How vitamin B3 helps with glaucoma
Nicotinamide prevented metabolic disorders in retinal neurons of rats with glaucoma
Anastasia Kuznetsova, N+1
Nicotinamide (vitamin B3) prevented metabolic disorders and preserved the morphology of mitochondria in retinal neurons of rats with glaucoma. Swedish scientists have studied the effect of using nicotinamide in sick and healthy animals. They hope to use the drug for the early prevention of glaucoma in humans.
The study was published in Redox Biology (Tribble et al., Nicotinamide provides neuroprotection in glaucoma by protecting against mitochondrial and metabolic dysfunction).
Glaucoma is one of the most common neurodegenerative diseases. It mainly affects the elderly, its prevalence at the age of 40-80 years worldwide is 3.54 percent. The main risk factors are genetic predisposition, age, as well as increased intraocular pressure. In addition to medical therapies (eye drops), operations are used to stop the progression of the disease. At the same time, there are no treatment methods aimed at neurons that are affected by glaucoma. After their degradation, blindness occurs (42 percent of all patients).
Glaucoma affects the ganglion cells of the retina, the fibers of which form the optic nerve. With an increase in intraocular pressure, an abnormal structure of mitochondria was noticed in them, which occurs before the onset of degenerative changes. Another sign of retinal neuron dysfunction is a decrease in the content of nicotinamide adenine dinucleotide (NAD), which is involved in redox reactions and plays an important role in cell metabolism. Studies on mice have shown that with age, its content in the retinal ganglia decreases. The use of nicotinamide (from which NAD is synthesized) in food or its intravenous administration protected mice from neurodegenerative changes in glaucoma. This prompted scientists to study its use in sick people. In studies conducted in patients with glaucoma, the condition of the retina improved after treatment with nicotinamide. For widespread use in sick people, it is necessary to study in more detail the mechanism of its action and assess how it affects damaged and healthy neurons. This is important in clinical practice, since patients usually have a mixture of diseased and healthy neurons.
Swedish scientists led by Pete Williams (Pete A Williams) from the Karolinska Institute studied the effects of nicotinamide on the visual system under normal conditions and during glaucoma. The study was conducted on rats in which glaucoma was induced, and healthy animals were a control group. Nicotinamide was added to the water of both sick and healthy animals (to test the effect of nicotinamide on preserved cells). After the experiment was completed, retinal samples were taken from the animals. The researchers measured the metabolic profile of ocular neurons in healthy and sick animals using mass spectrometry. The state of mitochondria was assessed by microscopy.
A picture from an article in Redox Biology – VM.
Nicotinamide improved the condition of neurons in rats with glaucoma (p<0.01). The researchers did not register any abnormalities in the metabolism of healthy neurons during treatment with niacinamide. The damaged neurons had an increased content of alpha-ketoglutaric acid, homocysteine and glycerophosphocholine. Nicotinamide treatment completely prevented these changes. Also, in rats with glaucoma, a decrease in the size of the mitochondria of ganglion cells was found, while nicotinamide partially protected against such changes.
The researchers not only once again confirmed the neuroprotective effect of nicotinamide, but also discovered its mechanisms: protecting neurons from metabolic disorders and maintaining normal mitochondrial function. Scientists suggest using nicotinamide for early prevention of glaucoma, as it does not harm healthy neurons. In September 2021, they plan to start a new study involving people.
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