Generative Adversarial Networks in Digital Histopathology: Current Applications, Limitations, Ethical Considerations, and Future Directions

Generative adversarial networks (GANs) have gained significant attention in the field of image synthesis, particularly in computer vision. GANs consist of a generative model and a discriminative model trained in an adversarial setting to generate realistic and novel data. In the context of image synthesis, the generator produces synthetic images, whereas the discriminator determines their authenticity by comparing them with real examples. Through iterative training, the generator allows the creation of images that are indistinguishable from real ones, leading to high-quality image generation. Considering their success in computer vision, GANs hold great potential for medical diagnostic applications. In the medical field, GANs can generate images of rare diseases, aid in learning, and be used as visualization tools. GANs can leverage unlabeled medical images, which are large in size, numerous in quantity, and challenging to annotate manually. GANs have demonstrated remarkable capabilities in image synthesis and have the potential to significantly impact digital histopathology. This review article focuses on the emerging use of GANs in digital histopathology, examining their applications and potential challenges. Histopathology plays a crucial role in disease diagnosis, and GANs can contribute by generating realistic microscopic images. However, ethical considerations arise because of the reliance on synthetic or pseudogenerated images. Therefore, the manuscript also explores the current limitations and highlights the ethical considerations associated with the use of this technology. In conclusion, digital histopathology has seen an emerging use of GANs for image enhancement, such as color (stain) normalization, virtual staining, and ink/marker removal. GANs offer significant potential in transforming digital pathology when applied to specific and narrow tasks (preprocessing enhancements). Evaluating data quality, addressing biases, protecting privacy, ensuring accountability and transparency, and developing regulation are imperative to ensure the ethical application of GANs.

A multi-laboratory preclinical trial in rodents to assess treatment candidates for acute ischemic stroke

Human diseases may be modeled in animals to allow preclinical assessment of putative new clinical interventions. Recent, highly publicized failures of large clinical trials called into question the rigor, design, and value of preclinical assessment. We established the Stroke Preclinical Assessment Network (SPAN) to design and implement a randomized, controlled, blinded, multi-laboratory trial for the rigorous assessment of candidate stroke treatments combined with intravascular thrombectomy. Efficacy and futility boundaries in a multi-arm multi-stage statistical design aimed to exclude from further study highly effective or futile interventions after each of four sequential stages. Six independent research laboratories performed a standard focal cerebral ischemic insult in five animal models that included equal numbers of males and females: young mice, young rats, aging mice, mice with diet-induced obesity, and spontaneously hypertensive rats. The laboratories adhered to a common protocol and efficiently enrolled 2615 animals with full data completion and comprehensive animal tracking. SPAN successfully implemented treatment masking, randomization, prerandomization inclusion and exclusion criteria, and blinded assessment of outcomes. The SPAN design and infrastructure provide an effective approach that could be used in similar preclinical, multi-laboratory studies in other disease areas and should help improve reproducibility in translational science.

Automated Diagnosis of Diabetic Retinopathy Using Deep Learning: On the Search of Segmented Retinal Blood Vessel Images for Better Performance

Diabetic retinopathy is one of the most significant retinal diseases that can lead to blindness. As a result, it is critical to receive a prompt diagnosis of the disease. Manual screening can result in misdiagnosis due to human error and limited human capability. In such cases, using a deep learning-based automated diagnosis of the disease could aid in early detection and treatment. In deep learning-based analysis, the original and segmented blood vessels are typically used for diagnosis. However, it is still unclear which approach is superior. In this study, a comparison of two deep learning approaches (Inception v3 and DenseNet-121) was performed on two different datasets of colored images and segmented images. The study’s findings revealed that the accuracy for original images on both Inception v3 and DenseNet-121 equaled 0.8 or higher, whereas the segmented retinal blood vessels under both approaches provided an accuracy of just greater than 0.6, demonstrating that the segmented vessels do not add much utility to the deep learning-based analysis. The study’s findings show that the original-colored images are more significant in diagnosing retinopathy than the extracted retinal blood vessels.

Toxoplasma gondii in lactating animals: potential risk to milk consuming population in Khyber Pakhtunkhwa

Toxoplasma gondii is an intracellular zoonotic protozoan parasite usually infects human and animal worldwide. This study aimed to analyze the sero-prevalence of T. gondii in blood of lactating animals and human living in close proximity and also to detect Toxoplasma DNA in unpasteurized milk of the studied animals. A total of 233 blood and milk samples were collected from lactating animals, and 735 blood samples were taken from humans in District Upper Dir, Khyber Pakhtunkhwa, Pakistan. The blood samples were analyzed through ELISA while the milk samples were analyzed by PCR for the presence of T. gondii DNA. A standard questionnaire was introduced to collect the data from the participants. In animals, the reported sero-prevalence was 32.18% for IgM, 17.16% for IgG, and 6.4% for both IgM and IgG. The reported positivity for T. gondii DNA in milk was 14.44%, 34.8%, 20%, and 26% in sheep, goats, cows, and buffaloes, respectively. In the human blood samples, 9.8% were found positive for IgM and 11.2% for IgG while none of the samples was found positive for both IgM and IgG. Overall sero-prevalence reported in females was significantly higher than the male (p<0.05) poor hygiene condition (p < 0.0001) were the significant risk factors associated with T. gondii infections in animals. In conclusion, T. gondii infection is prevalent in lactating animals and humans using their raw milk in the study area. It is suggested that raw milk should be considered as a vehicle for the transmission of T. gondii to humans. Proper pasteurization of milk is very useful in limiting the transmission of infection. Awareness and control programs should be implemented to prevent the infection.

Lyophilized Extracellular Vesicles from Adipose-Derived Stem Cells Increase Muscle Reperfusion but Degrade Muscle Structural Proteins in a Mouse Model of Hindlimb Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury is a complication impacting multiple organs and tissues in clinical conditions ranging from peripheral arterial disease to musculoskeletal trauma and myocardial infarction. Stem cell-derived extracellular vesicles (EVs) may represent one therapeutic resource for preventing the tissue damage associated with I/R injury. Here we tested the hypothesis that lyophilized extracellular vesicles derived from adipose stem cells could serve as an "off-the-shelf" treatment modality for I/R injury in a mouse hindlimb ischemia model. Ischemia was induced for 90 min using a rubber band tourniquet and extracellular vesicles (0, 50, or 100 µg) administered via tail vein injection immediately prior to reperfusion. Perfusion was measured prior to, during, and after ischemia using laser Doppler imaging. Serum and tissue were collected 24 h after reperfusion. Mass spectrometry (MS)-based proteomics was used to characterize the EV cargo and proteins from the ischemic and non-ischemic hindlimb. Inflammatory cytokines were measured in muscle and serum using a multiplex array. Results indicate that EVs significantly increase reperfusion and significantly increase expression of the anti-inflammatory factor annexin a1 in skeletal muscle; however, the increased reperfusion was also associated with a marked decrease in muscle structural proteins such as dystrophin, plectin, and obscurin. Circulating inflammatory cytokines TNF-alpha and IL-6 were increased with EV treatment, and serum TNF-alpha showed a significant, positive correlation with reperfusion level. These findings suggest that, while EVs may enhance reperfusion, the increased reperfusion can negatively impact muscle tissue and possibly remote organs. Alternative approaches, such as targeting mitochondrial permeability, may be more effective at mitigating I/R injury.

Abstract WP226: Circadian Rhythm Influences Immune Response In Ischemic Stroke Mice

Background: Stroke leads to disability and death worldwide. There is evidence that stroke affects the immune system function, and the clock gene controls the immune system. Stroke elevates the inflammatory cascade. Immune response controls the stroke pathology. However, it is unclear if the circadian rhythm influences the immune system in ischemic stroke mice and affects stroke outcomes.

Hypothesis: We hypothesized that immune response might be affected by a circadian rhythm that aggravates stroke pathology in a mouse suture occlusion model

Methods: Seven to eight-month-old C57BL/6J (Wild Type, n=8-10 mice/group) mice were randomly assigned to do stroke at the different time points of the day following zeitgeber time at ZT0, ZT6, ZT12, and Z18. Cerebral Ischemia was induced by occlusion of the middle cerebral artery (MCAO) for 60 min. Whole blood was analyzed using flow cytometry, and we observed macrophages (M1, M2), neutrophils (N1, N2), Anti-inflammatory IL10, and pro-inflammatory TNF-α cytokines at 24h and 48h. Forty-eight hours after stroke, TTC staining was done to estimate brain infarction, and the infarct area was measured using NIH-Image J software.

