Aß (Amyloid Beta) and Tau Tangle Pathology Modifies the Association Between Small Vessel Disease and Cortical Microinfarcts.

BACKGROUND AND PURPOSE: There is increasing recognition of the importance of cortical microinfarcts to overall brain health, cognition, and Alzheimer dementia. Cerebral small vessel pathologies are associated with microinfarcts and frequently coexist with Alzheimer disease; however, the extent to which Aß (amyloid beta) and tau pathology modulates microvascular pathogenesis is not fully understood. Study objective was to examine the relationship of small vessel pathologies, arteriolosclerosis, and cerebral amyloid angiopathy, with cortical microinfarcts in people with differing levels of Aß or tau tangle burden. METHODS: Participants were 1489 autopsied older people (mean age at death, 89 years; 67% women) from 1 of 3 ongoing clinical-pathological cohort studies of aging. Neuropathological evaluation identified cortical Aß and tau tangle burden using immunohistochemistry in 8 brain regions, provided semiquantitative grading of cerebral vessel pathologies, and identified the presence of cortical microinfarcts. Logistic regression models adjusted for demographics and atherosclerosis and examined whether Aß or tau tangle burden modified relations between small vessel pathologies and cortical microinfarcts. RESULTS: Cortical microinfarcts were present in 17% of older people, moderate-to-severe cerebral amyloid angiopathy pathology in 36%, and arteriolosclerosis in 34%. In logistic regression models, we found interactions with Aß and tau tangles, reflecting that the association between arteriolosclerosis and cortical microinfarcts was stronger in the context of greater Aß (estimate, 0.15; SE=0.07; P=0.02) and tau tangle burden (estimate, 0.13; SE=0.06; P=0.02). Interactions also emerged for cerebral amyloid angiopathy, suggesting that the association between cerebral amyloid angiopathy and cortical microinfarcts is more robust in the presence of higher Aß (estimate, 0.27; SE=0.07; P<0.001) and tangle burden (estimate, 0.16; SE=0.06; P=0.005). CONCLUSIONS: These findings suggest that in the presence of elevated Aß or tangle pathology, small vessel pathologies are associated with greater microvascular tissue injury, highlighting a potential link between neurodegenerative and vascular mechanisms.

Vascular contributions to cognitive impairment, clinical Alzheimer's disease, and dementia in older persons.

There is growing evidence suggesting that vascular pathologies and dysfunction play a critical role in cognitive impairment, clinical Alzheimer's disease, and dementia. Vascular pathologies such as macroinfarcts, microinfarcts, microbleeds, small and large vessel cerebrovascular disease, and white matter disease are common especially in the brains of older persons where they contribute to cognitive impairment and lower the dementia threshold. Vascular dysfunction resulting in decreased cerebral blood flow, and abnormalities in the blood brain barrier may also contribute to the Alzheimer's disease (AD) pathophysiologic process and AD dementia. This review provides a clinical-pathological perspective on the role of vessel disease, vascular brain injury, alterations of the neurovascular unit, and mixed pathologies in the Alzheimer's disease pathophysiologic process and Alzheimer's dementia. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock.

Outcomes of Lung Transplantation in Recipients With Hepatitis C Virus Infection.

Hepatitis C virus (HCV) infection negatively impacts patient and graft survival following nonhepatic solid organ transplantation. Most data, however, are in kidney transplant, where despite modest impact on outcomes, transplantation is recommended for those with mild to moderate hepatic fibrosis given overall benefit compared to remaining on dialysis. In lung transplantation (LuTx), there is little data on outcomes and international guidelines are vague on the criteria under which transplant should be considered. The University of Alberta Lung Transplant Program routinely considers patients with HCV for lung transplant based on criteria extrapolated from the kidney transplant literature. Here we describe the outcomes of 27 HCV-positive, compared to 443 HCV-negative LuTx recipients. Prior to transplant, five patients were treated for HCV and cured. At the time of transplant, 14 patients remained HCV RNA positive. The 1-, 3-, and 5-year survival were similar in HCV RNA-positive versus -negative recipients at 93%, 77%, and 77% versus 86%, 75%, and 66% (p = 0.93), respectively. Long-term follow-up in eight patients demonstrated no significant progression of fibrosis. In our cohort, HCV did not impact LuTx outcomes and in the era of interferon-free HCV therapies this should not be a barrier to LuTx.

