No Known Limit On Human Lifespan

Infinity Symbol

Emma Morano passed away last April. At 117 years old, the Italian woman was the oldest known living human being.

Super centenarians, such as Morano and Jeanne Calment of France, who famously lived to be 122 years old, continue to fascinate scientists and have led them to wonder just how long humans can live. A study published in Nature last October concluded that the upper limit of human age is peaking at around 115 years.

Now, however, a new study in Nature by McGill University biologists Bryan G. Hughes and Siegfried Hekimi comes to a starkly different conclusion. By analyzing the lifespan of the longest-living individuals from the USA, the UK, France and Japan for each year since 1968, Hekimi and Hughes found no evidence for such a limit, and if such a maximum exists, it has yet to be reached or identified, Hekimi says.

Far into the foreseeable future

“We just don’t know what the age limit might be. In fact, by extending trend lines, we can show that maximum and average lifespans, could continue to increase far into the foreseeable future,” Hekimi says. Many people are aware of what has happened with average lifespans. In 1920, for example, the average newborn Canadian could expect to live 60 years; a Canadian born in 1980 could expect 76 years, and today, life expectancy has jumped to 82 years. Maximum lifespan seems to follow the same trend.

It’s impossible to predict what future lifespans in humans might look like, Hekimi says. Some scientists argue that technology, medical interventions, and improvements in living conditions could all push back the upper limit.

“It’s hard to guess,” Hekimi adds. “Three hundred years ago, many people lived only short lives. If we would have told them that one day most humans might live up to 100, they would have said we were crazy.”

Reference: Bryan G. Hughes, Siegfried Hekimi. Many possible maximum lifespan trajectories. Nature, 2017; 546 (7660): E8 DOI: 10.1038/nature22786

Toxins in Your Tap Water

Toxins in Your Tap Water

America has a drinking water crisis. An NRDC study has found that contaminants that may harm human health are found in tap water in every state in the nation. This is a problem even for people who don’t drink tap water since water borne toxins can be absorbed through the skin and lungs while bathing and into food if used for cooking.

Established in 1974, the Safe Drinking Water Act is one of the bedrock environmental laws in the United States, consisting of rules that regulate about 100 contaminants found in drinking water. NRDC has documented serious problems with our outdated and deteriorating water infrastructure, widespread violations and inadequate enforcement of the Safe Drinking Water Act for more than 25 years.

The study shows that in 2015 alone, there were more than 80,000 reported violations of the Safe Drinking Water Act by community water systems. Nearly 77 million people were served by more than 18,000 of these systems with violations in 2015. These violations included exceeding health-based standards, failing to properly test water for contaminants, and failing to report contamination to state authorities or the public. What?s worse, 2015 saw more than 12,000 health-based violations in some 5,000 community water systems serving more than 27 million people.

In 2016, the publication “What?s in Your Water: Flint and Beyond” detailed the lead crisis in Flint, Michigan, and contextualized a larger, national crisis around lead in drinking water. The new study picks up where that one left off, detailing a stunning number of violations of the Safe Drinking Water Act around the nation.

1. Combined Disinfectants and Disinfection Byproducts

Exposure to these contaminants can lead to cancer and may be linked to reproductive impacts such as miscarriages and birth defects. In 2015, there were 11,311 violations (4,591 health-based) at community water systems serving 25,173,431 people (12,584,936 health-based). Formal enforcement measures were taken in 12.4 percent of all cases and 23.0 percent of health-based cases.

2. Total Coliform

The presence of coliforms in drinking water indicates that possible presence of organisms that can cause diarrhea, cramps, nausea, and headaches in otherwise-healthy people. These impacts can be much more serious and even life-threatening for children, the elderly, and immune-compromised people. In 2015, there were 10,261 violations (2,574 health-based) at community water systems serving 17,768,807 people (10,118,586 health-based). Formal enforcement was taken in 8.8 percent of cases (and 8.3 percent of health-based cases).

3. Combined Surface, Ground Water, and Filter Backwash Rules

Exposure to some of these pathogens, such as Cryptosporidium or Giardia, can cause severe gastrointestinal distress, nausea, and diarrhea. They can cause serious, life-threatening infections for the very young, elderly, and immune-compromised. In 2015 there were 5,979 violations (1,790 health-based) at community water systems serving 17,312,604 people (5,336,435 health-based). Formal enforcement was taken in 13.7 percent of cases (28.2 percent of health-based cases).