Results: There was a significant increase ( p <0.005) in TNF-α (9±2.50) and significant low IL-10 (5.12±1.35) ( p <0001) at (ZT6, noon) stroke at 48h during a deep sleep period (ZT6, noon) stroke in comparison to fully awake period stroke. We found a significant increase ( p <001) in M1 (54.12±5.16) macrophage and a significant decrease ( p <001) in M2 (45.87±5.16) macrophage at ZT6 (noon) compare to other zeitgeber time points. We also found a significantly higher M1:M2 ratio (1.17) at ZT6. Additionally, we found that neutrophil N1 (66.88±4.39) level was significantly ( p <0001) elevated while neutrophil N2 (33.88±4.43) was significantly reduced at ZT6 (noon) sleep period in comparison to ZT0, ZT12, and Z18 time points. We also found a considerably higher N1:N2 ratio (1.97) at ZT6.

Conclusion: This study demonstrates that mice brain infarcts are influenced by immune responses that aggravate stroke pathology during their sleep period (noon/ZT6) than during their awake period (midnight/ZT18).

Abdominal Visceral Injury, a Devastating Consequence of Abdominal Liposuction: A Case Report and Literature Review

Abdominal liposuction is a commonly performed cosmetic procedure. However, as with any procedure, it can be associated with complications. One of the life-threatening complications of this procedure is visceral injury and bowel perforation. This complication is very rare, nevertheless general, and acute care surgeons must be aware of its possibility, its management, and its possible sequelae. We report a case of a 37-year-old female who underwent abdominal liposuction which was complicated by bowel perforation and was transferred to our facility for further care. She underwent an exploratory laparotomy in which multiple perforations were repaired. The patient then underwent multiple surgeries including stoma creation and had a long postoperative course. A literature review reveals the devastating sequelae of reported similar visceral and bowel injuries. The patient eventually did well and her stoma was reversed. This patient population will require close intensive care unit observation and a low threshold of suspicion for missed injuries during initial exploration. Further down the line, they will need psychosocial support and the mental health implications of this outcome must be cared for. The long-term aesthetic outcome is yet to be addressed.

The Stroke Preclinical Assessment Network: Rationale, Design, Feasibility, and Stage 1 Results

Cerebral ischemia and reperfusion initiate cellular events in brain that lead to neurological disability. Investigating these cellular events provides ample targets for developing new treatments. Despite considerable work, no such therapy has translated into successful stroke treatment. Among other issues-such as incomplete mechanistic knowledge and faulty clinical trial design-a key contributor to prior translational failures may be insufficient scientific rigor during preclinical assessment: nonblinded outcome assessment; missing randomization; inappropriate sample sizes; and preclinical assessments in young male animals that ignore relevant biological variables, such as age, sex, and relevant comorbid diseases. Promising results are rarely replicated in multiple laboratories. We sought to address some of these issues with rigorous assessment of candidate treatments across 6 independent research laboratories. The Stroke Preclinical Assessment Network (SPAN) implements state-of-the-art experimental design to test the hypothesis that rigorous preclinical assessment can successfully reduce or eliminate common sources of bias in choosing treatments for evaluation in clinical studies. SPAN is a randomized, placebo-controlled, blinded, multilaboratory trial using a multi-arm multi-stage protocol to select one or more putative stroke treatments with an implied high likelihood of success in human clinical stroke trials. The first stage of SPAN implemented procedural standardization and experimental rigor. All participating research laboratories performed middle cerebral artery occlusion surgery adhering to a common protocol and rapidly enrolled 913 mice in the first of 4 planned stages with excellent protocol adherence, remarkable data completion and low rates of subject loss. SPAN stage 1 successfully implemented treatment masking, randomization, prerandomization inclusion/exclusion criteria, and blinded assessment to exclude bias. Our data suggest that a large, multilaboratory, preclinical assessment effort to reduce known sources of bias is feasible and practical. Subsequent SPAN stages will evaluate candidate treatments for potential success in future stroke clinical trials using aged animals and animals with comorbid conditions.

Abstract WMP118: Preclinical Evaluation Of Circadian Rhythm In Ischemic Stroke Outcomes

Background: Stroke is a leading cause of disability and death worldwide. There is evidence that there is a circadian rhythm in stroke with peak occurrence in the morning (6 to 10 am). However it is not clear if the size of infarcts and the outcomes of stroke also varies during the 24 hour period

Hypothesis: We hypothesized that the size of cerebral infarct and outcome from stroke would show circadian variation in a mouse suture occlusion model.

Methods: Seven to eight-month-old C57BL/6J (Wild Type, n=10-15 mice/group) mice were randomly assigned to do stroke at the different time points of the day following zeitgeber time at ZT0, ZT6, ZT12, and Z18. Cerebral Ischemia was induced by occlusion of the middle cerebral artery (MCAO) for 60 min. Blood flow was monitored by Laser Speckle before, after occlusion, and at 24h. Neurological deficit was observed by using Bederson score at 24h and 48h. The corner test was used to detect unilateral abnormalities of sensory and motor functions in the stroke mice at 48h. TTC staining was done, 48 hours after stroke, to estimate brain infarction, and the infarct area was measured by using NIH-Image J software.

Results: We did not find a significant difference in CBF at any time points. There was a significant increased ( p <0.05) neurological deficit (Bederson score) at 48h during deep sleep period (ZT6, noon) stroke (1.55±0.17) in comparison to fully awake period stroke (1.1±0.1). In the corner test, we found right turn preference significantly higher ( p <0.005) at noon/ZT6 (9.5±0.34) compared to the fully awake (5.5±0.34) (midnight, ZT18) period. Similarly, the infarction volume was significantly higher ( p <0.05) during the sleep (ZT6, noon) period (29.32±5.03) in comparison to a fully awake midnight/ZT18 period (15.68±2.38).

Conclusion: This is the first report demonstrating that mice have larger infarcts and worse short term outcomes during their sleep period (noon/ZT6) than during their awake period (midnight/ZT18).

Abstract WMP13: Delayed Stimulation Of Angiotensin II Type 2 Receptor Ameliorates Sensorimotor Deficits And Cognitive Decline After Stroke In Aged Hypertensive Rats

Hypertension and aging are leading risk factors for stroke and cognitive decline. Animal models fail to capture the complex interplay between these two pathophysiologic processes, limiting human translation of interventions. In the current study, we investigated the development of cognitive impairment in 18-month-old spontaneously hypertensive rats (SHRs) prior to and following a 30-minute tMCAO or SHAM. Sixty SHRs were kept for 18 months with cognitive assessments performed prior to and post-surgery. Baseline brain MRI was done at 18 months and then at day 3 and week 8 post-surgery. At day 3, rats were randomly assigned to blindly receive either C21 or normal drinking water for 8 weeks.

Results: Over 18 months, SHRs demonstrated a progressive cognitive decline and significant abnormalities on MRI. Aged SHRs demonstrated an acceptably low 14% peri-operative mortality within 72 hours of tMCAO. Stroke resulted in sustained, significant sensorimotor deficits and C21 effectively enhanced sensorimotor recovery at week 8. Progressive cognitive decline continued after surgery, but C21 enhanced post-stroke, subacute associative and reference memory at week 5. There was no evidence of anhedonia at 8 weeks. MRI scans revealed no difference in ischemic lesion resolution between C21 and control. However, C21 treated rats had less cortical atrophy and reduced WM injury at 8 weeks.

Conclusions: Aged SHRs with minor stroke demonstrated persistent sensorimotor deficits, which were significantly lessened with C21. The dramatic decline in exploration time with age was ameliorated with C21 treatment, evidence of preserved cognition.

Abstract WMP117: Effects Of Chronic Remote Ischemic Conditioning In A VCID Mouse Appears RBCNOS3 Dependent

Background and Purpose: Chronic remote ischemic conditioning (C-RIC) is effective at improving cerebral blood flow (CBF) inducing vascular remodeling, and improving cognition in a bilateral carotid artery stenosis (BCAS) mouse model, a model for Vascular Cognitive Impairment and Dementia (VCID). This augmentation is associated with increases of plasma nitrite. Our aim was to determine if the beneficial effect of C-RIC was red blood cell (NOS3) dependent.

Methods: Microcoil (01.8 mm) induced BCAS model was used to induce chronic hypoperfusion. Aged RBCNOS3-KO and its control groups, NOS3flox-flox male mice (>12 months ) were randomly assigned to Sham RIC and RIC of both strains. RIC was started 7d post-surgery daily for 4 weeks. Behavioral test and CBF was performed before termination. Functional outcomes were assessed using novel object recognition (NOR) test for non-spatial working memory, and hanging wire and beam walk test for motor/muscular impairment. Histopathological staining was also assessed of the brain tissues.

Results: C-RIC-therapy for 4 weeks did not improve CBF in the RBCNOS3KO groups at 4 th weeks compared to ShamRIC groups. However, C-RIC therapy for 4 weeks significantly improved CBF in NOS3flox-flox groups compared to ShamRIC groups. Similarly, there was no significant change in the RBCNOS3 KO mice between the ShamRIC and RIC groups in the discrimination index/exploration time as determined by the NOR test or poor motor function as determined by hanging wire and beam walk test whereas the NOS3flox-flox mice did show improved cognition with RIC.