Morphine promotes apoptosis in Jurkat cells.

Patients with intravenous heroin addiction are prone to recurrent infections and at times these infections are fatal. We evaluated the effect of morphine on the apoptosis of Jurkat cells and freshly isolated human T lymphocytes. Morphine promoted apoptosis of both the Jurkat cells and the freshly isolated T lymphocytes in a dose-dependent manner. DAGO, a specific mu receptor agonist, also promoted Jurkat cell apoptosis. DNA isolated from morphine-treated Jurkat cells and T lymphocytes also showed integer multiples of 200 base pairs. Superoxide dismutase (SOD) enhanced lymphocyte apoptosis; whereas catalase attenuated the morphine-induced apoptosis of Jurkat cells as well as of T lymphocytes. Morphine-treated Jurkat cells also showed a decreased expression of bcl-2 and an enhanced expression of bax. In addition, morphine-treated Jurkat cells showed activation of caspase-3. These results indicate that morphine-induced T lymphocyte apoptosis may be mediated through the generation of reactive oxygen species. The change in ratio of bax and bcl-2 seems to tilt the balance toward apoptosis, leading to the activation of caspase-3. This study provides further support for the hypothesis that morphine may be directly compromising immune function by enhancing apoptosis of T lymphocytes in patients with heroin addiction.

Ethanol-induced neutrophil apoptosis is mediated through nitric oxide.

Clinical reports indicate that acute ethanol intoxication in chronic ethanol abusers is associated with neutropenia. We hypothesize that ethanol accelerates the apoptosis of neutrophils thus decreasing the peripheral blood count of neutrophils. We studied the effect of ethanol on neutrophil apoptosis in vivo as well as in vitro. Human neutrophils harvested from healthy subjects after an alcohol drinking binge showed enhanced apoptosis (before, 0.5+/-0.25 vs. after, 26.1+/-2.6% apoptotic neutrophils/field). Peritoneal neutrophils isolated from ethanol-treated rats also showed increased (P < 0.0001) apoptosis when compared with neutrophils isolated from control rats (control, 0.8+/-0.2% vs. ethanol, 11.8+/-0.7% apoptotic neutrophils/field). In in vitro studies, ethanol in concentrations of 50 mM and higher accelerated the apoptosis of human and rat neutrophils. This effect of ethanol on human neutrophils was time dependent. DNA isolated from ethanol-treated human neutrophils displayed integer multiples of 180 base pairs (ladder pattern), further confirming the effect of ethanol on neutrophil apoptosis. N(G)-monomethyl-L-arginine monoacetate and N(G)-nitro-L-arginine methyl ester, inhibitors of nitric oxide (NO) synthase, attenuated the ethanol-induced neutrophil apoptosis. Sodium nitroprusside, a NO donor, also promoted neutrophil apoptosis. Moreover, ethanol enhanced neutrophil expression of inducible NO synthase. In addition, ethanol stimulated neutrophil NO generation. These results suggest that ethanol accelerates neutrophil apoptosis. This effect of ethanol on neutrophil apoptosis seems to be mediated through the generation of NO.

A case report of living-donor lobar lung transplantation for scleroderma-associated usual interstitial pneumonia: eight years and counting.

INTRODUCTION: Scleroderma-associated interstitial lung disease is a life-limiting complication of scleroderma, often requiring lung transplantation. Living-donor lobar lung transplantation (LDLLT) is a viable alternative to deceased-donor lung transplantation in specialized centers under select circumstances. CLINICAL CASE: A 47-year-old female underwent LDLLT after nine years of symptomatic scleroderma-associated usual interstitial pneumonia and three years awaiting deceased-donor lung transplantation. Her manifestations of scleroderma included mild sclerodactyly, periungual erythema, Raynaud's phenomenon, and gastroesophageal reflux, with positive antinuclear autoantibodies. Several years post-transplantation, manometry revealed feeble lower esophageal sphincteric pressure with ineffective esophageal motility. Bronchiolitis obliterans syndrome developed 64 months post-transplantation without evidence of aspiration or reflux on transbronchial biopsy. Currently, she has normal renal function and good allograft function [FEV1 1.52 L (73% predicted) and FVC 2.50 L (99% predicted)]. RELEVANCE: This is the second reported case of LDLLT in scleroderma, and the first reporting long-term pulmonary, renal, and esophageal function post-transplantation.