4. Nitrites and Nitrates

Exposure can lead to blue baby syndrome in infants (potentially leading to death in extreme cases), developmental effects, and cardiovascular disease. In extreme cases, blue baby syndrome can be severe and lead to death. In 2015, there were 1,529 violations (459 health-based) at community water systems serving 3,867,431 people (1,364,494 health-based). Formal enforcement action was taken in 11.3 percent of all cases (and 27.9 percent of health-based cases).

5. Lead and Copper

Exposure to lead is particularly toxic to children and can cause serious, irreversible damage to their developing brains and nervous systems. Lead exposure can also cause miscarriages and stillbirths in pregnant women, as well as fertility issues, cardiovascular and kidney effects, cognitive dysfunction, and elevated blood pressure in healthy adults. In 2015, there were 8,044 violations (303 health-based) by systems serving 18,350,633 people (582,302 health-based). Formal enforcement action was taken in 12.0 percent of the cases (and in 14.2 percent of health-based cases).

6. Radionuclides

Exposure can lead to cancers and compromised kidney function. In 2015, there were 2,297 violations (962 health-based) in community water systems serving 1,471,364 people (445,969 health-based). Formal enforcement was taken in 11.7 percent of all cases (and 16.1 percent of health-based cases).

7. Arsenic

A known human carcinogen, exposure can lead to cancers, development effects, pulmonary disease, or cardiovascular disease. In 2015, there were 1,537 violations (1,135 health-based) at community water systems serving 1,842,594 people (358,323 health-based). Formal enforcement was taken in 28.9 percent of cases (37.1 percent of health-based cases).

8. Synthetic Organic Contaminants

Exposure can lead to cancers, developmental effects, central nervous system and reproductive difficulties, endocrine issues, or liver and kidney problems. In 2015 there were 6,864 violations (17 health-based) serving 2,669,594 people (301,099 health-based). Formal enforcement action was taken in 7.3 percent of cases (and 5.9 percent of health-based cases).

9. Inorganic Contaminants

Exposure can lead to increased cholesterol, kidney damage, hair loss, skin irritation, and cancer. In 2015, there were 1,505 violations (291 health-based) in community water systems serving 1,312,643 people (83,033 health-based). Formal enforcement was taken in 5.2 percent of cases (15.1 percent of health-based cases).

10. Volatile Organic Contaminants

Exposure can lead to cancers; developmental, skin, and reproductive issues; and cardiovascular problems. Exposure can also cause adverse effects on the liver, kidneys, and immune and nervous systems. In 2015 there were 10,383 violations (15 of them health-based) at community water systems serving 3,451,072 people (5,276 health-based). Formal enforcement was taken in 6.1 percent of cases (and 26.7 percent of health-based cases).

11. Public Notification

All community water systems are required to directly deliver information about their drinking water quality to each customer once a year. In 2015 there were 13, 202 violations by community water systems serving 8,381,050 people. Formal enforcement action was taken in 10.3 percent of cases.

The take away from this is to either install a water purifier or use natural spring water. Purifiers are also available for showers and are typically installed between the shower head and pipe.

High Activity Level Associated With Up To 9 Years Less Aging Based on Telomere Length

Walking my way to 100

New research from Brigham Young University reveals you may be able to slow one type of aging the kind that happens inside your cells. As long as you’re willing to sweat.

“Just because you’re 40, doesn’t mean you’re 40 years old biologically,” Tucker said. “We all know people that seem younger than their actual age. The more physically active we are, the less biological aging takes place in our bodies.”

The study, published in the medical journal Preventive Medicine, finds that people who have consistently high levels of physical activity have significantly longer telomeres than those who have sedentary lifestyles, as well as those who are moderately active.

Telomeres are the protein endcaps of our chromosomes. They’re like our biological clock and they’re extremely correlated with age; each time a cell replicates, we lose a tiny bit of the endcaps. Therefore, the older we get, the shorter our telomeres.

Exercise science professor Larry Tucker found adults with high physical activity levels have telomeres with a biological aging advantage of nine years over those who are sedentary, and a seven-year advantage compared to those who are moderately active. To be highly active, women had to engage in 30 minutes of jogging per day (40 minutes for men), five days a week.

