observational study Archives - Amazing Health Advances

Study Reveals Protein Structure Similarities in Alzheimer’s & Down Syndrome

The AHA! Team — Wed, 29 May 2024 08:12:33 +0000

Indiana University School of Medicine via News-Medical – More than 90% of people with Down syndrome, the most common chromosomal disorder in humans and the most frequent genetic cause of intellectual disability, are diagnosed with Alzheimer’s disease by ages 55-60. More than 90% of people with Down syndrome, are diagnosed with Alzheimer’s disease by ages 55-60. A new study recently published in Nature Structural and Molecular Biology uses leading-edge cryo-electron microscopy imaging technology to determine whether differences exist between the protein structures in those with Alzheimer’s disease and those with both Alzheimer’s disease and Down syndrome. Just like in Alzheimer’s disease, the neuropathological phenotype in those with Down syndrome and Alzheimer’s disease is characterized by the presence of amyloid β (Aβ) and by abnormal accumulation of tau protein. The structures of Aβ and tau filaments in Down syndrome have not been previously investigated, and it is unknown whether they are different from those of Alzheimer’s disease.” Ruben Vidal, PhD, the Luella McWhirter Martin Professor of Clinical Alzheimer’s Research at the Indiana University School of Medicine and lead investigator of the study Researchers studied images of Aβ and tau filaments, which occurs in individuals with Down syndrome, and compared with those seen in the most common form of Alzheimer’s disease. They found that the protein structures of Aβ and tau filaments in people with both Down syndrome and Alzheimer’s disease have similarities to those found in Alzheimer’s disease. Vidal said their findings may lead to better treatments for Alzheimer’s disease patients and individuals with Down syndrome. “This study is the first comparison at the near atomic level of Aβ and tau filaments between individuals with both Down syndrome and Alzheimer’s disease and individuals with only Alzheimer’s disease,” Vidal said. “Importantly, the study found variations in the structure of Aβ, but no substantial variation in the structure of tau filaments between individuals with Alzheimer’s disease and both Down syndrome and Alzheimer’s disease. This supports the notion of common mechanisms operating in people with sporadic Alzheimer’s disease and in people with both Down syndrome and Alzheimer’s disease. This knowledge is crucial for understanding Alzheimer’s disease in people with Down syndrome and assessing whether adults with both conditions could be included in Alzheimer’s disease clinical trials. People with Down syndrome are living longer than ever, but almost all of them are dying of Alzheimer’s disease when they get older” Vidal, also an investigator in IU School of Medicine’s Stark Neurosciences Research Institute, said the research team used cryogenic electron microscopy to get a close-up, 3D view of the structure of Aβ and tau filaments in two individuals with both Down syndrome and Alzheimer’s disease. The study revealed two novel types of Aβ filaments in the vascular compartment with structures different from those previously reported in Alzheimer’s disease. Vidal said the study’s findings show it is important to include people with both Down syndrome and Alzheimer’s disease in clinical trials targeting the Aβ or tau filaments. He said there are similarities between the mechanisms at play in amyloid aggregation, but more research is needed to determine whether the differences observed in vascular Aβ deposition are unique to those with Down syndrome. “We are thrilled that our cryo-EM imaging and 3D modeling techniques have facilitated the determination of the atomic structures of amyloid beta and tau fibrils in individuals with Down syndrome, shedding light on the connection between Down syndrome and Alzheimer’s disease,” said Wen Jiang, PhD, professor of biology at Purdue University and co-corresponding author of the study. “We are fortunate to have the Purdue Cryo-EM Facility, which provides exceptional resources and services that have made this research possible. We are grateful to the patients who donated their brains to the research and thankful to the NIH for funding our work.” Other study authors include co-corresponding author Bernardino Ghetti, Anllely Fernandez, Grace Hallinan, Kathy Newell and Holly Garringer, all from the IU School of Medicine; and Rejaul Hoq, Daoyi Li, Sakshibeedu Bharath, Frank Vago, Xiaoqi Zhang and Kadir Ozcan, all from Purdue University. This research was funded by the National Institutes of Health and the IU School of Medicine Department of Pathology and Laboratory Medicine. Source: Indiana University School of Medicine Journal reference: Fernandez, A., et al. (2024). Cryo-EM structures of amyloid-β and tau filaments in Down syndrome. Nature Structural & Molecular Biology. doi.org/10.1038/s41594-024-01252-3. To read the original article click here.

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Can Soy Prevent and Treat Prostate Cancer?

