disease. The T stage of the recurrent tumors appeared to be an important prognostic factor. Age, sex, pathologic findings, and disease-free interval (time between previous radiotherapy and local recurrence) were not significant prognosis-affecting factors by the log-rank test. Multivariate analysis showed that patients with recurrent tumors of undifferentiated carcinoma, sarcoma, or small cell carcinoma had unfavorable prognoses. Uncontrolled local disease and the emergence of distant metastasis predicted grave results as well. Postoperative irradiation showed some benefit to patients, but the difference was not statistically significant.

CONCLUSIONS

The T stage of the recurrence was the prominent prognosis-affecting factor in patients with recurrent nasopharyngeal carcinoma who received salvage surgery. Patients with local recurrence should be carefully selected for the salvage surgery. We recommend this surgery for patients with rT1, rT2, or limited rT3 lesions. The results of surgical resection in terms of local control and overall survival were slightly better than those of high-dose reirradiation, with fewer late complications.

Treatment of lateral epicondylitis of the elbow with shock waves

In a prospective clinical study, the effectiveness of shock wave treatment for lateral epicondylitis in 56 elbows in 53 patients (27 men and 26 women) with an average age of 46 years was investigated. Three patients received treatment for both elbows. Each elbow was treated with 1,000 impulses of shock waves at 14 kV. A 100-point scoring system was used for evaluation including 40 points for pain, 30 points for function, 20 points for strength, and 10 points for elbow motion. The intensity of pain was measured using a visual analogue scale from 0 to 10. The overall results were 13.2% excellent, 44.7% good, 36.8% acceptable, and 5.3 unchanged in 35 patients with 12 weeks followup; 30.8% excellent, 42.3% good, and 26.9% acceptable in 25 patients with 24 weeks followup. Considerable improvement was observed from 6 weeks to 6 months after the treatment. None of the patients' symptoms became worse. The results of nine patients who also received a second treatment were good in three patients, acceptable in five patients, and unchanged in one patient. There was no device-related problems, systemic, or local complications. Shock wave therapy may offer a new and safer nonoperative treatment for patients with lateral epidoncylitis of the elbow.

Treatment of calcifying tendinitis of the shoulder with shock wave therapy

In a prospective clinical study, the effectiveness of shock wave treatment for calcifying tendinitis in 31 shoulders in 29 patients (14 women and 15 men) with an average age of 52 years was assessed. Each shoulder was treated with 1,000 impulses of shock waves at 14 kV. A 100-point Constant score system was used for evaluation. The overall results of 20 patients (21 shoulders) with 12 weeks followup were no complaints in 23.8%, significantly improved in 38.1%, some improvement in 14.3%, and unchanged in 23.8%. Considerable improvement was observed between 6 and 12 weeks. The results of seven patients with 24 weeks followup were no complaints in two patients, significantly improved in three, and unchanged in two patients. Radiographs showed complete elimination of the calcium deposits in six patients (28.6%), incomplete elimination in two patients (9.5%), and three patients (14.3%) had fragmentation of the calcium deposits. There was no recurrence of calcium deposits observed at 24 weeks. There was a correlation between the functional improvement and the elimination of calcium deposits. There were no device-related problems, systemic or local complications. Low-energy shock wave therapy may offer a new and safer additional nonoperative treatment for patients with calcifying tendinitis of the shoulder.

Nonstationary chaotic oscillations in lasers with frequency-shifted feedback

The nonlinear dynamics of lasers with frequency-shifted delayed feedback are investigated. Resonant excitation of sustained relaxation oscillations by harmonic resonance is demonstrated. Self-induced switching between sustained relaxation oscillation and spiking oscillation is observed as the feedback coefficient is increased. Observed instabilities are well reproduced by numerical simulations of proposed model equations. A statistical analysis of this switching phenomenon is carried out numerically, and the results indicate that an inverse-power relation with the feedback coefficient determines the periods over which the system dwells in its relaxation-oscillation state.

Quantum-noise-induced order in lasers placed in chaotic oscillation by frequency-shifted feedback

A kind of chaotic oscillations featuring random switching between sustained relaxation oscillations (RO) and spiking oscillations (SO) has been demonstrated in lasers with frequency-shifted feedback. The presence of stochastic frequency locking between two periodicities of RO and SO motions and selective quantum-noise-induced ordering of chaotic spiking oscillations is demonstrated theoretically and experimentally.

Pulsations induced by quantum interference in a microchip solid-state laser operating on a ? transiton

Self-induced pulsations that are associated with atomic interference have been found in a laser-diode-pumped LiNdP(4)O(12) microchip laser with an intracavity KTP frequency-doubling crystal operating in a ? scheme. The instability and peculiar pulsations that were observed have been verified by a linear stability analysis and numerical simulation of two-mode laser equations, including nonlinear absorptions of a purely quantum nature and spontaneous-emission noise.

Diabetes and the associated incidence of subclinical atherosclerosis and coronary artery disease: Implications for management

BACKGROUND

We sought to examine the prevalence, sensitivity, and specificity of coronary calcium (CC), a marker of atherosclerosis, in a population of symptomatic and asymptomatic diabetic persons.

METHODS

We used electron beam tomography (EBT) to quantitate CC in 168 symptomatic (chest pain or anginal equivalent) persons with diabetes who underwent coronary angiography and then compared this with a cohort of 155 asymptomatic persons with diabetes.

RESULTS

In the 168 symptomatic diabetic persons, 124 (74%) had obstructive coronary artery disease (CAD) by angiography. Receiver-operator characteristic curve analysis was used to maximize sensitivity and specificity for obstructive CAD (>50% stenosis), which established a CC score of 102 as optimal. With use of this cut point, EBT has a sensitivity of 77% and a specificity of 77% for detecting obstructive CAD. Of the 155 asymptomatic diabetic persons, 72% had CC and 48% had a CC score >102. The presumed prevalence of obstructive disease (on the basis of EBT scores and prevalence of CC) among asymptomatic diabetic persons is quite high (as high as symptomatic persons without diabetes). Analyzing the 323 diabetic patients demonstrated no significant age difference in CC scores between women and men.

CONCLUSIONS

This study confirms that higher CC scores should be used in diabetic patients to improve the specificity of CC to determine obstructive disease. EBT can allow a noninvasive diagnosis of CAD before clinical presentation, allowing for more therapy for those in which CC is detected. These results suggest that asymptomatic diabetic persons have the same atherogenic burden of those patients with CAD without diabetes. The high prevalence of CC in asymptomatic persons with diabetes supports the need for aggressive management of diabetes and associated risk factors.