“If you want to see a real difference in slowing your biological aging, it appears that a little exercise won’t cut it,” Tucker said. “You have to work out regularly at high levels.”

Tucker analyzed data from 5,823 adults who participated in the CDC’s National Health and Nutrition Examination Survey, one of the few indexes that includes telomere length values for study subjects. The index also includes data for 62 activities participants might have engaged in over a 30-day window, which Tucker analyzed to calculate levels of physical activity.

His study found the shortest telomeres came from sedentary people–they had 140 base pairs of DNA less at the end of their telomeres than highly active folks. Surprisingly, he also found there was no significant difference in telomere length between those with low or moderate physical activity and the sedentary people.

Although the exact mechanism for how exercise preserves telomeres is unknown, Tucker said it may be tied to inflammation and oxidative stress. Previous studies have shown telomere length is closely related to those two factors and it is known that exercise can suppress inflammation and oxidative stress over time.

“We know that regular physical activity helps to reduce mortality and prolong life, and now we know part of that advantage may be due to the preservation of telomeres,” Tucker said.

Reference: Larry A. Tucker. Physical activity and telomere length in U.S. men and women: An NHANES investigation. Preventive Medicine, Volume 100, July 2017, Pages 145?151

Stem Cells Utilized to Repair Severe Bone Fractures

Bone Fracture

A Cedars-Sinai-led team of investigators has successfully repaired severe limb fractures in laboratory animals with an innovative technique that cues bone to regrow its own tissue. If found to be safe and effective in humans, the pioneering method of combining ultrasound, stem cell and gene therapies could eventually replace grafting as a way to mend severely broken bones.

“We are just at the beginning of a revolution in orthopedics,” said Dan Gazit, PhD, DMD, co-director of the Skeletal Regeneration and Stem Cell Therapy Program in the Department of Surgery and the Cedars-Sinai Board of Governors Regenerative Medicine Institute. “We’re combining an engineering approach with a biological approach to advance regenerative engineering, which we believe is the future of medicine.”

Gazit was the principal investigator and co-senior author of the research study, published in the journal Science Translational Medicine.

More than 2 million bone grafts, frequently necessitated by severe injuries involving traffic accidents, war or tumor removal, are performed worldwide each year. Such injuries can create gaps between the edges of a fracture that are too large for the bone to bridge on its own. The grafts require implanting pieces from either the patient’s or a donor’s bone into the gap.

“Unfortunately, bone grafts carry disadvantages,” said Gazit, a professor of surgery at Cedars-Sinai. “There are huge unmet needs in skeleton repair.”

One problem is that enough healthy bone is not always available for repairs. Surgeries to remove a bone piece, typically from the pelvis, and implant it can lead to prolonged pain and expensive, lengthy hospitalizations. Further, grafts from donors may not integrate or grow properly, causing the repair to fail.

The new technique developed by the Cedars-Sinai-led team could provide a much-needed alternative to bone grafts.

In their experiment, the investigators constructed a matrix of collagen, a protein the body uses to build bones, and implanted it in the gap between the two sides of a fractured leg bone in laboratory animals. This matrix recruited the fractured leg’s own stem cells into the gap over a period of two weeks. To initiate the bone repair process, the team delivered a bone-inducing gene directly into the stem cells, using an ultrasound pulse and microbubbles that facilitated the entry of the gene into the cells.

Eight weeks after the surgery, the bone gap was closed and the leg fracture was healed in all the laboratory animals that received the treatment. Tests showed that the bone grown in the gap was as strong as that produced by surgical bone grafts, said Gadi Pelled, PhD, DMD, assistant professor of surgery at Cedars-Sinai and the study’s co-senior author.

“This study is the first to demonstrate that ultrasound-mediated gene delivery to an animal’s own stem cells can effectively be used to treat nonhealing bone fractures,” Pelled said. “It addresses a major orthopedic unmet need and offers new possibilities for clinical translation.”

The study involved six departments at Cedars-Sinai, plus investigators from Hebrew University in Jerusalem; the University of Rochester in Rochester, New York; and the University of California, Davis.

“Our project demonstrates how scientists from diverse disciplines can combine forces to find solutions to today’s medical challenges and help develop treatments for the patients of tomorrow,” said Bruce Gewertz, MD, surgeon-in-chief and chair of the Department of Surgery at Cedars-Sinai.