Conclusions: The beneficial effect of C-RIC in the BCAS model is abrogated in RBCNOS3 KO mice indicating that the effect of C-RIC is NOS3 dependent.

Cannabidiol Ameliorates Cognitive Function via Regulation of IL-33 and TREM2 Upregulation in a Murine Model of Alzheimer's Disease

There is a dire need for due innovative therapeutic modalities to improve outcomes of AD patients. In this study, we tested whether cannabidiol (CBD) improves outcomes in a translational model of familial AD and to investigate if CBD regulates interleukin (IL)-33 and triggering receptor expressed on myeloid cells 2 (TREM2), which are associated with improved cognitive function. CBD was administered to 5xFAD mice, which recapitulate early onset, familial AD. Behavioral tests and immunoassays were used to evaluate cognitive and motor outcomes. Our findings suggest that CBD treatment enhanced IL-33 and TREM2 expression, ameliorated the symptoms of AD, and retarded cognitive decline.

Food habits of indian crested porcupine (Hystrix indica) (Kerr 1792), in district Bagh, Azad Jammu and Kashmir

The Indian Crested Porcupine (Hystrix indica) is classified as an agricultural pest species. It feeds on plants and crops; hence, it is responsible for massive financial losses worldwide. The current study was conducted to assess the diet composition of Indian Crested Porcupine in District Bagh, Azad Jammu and Kashmir (AJ&K). Thus, fecal samples were collected and examined from different sampling sites. Reference slides of the material collected from the study area were prepared for identification of dietary components in fecal pellets. A total of 80 fecal samples were collected and processed. Percent relative frequencies (P.R.F.) were calculated for each plant species recovered from pellets. Data revealed that Indian Crested Porcupine consumed 31 plant species in its diet, among them Zea mays (34.31±7.76) was the most frequently selected species followed by Rumex obtusifolius (15.32±2.57) and Melia azedarach (12.83±4.79). The study revealed that the greatest diversity of (n=20) plant species were consumed in summer season while minimum (n=13) species were used during winter. Among the parts of plants, stem was highly consumed in spring (57.2%) as compared to seed in fall (36.7%) while spikes and leaf were the least recovered parts from the fecal matter. The Berger-Parker diversity index showed highly diversified food (10.92) in the summer time of the year as compared to the autumn season (2.95). This study provides a baseline for the diet preference of this pest in the study area. Based on current findings, a detailed investigation on damage assessment, exploration, habitat use and management of Indian Crested Porcupine in AJ&K has been recommended.

Pulsed Focal Ultrasound as a Non-Invasive Method to Deliver Exosomes in the Brain/Stroke

Exosomes, a component of extracellular vesicles, are shown to carry important small RNAs, mRNAs, protein, and bioactive lipid from parent cells and are found in most biological fluids. Investigators have demonstrated the importance of mesenchymal stem cells derived exosomes in repairing stroke lesions. However, exosomes from endothelial progenitor cells have not been tested in any stroke model, nor has there been an evaluation of whether these exosomes target/home to areas of pathology. Targeted delivery of intravenous administered exosomes has been a great challenge, and a targeted delivery system is lacking to deliver naïve (unmodified) exosomes from endothelial progenitor cells to the site of interest. Pulsed focused ultrasound is being used for therapeutic and experimental purposes. There has not been any report showing the use of low-intensity pulsed focused ultrasound to deliver exosomes to the site of interest in stroke models. In this proof of principle study, we have shown different parameters of pulsed focused ultrasound to deliver exosomes in the intact and stroke brain with or without intravenous administration of nanobubbles. The study results showed that administration of nanobubbles is detrimental to the brain structures (micro bleeding and white matter destruction) at peak negative pressure of >0.25 megapascal, despite enhanced delivery of intravenous administered exosomes. However, without nanobubbles, pulsed focused ultrasound enhances the delivery of exosomes in the stroke area without altering the brain structures.

Decreased parenchymal arteriolar tone uncouples vessel-to-neuronal communication in a mouse model of vascular cognitive impairment

Chronic hypoperfusion is a key contributor to cognitive decline and neurodegenerative conditions, but the cellular mechanisms remain ill-defined. Using a multidisciplinary approach, we sought to elucidate chronic hypoperfusion-evoked functional changes at the neurovascular unit. We used bilateral common carotid artery stenosis (BCAS), a well-established model of vascular cognitive impairment, combined with an ex vivo preparation that allows pressurization of parenchymal arterioles in a brain slice. Our results demonstrate that mild (~ 30%), chronic hypoperfusion significantly altered the functional integrity of the cortical neurovascular unit. Although pial cerebral perfusion recovered over time, parenchymal arterioles progressively lost tone, exhibiting significant reductions by day 28 post-surgery. We provide supportive evidence for reduced adenosine 1 receptor-mediated vasoconstriction as a potential mechanism in the adaptive response underlying the reduced baseline tone in parenchymal arterioles. In addition, we show that in response to the neuromodulator adenosine, the action potential frequency of cortical pyramidal neurons was significantly reduced in all groups. However, a significant decrease in adenosine-induced hyperpolarization was observed in BCAS 14 days. At the microvascular level, constriction-induced inhibition of pyramidal neurons was significantly compromised in BCAS mice. Collectively, these results suggest that BCAS uncouples vessel-to-neuron communication-vasculo-neuronal coupling-a potential early event in cognitive decline.

Abstract WP480: Beneficial Effect of Chronic-Remote Ischemic Conditioning (C-RIC) is Dependent Upon Circulating Blood Cell NOS3 in a Vascular Cognitive Impairment and Dementia (VCID) Model

Background and Purpose: Chronic remote ischemic conditioning (C-RIC) is effective at improving cerebral blood flow (CBF) inducing vascular remodeling, and improving cognition in a bilateral carotid artery stenosis (BCAS) mouse model, a model for Vascular Cognitive Impairment and Dementia (VCID). This effect is lost in NOS3-KO mice. We wanted to determine if the beneficial effect of C-RIC can be restored by bone marrow cell-derived NOS3.

Methods: We prepared BM chimera from adult WT (B6.SJL-Ptprc a ; CD45.1) to adult NOS3-KO (B6.129; CD45.2) & vice versa in male mice (5-6 months) following confirmation for BM engrafting with flow cytometry at 2 weeks. Microcoil (0.18 mm) induced BCAS model was used to induce chronic hypoperfusion. Mice were randomly assigned to 3-groups: (1) Sham (2) BCAS and (3) BCAS+RIC. RIC was started 7d post-surgery daily for 3-4 weeks. Behavioral test and CBF was performed before termination. Functional outcomes were assessed using novel object recognition (NOR) test for non-spatial working memory, and hanging wire and beam walk test for motor/muscular impairment. We measured whole blood P-NOS3, P-AMPK and VEGFR2/CD31 by flow cytometry.

Results: C-RIC-therapy for 3-4 weeks improves CBF in engrafted BM of WT into NOS3-KO in the BCAS+RIC groups at both 2 weeks and 4 weeks compared to BCAS (Sham RIC groups).No effect of C-RIC was shown in engrafted BM of NOS3 into WT. There was significant change between the BCAS and BCAS+RIC groups in the functional outcomes and histopathological evidences also reflects major changing in the groups in the BM of WT into NOS3-KO mice. Whole blood P-NOS3, P-AMPK and VEGFR2/CD31 was increased by C-RIC. However, no effect was shown in the NOS3-KO into WT chimera.

Conclusions: The Beneficial effect of C-RIC is dependent upon bone marrow derived NOS3.Further studies are needed to determine if the red blood cell is the key cell carrying NOS3

Malformation of the Posterior Cerebellar Vermis Is a Common Neuroanatomical Phenotype of Genetically Engineered Mice on the C57BL/6 Background

C57BL/6 mice exhibit spontaneous cerebellar malformations consisting of heterotopic neurons and glia in the molecular layer of the posterior vermis, indicative of neuronal migration defect during cerebellar development. Recognizing that many genetically engineered (GE) mouse lines are produced from C57BL/6 ES cells or backcrossed to this strain, we performed histological analyses and found that cerebellar heterotopia were a common feature present in the majority of GE lines on this background. Furthermore, we identify GE mouse lines that will be valuable in the study of cerebellar malformations including diverse driver, reporter, and optogenetic lines. Finally, we discuss the implications that these data have on the use of C57BL/6 mice and GE mice on this background in studies of cerebellar development or as models of disease.

