131. Given below are two statements:
Statement I: Tissues that are non-regenerative, such as neurons in the brain, do have stem cells.
Statement II: Tissue localization does not necessarily mean lineage commitment and reduced
potency, as liver stem cells can generate neurons.
In light of the above statements, choose the most appropriate answer from the options given
below:
(a) Both statement I and II are correct,
(b) Both statement I and II are incorrect,
(c) Statement I is correct but statement II is incorrect,
(d) Statement I is incorrect but statement II is correct

Understanding Stem Cells and Tissue Regeneration: Key Insights

Introduction

Stem cells are remarkable entities in the body that have the potential to differentiate into various cell types and are essential for tissue repair and regeneration. However, not all tissues in the body exhibit the same regenerative capabilities. Some tissues are more prone to regeneration than others, which has led to intriguing discussions about the role of stem cells in different tissues, particularly in non-regenerative tissues like neurons in the brain.

In this article, we will examine two important statements regarding stem cells and their role in tissue regeneration, particularly focusing on neurons in the brain and liver cells. These statements help us understand the complexities of stem cell functionality and their regenerative potential across various tissues.

The Role of Stem Cells in Non-Regenerative Tissues

Statement I: Tissues that are non-regenerative, such as neurons in the brain, do have stem cells.

At first glance, it might seem like tissues that do not regenerate, like neurons in the brain, are devoid of stem cells. However, this is not entirely true. While it is widely accepted that neurons in the central nervous system (CNS) have limited regenerative capacity compared to other tissues, certain areas of the brain, such as the hippocampus, do harbor neural stem cells. These stem cells are capable of generating new neurons under certain conditions, but the overall regenerative capacity of the CNS is much lower than that of other tissues, like the skin or liver. Hence, while these tissues are considered non-regenerative in the strictest sense, stem cells can still exist and contribute to some extent to repair processes.

Statement II: Tissue localization does not necessarily mean lineage commitment and reduced potency, as liver stem cells can generate neurons.

This statement touches on an exciting and somewhat controversial area of stem cell research. Liver stem cells, which are usually thought of as being specialized for liver regeneration, have demonstrated the ability to differentiate into other cell types, including neurons in certain experimental settings. This phenomenon highlights the plasticity and potency of certain stem cells, even those derived from tissues typically considered to be more lineage-committed, like the liver. While these findings are still being explored and the ability of liver stem cells to generate neurons is not yet fully understood in vivo, the notion that stem cells can exhibit broader differentiation potential challenges traditional views of potency and lineage commitment.

Correct Answer to the Question

Based on the discussion above, we can now analyze the statements:

• Statement I is correct because it acknowledges that even tissues traditionally considered non-regenerative, such as neurons in the brain, still harbor some stem cells that can contribute to regeneration, though their capacity is limited.

• Statement II is also correct, as it highlights the surprising finding that liver stem cells can sometimes differentiate into cell types outside their expected lineage, like neurons, pointing to the plasticity of stem cells.

Thus, the most appropriate answer is:

(a) Both statement I and II are correct.

Conclusion

Stem cells continue to be an area of active research, and new findings constantly challenge our understanding of their potential and limitations. While non-regenerative tissues like neurons in the brain have limited regenerative capacity, the discovery of stem cells in these tissues opens up new possibilities for treating neurological disorders. Furthermore, the ability of liver stem cells to differentiate into other cell types, including neurons, reinforces the idea that stem cells have greater plasticity and potency than we once thought.