Reference: Maxim Bez, Dmitriy Sheyn, Wafa Tawackoli, Pablo Avalos, Galina Shapiro, Joseph C. Giaconi, Xiaoyu Da, Shiran Ben David, Jayne Gavrity, Hani A. Awad, Hyun W. Bae, Eric J. Ley, Thomas J. Kremen, Zulma Gazit, Katherine W. Ferrara, Gadi Pelled, Dan Gazit. In situ bone tissue engineering via ultrasound-mediated gene delivery to endogenous progenitor cells in mini-pigs. Science Translational Medicine, 2017; 9 (390): eaal3128 DOI: 10.1126/scitranslmed.aal3128

Sleep and Eating Times Affect Liver Health


Among all the organs in the human body, the liver is something of a superhero. Not only does it defend our bodies against the liquid toxins we regularly ingest, it has the ability to regenerate itself, and, as new research shows, it increases its size by nearly half over the course of a day.

Working in mice, researchers in Switzerland documented this process of regular stretching and shrinking, watching as liver cells swelled in size and contracted up to 40 percent along with the mice?s daily activities. There?s a catch though, a kind of hepatological kryptonite. Their livers only exhibited this ability when the mice followed their normal cycles of eating and resting. They?re nocturnal creatures, and if they began eating during the day when they usually rest, their livers stubbornly refused to grow.

The liver is the only organ known to display such significant cyclical growth, although it does make sense. During the half of the day when we?re not eating, our organs have far less to do. By growing and shrinking to meet demand, our livers are actually trying to save us wasted energy.

The Swiss researchers say that they observed hepatocytes, the main kind of cell in livers, growing during the night when mice were active, something they they attribute largely to an increase in ribosomes, structures in cells that take RNA instructions and use them to produce proteins, among other things. The liver takes material from the food and converts it into useful proteins and other molecules crucial for bodies to function, so possessing more ribosomes means they?re that much better at their jobs. When their daily cycle comes to a close, livers begin breaking down the ribosomes again, like street vendors packing up for the night.

It makes sense that livers would swell when they have to work the hardest. What the researchers found, though, was that it?s not just food intake that tells the liver to ramp up ribosome production ? it?s also dependent on what time of day it is. Cells in our livers are also sensitive to circadian rhythms and they found that mouse livers would only begin to grow at night when they ate. Mice fed during the day did not exhibit the same kind of liver growth that their nocturnal counterparts did. The cues that tell the liver to begin preparing for action don?t just come from our food, in other words, they also come from the environment.

Because a bigger liver can work faster and pull out nutrients more efficiently, there?s an obvious advantage to maintaining this kind of cycle. In mice kept nocturnal, there was a noticeable smooth curve of growing and shrinking, and the researchers noticed a 1.6-fold difference in the level of proteins in the liver between the two extremes. In day-fed mice, there was no difference, indicating that their livers weren?t able to produce as much. They published their work Thursday in Cell.

There is evidence that human livers may exhibit the same ability based on a 1986 study that used ultrasound to measure people?s livers over the course of six hours. They found variations of around 20 percent, although they didn?t take any measurements during the night, when our bodily rhythms slow down.

These findings in the liver add to a mounting case for returning to sleep cycles based on environmental cues. Illuminating the night with artificial brilliance has been tied to disrupted sleep cycles in humans, as well as an increased risk for obesity, diabetes, depression and some types of cancer. For millennia, our bodies regulated themselves with the daily rising and setting of the sun, ramping us up when it was light and settling us back down when it got dark. Now, it appears that this extends to our digestive systems as well.

Our livers cleanse toxins from our bodies, produce proteins and chemicals necessary for digestion, recycle old red blood cells and regulate glycogen levels in our bodies. If they aren?t working properly, we can die. While the authors don?t address the implications of their work for humans, their findings could help to explain why it’s unhealthy to go to bed late at night.

Reference: Flore Sinturel, Alan Gerber, Daniel Mauvoisin, Jingkui Wang, David Gatfield, Jeremy J. Stubblefield, Carla B. Green, Fr?d?ric Gachon, Ueli Schibler. Diurnal Oscillations in Liver Mass and Cell Size Accompany Ribosome Assembly Cycles. Cell, Volume 169, Issue 4, 651 – 663