Selective activation of cannabinoid receptor-2 reduces neuroinflammation after traumatic brain injury via alternative macrophage polarization

Inflammation is an important mediator of secondary neurological injury after traumatic brain injury (TBI). Endocannabinoids, endogenously produced arachidonate based lipids, have recently emerged as powerful anti-inflammatory compounds, yet the molecular and cellular mechanisms underlying these effects are poorly defined. Endocannabinoids are physiological ligands for two known cannabinoid receptors, CB1R and CB2R. In the present study, we hypothesized that selective activation of CB2R attenuates neuroinflammation and reduces neurovascular injury after TBI. Using a murine controlled cortical impact (CCI) model of TBI, we observed a dramatic upregulation of CB2R within infiltrating myeloid cells beginning at 72 h. Administration of the selective CB2R agonist, GP1a (1-5 mg/kg), attenuated pro-inflammatory M1 macrophage polarization, increased anti-inflammatory M2 polarization, reduced edema development, enhanced cerebral blood flow, and improved neurobehavioral outcomes after TBI. In contrast, the CB2R antagonist, AM630, worsened outcomes. Taken together, our findings support the development of selective CB2R agonists as a therapeutic strategy to improve TBI outcomes while avoiding the psychoactive effects of CB1R activation.

Abstract TP428: The Beneficial Effects of Chronic Remote Ischemic Conditioning in a VCID Mouse Model are eNOS Dependent

Background and Purpose: Chronic remote ischemic conditioning (C-RIC) is effective at improving cerebral blood flow (CBF) inducing vascular remodeling, and improving cognition in a bilateral carotid artery stenosis (BCAS) mouse model, a model for Vascular Cognitive Impairment and Dementia (VCID). This improvement is associated with elevations of plasma nitrite. Our aim was to determine if the beneficial effect of C-RIC was eNOS dependent.

Methods: Microcoil (01.8 mm) induced BCAS model was used to induce chronic hypoperfusion. Adult eNOS-KO male mice (5-6 months) were randomly assigned to 2-groups (N=5): (1) BCAS and (2) BCAS+RIC. RIC was started 7d post-surgery daily for 3 weeks. Behavioral test and CBF was performed before termination. Functional outcomes were assessed using novel object recognition (NOR) test for non-spatial working memory, and hanging wire and beam walk test for motor/muscular impairment. Mice were followed for 4 weeks.

Results: C-RIC-therapy for 3 weeks did not improve CBF in the BCAS+RIC groups at either a 2 nd weeks or 4 th weeks compared to BCAS-Sham RIC groups. There was no significant change between the BCAS and BCAS+RIC groups in the discrimination index as determined by the NOR test or poor motor function as determined by hanging wire and beam walk test.

Conclusions: The beneficial effect of C-RIC in the BCAS model is abrogated in eNOS KO mice indicating that the effect of C-RIC is eNOS dependent.

Abstract WP296: Short Term Acute Preconditioning Exercise Improves Stroke Outcomes and Reduces Neurovascular Injury via Increased Endothelial Nitric Oxide Synthase Activity

Physical exercise is becoming a prominent therapeutic strategy to improve stroke outcomes. It was previously shown that long term exercise reduces infarct volume, but this was never tested in acute short term preconditioning exercise in a thromboembolic model of stroke. Exercise induced shear stress improves vascular function through increased activity of endothelial nitric oxide synthase (eNOS) and its upstream principal activator, AMP-activated protein kinase (AMPK). However, this was not previously tested in a stroke setting. Accordingly, we tested the hypothesis that acute short term preconditioning exercise improves stroke outcomes through increased AMPK and eNOS activity.

Methods: Male Wistar rats (300g) were subjected to treadmill exercise for four days (25 minutes/day), break for 2 days and then one acute bout for 30 minutes. Exercised animals were subjected to thromboembolic stroke at 1h, 6h or 24h after the last exercise session. At 24h, control (sedentary) and exercised rats were tested for neurological outcomes, infarct size and edema. Western Blotting was used to measure the expression of active eNOS (p-S1177-eNOS) and active AMPK (p-T172-AMPK).

Results: Acute exercise significantly reduced infarct size and edema and improved functional outcomes compared to control. It also significantly increased the expression of peNOS and pAMPK in the brain, cerebral vessels and aorta (Table).

Conclusion: Acute exercise preconditioning significantly reduced neurovascular injury and improved functional outcome after stroke through increased eNOS activity. Our findings are novel to point out the role of preconditioning exercise induced AMPK and eNOS activation in improving stroke outcomes.

Abstract TP435: Remote Ischemic Conditioning Augments Collateral Circulation and Angiogenesis in a Bilateral Carotid Artery Stenosis Model in Mice

Background and Purpose: The Bilateral carotid artery stenosis model in mice (BCAS) is regarded as a model for vascular cognitive impairment (VCI) and cerebral small vessel disease (SVD). We have shown that repetitive remote ischemic conditioning (RIC) increases cerebral blood flow (CBF), reduces white matter damage and improves cognition in the BCAS mouse model. The purpose of this study was to determine whether RIC increased angiogenesis and increased endothelial progenitor cells (EPC) in the blood or changed the polarization of macrophages in the blood.

Methods: Microcoil induced bilateral common carotid artery (BCAS) model was used to induce chronic hypoperfusion. Adult C57BL/6J male mice of (10-weeks) were randomized to 3-different groups (N=9), and subjected to Sham-(procedures of BCAS and RIC), BCAS+shamRIC and BCAS+RIC. RIC was started 7d post-surgery daily for 3 weeks. In all the experimental groups and after 3 weeks blood were collected through cardiac puncture and perfused with BriteVu. EPC (CD31, VEFR2, CD34) and M1/M2 macrophages were assessed through flow cytometry and angioarchitecture (vascular volume, number of vessels, linear spacing between vessels, density, average lumen thickness, and collateral circulation vessels) was performed with micro-CT scanner. All observers were blinded. Statistical significance was determined at p <0.05.

Results: RIC-therapy significantly improved CBF in the BCAS+RIC group compared to BCAS +shamRIC. EPCs were increased in the blood of the BCAS+RIC compared to BCAS+sham RIC and there was increased polarization (ratio of M2/M1) of macrophages in the blood in BCAS+RIC group compared to BCAS+shamRIC. RIC increased angiogenesis compared to sham RIC with increased vascular volume, number of vessels and decreased space between vessels.

Conclusions: Repetitive RIC increases angiogenesis and increases EPCs in the blood after BCAS. RIC also polarizes macrophages to the M2 (anti-inflammatory subset). Repetitive RIC may be an effective therapy to slow down the progression of VCI and SVD by promoting angiogenesis and vascular remodeling.

Abstract WP449: Short Term (1 month) Daily Remote Ischemic Conditioning (RIC) Induces Vascular Remodeling and Improves Long Term Outcomes (6 month) in a Mouse Model of Vascular Cognitive Impairment (VCI)

Background and Purpose: There is presently no specific therapy for the treatment of VCI. The bilateral carotid artery stenosis (BCAS) model is regarded as a valid model for VCI and vascular dementia. We reported that daily RIC is effective by improving cerebral blood flow (CBF), reducing white matter (WM) damage and improving cognition. The purpose of this study was to determine if 1MO RIC is as effective as 4MO RIC and if the treatment effects are durable out to 6MO.

Methods: Microcoil induced BCAS model was used to induce chronic hypoperfusion. Adult C57BL/6J male mice (10-weeks) were randomly assigned to 4-different groups (N=10), and subjected to Sham-BCAS, BCAS-(+sham RIC), BCAS+RIC-1MO and BCAS+RIC-4MO. RIC was started 7d post-surgery daily for 1MO or 4MOs. Behavioral test and CBF was performed at 1, 4 and 6MO after BCAS surgery. Functional outcomes were assessed using novel object recognition (NOR) test for non-spatial working memory, and hanging wire test for motor impairment. Histopathology as well as immunohistochemistry for CD31 and myelin basic protein (MBP) were also performed on the of the brain tissue collected after the neurobehavioral tests. Statistical significance was determined at p <0.05.

Results: RIC-therapy for 1MO or 4MO significantly improved CBF in the BCAS+RIC groups. The RIC-1MO treatment was effective as the RIC-4MO treatment at improving CBF at 6MO. Mice from the BCAS group showed significant loss in the discrimination index as determined by the NOR test, and poor motor function in hanging wire test. RIC-therapy in BCAS+RIC (1MO & 4MO) groups significantly improved functional outcomes as compared to the BCAS group whereas there was no difference between the RIC groups. Histopathological studies showed prevention of WM degeneration by RIC. Immunohistochemical analysis at 6 MOs showed increased CD31 staining (angiogenesis) and increased MBP staining (myelination) in the RIC groups compared to sham RIC.

Conclusions: Both 1MO and 4MO RIC-therapy improve long term CBF and angiogenesis at 6 MO and reduce WM damage and improve functional outcomes. One month of daily RIC is as effective as 4MO of daily RIC at improving CBF and long term functional outcomes (6MO) in the BCAS model. This suggests that 1MO of RIC induces durable vascular remodeling.