Case report of vertebral osteomyelitis and mycotic abdominal aortic aneurysm caused by Scedosporium apiospermum in a lung transplant patient with cystic fibrosis.

Cystic fibrosis patients are frequently plagued by infections, often with unusual or hardy organisms. Their infections are only complicated by transplantation. In this report, we review the case of a young woman who had a double lung transplant secondary to cystic fibrosis who developed a lumbar osteomyelitis/discitis several years after transplantation. After treatment, she went on to develop a mycotic abdominal aortic aneurysm. The patient underwent thoracic and abdominal aortic replacement, and histopathology revealed Scedosporium apiospermum infection. The patient recovered well from surgery and was discharged home on long-term antifungal therapy. This represents the first reported case of S apiospermum mycotic aneurysm in a lung transplant patient, and possibly the largest number and longest duration of S apiospermum infections reported in a single patient.

Differential expression and autoradiographic localization of atrial natriuretic peptide receptor in spontaneously hypertensive and normotensive rat testes: diminution of testosterone in hypertension.

Previous studies have shown that the diuretic hormone atrial natriuretic peptide (ANP) also regulates the steroidogenic responsiveness in isolated Leydig cells from mouse and rat testes. In the present study, we examined the distribution of specific receptors for ANP and C-type natriuretic peptide (CNP) in the testicular compartments of 12-week-old Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). We used an in vitro autoradiographic procedure on slide-mounted frozen testicular sections to localize the receptors of the natriuretic peptide hormone family using 125I-ANP and 125I-CNP as radioligands. A high level of specific 125I-ANP binding sites was localized largely in the Leydig cells of the interstitial compartment; other testicular cells were not significantly labeled. On the other hand, no significant difference was observed in 125I-CNP binding sites in the testicular cells of SHR and WKY. Semiquantitative analysis of the binding sites indicated that the density of 125I-ANP receptor binding in Leydig cells of WKY testis was ninefold higher than in those of SHR testis. A moderate level of 125I-ANP binding was also observed in seminiferous tubules, particularly in the spermatids of both SHR and WKY. 125I-ANP binding in WKY spermatids was approximately 2.5-fold higher than in SHR spermatids. Northern blot analysis showed that mRNA specific for guanylyl cyclase type A (Npra) was expressed at approximately twofold higher levels in WKY than in SHR testis. ANP (1 x 10(-8) mol/L) stimulated fourfold to fivefold increased levels of testosterone production in isolated Leydig cells from normotensive WKY compared with those from SHR. These findings support a new physiological role of ANP in Leydig cells, in which a functional relationship seems to exist between testicular ANP receptor expression and testosterone production and the state of hypertension in SHR.

Transforming growth factor beta induces mesangial cell apoptosis through NO- and p53-dependent and -independent pathways.

BACKGROUND: Because transforming growth factor beta (TGF-beta) has been shown to have a bimodal effect on mesangial cell (MC) proliferation, we studied its effect on MC apoptosis. METHODS: Cultured mouse MCs were used to evaluate the effect of TGF-beta. Morphologic evaluation of MC apoptosis was performed by staining cells with H-33342 and propidium iodide. To confirm the effect of TGF-beta on MC apoptosis, DNA was extracted from control and TGF-beta-treated MCs and run on gel electrophoresis. We evaluated the effect of NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, on TGF-beta-induced MC apoptosis to determine the role of NO and studied the effect of sodium nitroprusside (SNP) and SNAP (S-nitroso-N-acetyl-penicillamine) on MC apoptosis to confirm the effect of NO. We examined the role of p53 by studying the effect of TGF-beta on MCs derived from p53 knockout mice (p53KO-MC) as well as a normogenic strain (N-MC). We also examined the effect of TGF-beta, SNP, and SNAP on apoptosis of p53 mutant (MDAMB-231) and wild-type p53 (MCF-7) breast cancer cell lines. In addition, Western blots were generated from control, TGF-beta-treated, and SNAP-treated MCs and probed for the expression of p53. RESULTS: TGF-beta promoted MC apoptosis. Moreover, TGF-beta-treated MCs displayed integer multiples of 180 base pairs (ladder pattern). L-NAME inhibited TGF-beta-induced MC apoptosis. Furthermore, SNP and SNAP, NO donors, promoted MC apoptosis. TGF-beta also enhanced the MC expression of p53. TGF-beta induced only a moderate degree of apoptosis in MCs derived from p53KO-MC when compared with N-MCs. Similarly, the TGF-beta-induced apoptosis of MDAMB-231 was of a moderate degree when compared with MCF-7 cells. CONCLUSIONS: We hypothesize that TGF-beta promotes MC apoptosis through NO generation and p53-dependent and -independent pathways.

