How do mitochondrial protonophores (like DNP) differ from a brown-fat approach?

Mitochondria are often described as the cell’s power plants, and they are central to this discussion. Cells use nutrients such as sugars and fats to produce the energy they need to function. Much of the breakdown of these nutrients happens in mitochondria, which are specialized structures inside cells. As nutrients are processed, protons are actively pumped across the inner mitochondrial membrane, creating stored energy much like water held behind a dam. Those protons then passively flow back through a protein called ATP synthase, which uses their energy to make adenosine triphosphate (ATP), the main form of energy that cells can use. When proton flow through ATP synthase leads to ATP production, mitochondrial function is said to be “coupled.”

Brown fat cells, or brown adipocytes, however, contain a protein called UnCoupling Protein-1 (UCP1). UCP1 provides an alternative pathway for protons to cross the mitochondrial membrane without going through ATP synthase. This “uncouples” mitochondrial function and releases the stored energy as heat rather than converting it into ATP. As a result, the cell must then burn more stored fat and sugar to meet its normal energy needs. Over time, if brown fat activity is sufficient, this can reduce fat stores and contribute to weight loss.

UCP1 activity is tightly regulated by the body, mainly by controlling how much of the protein the cells produce [1]. The formation and abundance of brown fat cells is also tightly regulated [1]. In this way, brown fat provides a natural and highly controlled mechanism for dissipating excess energy.

Protons can also be moved across the mitochondrial membrane without producing ATP through an artificial, drug-induced process. Certain compounds known as chemical uncouplers, or more recently as “mitochondrial protonophores”, can let protons cross the mitochondrial membrane in an uncontrolled fashion, creating a proton “leak”. In the 1930s, one such compound, 2,4-dinitrophenol (DNP), was used as a highly effective weight-loss agent. However, DNP and similar compounds act directly on mitochondria in virtually all cell types, not just brown fat, and create a proton leak that depends solely on their dose. Unlike UCP1, they are not subject to the body’s normal control mechanisms. In some people, this uncontrolled proton leak caused too little energy production for cells to carry out their normal functions, leading to organ dysfunction and, in a few cases, death. Because the margin between an effective dose and a dangerous one was very small, and the chances for overdose (and serious outcomes) in patients wishing to lose weight was high, DNP was removed from the market [2, 3].

A few companies are now developing newer mitochondrial protonophores, some derived from DNP or using a similar mechanism [4, 5, 6, 7, 8, 9]. Some are designed as prodrugs, meaning they are inactive at first and become active mainly in specific tissues such as the liver. Compared with DNP, these compounds are intended to produce lower peak levels in the blood and act more selectively. They are being developed for obesity and related conditions, including metabolic dysfunction-associated steatohepatitis (MASH), a serious form of liver disease, as well as heart failure. It remains to be seen however whether these newer compounds can be made substantially safer than DNP while still being effective enough for their intended uses.

Our approach is fundamentally different. Rather than directly uncoupling mitochondria like mitochondrial protonophores, it increases the body’s capacity to dissipate energy by recruiting additional brown fat cells, which are naturally designed to dissipate stored energy as heat and are tightly controlled by the body. In this way, it avoids creating an uncontrolled proton leak and instead amplifies the effects of the system that naturally developed to dissipate excess energy.

Preclinical Disclaimer: Energesis’ programs, including EGS-2632, are currently in preclinical development. They have been evaluated only in laboratory and animal models and have not yet been tested in humans. They are not approved by any regulatory authority, and preclinical results may not predict human safety or efficacy.

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Does brown fat decline with obesity and aging? What PET/CT evidence shows

Around 2007, doctors using PET/CT scans to look for cancer began noticing that some “hot spots” seen with this type of imaging were not tumors at all. Researchers later identified much of this activity as brown adipose tissue (BAT), or brown fat. Brown fat is unusually active metabolically, so it takes up a lot of glucose and shows up clearly on PET/CT scans.

Beginning in 2009, studies using PET/CT in humans showed that the amount of brown fat varies widely from person to person. One of the most consistent findings was that people with obesity tend to have less brown fat than lean people.

Key Health Benefits of Brown Fat

Higher amounts of brown fat have been linked to:

-          Leanness [1-17]

-          Better blood sugar control and insulin sensitivity [17-19]

-          Increased fat oxidation (using fat for energy)

-          Lower triglyceride levels

-          Higher HDL (“good”) cholesterol [17]

These human findings match decades of animal research, especially in mice and rats. In animals, reducing brown fat tends to promote obesity and type 2 diabetes, while increasing it helps protect against those conditions. [1, 20-23]

Can We Increase Brown Fat in Humans?

Yes, brown fat can also be increased in humans. For example, repeated cold exposure for 10 days or more can raise brown fat volume and activity, increase resting energy use, and improve insulin sensitivity while reducing body fat. [17,24]

The Role of Aging

Brown fat activity naturally declines as we age [27,28]. Studies suggest this happens for two main reasons:

Reduced Stem Cell Renewal: The precursor cells responsible for generating new brown fat cells become less efficient over time [17].
Decreased Activity: The brown fat cells that do form in older adults are less active than those in younger adults [25,26].

This age-related decline in brown fat activity may help explain why maintaining a healthy weight becomes increasingly challenging as we get older.

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