Abstract TMP118: Increased Brain Derived Neurotrophic Factor (BDNF) and Vascular Endothelial Growth (VEGF) After Long Term Remote Ischemic Conditioning (RIC): Possible Role in Neurovascular Plasticity During Vascular Cognitive Impairment (VCI)

Background and Purpose: Vascular dysfunction and resultant chronic cerebral hypoperfusion leads to VCI, the second most common cause of dementia. We reported that RIC-therapy improves cerebral blood flow (CBF) in both murine stroke and VCI models. In the present work, we hypothesized that long-term RIC-therapy after VCI will promote neurovascular plasticity via up-regulation of growth factors.

Methods: Microcoil induced bilateral common carotid artery (BCAS) model was used to induce chronic hypoperfusion. Adult C57BL/6J male mice of (10-weeks) were assigned to 3-different groups (N=6), and subjected to Sham- (procedures of BCAS and RIC), BCAS- (induced VCI followed by RIC-Sham), and BCAS+RIC (induced VCI followed by RIC-therapy). RIC was started 7d post-surgery for 2-wks. At 4-wks post-surgery (1-wk after the cessation of RIC) CBF was determined using laser speckle contrast imager (LSCI). Functional outcomes were assessed using novel object recognition (NOR) test for non-spatial working memory, and hanging wire test for motor impairment. Histopathology as well as immunohistochemistry for BDNF and VGEF were also performed on the of the brain tissue collected after the neurobehavioral tests. Statistical significance was determined at p <0.05.

Results: RIC-therapy significantly improved CBF in BCAS+RIC group compared to the BCAS group. Mice from the BCAS group showed significant loss in the discrimination index as determined by the NOR test, and poor motor function strength in hanging wire test. RIC-therapy in BCAS+RIC group significantly improved functional outcomes as compared to the BCAS-group. Histopathological studies clearly showed prevention of neurovascular degeneration by RIC. Interestingly, immunohistochemical analysis revealed loss in BDNF and VEGF expressions in the BCAS-group as compared to Sham that was increased in the BCAS+RIC-group.

Conclusions: RIC-therapy attenuates neurovascular stress via improved CBF that attenuates neurovascular degeneration and prevents functional impairments. RIC increases BDNF and VEGF levels. Long term RIC-therapy could be a conventional therapy for aged individuals suffering from VCI and resultant motor impairment.

Humoral Mediators of Remote Ischemic Conditioning: Important Role of eNOS/NO/Nitrite

Remote ischemic conditioning (RIC) is a powerful cardioprotectant and neuroprotectant. The mechanism of protection likely involves circulating, blood-borne mediators that transmit the signal from the periphery to the brain. The neuroprotective effect of RIC may be partially related to improvements in cerebral blood flow (CBF). Nitrite is a key circulating mediator of RIC and may be a mediator of increased CBF and also mediate cytoprotection through its effects on nitrosylation of mitochondrial proteins such as complex I. Measuring plasma nitrite may serve as an important blood biomarker, and measuring CBF by techniques such as MRI arterial spin labeling (ASL) may be an ideal surrogate imaging biomarker in clinical trials of RIC.

Remote ischemic conditioning: a treatment for vascular cognitive impairment

There is a strong link between hypoperfusion and white matter (WM) damage in patients with leukoaraiosis and vascular cognitive impairment (VCI). Other than management of vascular risk factors, there is no treatment for WM damage and VCI that delays progression of the disease process to dementia. Observational studies suggest that exercise may prevent or slow down the progression of Alzheimer's disease (AD) and VCI. However, getting patients to exercise is challenging especially with advancing age and disability. Remote ischemic conditioning, an "exercise equivalent", allows exercise to be given with a "device" in the home for long periods of time. Since RIC increases CBF in pre-clinical studies and in humans, RIC may be an ideal therapy to treat VCI and WM disease and perhaps even sporadic AD. By using MRI imaging of WM progression, a sample size in the range of about 100 subjects per group could determine if RIC has activity in WM disease and VCI.

Abstract T P417: Remote Ischemic Post Conditioning (RIPostC) Is Effective In A Mouse Model Of Vascular Cognitive Impairment

Background and Purpose: The mouse bilateral common carotid artery stenosis (BCAS) model is regarded as the best animal model for vascular cognitive impairment (VCI). RIPostC is a simple and safe therapy that others and we found protective in ischemic stroke. Other than risk factor control, there are no established treatments for VCI. However observational studies suggest exercise may be effective in patients with leukoaraiosis and cognitive impairment, the major form of VCI. Since RIPostC and exercise share some common mechanisms of action, we hypothesized that RIPostC would be effective in the mouse BCAS model and in VCI.

Methods: Adult C57BL/6J male mice of (10-weeks) were subjected to either Sham for BCAS or BCAS surgery using micro coils twined around common carotid arteries. We randomized BCAS mice to daily RIPostC or sham procedure for RIPostC beginning 7 days post-BCAS for 2 weeks until day 21. Cerebral blood flow (CBF) was measured by laser speckle contrast imager. All mice underwent blinded testing for cognitive functions using novel object recognition (NOR). Histopathological examination and beta amyloid contents were investigated in the brain at day 30 post-BCAS. Statistical significance was determined at p <0.05.

Results: At 1 hour, CBF was decreased significantly in all animals subjected to BCAS. RIPostC improved CBF in comparison to sham-operated group for RIPostC at day 14 and 28 post-VCI (p<0.05). BCAS impaired the discrimination index of mice in the NOR test but this was improved in the BCAS group treated with RIPostC (p<.05). Histopathological studies revealed that BCAS caused frequent vacuolization, cell death, microglial activation, loss in white matter (WM) and increased accumulation of beta amyloid. This was all attenuated significantly with RIPostC.

Conclusions: RIPostC improves CBF, cognition and reduces cell death, WM damage and beta amyloid accumulation in the mouse BCAS model. Chronic RIPostC-therapy might be an effective treatment for VCI and in patients with leukoaraiosis and cognitive impairment

Key words: RIPostC, VCI, white matter, beta-amyloid

Abstract W P253: Repeated Remote Ischemic Conditioning (RIC) after Intracerebral Hemorrhage Regulates Macrophage Polarization and CD36 Expression to Promote Hematoma Resolution

Background: RIC-therapy during sub-arachnoid hemorrhage in humans was found well tolerated. We tested the hypothesis that repeated daily RIC-therapy would improve post-ICH outcomes in mice.

Methods: ICH was induced by collagenase injection into the brain of CD1 male mice (4-mo old). Mice were randomized for either once daily RIC-therapy or related sham-procedure starting 2-hours post-ICH until sacrifice. RIC-therapy post-ICH was also tested in mice pre-treated with clodronate-liposome consequently deficient in macrophage population. Laser speckle imager (LSCI) was used to detect changes in peripheral ischemia resulting from space occupying hematoma. SWI/ FLASH (T2*W) MRI was used to estimate hematoma size. Behavioral outcomes were assessed by focal deficit score and beam walk challenge. Hemoglobin content in the brain tissue by spectrophotometry, macrophage polarization with CD36 expression in peripheral blood by flowcytometry, and histopathological analyses in the brain, were also performed. Statistical significance was determined at p<0.05.

Results: Even after 5-days post-ICH, peripheral cerebral ischemia was evident, which was significantly attenuated by RIC-therapy due to reduced hematoma size. Effect of RIC-therapy on hematoma resolution was abolished in the clodronate-liposome treated mice. Higher focal deficit score and impaired fine motor coordination were significantly evident in ICH mice, which was attenuated by RIC-therapy. Post-ICH increased hemoglobin content at day 5 was significantly reduced by RIC-therapy. Interestingly, repeated RIC-therapy promoted macrophage polarization towards M2 (anti-inflammatory) phenotype with increased CD36 expression. At 2-weeks post ICH, cresyl violet and Luxol-Fast blue staining showed significantly increased cell death and white matter degeneration (WMD), respectively, in the ICH mice. RIC-therapy after ICH significantly reduced the cell death and WMD in a 2-weeks follow up.

Conclusion: Human subjects deficient in CD36 have impaired capability of hematoma resolution. Long-term RIC-therapy might be helpful in spontaneous hematoma resolution via increased M2-type macrophage and CD36 expression.

Abstract T P92: Remote Ischemic Conditioning (RIC) Attenuates Post-TBI Ischemic Injury and Improves Behavioral Outcomes

Background: Others and we reported that RIC-therapy is safe in humans, and protective in rodents that can be repeatedly used under both, hemorrhagic and ischemic stroke. Since TBI shares some common features of ischemic and hemorrhagic injury as in stroke, we hypothesized that RIC-therapy will remain protective in TBI, too.