Age and sex modulate renal expression of SGP-2 and transglutaminase and apoptosis of splenocytes, thymocytes, and macrophages.

BACKGROUND: Aging in humans has been associated with the progressive loss of renal mass. This has been considered to account for a significant reduction of glomerular filtration rate in the aging population. In addition, aging is associated with a compromised immune system. Macrophages, thymocytes, and splenocytes play an important role in the maintenance of the immune system. We studied the effect of sex and aging on apoptosis of peritoneal macrophages, thymocytes, and splenocytes. In addition, we also studied the effect of sex and aging on mRNA expression of active cell death genes on the renal cortex. METHODS: Rats in groups of 4 to 12 were killed at ages 2, 14, 30, 50, 75, and 100 weeks. Renal cortices, peritoneal macrophages, thymocytes, and splenocytes were isolated. DNA was isolated and run on agarose gel electrophoresis. Apoptosis of renal cells was evaluated by the TUNEL method and transmission electron microscopy. RNA was isolated from renal cortices and probed with specific cDNA probes for genes associated with active cell death, such as SGP-2, cathepsin-B, and tissue transglutaminase. Mesangial cells (MC) derived from younger and older rats were examined for the occurrence of apoptosis. The effect of estradiol and testosterone was studied on mesangial cell apoptosis. RESULTS: At 2 weeks, peritoneal macrophages, thymocytes, and splenocytes showed no DNA fragmentation. Apoptosis of macrophages, splenocytes, and thymocytes increased with age in the males as well as females. Mesangial cells derived from aged rats showed a greater percentage of apoptosis when compared to MC derived from younger rats. Estradiol and testosterone directly affect mesangial cell apoptosis. Renal cortices of male rats showed enhanced mRNA expression of SGP-2 and tissue transglutaminase with aging; whereas expression of cathepsin-B peaked at 30 weeks in both male and female rats. CONCLUSION: Age and sex modulate renal cortical mRNA expression of genes associated with active cell death. Age and sex also modulate apoptosis of macrophages, splenocytes, and thymocytes.

Monocyte apoptosis in dialysis patients is Fas ligand-mediated.

BACKGROUND: The mononuclear phagocyte system plays an important role in host defense. Since dialysis patients have been reported to show enhanced leukocytes apoptosis, we evaluated the mechanism of increased apoptosis of monocytes in dialysis patients. METHODS: Apoptotic studies were carried out on monocytes isolated from dialysis patients as well as healthy subjects. The effect of dialysis sera and membranes was evaluated on monocyte apoptosis as well as monocyte expression of proapoptotic proteins such as Fas and FasL. To confirm the role of FasL, we evaluated the effect of activated secretory products on T cell apoptosis. In addition, we studied FasL content of dialysis sera and supernatants of activated monocytes. RESULTS: Monocytes isolated from dialysis patients (MDP) showed a greater magnitude of apoptosis when compared to monocytes isolated from healthy subjects (MHS) (MHS, 3.6 +/- 1.1% vs. MDP, 24.3 +/-1.4%). Sera of hemodialysis patients (SHD) promoted (p < 0.001) apoptosis of MHS when compared to pooled control sera (HPS) (HPS, 0.8 +/- 0.5% vs. SHD, 11.5 +/- 0.5% apoptotic cells/field). Dialysis membranes, cellulose acetate membranes in particular, promoted monocyte apoptosis. Interestingly, anti-FasL antibodies partly inhibited dialysis sera-induced monocyte apoptosis. Dialysis membranes also modulated monocyte expression of both Fas and FasL. Secretory products of activated monocytes also promoted T cell apoptosis. Dialysis sera and activated monocyte secretory products showed increased FasL content. CONCLUSIONS: These results suggest that dialysis patients have an increased rate of monocyte apoptosis, which is mediated through a uremic milieu (serum factors). One of these serum factors seems to be FasL. In addition, dialysis membranes seem to promote apoptosis independent of the uremic milieu. The present study provides a mechanistical insight into the enhanced apoptosis of monocytes in dialysis patients.