AHA Publisher — Fri, 13 Nov 2020 08:00:34 +0000

Michael Greger M.D. FACLM via NutritionFacts – As I discuss in my video The Role of Soy Foods in Prostate Cancer Prevention and Treatment, a compilation of 13 observational studies on soy food consumption and the risk of prostate cancer found that soy foods appear to be “protective.” What are observational studies? As opposed to interventional studies, in observational studies, researchers observe what people are eating but don’t intervene and try to change their diets. In these studies, they observed that men who ate more soy foods had lower rates of prostate cancer, but the problem with observational studies is that there could be confounding factors. For example, “people who choose to eat soy also make other lifestyle decisions that lower the risk of cancer (e.g., lower fat intake, higher vegetable and fruit intake, more frequent exercise),” maybe that is why they have less cancer. Most of the studies tried to control for these other lifestyle factors, but you can’t control for everything. What’s more, most of the studies were done in Asia, so maybe tofu consumption is just a sign of eating a more traditional diet. Is it possible that the reason non-tofu consumers got more cancer is that they had abandoned their traditional diet? If only we could look at a Western population that ate a lot of soy. We can: the Seventh-Day Adventists. In the 1970s, more than 12,000 Adventist men were asked about their use of soy milk and then were followed for up to 16 years to see who got cancer and who did not. So, what did they find? Frequent consumption of soy milk was associated with a whopping 70 percent reduction of the risk of prostate cancer, as you can see at 1:33 in my video. Similarly, in a multiethnic study that involved a number of groups, soy intake appeared protective in Latinos, too. Prostate cells carry beta type estrogen receptors, which appear to act as a tumor suppressor, a kind of “gatekeeper…inhibiting invasion, proliferation and…preventing” the prostate cells from turning cancerous. And, those are the receptors targeted by the phytoestrogens in soy, like genistein, which inhibits prostate cancer cell invasion and spread in a petri dish at the kind of levels one might get consuming soy foods. The prevention of metastases is critical, as death from prostate cancer isn’t caused by the original tumor, but its spread throughout the body, which explains why it “is recommended that men with prostate cancer consume soy foods, such as soybeans, tofu, miso and tempeh.” Wait a moment. Dean Ornish and his colleagues got amazing results, apparently reversing the progression of prostate cancer with a plant-based diet and lifestyle program. Was it because of the soy? Their study didn’t just include a vegan diet, but a vegan diet supplemented with a daily serving of tofu and a soy protein isolate powder. There have been studies showing that men given soy protein powders develop less prostate cancer than the control group, but what was the control group getting? Milk protein powder. Those randomized to the milk group got six times more prostate cancer than the soy group, but was that due to the beneficial effects of soy or the deleterious effects of the dairy? Dairy products are not just associated with getting prostate cancer, but also with dying from prostate cancer. Men diagnosed with prostate cancer who then ate more dairy tended to die sooner, and “both low-fat and high-fat dairy consumption were positively associated with an increased risk of fatal outcome.” The best study we have on soy protein powder supplementation for prostate cancer patients found no significant benefit, and neither did a series of soy phytoestrogen dietary supplements. But, perhaps that’s because they used isolated soy components rather than a whole soy food. “Taking the whole-food approach may be more efficacious,” but it can be hard to do controlled studies with whole foods: You can make fake pills, but how do you give people placebo tofu? A group of Australian researchers creatively came up with a specially manufactured bread containing soy grits to compare to a placebo regular bread and gave slices to men diagnosed with prostate cancer awaiting surgery. As you can see at 4:31 in my video, they saw a remarkable difference in just about three weeks time. It was the first study to show that a diet incorporating a whole soy food could favorably affect prostate cancer markers, but you can’t just go out and buy soy grit bread. Another study was a little more practical. Twenty men with prostate cancer who had been treated with radiation or surgery but seemed to be relapsing were asked to drink three cups of regular soy milk a day. The PSA levels in each of the 20 patients were all rising before they started the soy milk, suggesting they had relapsing or metastatic cancer growing inside of them. However, during a year drinking soy milk, 6 out of the 20 subjects got better, 2 got worse, and the remaining 12 remained unchanged, as you can see from 5:02 in my video. So, they concluded that soy food may help in a subset of patients. Based on all these studies, the results Ornish and his colleagues got were probably due to more than just the soy. Similarly, the low prostate cancer rates in Asia are probably because of more than just the soy, since the lowest rates are also found in parts of Africa, where I don’t think they’re eating a lot of tofu. Indeed, in the multiethnic study, other types of beans besides soy also appeared protective for Latinos and all the groups put together, when looking at the most aggressive forms of prostate cancer. So, the protection associated with plant-based diets may be due to eating a variety of healthy foods. To read the original article click here. For more articles from Dr. Greger click here.

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