Methods: We tested RIC-therapy in a closed-head injury model of pediatric TBI in male mice (28 days old). Mice were later randomized for either RIC-therapy or its sham-procedure once daily starting 1-hour post-TBI until sacrifice. Cerebral blood flow (CBF) was measured by laser speckle imager (LSCI), and MRI was used to estimate edema and cerebral perfusion. Mice were also tested for functional outcomes. Statistical significance was determined at p<0.05.

Results: Micro-CT showed a shallow dent along the median suture of skull. Closed-head TBI led to progressive acute ischemia, which was attenuated with time. However, reduced CBF and significant edema was observed at 48-hours post-TBI, which was attenuated by RIC-therapy. Open-field test showed no significant difference at 3 days post-TBI but in the narrow beam-walk challenge, TBI mice showed significantly impaired activity, which was improved by RIC-therapy. Flowcytometry in brain tissue confirmed significantly increased opening of mitochondrial permeability transition pore and necro-apoptotic cell death at 3 days post-TBI that was blocked by RIC-therapy. In a 3-weeks follow up, the mice with TBI were apparently normal but showed depressive phenotype in challenged environments, such as lesser mobility during forced swim test, and reduced cerebrovascular reserve capacity (CVRC). Flowcytometric analysis of the brain tissue at 3-weeks post-TBI showed reduced neuronal activity as detected by the poor population of cFOS positive neurons. RIC-therapy after TBI significantly attenuated the depressive phenotype, improved CVRC and cFOS positive neurons, collectively indicating improved neurovascular coupling and function.

Conclusion: Post-TBI RIC-therapy is safe and beneficial, and can be translated to prevent ischemic injury.

A 2 × 2 factorial design for the combination therapy of minocycline and remote ischemic perconditioning: efficacy in a preclinical trial in murine thromboembolic stroke model

Background

After the failure of so many drugs and therapies for acute ischemic stroke, innovative approaches are needed to develop new treatments. One promising strategy is to test combinations of agents in the pre-hospital setting prior to the administration of intravenous tissue plasminogen activator (IV-tPA) and/ or the use of mechanical reperfusion devices in the hospital.

Methods

We performed a 2 × 2 factorial design preclinical trial where we tested minocycline (MINO), remote ischemic perconditioning (RIPerC) and their combination treatment in a thromboembolic clot model of stroke in mice, without IV-tPA or later treated with IV-tPA at 4 hours post-stroke. Cerebral blood flow (CBF) was measured by laser speckle contrast imaging (LSCI), behavioral outcomes as neurological deficit score (NDS) and adhesive tape removal test, and infarct size measurement were performed at 48 hours post-stroke. Mice within the experimental sets were randomized for the different treatments, and all outcome measures were blinded.

Results

RIPerC significantly improved CBF as measured by LSCI in both with and without tPA treated mice (P < 0.001). MINO and RIPerC treatment were effective alone at reducing infarct size (p < 0.0001) and improving short-term functional outcomes (p < 0.001) in the tPA and non-tPA treated animals. The combination treatment of MINO and RIPerC significantly reduced the infarct size greater than either intervention alone (p < 0.05). There were trends in favor of improving functional outcomes after combination treatment of MINO and RIPerC; however combination treatment group was not significantly different than the individual treatments of MINO and RIPerC. There was no “statistical” interaction between minocycline and RIPerC treatments indicating that the effects of RIPerC and MINO were additive and not synergistic on the outcome measures.

Conclusion

In the future, combining these two safe and low cost interventions in the ambulance has the potential to “freeze” the penumbra and improve outcomes in stroke patients. This pre-clinical 2 × 2 design can be easily translated into a pre-hospital clinical trial.

Abstract T P78: Remote Ischemic Conditioning (RIC), a Combined Regimen of Per- and Post- Conditionings (RIPerC and RIPostC), Provides Long-term Motor and Cognitive Benefits in Murine Embolic Stroke Model (eMCAO)

The majority of stroke sufferers need rehabilitation and institutional grade long-term care even after IV-tPA therapy. RIC therapy is easier to perform, safe, promising and ideal for post-stroke rehabilitation. Long-term benefits of RIC have never been reported after eMCAO. Our objective here was to determine if RIC provides long-term behavioral benefits with and without IV-tPA.

Methods: eMCAO was induced in WT C57/Bl male mice (~6-mo old). Animals were randomized for the treatments (RIC, NO vs. YES; and IV-tPA, NO vs. YES, n=20/group) after eMCAO. Either IV-tPA (10 mg/kg b.wt.) or IV-saline was infused at 4 hours post-eMCAO. RIC was performed non-invasively on the left hind limb at 2, 8 and 24 hours post-eMCAO, followed by every alternate day till day 15. Neurological deficit score (NDS), and adhesive tape test were performed on day 2, 7 and 15 post-stroke to assess the motor function. Cognitive function was assessed by novel object recognition (NOR) test on day 8 and 16 post-stroke.

Results: RIC improved NDS and sensorimotor functions significantly (p<0.05) on day 2 and 7 with and without IV-tPA, but late IV-tPA alone was not effective. On day 15, there was a trend towards improved motor function in RIC treated groups, which was not significant. However, cognitive function was improved significantly (p<0.05) on day 8 and 16 in RIC-treated groups with and without IV-tPA. IV-tPA alone did not provide any significant improvement in cognition. RIC also improved the survival with and without IV-tPA.

Conclusion: RIC is a promising therapy for improved motor and cognitive functions during post-stroke rehabilitation and provides survival benefits. Further work is needed to determine the potential of RIC in aged animals and in animals with comorbidities.

Towards athermal organic-inorganic guided mode resonance filters

We demonstrate guided-mode resonance filters featuring an amorphous TiO(2) layer fabricated by atomic layer deposition on a polymeric substrate. The thermal properties of such filters are studied in detail by taking into account both thermal expansion of the structure and thermo-optic coefficients of the materials. We show both theoretically and experimentally that these two effects partially compensate for each other, leading to nearly athermal devices. The wavelength shift of the resonance reflectance peak (< 1 nm) is a small fraction of the peak width (~11 nm) up to temperatures exceeding the room temperature by tens of degrees centigrade.

Mapping of a new SGBS locus to chromosome Xp22 in a family with a severe form of Simpson-Golabi-Behmel syndrome

Simpson-Golabi-Behmel syndrome (SGBS) is an X-linked overgrowth syndrome with associated visceral and skeletal abnormalities. Alterations in the glypican-3 gene (GPC3), which is located on Xq26, have been implicated in the etiology of relatively milder cases of this disorder. Not all individuals with SGBS have demonstrated disruptions of the GPC3 locus, which raises the possibility that other loci on the X chromosome could be responsible for some cases of this syndrome. We have previously described a large family with a severe form of SGBS that is characterized by multiple anomalies, hydrops fetalis, and death within the first 8 wk of life. Using 25 simple tandem-repeat polymorphism markers spanning the X chromosome, we have localized the gene for this disorder to an approximately 6-Mb region of Xp22, with a maximum LOD score of 3.31 and with LOD scores <-2.0 for all of Xq. These results demonstrate that neither the GPC3 gene nor other genes on Xq26 are responsible for all cases of SGBS and that a second SGBS locus resides on Xp22.

Purification and characterization of hemolysin from Porphyromonas gingivalis A7436

Porphyromonas gingivalis, a periodontal pathogen, has the ability to lyse erythrocytes. The hemolytic activity of P. gingivalis A7436 was purified as a 45-kDa protein from the culture supernatant of a 3-days old culture using nickel-nitrilotriacetic acid chromatography. Erythrocytes treated with purified P. gingivalis hemolysin showed the presence of pores and extracellular debris by scanning electron microscopy. Active immunization of mice with 15 micrograms hemolysin induced neutralizing antibodies to hemolysin. Heating at 60 degrees C and treatment with trypsin and dithiothreitol abolished hemolytic activity, while incubation with the protease inhibitor Na-p-tosyl-L-lysine chloromethyl ketone caused no effect. We report here for the first time purification of a hemolysin from P. gingivalis A7436. The amino acid sequence of an internal peptide of hemolysin showed sequence similarity with fimbrillin from P. gingivalis HG564. However, the amino acid composition of purified hemolysin was different from that of P. gingivalis fimbrillin. Also, the ability to lyse but not agglutinate erythrocytes and to bind to nickel-nitrilotriacetic acid differentiates P. gingivalis hemolysin from fimbrillin.