Tubular cell and HIV-1 gp120 interaction products promote migration of monocytes.

Renal interstitial accumulation of monocytes is an important feature of HIV-associated nephropathy. We studied the effects of proximal tubular cell products (TCP) and proximal tubular cell-gp120 interaction products (TC-120IP) on the migration of monocytes across a modified Boyden chamber. TC-120IP promoted (P < 0.001) the migration of monocytes when compared with TCP (TCP, 45.0 +/- 5.9 vs. TC-120IP, 192.3 +/- 39.5 migrated monocytes/field). This effect of TC-120IP on monocyte migration was dose dependent. Anti-MCP-1 (TCP, 24.7 +/- 2.6; TC-120IP, 82.3 +/- 5.5; TC120-IP + anti-MCP-1 antibody, 46.5 +/- 3.5 migrated monocytes/field) as well as anti-TGF-beta antibodies (TCP, 25.8 +/- 3.4; TC120-IP, 80.3 +/- 6.9; TC-120IP + anti-TGF-beta antibody, 43.8 +/- 5.6 migrated monocytes/field) partly attenuated TC-120IP-induced migration of monocytes across a filter. Moreover, anti-MCP-1 and anti-TGF antibodies showed an additive inhibitory effect on TC-120IP-induced migration of monocytes across a filter. These results suggest that TC-120IP-induced migration of monocytes may be mediated through the generation of MCP-1 and TGF-beta by tubular cells. The present study provides the basis for a hypothesis that HIV-1 gp120 protein may be contributing to the infiltration of monocytes in the renal interstitium of patients with HIV-associated nephropathy.

Morphine stimulates mesangial cell TNF-alpha and nitrite production.

BACKGROUND: Intravenous opiate abusers are susceptible to develop heroin and HIV-associated nephropathies; however, the role of opiates in the development of these kidney lesions is not clear. Patients with opiate addiction are prone to recurrent infections. METHODS: The effect of morphine was studied on the generation of TNF-alpha with or without LPS (lipopolysaccharide) by cultured mouse mesangial cells. In addition, the effect of morphine was evaluated on mesangial cell nitrite production. To evaluate the role of opiate receptors, we studied the effect of naloxone and naltrexone on mesangial cell TNF-alpha and nitrite production. To determine the role of TNF-alpha on mesangial cell nitrite production, we examined the effect of anti-TNF-alpha antibody on morphine-induced nitrite production. Assay of TNF-alpha and nitrite production was carried by ELISA and Griess method respectively. RESULTS: Morphine alone did not enhance the generation of TNF-alpha by mesangial cells, however, an enhanced (P < 0.001) TNF-alpha production was observed when mesangial cells were first treated with morphine for 18 h and then activated further with LPS. Maximum release of TNF-alpha was seen at a concentration of 10(-12) M of morphine. Opiate receptor antagonists (naloxone and naltrexone) inhibited the effect of morphine. Morphine also amplified (P < 0.0002) the effect of LPS on mesangial cell nitrite production. Anti-TNF-alpha antibody attenuated morphine induced nitrite generation. CONCLUSION: We conclude that morphine stimulates the generation of TNF-infinity by LPS-activated mesangial cells. This effect of morphine seems to be opiate receptor mediated and has a downstream effect in the form of mesangial cell nitrite generation. The present in vitro study provides the basis for a hypothesis that morphine may be playing a role in the development of heroin and HIV-associated nephropathies.