Invasion of aortic and heart endothelial cells by Porphyromonas gingivalis

Invasion of host cells is believed to be an important strategy utilized by a number of pathogens, which affords them protection from the host immune system. The connective tissues of the periodontium are extremely well vascularized, which allows invading microorganisms, such as the periodontal pathogen Porphyromonas gingivalis, to readily enter the bloodstream. However, the ability of P. gingivalis to actively invade endothelial cells has not been previously examined. In this study, we demonstrate that P. gingivalis can invade bovine and human endothelial cells as assessed by an antibiotic protection assay and by transmission and scanning electron microscopy. P. gingivalis A7436 was demonstrated to adhere to and to invade fetal bovine heart endothelial cells (FBHEC), bovine aortic endothelial cells (BAEC), and human umbilical vein endothelial cells (HUVEC). Invasion efficiencies of 0.1, 0.2, and 0. 3% were obtained with BAEC, HUVEC, and FBHEC, respectively. Invasion of FBHEC and BAEC by P. gingivalis A7436 assessed by electron microscopy revealed the formation of microvillus-like extensions around adherent bacteria followed by the engulfment of the pathogen within vacuoles. Invasion of BAEC by P. gingivalis A7436 was inhibited by cytochalasin D, nocodazole, staurosporine, protease inhibitors, and sodium azide, indicating that cytoskeletal rearrangements, protein phosphorylation, energy metabolism, and P. gingivalis proteases are essential for invasion. In contrast, addition of rifampin, nalidixic acid, and chloramphenicol had little effect on invasion, indicating that bacterial RNA, DNA, and de novo protein synthesis are not required for P. gingivalis invasion of endothelial cells. Likewise de novo protein synthesis by endothelial cells was not required for invasion by P. gingivalis. P. gingivalis 381 was demonstrated to adhere to and to invade BAEC (0.11 and 0.1% efficiency, respectively). However, adherence and invasion of the corresponding fimA mutant DPG3, which lacks the major fimbriae, was not detected. These results indicate that P. gingivalis can actively invade endothelial cells and that fimbriae are required for this process. P. gingivalis invasion of endothelial cells may represent another strategy utilized by this pathogen to thwart the host immune response.

Haemolysin from Mycobacterium avium complex isolates from AIDS patients

Cell-bound haemolytic activity was observed in isolates of Mycobacterium avium complex (MAC) from AIDS patients. M. avium type strains showed negligible activity. None of the culture supernates exhibited any haemolytic activity. Zwitterionic detergent 3-[(3-cholamidopropyl)-dimethyl-ammonio]-1-propanesulphonate (CHAPS) was used to extract haemolysin from ethanol-treated M. avium complex strain 101 (MAC101) cells. Haemolysin was isolated from CHAPS extract (CE) by metal affinity chromatography and identified as a 32-kDa protein by polyclonal antibodies raised against M. tuberculosis haemolysin. Treatment of CE with trypsin resulted in reduction of haemolytic activity, whereas heating at 100 degrees C for 10 min did not affect its activity. A similar 32-kDa haemolysin was extracted from cells of M. avium K128 which was isolated from a monkey infected with simian immunodeficiency virus (SIV). The haemolysin produced by M. avium strains isolated from AIDS patients may be associated with the pathogenesis of M. avium infection.

Isolation of a contact-dependent haemolysin from Mycobacterium tuberculosis

Contact-dependent haemolytic activity was observed with cells of Mycobacterium tuberculosis H(37)Rv and M. tuberculosis H(37)Ra, but not with those of M. bovis, M. bovis BCG and M. africanum. Culture filtrates of all these strains did not exhibit any haemolytic activity. M. tuberculosis H(37)Rv was subsequently used for the isolation of haemolysin. Haemolytic activity was retained in the cell debris even after sonication of the cells and treatment with Tween 80 and lysozyme. Solubilisation of haemolysin was possible only after the cell debris was washed with ethanol 70% and then treated with Tween 80 0.1%. The haemolysin thus obtained showed a micellar M(r) of >200000 by gel-filtration on Sephadex G-200 and a subunit M(r) of 66000 by SDS-PAGE. It was sensitive to trypsin but stable when heated at 60 degrees C for 10 min. Polyclonal serum raised in rabbits against the haemolysin neutralised the haemolytic activity. The N-terminal amino-acid sequence of the 66-kDa subunit of haemolysin showed identity with TB66, the 66-kDa secretory protein of M. tuberculosis, and 30% homology with the haemolysin A precursor of Vibrio cholerae. Phosphatidylglycerol inhibited lysis of sheep erythrocytes by the haemolysin and is probably the receptor for the haemolysin. Haemolysin not only lysed erythrocytes, but was also cytotoxic to human lung cells. It appears that, among the members of the M. tuberculosis complex, the cell-bound contact-dependent haemolysin/cytolysin is restricted to M. tuberculosis and it may be associated with the pathogenesis of M. tuberculosis.

Isolation of a 33-kDa protein antigen from delipidified Mycobacterium tuberculosis H37Rv

A 33-kDa protein (TB33) was isolated from a delipidated cell sonicate (CS) of Mycobacterium tuberculosis H37Rv (grown in Middlebrook 7H9 broth supplemented with glucose) using immobilized metal affinity chromatography (IMAC) on a nickel-nitrilotriacetic acid (Ni-NTA) column. TB33 could not be isolated from the culture filtrate (CF) of M. tuberculosis H37Rv using Ni-NTA. TB33 was recognized by monoclonal antibodies (mAb) known to react with proteins of M. tuberculosis with a molecular mass of 33/34 kDa; namely, mAb F126-5, F67-1 and F126-2. The N-terminal amino acid sequence of TB33 was found to be Xaa-Xaa-Thr-Pro-Ala-Asp-Val-Ser/Cys-Asn-Val-Ala-Ile and thus, shows identity with the N-terminal of antigen 84 of M. tuberculosis except for two mismatches. Antibodies to TB33 could be raised in mice by administering four injections of TB33 (40 micrograms total protein). Sera from tuberculosis patients reacted with TB33, while those from normal healthy individuals did not.

Immunoaffinity chromatographic isolation of a high molecular weight seroreactive protein from Mycobacterium leprae cell sonicate

The purpose of this study was to isolate Mycobacterium leprae antigen(s) by immunoaffinity chromatography using immunoglobulins from leprosy patients and from rabbit anti-M. leprae hyperimmune serum coupled to CNBr-Sepharose 4B. A high molecular weight (M(r)) M. leprae protein (MLP) with a subunit M(r) of 22,000 was isolated. MLP was recognized by monoclonal antibody MMPII1G4 which is known to react with MMPII, a 22 kDa protein of M. leprae. The N-terminal sequence of the 22 kDa subunit (Met-gln-gly-asp-pro-asp-val-leu-arg-leu-leu-asn-glu-gln-leu-thr) was identical to MMPII and to antigen D (bacterioferritin) of M. paratuberculosis. It showed 44% homology with N-terminal end of E. coli bacterioferritin. In ELISA, MLP showed 100% and 60% positivity with leprosy and TB sera respectively as compared to normal healthy sera. The role of bacterioferritin in M. leprae and the importance of MLP as an immunogen has been discussed.

Perinatal mortality in the Cape Province, 1989-1991

OBJECTIVE

To determine the number of deliveries, the low-birth-weight rate and the perinatal mortality rate at provincial and province-aided hospitals and clinics in each planning region of the Cape Province.

DESIGN

A record of the number of deliveries, low-birth-weight infants, stillbirths and early neonatal deaths in provincial and province-aided hospitals and clinics in each planning region of the Cape Province between 1 January 1989 and 31 December 1991.

SETTING

All provincial and province-aided hospitals and clinics in the Cape Province.

PARTICIPANTS

Hospital and clinic staff of all provincial and province-aided hospitals and clinics in the Cape Province.

MAIN OUTCOMES MEASURED

Number of deliveries, low-birth-weight infants, stillbirths and early neonatal deaths in each planning region of the Cape Province.

RESULTS

A total of 373,768 births were recorded during the 3-year period with a low-birth-weight rate of 14.7%, a stillbirth rate of 17.9 per 1,000 and an early neonatal mortality rate of 9.1 per 1,000. All rates differed widely between regions. The regions with the highest perinatal mortality rates were in the northern and eastern Cape.

CONCLUSION

The perinatal demographics of most regions in the Cape Province are typical of a developing country. Regions which have been identified as having the highest low-birth-weight, stillbirth and early neonatal mortality rates are in greatest need of improved perinatal health care.

Isolation of a 43 kDa protein from Mycobacterium tuberculosis H37Rv and its identification as a pyridine nucleotide transhydrogenase

A 43 kDa protein (TB43) was isolated from the cell sonicate (CS) of Mycobacterium tuberculosis H37Rv with immobilized metal affinity chromatography (IMAC) on a Ni-nitrilotriacetic acid column. Two-dimensional electrophoresis of the IMAC fraction showed a major spot with an M(r) of 43,000 and a pI of approximately 6.0. The N-terminal amino acid sequence of TB43 was met-arg-val-gly-ile-pro-asn-glu-thr-lys-asn-asn-glu-phe-arg-val-ala- ile-thr-pro-ala. It showed 86% homology with the N-terminal end of the alanine dehydrogenase of Myco. tuberculosis and 65% homology with the N-terminal end of the alpha-subunit of the Escherichia coli pyridine nucleotide transhydrogenase (Tsh). TB43 did not show any alanine dehydrogenase activity and did not react with monoclonal antibody (MAb) HBT10, which is known to recognize the 40 kDa alanine dehydrogenase of Myco. tuberculosis. It was also not recognized by MAb F29-29 which is known to react with a 43 kDa protein of Myco. tuberculosis complex. This protein exhibited strong Tsh activity. A similar 43 kDa protein showing Tsh activity was also isolated by IMAC from Myco. bovis CS. However, the pI of the protein was approximately 7.0. A similar protein could not be isolated from the CS or culture filtrate of Myco. bovis BCG and Myco. tuberculosis H37Ra. TB43 is a cell-associated pyridine nucleotide transhydrogenase and is distinct from the 40/44 kDa secreted alanine dehydrogenase of Myco. tuberculosis.

Skin reactivity and fibronectin-binding property of TB66 (66-kDa protein of Mycobacterium tuberculosis)

A 66-kDa protein (TB66) was purified from culture filtrate (CF) and cell sonicate (CS) of Mycobacterium tuberculosis H37Rv by immobilised metal affinity chromatography (IMAC) on a Ni-nitrilotriacetic acid (NTA) column. TB66 was found to be a fibronectin-binding protein as determined by ELISA and could be purified by affinity chromatography with fibronectin-Sepharose. A similar 66-kDa protein could be isolated also from M. bovis, M. bovis BCG, M. africanum and M. tuberculosis H37Ra by IMAC, but not from any other mycobacteria. The NH2-terminal amino-acid sequence of TB66 from H37Rv and M. bovis was identical and showed 85% homology with the N-terminal sequence of bovine serum albumin (BSA). A monoclonal antibody (MAb) OD4AG3 recognised a heat-stable and trypsin-sensitive epitope near the C-terminal end of TB66. This MAb also recognised the 66-kDa protein isolated from the other members of the M. tuberculosis complex. In tests of immunogenicity, TB66 elicited a delayed type hypersensitivity reaction in guinea-pigs immunised with either TB66 or with M. tuberculosis H37Rv. TB66 also elicited an antibody response in immunised guinea-pigs and stimulated murine macrophages to produce tumour necrosis factor.

Purification and partial characterisation of a novel 66-kDa seroreactive protein of Mycobacterium tuberculosis H37Rv

A seroreactive protein (TB66) was purified from culture filtrate (CF) and cell sonicate (CS) of Mycobacterium tuberculosis H37Rv by immobilised metal affinity chromatography (IMAC) on a Ni-nitrilotriacetic acid (NTA) column. The TB66 preparations obtained by IMAC contained predominantly a 66-kDa protein with a pI of c. 5.5 as determined by two-dimensional electrophoresis. TB66 was detected in the CF as early as 1 week of growth of H37Rv. The NH2-terminal amino-acid sequence showed 85% homology with the N-terminal sequence of bovine serum albumin (BSA) and 80% homology with human serum albumin. Amino-acid analysis indicated a difference in the amino-acid content of TB66 when compared to BSA, with an abundance of acidic amino acids. A monoclonal antibody (MAb) OD4AG3, raised in this laboratory against an M. avium complex (MAC 101) sonicate cross-reacting with H37Rv sonicate, recognised a heat-stable and trypsin-sensitive epitope of this protein. TB66 was also recognised by MAbs IT1 and IT20 which also react with the 14-kDa antigen of the M. tuberculosis complex. Antibodies against TB66 were present in the sera of 62 of 64 patients with tuberculosis; sera from normal healthy individuals showed no significant reactivity. TB66 appears to be a predominant secretory protein of M. tuberculosis and could play an important role in the pathogenesis of this organism.

Superoxide dismutase activity of Mycobacterium tuberculosis isolated from tuberculosis patients and the immunoreactivity of superoxide dismutase from M. tuberculosis H37Rv

OBJECTIVE

To determine the superoxide dismutase (SOD) activity from clinical isolates of Mycobacterium tuberculosis and to study the seroreactivity of SOD from M. tuberculosis H37Rv.

DESIGN

Crude cell extracts of 16 strains of M. tuberculosis isolated from tuberculosis (TB) patients were assayed for SOD activity. SOD from H37Rv was partially purified and characterized, and the seroreactivity was studied by ELISA using sera from 36 active pulmonary TB and 31 leprosy patients.

RESULTS

SOD activity was detected in all the 16 strains of M. tuberculosis and also in the medium of logarithmic and stationary cultures of H37Rv. SOD activity from H37Rv extract was not affected by 1 mM KCN or by 5 mM H2O2 and was only 20% inhibited by 10 mM NaN3, suggesting that it is a Mn-containing enzyme. SOD was partially purified from H37Rv extract by gel filtration chromatography as a tetramer of molecular weight (MW) of 80,000 and a subunit MW of approximately 23,000. A delayed type hypersensitivity was elicited by SOD in guinea pigs sensitized with H37Rv or M. leprae sonicate. ELISA using SOD as antigen indicated 100% positivity with TB sera, while 84% positivity was observed with leprosy sera. Western blotting with pooled TB and leprosy sera indicated the presence of antibodies to the 23 kD SOD protein.

CONCLUSION

Our data indicate that M. tuberculosis strains are rich in SOD, and the secretion of SOD may play a valuable role in the pathogenesis of M. tuberculosis.

Immunological evaluation of a 12-kilodalton protein of Mycobacterium tuberculosis by enzyme-linked immunosorbent assay

OBJECTIVE

To purify and study the seroreactivity of native and recombinant 12-kilodalton protein of Mycobacterium tuberculosis H37Rv.

DESIGN

M. tuberculosis H37Rv cells and Escherichia coli XL-1 containing the plasmid PRL4 encoding the M. tuberculosis heat shock protein GroES homolog were used as sources for the purification of native and recombinant 12 kD of M. tuberculosis respectively. The seroreactivity of the 12 kDs was studied by ELISA using sera from 35 leprosy and 25 active pulmonary tuberculosis (TB) patients, and from 10 normal healthy controls.

RESULTS

The 12 kD protein was purified from H37Rv extract (s12 kD) and from recombinant E. coli (r12 kD) by ultrafiltration and MonoQ fast pressure liquid chromatography (FPLC). Analysis of s12 kD and r12 kD by SDS-PAGE revealed a single protein band in both cases with an approximate molecular weight of 12,000 which was recognized by monoclonal antibody SA-12 in immunoblotting. Both the proteins exhibited a pI of approximately 4.6 by isoelectric focusing. Both the 12 kD proteins exhibited 96% positivity with TB sera as compared to normal control sera (P < 0.01). Only one serum sample from the 35 leprosy sera tested exhibited binding to both the s12 kD and r12 kD proteins. Delayed type hypersensitivity reaction to the 12 kD proteins was elicited in guinea pigs that had been immunized with H37Rv sonicate.

CONCLUSION

The 12 kD protein could be easily purified and could serve as a valuable serodiagnostic tool in the screening of TB cases from a large population in an endemic area.

Superoxide dismutase activity of Mycobacterium avium complex (MAC) strains isolated from AIDS patients

OBJECTIVE

To explore whether Mycobacterium avium complex (MAC) strains isolated from AIDS patients produce and secrete superoxide dismutase (SOD).

DESIGN

SOD was assayed in the crude extracts and in cell-free medium of 18 MAC strains (MAC 101, LR and SK strains) isolated from AIDS patients to determine intracellular and extracellular activity. The SODs were characterized by PAGE and by their sensitivity to azide, cyanide and hydrogen peroxide.

RESULTS

SOD activity was detected in cell extracts as well as in extracellular medium of all AIDS-MAC strains. PAGE demonstrated a single activity band for each strain, though there were differences in mobility. All LR strains demonstrated an activity band with Rf = 0.30, while SOD band for MAC 101 and for SK strains migrated further (Rf = 0.87). The differences in mobility correlated with differences in sensitivity to NaN3 and H2O2. The SOD activity of LR strains was irreversibly inhibited 100% by 5 mM H2O2, and exhibited greater sensitivity to NaN3, suggesting the presence of iron in the enzyme. The SOD activity of SK strains and MAC 101, however, was not inhibited by 5 mM H2O2 but was inhibited to a lesser extent by NaN3, which is characteristic of a manganese-containing SOD.

CONCLUSION

Our data indicate that MAC strains are rich in manganese- or iron-containing SOD, which could contribute to the organism's resistance to the oxidative burst of activated macrophages. The secretion of SOD may play an important role in the pathogenesis of MAC strains.