Resection of renal cell carcinomas with inferior vena caval extension using deep hypothermic circulatory arrest.

Renal cell carcinoma with tumour thrombus extension into the inferior vena cava presents a difficult surgical challenge. The conventional surgical approach, which involves isolating the inferior vena cava, incising its wall and removing the thrombus, can have high incidences of perioperative mortality and embolization of the tumour thrombus compounded by severe hemorrhage. Four patients with renal cell carcinomas extending into the inferior vena cava were supported with cardiopulmonary bypass and deep hypothermic circulatory arrest during tumour excision. All of the operations were successfully performed with no mortality and minimal morbidity. The technique allowed the surgeon to operate in a bloodless field, thereby improving visibility and allowing complete tumour excision without significantly prolonging operative time. It is believed that this technique has improved the safety and technical feasibility of what had previously been a complicated and risky surgical procedure.

Opiates promote T cell apoptosis through JNK and caspase pathway.

Opiate addicts are prone to recurrent infections. In the present study we evaluated the molecular mechanism of opiate-induced T cell apoptosis. Both morphine and DAGO ([D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin) enhanced T cell apoptosis. Morphine as well as DAGO activated c-Jun NH2-terminal kinase (JNK) in T cells. Moreover, opiates increased the expression of ATF-2. a specific substrate for JNK and P38 mitogen activated kinases (MAPK). Furthermore, opiates attenuated extracellular signal related kinase (ERK) in T cells. Both morphine and DAGO cleaved pro-caspases 8, 9, and 10 and generated caspases 8, 9 and 10 (active products). Morphine as well as DAGO also cleaved poly-(ADP-ribose) polymerase (PARP) into 116 and 85 kD proteins indicating the activation of caspase-3. These results suggest that opiate-induced T cell apoptosis may be mediated through the JNK cascade and activation of caspases 8 and 3.

Differential distribution of inhibin in the anatomical regions of monkey stomach.

Inhibin, a 10.7 kD FSH (follicle-stimulating hormone) suppressing prostatic peptide has been shown to be synthesized and localized in stomach specimen of monkey. In vitro incorporation of labelled amino acid (3H-leucine) into inhibin followed by specific immunoprecipitation by antiserum to inhibin demonstrated an in vitro de novo biosynthesis of inhibin by monkey stomach. Moreover, the synthesis of inhibin was found to be maximum in fundic zone of gastric mucosa compared to cardiac and antral zone. This was supported by immunohistochemical study of three anatomically different regions, especially wherein fundic zone showed intense positive staining for inhibin. Furthermore, the above data was supplemented by quantitative study of tissue inhibin content by RIA which revealed that the fundic zone of gastric mucosa has a much higher concentration of inhibin than cardiac and antral region. The relationship of zonal concentration of inhibin to gastric anatomy appears to be a noteworthy observation and may serve as an useful tool in our understanding of gastric metabolism and activity.

Endocrine profiles in six patients with acanthosis nigricans.

Six women (age range 17-38 years), who presented to the dermatology services with biopsy-proven acanthosis nigricans of variable duration were evaluated to rule out endocrine diseases. Menstrual abnormalities (5/6 patients), pallid striae (4/6 patients), hirsutism (4/6 patients) and acne vulgaris (2/6 patients) were found on physical examination. All the patients had body mass indices in the obese (> 27 kg/m2) range, and in association we found ovarian hyperthecosis, PCOD, premature ovarian failure, glucose intolerance and hyperprolactinaemia in the above six patients. The importance of appropriate endocrinal evaluation in patients with biopsy-proven acanthosis nigricans is emphasized.

Long-term outcome of lung transplantation in previous intravenous drug users with talc lung granulomatosis.

Talc lung granulomatosis results from the intravenous use of medication intended for oral use. Talc (magnesium silicate) acts as filler in some oral medications; when injected intravenously, it deposits in the lungs leading to airflow obstruction and impaired gas exchange. Allocation of donor lungs to previous intravenous drug users is controversial. After a careful selection process, 19 patients with talc lung granulomatosis have received lung allografts in our program. Long-term survival for these patients is excellent and our results suggest the previous use of intravenous drugs should not necessarily preclude lung transplantation.